Keywords List

Coronal (Frontal) Plane: divides body into anterior (ventral) & posterior (dorsal) Axial Plane: divides body into superior (cephalad) & inferior (caudad) Sagittal (Median) Plane: divides body into right & left (medial/lateral) Proximal: closer to torso or beginning of a system Distal: farther from torso or beginning of system Superficial: closer to surface of body or body part or organ Deep: farther from surface of body or body part or origin Intermediate: somewhere between superficial & deep Fascia: visibly organized, sheet-like connective tissue of varying thickness & composition Superficial Fascia: substrate of skin; contains varying amounts of adipose tissue Axial Skeleton: Skull, spinal column, ribs & sternum, hyoid bone Appendicular Skeleton: pectoral girdle (scapula & clavicle), pelvic girdle (hip bones), free limbs Sesamoid Bones: Bones that develop in tendons over high stress regions of a joint; part facing joint cavity is

covered with articular hyaline cartilage; often acts as a moveable pulley, reducing friction, modifying pressure, & altering a tendon’s direction of pull for best mechanical advantage. IE: patella of knee, thumb, great toe, fabella

Articulations:o Condyle: rounded articulated knobo Facet: smooth, flat, concave/convex articulating surfaceo Head: prominent expanded end of a long bone

Extensions & Projections:o Crest: narrow ridgeo Epicondyle: projection superior to condyleo Line: slightly raised elongated ridgeo Process: any bony prominenceo Protuberance: outgrowth or protruding part of boneo Spine: sharp, slender, narrow processo Trochanter: massive process unique to femuro Tubercle: small rounded processo Tuberosity: large tubercle, usually roughened surface

Depressions:o Alveolus: pit or socket (tooth socket)o Fossa: (ditch) a shallow basin of variable sizeo Foveola: tiny pito Sulcus/Groove: groove for tendon, nerve, or blood vessel

Passages:o Canal: tubular passage or tunnel in a boneo Fissure: slit through a boneo Foramen: rounded hole of short length in a boneo Meatus: opening or passage, usually air-filled

Red Marrow: hematopoietic; mainly in axial skeleton, ilium, some in head & metaphysis of humerus; glenoid (scapula); neck & metaphysis of femur

Yellow Marrow: mainly fat; in rest of skeleton Synarthrosis: solid joint with limited or no movement

o Fibrous joint: non-osseous bonding material is collagenous Suture: bone-collagenous sutural element- bone (cranium) Syndesmosis: bone-interosseous membrane or ligament –bone (radius & ulna) Gomphosis: mandibular alveolus-complex collagenous periodontium-dental cement (teeth)

o Primary Cartilaginous Joint (Synchondrosis): growth plates of bones. Eventually ossification supervenes forming bony union (synostosis) (epiphyseal line)

o Secondary Cartilaginous Joint (Symphysis): bone-hyaline cartiliage-fibrocartilaginous pad or disk-hyaline cartilage-bone. Permits limited movement (amphiarthrosis). IE: pubic symphysis & intervertebral disks

Physis: (epiphyseal growth plate) location of germinal proliferative centers Metaphysis: site of addition of matured cartilage; where osteogenesis occurs Diaphysis: growing long bone Synostosis: ossified physis; forms epiphyseal line Harris Lines: growth arrest lines produced after a period of arrest of 10 days or more following disease state or

malnutrition that has interrupted bone growth Avulsion Fractures: fracture through the growth plate in the pediatric population Apophysitis: inflammation through the growth plate Diarthrosis: cavitated, synovial joint permitting movement

o Joint capsule: fibrous capsule + synovial membrane Fibrous capsule: merges with periosteum of joining bones Ligaments: thickenings of the fibrous capsule

o Synovial membrane: vascularized cellular membrane that secretes viscous synovial fluid, containing synovial mucin which is rich in hyaluronate

o Synovial Joint Modifications: Articular Disk: fibrocartilaginous pad-like extension of fibrous capsule that completely divides a

joint into 2 cavities Meniscus: crescent-shaped, fibrocartilaginous extensions of fibrous capsule of knee joint

o Synovial Modifications: Synovial Sheath: flattened synovial sac Bursa: flattened synovial sac that reduced friction & pressure between either a tendon, muscle

or skin overlying bony prominenceso Synovitis: inflammation of synovium; can lead to joint effusion, & protrude as synovial cysto Tenosynovitis: inflammation of synovial tendon sheatho Bursitis: inflammation of bursa

Pulmonary Circulation: blood that undergoes exchange & passes through 1 set of capillaries before returning to heart

Systemic Circulation: blood that may pass through exchange vessels or bypass them Nephron Circulation: arterial capillary bed, glomerulus, is interposed between proximal afferent & distal

efferent arterioles. Efferent arteriole then ramifies to a 2nd true capillary bed, peritubular capillaries Portal System: consists of true capillary beds connected to beds of venous capillaries called sinusoids via portal

vessels. Venous blood travels in venules, then veins, then in a single hepatic portal vein, which enters liver & ramifies into sinusoids where additional exchange occurs.

Hypophyseal Portal System: short & long portal vessels (postcapillary veins) connect proximal neural capillary beds with venous sinusoids of pars distalis

Musculovenous Pump: contracting muscle that milks valve-oriented blood towards the heart Varicose veins: the result of Valvular incompetence in the lower limb

Thrombophlebitis: inflammation of a vein in response to thrombosis; can dislodge, travel to the right heart & form a pulmonary thromboembolism

Homans’ Sign: the pain produced in the calf with passive dorsiflexion of the foot in the acute phase of deep vein thrombosis & thrombophlebitis

Hematogenous: spread or metastasis through veins Anastomosis: joining of similar blood vessels such that the net flow in some point of the anastomosis is zero

o End-to-End Anastomosis: two blood vessels from different anatomical sources form a blunt uniono Transveral anastomosis: connecting vessel joints 2 vesselso Convergence anastomosis: 2 vessels converge to form a single vessel o Accompanying Veins (venae comitantes): course with & surround medium-size arteries & are bound in

the same noncompliant vascular sheath Angiosome: a 3D territory of tissue supplied by a source artery & its accompanying veins Functional End Artery: a set of vessels whose anastomoses are insufficient to prevent ischemia with blockage of

one of the arteries Anatomical End Artery: an artery that does not engage in anastomoses IE: central artery of the retina, renal

interlobular arteries Arteriole-Muscular Venule Connections (Preferential Thoroughfare Channels), Small Artery- Small vein

Connections (Arteriovenous Shunts): connections between arterial & venous vessels but technically not anastomoses because there is no zero flow point

Arteriovenous Fistulas: abnormal connections between arteries & veins Vascular Ectasia: abnormal dilatation of a blood vessel, especially in capillary beds in the GI tract that can lead to

an incompetent arteriovenous fistula & blood loss Primary Lymphoid Organs: thymus gland, red bone marrow. Production of lymphocytes Secondary Lymphoid Organs: Spleen (reservoir for macrophages), Mucosa-associated lymphoid tissue, Lymph

nodes Lymphatic vessels: lymphatic capillaries, afferent lymphatic vessels (to lymph node), efferent lymphatic vessels

(exiting lymph node), lymphatic trunks, lymphatic ducts Afferent lymphatic vessels: 3-4 afferent lymphatic vessels enter a lymph node Efferent lymphatic vessels: a single efferent lymphatic vessels leaves a lymph node Lymphangitis: inflammation of lymphatic vessels Lymphedema: edema of a drained region that is high in protein Chyle: lymph from the lacteals of the small intestine; dense & milky from the chylomicrons Lymphocenters: clusters of lymph nodes draining a region Lymphogenous metastis: lymphatic pathways & lymph nodes serve as a means to disseminate cancer cells Sentinel node: node of high probability that cancer cells from a tumor will drain first Lymphoscintigraphy: tumor site is injected with radioactive lymphatic-avid material to identify & evaluate nodes

for metastasis Signal node: palpable, cancerous node that signals presence of primary carcinoma deep within body Lymphadenitis: inflammation of lymph node due to infection; tends to be tender, warm, enlarged, soft &

movable Central Nervous System: comprised of neuronal cell bodies, nerve fibers, & connective tissues of brain & spinal

cord; communicates with other functional components of body via PNS. o Nucleus: collection of neuronal cell bodies within CNS

Peripheral Nervous System: comprised of neuronal cell bodies, nerve fibers, & connective tissues outside the CNS; connects & conveys information between peripheral structures & the CNS

o Ganglion: collection of neuronal cell bodies outside the CNS

Neuron: anatomical unit of the nervous system consisting of cell body, dendrites, & an axon Motor (Efferent)Neuron: multipolar; carries information away from CNS Somatic (general) Motor Neurons: cell bodies in nuclei within ventral horn of spinal cord; stimulate contraction Sensory (Afferent) Neuron: pseudounipolar; carries information towards CNS; cell bodies are in ganglia outside

CNS; central process projects into dorsal horn of spinal cord Somatic (general) Sensory Neurons: convey sensation from somatic structures (pain, touch, temperature) White Matter: bundles of myelinated fibers arranged in discrete tracts Gray Matter: arranged into ventral (anterior), dorsal (posterior, somatic & autonomic sensory) & lateral

(autonomic motor) horns Ventral Rami: innervate everything else & form plexuses Dorsal Rami: innervate zygapophyseal joints, intrinsic back muscles, & skin of 2/3rds of the back Cervical Plexus: formed by C1-C4 Brachial Plexus: formed by C5-T1 Lumbar Plexus: formed by T12/L1-L4 Sacral Plexus: formed by L4-S3 (paired with lumbar plexus to form lumbosacral plexus) Dermatome: region of skin innervated by a single spinal nerve Cutaneous Nerves: have autonomic motor fibers & sensory fibers Myotome: mass of muscle innervated by a single spinal nerve; have motor fibers & autonomic motor & somatic

sensory fiberso Important Dermatomes:

T4: across nipple T6: across xiphoid process T10: across umbilicus T12: across top of pubic bone L1: across groin fold

Anesthesia: loss of sensation Hypesthesia: reduced sensation Analgesia: loss of pain sensation Hypalgesia: reduced pain sensation Paresthesia: uncomfortable sensation Dysesthesia: painful sensation Concordant Parethesia/Pain: paresthesia & pain produced during procedures that indicate the physician is in

the right place Autonomous Dermatomal Region/Zone: a region where there is lack of dermatomal overlap

o C5: skin over deltoido C6: thumb pado C7: pad of index fingero C8: pad of little fingero T1: skin over anteromedial elbow

Motor Unit: somatic motor neuron & all the muscle fibers to which it is connected Paralysis: complete loss of muscle cell contraction as a result of lesion of a somatic motor neuron Paresis: profound weakness in a mytome as a result of injury to a particular spinal nerve or its ventral ramus Rami Levels of Motor Innervation

o C5: shoulder abductiono C6,C7: shoulder adduction, elbow flexion/extension, wrist flexion/extensiono C6, C7, C8: pronation/supination

o C7: finger extensiono C7, C8: finger flexiono C8: deep extension & thumb (pollicis) abduction, deep flexion o T1: intrinsics of the hand

ANS: part of the PNS responsible for monitoring & regulating visceral functions; carries signals to & from visceral structures such as internal organs, glands, & blood vessels via visceral motor (efferent) & visceral sensory (afferent) neurons

o Sympathetic Division: primarily responsible for motor innervation of smooth muscle lining blood vessels, cardiac muscle & sweat glands, & sensory innervation of viscera

o Parasympathetic Division: primarily response for motor innervation of smooth muscle lining digestive tract, cardiac muscle, & salivary glands & sensory innervation of viscera

Somatic Motor Neurons: innervate skeletal muscle; have single neuronal pathway from CNS to skeletal muscle. Cell bodies are multipolar 7 located in the ventral horn of the spinal cord; axons are myelinated & directly innervate somatic peripheral effectors (skeletal muscles)

Visceral Motor Neurons: innervate smooth muscle, modified cardiac muscle, & glands; have a 2-motor-neuron-pathway with a preganglionic neuron (1st multipolar neuron in lateral horn of spinal cord with myelinated axon) which synapses with a postganglionic neuron (cell body in a ganglion with unmyelinated axon which innervates visceral peripheral effector)

Sudomotor: eccrine sweat glands Pilomotor: piloerector muscles Vasomotor: vasoconstriction & vasodilation in skeletal muscle Lateral Horn: has preganglionic cell bodies found from T1-L2 spinal cord segments Ventral Root: has preganglionic axons to spinal nerves T1-L2 (& somatic motor axon) Spinal Nerve: carry somatic motor axons, somatic sensory fibers & postganglionic sympathetic axons. T1-L2 also

have visceral sensory fibbers & preganglionic motor axons White Ramus Communicans: connects spinal nerves T1-L2 anatomically to ventral rami with sympathetic trunk

ganglion. Carries preganglionic motor axons & visceral sensory fibers Gray Ramus Communicans: connects all spinal nerves (anatomically to ventral rami) with sympathetic trunk

ganglion. Carries postganglionic motor axons to spinal nerve. Accepts visceral sensory fibers from spinal nerves C1-C8, & L3-Co1

Sympathetic Trunk (paravertebral) Ganglion: contains postganglionic cell bodies Splanchnic nerve: connects sympathetic trunk ganglia with prevertebral ganglia. Carries preganglionic motor

axons & visceral sensory fibers Prevertebral Ganglion: contains postganglionic cell bodies whose axons are distributed to abdominopelvic

viscera by coursing in the adventition of the arteries supplying those viscera Spinal Nerve Innervation Distribution:

o T1-L2: trunko C1-C4: necko C5-C8: upper limbo L3-S4: lower limb

Autonomic Sensory Innervation:o Somatic Sensory Neurons: innervate skin, muscle, joints. Convey pain, temperature, touch,

proprioception. Cell bodies located in dorsal root ganglia of spinal nerves C2-Co1. Pathway same as motor, up to spinal nerve, through dorsal root to dorsal horn.

o Visceral Sensory Neurons: innervate viscera, glands, blood vessels. Convey distension, nausea, hunger. Cell bodies located in dorsal root ganglia of spinal nerves T1-L2 & S2-S4. Pathway same as motor, up to spinal nerve, through dorsal root & to dorsal horn.

Viscerosomatic Referred Pain: pain from a visceral organ that is interpreted by the brain as coming from a somatic region of the body having the same spinal cord segmental innervation

Raynaud’s Phenomenon: the condition when it is associated with a pre-existing disease state such as diabetic neuropathy

Raynaud’s Disease: used to describe the condition when it is idiopathic Raynaud’s Characteristics: abnormal, episodic vasospasm of the digits in response to cold exposure. Upon

warming, the affected digits undergo reactive hyperemia, becoming engorged with blood. Characteristic biphasic or triphasic color response of affected digits, from pallor to cyanosis. & upon rewarming, rubor. During rubor phase there is considerable pain & throbbing

Complex Regional Pain Syndrome:o Type I (Reflex Sympathetic Dystrophy): abnormal sympathetic response to soft tissue injury marked by

pain & swelling of a distal extremity accompanied by vasomotor instability, trophic skin changes & rapid development of bone demineralization

Phase I: period of sympathetic hypoactivity; allodynia, hyperesthesia & hyperrpathia (hyperalgesia); anhidrosis, edema, pain, throbbing, tender joints

Phase II: period of sympathetic hyperactivity; intense vasoconstriction, pallor, cyanosis, skin mottling, cold intolerance

Phase III: persistent sympathetic hyperactivity causing gradual atrophy of skin & subcutaneous tissue with flexion contracture & osteopenia

o Type II (Causalgia): characterized by persistent pain in limb after injury to a peripheral nerve or major nerve trunk; a complication of brachial plexus surgery or decompression; persistent pain is said to be in the form of burning & throbbing. Also focal vasomotor & sudomotor abnormalities, with localized sweating & edema of affected limb. Does not appear to progress to atrophy as CRPS Type I.

Dysautonomia: autonomic dysfunction associated with disease stateso Idiopathic:

Shy-Drager Syndrome: cases of multiple system atrophy in which autonomic failure predominates

o Autoimmune: Acute Pandysautonomic Neuropathy: autonomic failure due to ganglionic anti-nicotinic

acetylcholine receptor antibodies (postsynaptic Ach receptor destruction) Guillain-Barre Syndrome: autoimmune acute polyneuropathy; 2/3rds of patients have some

degree of autonomic failureo Paraneoplastic: autonomic neuropathy & failure associated with small cell carcinoma (type of lung

cancer) due to carcinoma secreting anti-nuclear antibody Type Io Toxins:

Botulinum toxin: binds to presynaptic cholinergic terminals & block Ach release leading to widespread autonomic depression

Tetanus: tetanospasmin blocks inhibitory post-synaptic potentials regulating preganglionic autonomic neurons leading to widespread autonomic overactivity (sweat, high BP)

Semen: pH 7.2-7.8; transient buffer effect is 6.0-6.5, optimal for sperm motility; fertility requires more than 20 million/mL & 60% having motility with forward progression

Vagina: pH 4.3; bactericidal & spermicidal

Sperm Capacitation: removal of cholesterol & epididymal glycoproteins. Results in increased motility & directionality in response to cumulus-oocyte complex & follicular fluid chemoattractants & progesterone & thermal stimuli of uterine tube

Sperm Lifesspans: 80 hours in uterine tube, 20 hours if capacitated Fertilization Steps

o Penetrate corona radiata: assisted by sperm hyaluronidaseo Attach to ZP3 protein of Zona Pellucida: initiate acrosome reaction & release acrosomal enzymeso Penetrate Zona Pellucida: acrosin enzyme to digest zona pellucidao Cross Perivitelline space: initiation of cortical reaction; complete meiosis with 2nd polar bodyo Bind ovum plasma membrane: release of ovum cortical granules to denature zona pellucida; ZP3

protein is lost preventing polyspermy; corona radiata is lost; zona pellucida becomes semipermeable to nutritive substances of uterine tube

o 2nd Meiotic Division: reduction of DNA to half of typical somatic cell (haploid) Zona Pellucida: promotes maturation of oocyte & follicle, permits only species-specific fertilization, initiates

acrosome reaction, prevents polyspermy, permeable to tubal nutritive substance, immunological barrier to maternal rejection, keeps blastomeres together during cleavage, facilitates trophoblast differentiation, prevents premature implantation

Accomplishments of Fertilization: Stimulates secondary oocyte to complete 2nd meiotic division for haploid state & half DNA content, restores diploid number of chromosomes with somatic cell DNA content, sex of future embryo determined by spermatozoon, produces genetically unique product, activates maternal RNA transcripts & zygote metabolism for cleavage & early embryonic development

Parental Imprinting: maternal chromosomes favor embryonic development; paternal chromosomes favor placental development; maleness of placenta & decreased immunological privilege may play a role in preeclampsia

Cleavage Steps:o Single polar body of secondary oocyte/ovum & 2 polar bodies of fertilized ovum (2 pronuclei)o Cleavage: mitosis without cell growtho Blastomeres: daughter cellso Compaction: increasing numbers of blastomeres compacted by zona pellucidao Morula: 16-cell stage; looks like mulberryo Cavitation: cells of morula begin to segregate & produce eccentrically placed cavity; 4 days after

fertilization o Blastocyst: cells after cavitation with blastocyst cavity; about 110 cellso Trophoblast layer: outer layer of cells next to zona pellucida; supplies embryo with nutrition.

Differentiates into placentao Embryoblast: inner mass that contains cell that will form the embryo; as few as 10 cells go on to develop

into individualo Poles: embryonic pole trophoblasts digest zona pellucida; blastocyst hatches from zona pellucida at day

4.5-5. Embryonic pole undergoes implantation into uterine wall (day 6)o Ovum Transport: if fertilization occurs, zygote is transported through uterine tube; transport is timed to

maximize fertilization within 20 hours of ovulation; implanation at day 6. Secondary oocyte delayed in ampulla for 1 day to prepare for fertilization (physiological amullary isthmic junction block for 1-2 days). Enters uterine cavity at day 4 as advanced morula (rise in progesterone helps b break through block). Implantation completed by 12 days after fertilization

Blastocyst Stages:

o Day 8: human chorionic gonadotropic maintains corpus luteum of pregnancy for progesterone production (6-8 wks). Firsts detected 6-8 days after pregnancy. Doubles in concentration in maternal blood every 2-3 days, reaching peak at 60-90 days of pregnancy. Falls to plateau concentration 20 wks to term

o Day 9: embryo is almost completely implanted into uterine wall; extraembryonic endoderm (hypoblast cells line cytotrophoblast container) goes onto develop into gut & derivatives; lacunae developing in syncitiotrophoblast & will fill with maternal blood

o Day 12: complete implantation; eroded maternal blood vessels/dilated sinusoids have connected with trophoblastic lacunae; cell to cell transferring of substance between embryo & maternal blood

o Day 13: extraembryonic endoderm pinches off from exocoelomic cavity to form definitive yolk sac.. extraembryonic mesoderm reinforces chorionic cavity as chorionic plate, reinforces definitive yolk sac & amniotic cavity, & forms body stalk; lacunae replete with maternal blood; cytotrophoblast villi formation

Extraembryonic Mesoderm: provides CT support for amnion & definitive yolk sac, forms chorionic plate & body stalk, forms support for placental villi (those closes to embryo expand, branch & grow forming chorion frondosum), serves as center for vasculogenesis (de novo blood vessel development), angiogenesis (sprouting of new blood vessels from existing ones), & hematopoiesis (blood cell development)

Hemangioma: most common tumors of infancy; abnormally dense collections of capillary blood vessels. Often associated with facial structures.

Sites of Ectopic Pregnancyo Tubal: cause rupture & hemorrhageo Placenta Previa: close to internal os (opening) of uterus; too close to cervical opening. Can bridge the

opening as they grow & tear away from wall causing bleeding & spontaneous abortion. Placenta presents ahead of fetus

Chorion Maturation Steps:o Primary villus: projection of cytotrophoblast covered by syncytiotrophoblasto Secondary villus: layers around central extraembryonic mesoderm core from chorionic plateo Tertiary villus: development of fetal capillaries & sinusoids within mesodermal core

Amniocentesis: performed at 15-20 wks pregnancy; prenatal screening Chorionic Villi Sampling: performed at 11 wks. Prenatal screening Molar Pregnancy: part of a spectrum of gestational trophoblastic neoplasia; may lead to development of

malignant tropohoblastic disease (choriocarcinoma) – excessive paternal imprinting. Can result in hemorrhage, & secretion of excessive hCG can cause gestational hyperthyroidism

Neural Tube Defects & Amniotic Fluido Excessive Amniotic Fluid: polyhydramnios; due to failure of fetus to swallow or process fluid in GI tract.

Can be caused by anencephalyo Too Little Amniotic Fluid: oligohydramnios; due to failure of fetus to urinate into the amniotic fluid;

amniotic fluid is necessary for lung maturation & mechanical buffering; newborn is delivered with anuria, poorly developed lungs, squashed facial features, stumpy digits, & clubbed feet (Potter sequence)

Lecithin-Sphingomyelin Ratio: a good indicator of development of alveolar surfactant (keeps alveoli from collapsing when newborn starts to breathe air); ratio of less than 1.5 is not good – these infants have a high risk of respiratory distress syndrome

Bilaminar Germ Disc: embryho at 2 weeks with epiblast & hypoblast Amnioblasts: formed in epiblast Hypoblast: cells line definitive yolk sac Definitive Yolk Sac: source of vitamins A, B12, & E, & folic acid

Epiblast Fate Mapo Primitive Streak: groove where cells sink into the midline & internalizeo Polarities: hypoblast = ventral, epiblast = dorsal, oropharyngeal membrane = cranial, opposite pole =

caudalo Cloacal Membrane: spot-welded region that forms in the caudal region of the bilaminar embryo;

demarcates future site of the anal canal & terminal portions of the urogenital systemo Cilia: confer laterality (left-right differences) through their beating at Henson’s node. They beat leftward,

moving various signaling factors

Cell Lineageso Zygote Cleavage Inner Cell Mass

Trophoblast

Cytotrophoblast

Syncytiotrophoblast

Neurulation (20-23 day embryo)o Neural tube: closes first in middle then cranially & caudallyo Cranial Neuropore: closes at 25 dayso Caudal Neuropore: closes at 28 days

Derivatives of Embryonic Ectodermo Surface ectoderm: epidermis, hair, nails, subcutaneous glands, mammary glands, adenopophysis,

membraneous inner ear, lens, anoderm of anal canal, oral epithelium, ameloblasts (tooth enamel), sensory epithelium of nasal cavity

o Neural tube ectoderm (neural plate; neural placode): brain & cranial motor neurons, spinal cord & motor neurons, retina, pineal gland, infundibulum

o Neural crest: CT & bones of face & skull, cranial nerve ganglia, calcitonin cells of thyroid gland, conotruncal septum of heart, odontoblasts, dermis of face & neck, dorsal root ganglia, sympathetic trunk & prevertebral ganglia, enteric neurons, adrenal medulla, schwann cells, glial cells, forebrain meninges, melanocytes, vascular smooth muscle of face & forebrain

Embryonic Mesoderm (17-20 day embryo)o Lateral infolding progresseso Endoderm rolled into tubeo Intercellular clefts developo Lateral plate layers develop:

Embryonic Endoderm:Neural ectoderm, neural crest,

surface ectoderm

Epiblast

Hypoblast Primordial Germ Cells

Extraembryonic Endoderm(definitive yolk sac)

AmnionGastrulation

Extraembryonic Mesoderm(chorionic plate, chorionic

villi, body stalk, support for amnion & definitive yolk sac,

extraembryonic angiogenesis)

Extraembryonic Mesoderm:Prechordal,

notochordal, & intraembryonic

mesoderm

Embryonic Endoderm

Extraembryonic Mesoderm

Somatopleure: parietal layer Splanchnopleure: visceral layer

Embryonic Endoderm Derivatives: epithelial lining of respiratory tract, GI tract, tympanic cavity & pharyngotympanic tube, most of the urine-collecting portion of the urinary system, distal genital system, parenchyma of thyroid, parathyroid, liver & pancreas, reticular stroma of thymus & palatine tonsils

Derivatives Intraembryonic Mesodermo Paraxial Mesoderm: axial skeleton (except cephalic structures), axial muscles, anterolateral body wall

muscles, dermis of skin, limb muscleso Intermediate Mesoderm: nephron, gonads, efferent ductules, epididymis, ductus deferens, seminal

vesicles, ejaculatory ducts, uterine tubes, uterus, upper 1/3rd of vagina, adrenal cortexo Parietal Mesoderm: limb skeleton, parietal pleurae, parietal pericardium, parietal peritoneumo Visceral Mesoderm: wall of respiratory tract, wall of GI tract, walls of peritoneal organs,

hemangioblastic tissues (blood cells, vascular endothelium, epicardium, myocardium, endocardium), mesenteries

Mechanisms of Twinningo Dizygotic/Fraternal: double ovulation & fertilization; normal development of zygotes & 2 implanting

blastocyst Diamniotic-Dichorionic Implantation: each has its own amnion & chorion; normal development Twin-Twin Transfusion Syndrome: implant too close together & chorions & placentae fuse;

anastomosis of placental vessels allows 1 twin to dominate for obtaining maternal blood supplyo Monozygotic/Identical:

Diamniotic-Dichorionic: Separation of 2-cell blastomeres/early embryo; leads to 2 complete, identical blastocyst

Diamniotic-Monochorionic: inner cell mass splits to form 2 separate inner cell masses with common trophoblastic layer (20% of all twinning); common implantation with common chorionic cavity & common placenta; possible twin-twin transfusion syndrome

Monoamniotic-Monochorionic: rarest condition; splitting of bilaminar germ disc after amnion has formed; problems of embryos twisting & twin-twin transfusion syndrome & conjoined twinning

Consequences of Twin-Twin Transfusion Syndrome: fetus papyraceus (twin ends up sucked dry) Consequences of Monoamniotic Monochorionic Twinning: craniopagus (head to head fusion), pygopagus

(rump to rump fusion), thoracopagus (chest to chest fusion) Common reasons for chest discomfort: observable anatomical basis, osteoligamentous, pneumonia,

pneumothorax, complicated severe asthmatic attack, left ventricular failure, pleural effusion, pulmonary embolism, aortic dissection/rupture, foreign body

Functions of Rib Cage: protection, prevent paradoxical motion True Ribs: vertebrosternal, 1-7 False Ribs: vertebrochondral: 8-10 Floating Ribs: vertebral, 11-12 Thoracic Vertebra: form zygapophyseal joints with cephalad & caudad vertebrae; have spinous process, &

articular facets for heads of ribs Sternum: manubrium (upper segment), gladiolus (body), xiphoid process (cartilaginous); rich erythropoietic

center; fractures are rare; can be caved in (pectus excavatum) or bowed out (pectus carinatum) Manubriosternal Juction: 1st rib articulates with manubrium via synchondrosis (little movement) Structure of Rib: head with 2 articular facets or demifacets, capitular facets separated by interarticular crest

(inferior capitular facet larger, articulates with superior costocapitular demifacet); neck oof rib, tubercular facet

(ribs 1-10) to articulate with costotubercular facet of transverse process of vertabra, shaft of rib (roughened for muscle attachment), costal angle (site of highest frequency of rib fracture), costal groove (V-A-N)

Somite: dermatome, Myotome, sclerotome Derivatives of Sclerotome: vertebra & joint surfaces, annulus fibrosus of intervertebral disk, ribs, spinal

meninges, tendons of intrinsic back muscles Derivatives of Dermatome: dermis, blade of scapula Derivatives of Myotome: intrinsic back muscles, limb muscles, anterolateral body wall muscles Cleidocranial Dysostosis (Dysplasia): clavicles are absent or hypoplastiic; delayed ossification of skull bones &

fontanelles close late oro fail to close; supernumerary teeth. Patients can approximate their shoulders in the midline

Angle of Louis: level of T4/T5 intervertebral disk Traube’s Semilunar Space: for spleen; 6th rib costal margin midaxillary line Xiphisternal Junction: level of T9 Larrey’s Point: landmark for performing pericardiocentesis; apex of left xiphi-costal angle Rib Flail/Flail Chest: fracture of panel of ribs, usually at angles & costochondral junctions; get paradoxical

motion & decreased vital capacity Rib Fracture: generally occurs at angle; pain while attempting to sleep supine is pathognomonic Thoracic Outlet Syndrome: neurovascular problems arising between first rib & clavicle Pancoast’s tumor: apical lung adenocarcinoma; erosion of a rib or clouding of its contours may be sign of

metastasis Condrocalcinosis: calcification with old age; causes dowager’s hump (increased kyphosis) Costochondritis: inflammation usually at synovial joints; can mimic angina pectoris Tietze’s Syndrome: intensely painful inflammation of synovial joints of unknown etiology; may be due to

microtrauma of joints after thoracic strain (coughing, vomiting, strong laughter, weightlifting) Rib Infection: becomes infectious foreign body & must be resected Ewing’s Sarcoma: tends to develop on lateral side of osseous portion of rib; onion-skin appearance in CXR due

to concentric regions of bone growth & destruction Chondrosarcoma: cancer of cartilage; tendency to develop between sternocostal joint & costochondral junction;

locally invasive Anaplastic Sarcoma: favors the sternum; locally invasive External Intercostal Layer: external intercostal muscle that is well-developed posteriorly whose fibers course

anteroinferiorly from cephalad rib to subjacent rib (hands in pockets) Internal Intercostal Layer: muscle is well developed anteriorly near sternum, but as it courses posteriorly just

beyond the midaxillary line, it fads & continues as an internal intercostal membrane; direction of fibers is orthogonal to external intercostal muscle, from cephalad rib to subjacent rib; (hands on boobs!)

Innermost Intercostal Layer: muscle fibers are best developed laterally & then become transparent membranes anteriorly at level of costochondral junctions & posteriorly at the level of the angle of the ribs; orientation of fibers is similar to internal intercostal layer; V-shaped fibers (Christmas tree)

Intercostal Neurovasculature: superior to inferior in costal groove order is vein, artery, nerve (VAN) Coarctation of Aorta: congenital stenosis of descending thoracic aorta distal to the take-off of the left subclavian

artery. Pressure & blood flow proximal to the stenosis is high, expanding collateral arteries about the scapula & anastomosis with posterior intercostal arteries distal to the stenosis. High flow causes posterior intercostal arteries to become torturous, which notches the inferior border of the ribs; causes the aortic knuckle to resemble a “3” in CXR

Notching of the lower borders of ribs: indicates dilatation of posterior collaterals joining the posterior intercostal arteries; may be due to stenosis of a portion of the descending thoracic aorta due to gradual atherosclerosis

Azygos & hemiazygos: accept most of the posterior intercostal veins Descending thoracic aorta: gives rise to most of the posterior intercostal arteries Thoracic Ventral Rami: give rise to intercostal nerves Superior Costotransverse Ligament: the rami of the thoracic spinal nerves course to respective sides of the

ligament. Syndesmophytes (osteophytes) in the ligament can compress these neural structures; attaches a rib to the transverse process of the cephalad vertebra

Branches of Typical Intercostal nerve: rami communicantes, collateral branch to rib below, lateral cutaneous branch, anterior cutaneous branch, motor branches to segmental intercostal muscle, motor branches to levatores costarum muscles, motor branches to serratus posterior muscles

2nd Intercostal nerve: has a lateral cutaneous branch that is intercostalbrachial nerve, which supplies skin of the armpit. Called the heart nerve because it carries referred pain during myocardial ischemia

First 11 intercostal nerves: supply sensory innervation to parietal pleura Lower 5 intercostal nerves & subcostal nerve: supply anterolateral abdominal wall muscle, skin & parietal

peritoneum Thoracotomy: cutting into thorax Thoracostomy: inserting a tube into the thorax Hemothorax: blood in the thorax Pneumothorax: air in the pleural cavity Thoracentesis: pleurocentesis; inserting a needle to reduce the abnormal situation in the pleural cavity To anesthetize an intercostal space for these procedures: anesthetize the main branch of the intercostal nerve

of the superjacent rib, & the collateral of the same nerve to the subjacent rib. Posteriorly, you can anesthetize the nerve before it gives off the collateral but hard to do because of back muscles

Lymphatic Drainage of Thorax: o Deep fascia & deeper: infection/metastasis follows arteries deeply; drains to internal thoracic lymph

nodes (internal mammary lymph nodes) & along sides of descending thoracic aorta (para-aortic nodes)o Superficial Fascia (dermis & skin): direction of drainage is determined by line encircling umbilicus

Above the line posteriorly: drains to posterior axillary lymph nodes Above the line anteriorly: drains to anterior axillary lymph nodes Below the line: drains to superficial inguinal lymph nodes

Septum Transversum: visceral mesoderm near the heart that segregates caudally where it is invaded by the liver parenchyma; forms a large part of the thoracoabdominal diaphragm & contributes to the formation of the liver sinusoids

Development of the Thoracic Cavity (pleural cavities & midline pericardial cavity):o Cranial part of intraembrynoic body cavity occupied by developing heart – future pericardial cavityo Lung buds bulge into future pericardial cavityo Pleuropericardial folds divide future pericardial cavity into definitive pericardial cavity & more dorsal

pleural cavity; pleuropericardial folds contain veins (right becomes inferior vena cava) & phrenic nerveso Pleuropericardial folds fuse & separate 2 pleural cavities from pericardial cavityo Lungs grow & push & enlarge pleural cavities ventrolaterally to almost completely surround midline

pericardial cavityo Parenchymal portion = mesothelium that secretes & absorbes serous fluid

Costodiaphragmatic Recess: inferior pouch of the pleural cavity; lungs never completely fill this recess Costophrenic angles: limits of the lung tissue form these

Sibson’s Fascia: a thickened fascia that protects the cervical pleura & apex of the lung Innervation of Visceral & Parietal Pleurae: visceral pleura & lung are insensitive to pain; parietal pleurae are

heavily innervated with pain fibers Chilaiditi’s Syndrome: constant swallowing of air & sputum from pneumonia produces gas in the GI tract; the

distended loop of the bowel insinuates itself between the stomach & diaphragm or diaphragm & liver Relationship between pleural cavity, lungs & rib cage

o Anteriorly: ribs 2-4 pleural cavities are in contact behind the sternum (anterior junction line)o Anteriorly: ribs 4-6 right parietal pleura stays midline, left parietal pleura deviates leftwardo Midclavicular line: lung inferior limit is rib 6, parietal pleura inferior limit is rib 8o Mixaxillary Line: lung inferior limit is rib 8, parietal pleura inferior limit is rib 10o Scapular Line: lung inferior limit is rib 10, parietal pleura inferior limit is rib 12

Beck’s Triad: hallmark feature of cardiac tamponade; rising central venous pressure manifesting as jugular venous distension & distension of other head, neck & upper limb veins, diminished heart sounds, diminished arterial & pulse pressures; pericardiocentesis is performed to relieve pressure of cardiac tamponade

o Trendelenberg Position: head elevated 15-30 degrees with respect to feet & supine; position used to perform pericardiocentesis; insert needle 45 degree angle to body into left xiphi-costal angle (Larrey’s Point) aimed at left shoulder

Cardiothoracic Ratio: normal-sized heart silhouette in PA CXR should fit in width of 1 lung field or ½ of chest cavity

Sniff Test: check for hemidiaphragm paralysis; paralyzed hemidiaphragm moves paradoxically upward Pleural Effusion: tend to collect in costodiaphragmatic recess & eventually blunt normally sharp costophrenic

angle Pneumothorax: air in the pleural space; causes partial collapse of the lung Pneumoconiosis: lung disease caused by inhalation of aerosolized particulates; chronic irritation leads to chronic

pleuritic & pleural adhesions Bulla: air-filled space of the lung greater than 1 cm in diameter; usually seen in emphysema Bleb: air-filled alveolar dilatation in the lung less than 1 cm in diameter Open Pneumothorax: pneumothorax retaining communication with atmospheric air; caused by wounding of

parietal pleura but sometimes by a spontaneous variety retaining a communication with pulmonary air; has danger of converting to tension pneumothorax

Tension Pneumothorax: air comes into the cavity with inspiration, but has a check-valve closed effect with expiration; pressure continues to rise in the pleural space as a result

Apical Bullous Lung Disease: of unknown etiology; occurs in the pediatric population, generally in asthenic males. Prone to recurring pneumothoraces.

Carinal Cartilage: last tracheal ring; surrounds the beginning of the main bronchi Tracheomalacia: disease states can put long-term pressure on the trachea causing chondromalacia of the

tracheal rings; leads to segmental collapse with inspiration Traumatic/Iatrogenic Tracheoesophageal fistula: a rare complication of endoscopy of the trachea or esophagus

in which the unsupported wall of the trachea abutting the esophageal wall provides opportunity for fistula formation.

Congenital Tracheoesophageal Fistula: if septation & separation fails in some part of the laryngeotracheal tube, TEF develops; incompatible with postnatal life, except the H type

Carina: internal keel of the carinal cartilage Right tracheobronchial angle: 25 degrees Left tracheobronchial angle: 40 degrees Hemoptysis: coughing up of blood;

Bronchial veins: superficial veins return to venous system via azygos & hemiazygos system Interbronchial angle: almost 90 degrees Widening/Flatteningo f interbronchial angle: left atrial enlargement, upper lobar atelectasis, carinal

lymphadenopathy Air Bronchogram: patent airways that become visible out to the tertiary divisions & beyond Bronchiectasis: permanent dilation of airways as a result of long-term inflammatory processes of airways Where is the Pneumonia? If it obscures:

o Superior right heart border: RULo Right atrial border: RMLo Superior left heart border: LULo Much of the ventricular border: Lingulao Either hemidiaphragm: lower portion of the respective LLo If in contact with either heart border but not obscuring it: behind the heart in the upper portion of the

respective LL Types of Acquired Atelectasis:

o Extrapulmonary: pneumothorax & pleural effusiono Intrapulmonary: collapsing segments pull on surrounding structures; the atelectatic portion is still held

in contact with parietal pleura but something pliable has to give. Can: Shift in fissure of lung Pull on root of lung causing a change in interbronchial angle Pull on enough to shift trachea Pull up on left diaphragm (peaking) Reduce normal space of ribs Any combination of these

Early Signs of Heart Failureo Cephalization: caliber of lower pulmonary veins begins to constrict & that of upper pulmonary veins

increaseso Perihilar Haze: distinct pattern of hilar vessels becomes vlurred because of increasing interstitial edemao Kerley B Lines: interstitial edema builuds up in interlobular septa producing lines at base of the lungs

adjacent to Correra’s Lineo Peribrronchial Cuffing: edema of the segmental bronchi walls

Late Signs of Heart Failureo Bat’s Wing Pattern: summation of shadows in high lymphatic flow toward the hilao Intersitial edema producing Kerley A Lines more centrallyo Larger bilateral pleural effusioniso Alveolar patchiness indicating spillover into alveoli

How to View a PA Chest X-Rayo R: Rotation of Patient: medial end of clavicles should be equidistant from midline spinous processeso I: Inspiratory Effort: should be able to count 10 ribs posteriorly, 8 ribs anteriorly; lung markings (vessels)

should be apparent right out to Correra’s Line. Left hilar point is generally higher (rib 6) than right (6th intercostal space). Left should never be lower than right.

o P: Position of Tubes after Procedureso A: Airway: contour & disposition of trachea, interbronchial angle, & secondary divisionso B: Bones: rib fracture, rib notching, coarctation of aorta, glenohumeral articulation, humeral fractureo C: cardiac silhouette, costophrenic angles, Kerley B lines

o D: Diaphragm: contours & dispositiono E: Emphysema: blebs, bullae, cysts, pneumatoceles, subcutaneous emphysema

How to View a Left Lateral Chest X-Rayo Lung areas: retrosternal area (airspace) (right ventricle); recrocardiac area (airspace) (left atrium)o Cardiac Silhouetteo Diaphragm: right hemidiaphragm extends from anterior chest wall to posterior costophrenic angle; left

has fundic gas buggle & extends from posterior aspect of heart shadow to posterior costophrenic angleo Thoracic Vertebrae: lower vertebrae appear more transradiant (darker) than middle & upper levels

Obtuse Border/Margin: left border of the heart wit hthe left atrial appendage, pulmonary trunk & aortic arch Inferior border/Acute Margin: right ventricle over to apex (left ventricle) Sternocostal Surface: formed by the right ventricle & atrial appendage Diaphragmatic Surface: formed by left ventricle & some of the right ventricle Apex beat: apex strikes anterior 5th intercostal space Base: left atrium & roods of the great vessels connecting the heart to the mediastinum Coronary Sulcus: atrioventricular sulcus, largely obscured by the pulmonary trunk & aorta; visible posteriorly at

the base & represent the position of the cardiac fibrous skeleton Crux of the Heart: point of junction of interatrial, coronary, & posterior interventricular sulci; divides the

coronary sulcus into right & left portions Right atrium: divided into rough-walled anterior portion (pectinate muscles) & smooth walled venous

component (sinus venarum) by terminal crest (crista terminalis) which is represented by the terminal groove (sulcus terminalis); this groove contains the SA node. Right atrial appendage (auricle) projects anteriorly covering part of ascending aorta & proximal portion of right coronary artery. Sinus venarum receives superior & inferior vena cava & coronary sinus. Inferior vena cavae has Eustachian valve (was foraemen ovale) & plays a role in formation of crytogenic emboli; Fossa ovalis is remnant of septum primum that patches foramen ovale. Superior lip of this is limbus fossae ovalis. Above limbus fossae ovalis is intervenous tubercle & tricuspid valve. In atrial wall above opening of coronary sinus is AV node

AV Node: located in triangle of Koch. Triangle is bordered by tendon of Todaro Left atrium: entirely smooth-walled except for atrial appendage. Receives right & left pairs of superior & inferior

pulmonary veins. May exhibit probe patency from right to left atria if valve for foramen ovale didn’t close completely.

Trabeculae carnae: ridges & arches lining ventricular walls Papillary muscles: connected to the cusps of the AV valves by chordae tendineae Right Ventricle: commences at right AV orifice. Guarded by the tricuspid valve. Anterior papillary muscle

receives communication from right bundle branch by septomarginal trabecula (moderator band). Septal cusp attaches to membraneous interventricular septum. Inflow of right ventricle is separated from smooth walled ouflow tract (conus arteriorosus or infundibulum) by the supraventricular crest. Summit of right ventricular outflow tract is the pulmonary (semilunar) valve

COPD: causes constriction of pulmonary arterial branches & pulmonary hypertension. Characteristics include overaeration of lungs, flattening of hemidiaphragms, dilated pulmonary trunk & central branches, pruning of peripheral arterial branches, pulmonary hypertension

Left Ventricle: commences at left AV orifice. Guarded by the mitral (bicuspid) valve. 2 papillary muscles & chordae tendineae & cusps are thicker than right counterparts. Anterolateral papillary muscle is supplied by the LAD & LCX, and posteromedial papillary muscle is supplied by the PDA. Smooth walled outflow tract, aortic vestibule, ends with the aortic (semilunar) valve, having right coronary, left coronary, & posterior non-coronary cusps.

Cardiac Fibrous Skeleton: gasket of collagenous fibers situated between the atria & ventricles. supports the orifices & attached valves & prevents their collapse, the ventricular myocardial syncytial bands directly begin & end on the skeleton, & it serve as an electron conduction barrier between atria & ventricles

Atrial Myocardium: superficial atrial fibers begin on the fibrous skeleton & wind through the atrial septum. Superficial fibers wring dimension of the chambers with atrial systole, & conduct to ensure impulses largely originating in the right atrium are rapidly brought to the left. Deep atrial fibers are restricted to each atrium. They direct blood toward AV orifices & form quasi-functional sphincters to minimize retrograde flow of blood into the veins

Aortic Valve Stenosis: common feature of the aged heart; leads to left ventricular hypertrophy & eventually left atrial hypertrophy

Right Coronary Arteries: proximal RCA gives off conus artery, SA nodal arteria, right atrial branches & right anterior ventricular arteries. Acute marginal artery demarcates beginning of distal RCA, which gives off posterior descending artery. SA node, AV node, & common AV bundle receive their blood supply from the right coronary artery

Left Coronary Arteries: divide into left anterior descending artery (divided into proximal LAD & distal LAD). Circumflex artery (divided into 2 obtuse marginal arteries)

Conduction System: SA node (supplied by RCA) innervated by right vagus nerve. AV node (supplied by RCA) innervated by left vagus nerve. Common AV bundle of His (supplied by RCA) as is right bundle branch. Left bundle branch is supplied by LCA. Occlusions of RCA give rise to conduction block.

Postganglionic Sympathetic Fibers:o Superior cervical sympathetic cardiac nerve derived from superior cervical gangliono Middle cervical sympathetic cardiac nerve derived from cervicothoracic (stellate) gangliono Postganglionic fibers from thoracic sympathetic ganglia T2-T5o Intercostobrachial Nerve (large component of T2) – heart nerve

Thebesian Veins: smallest cardiac veins, drain their respective myocardia Coronary Sinus: 80% of blood draining here comes from left ventricle via great cardiac vein; site of drainage

from posterior vein of left ventricle & oblique vein of left atrium Small cardiac vein : courses in right part of coronary sulcus; drains distal field of right coronary artery Middle cardiac vein: accompanies PDA Anterior cardiac veins: drains proximal field of right coronary artery Lymphatics of the Heart:

o Right: follows RCA, right trunk, left brachiocephalic node, left bronchomediastinal trunk, left lymphovenous portal (thoracic duct)

o Left: follows LCA, left trunk, inferior tracheobronchial node, right superior tracheobronchial nodes, right bronchomediastinal trunk, right lymphovenous portal (right lymphatic duct)

Primary Heart Field: cardiac crescent cranial to the oropharyngeal membrane Cardiac Crescent: forms left ventricle, most of atria, & has a minor contribution to the outflow tract & right

ventricle Secondary Heart Field: cells from this inner portion of the cardiac crescent form most of the outflow tract &

right ventricle & contribute to the formation of the atria Proepicardium Cells: form most of the visceral pericardium (epicardium), the coronary arteries, & the fibroblasts

of the heart; eventually form the definitive epicardium, & layer becomes continuous with parietal mesothelial layer

Cardiac Neural Crest Cells: invade the developing heart & contribute to the walls of the outflow tract & the conotruncal septum; play a critical role for the formation of the atrial & membranous ventricular septa

Conotruncal Septum: divide the outflow tract into the pulmonary trunk & the aorta

FROM 18-22 DAYS:o Myocardial Primordium: develops from the visceral mesoderm of the developing pericardial cavityo Visceral Mesoderm: gives rise to the endocardial tubes; eventually fuse to form a single tubeo Pericardial Cavity: with lateral infolding, encircles developing hearto Visceral Mesothelium: forms the scaffold for the myocardium & the contact support for the epicardium;

is eventually displaced by invading proepicardium cellso Dorsal Mesocardium: eventually breaks down, leaving developing heart free in pericardial cavityo Parietal Mesoderm: forms parietal pericardium

Primordial Heart: formed from fusing of endocardial tubes, with fusion occurring in the cranial-caudal direction; with cranial infolding, the heart primordium & pericardial cavity undergo 180 degree roation so they end up on the underside of the embryo

Endocardial Tube: comes to lie in front of part of gut tube which will become future esophagus First heart beat: 20-22 days of development Five Parts of Embryonic Heart & Their Fates

o Sinus Venosus: becomes sinus venarum, coronary sinus, & oblique vein of the left atrium (Oblique Vein of Marshall)

o Primitive Atrium: becomes rough walled parts of right & left atria & their atrial appendages (auricles) Right atrium: distinction between rough & smooth walls is separated by crista terminalis, with

pectinate muscle emanating from crista terminalis lining anterior aspects of RA Left atrium: incorporation of 4 pulmonary veins largely displaces most of the embryonic rough

wall, leaving it almost entirely smooth walled with rough wall restricted to left auricleo Primitive Left Ventricle: forms trabeculated part of left ventricleo Bulbus Cordis:

proximal portion becomes primitive right ventricle, which later becomes trabeculated portion of right ventricle

Conus Cordis: middle portion that becomes conus arteriorsus (infundibulum) of right ventricle & aortic vestibule of left ventricle (the smooth outflow regions of each ventricle)

Truncus Arteriosus: distal portion that becomes the pulmonary trunk & ascending thoracic aortao Aortic Sac: becomes aortic arch branches, proximal pulmonary artery branches, & ductus arteriorsus

Septation of Atriao Semptum primum grows down from roof of primitive atrium to bottom of primitive atrium to form left

& right atria without completely fusing with floor; gap formed is ostium primumo Ostium secundum develops by cell death in top part of septum primum before ostium primum is

completely closed by septum primum fusion with floor; maintains flow while atria are developingo in region of AV junction, endocardial cushions (mound of cardiac cells) push in from all sides to separate

atria from ventricles & provide anchoring point for interatrial & interventricular septa; complete AV separation

o septum secundum grow to right of floppy septum primum; free edge of septum secundum is thickened (crista dividens)

o foramen ovale: gap left in septum secundum; low on right atriumo right to left shunt maintained by blood pushing against floppy, valve-like septum primum & flowing over

top of valve into left atrium (septum primum = valve of foramen ovale)o with first breaths, pulmonary blood flow from left atrium causes pressure in left atrium to rise greater

than right atrium

o valve-like free upper edge of septum primum pushed against rigid septum secundum & crista dividens, & foramen ovale closes

o Crista dividens becomes limbus fossa ovalis in right atriumo Free edge of septum primum becomes foramen ovale in left atrium

Muscular part of IV septum: formed by selective cavitation through cell death; as ventricle grows outwards, relatively solid ventricle is sculpted out by cell death except for center (forming partition)

Derivatives of Aortic Archeso 1 & 2- drop out & become small arterieso 3 – becomes common carotid formed by remaining cranial extension of dorsal aorta; external carotid

develops by sprouting out from proximal part of 3rd archo 4 – arches of aorta from left common carotid to left subclavian arteries on left; proximal portion of right

subclavian artery on righto 6- left pulmonary artery & ductus arteriorsus, right pulmonary artery

Left umbilical vein: carries oxygenated blood from placenta to fetus; becomes sole source of oxygenated blood after right vein degenerates during development

Fetal circulation at the hearto 50% of oxygenated blood courses through fetal liver & then to IVS via hepatic veins, where it gets a little

desaturatedo Diversion to vena cava by ductus venosus (50%); mixed with desaturated blood in IVCo Ductus venosus: has a pressure –sensitive sphincter; if pressure in umbilical vein is too high, sphincter

closes & diverts more blood to liver & dissipate pressure that can damage fetal hearto Blood travels from IVC to RA & is directed through foramen ovale to LA by Eustachian valve o Most of SVC blood is prevented from mixing with oxygenated umbilical vein blood; diverted to right

ventricle by cascading over intervenous tubercleo Lungs don’t function in gas exchange; exhibit high pulmonary resistance – blood in pulm. Artery is

diverted to aortic arch through ductus arteriosus o Ductus arteriosus: prevents overload of incompliant lungs & resistance supports growth of right

ventricle for transition into neonatal lifeo Umbilical arteries: oxygen saturation 58% by time it reaches this point

Ductus venosus: closes by unknown mechanism; sphincter constricts & shunts umbilical venous blood to liver, causing pressure in right atrium to fall; becomes ligamentum venosum in left sagittal fissure of liver connecting left branch of hepatic portal vein with left hepatic vein

Umbilical vein: closes over time but remains patent neonatally, can be used therapeutically. Occlude to form round ligament of liver from umbilicus in falciform ligament to left sagittal fissure, then connecting to left branch of hepatic portal vein

DA becomes fibrous connection between left pulmonary artery & aortic arch – ligamentum arteriosum Distal part of umbilical arteries occlude & become medial umbilical ligaments Atrial Septal Defect: secundum atrial septal defect; pressure in left atrium is high after birth, causing oxygenated

blood to be shunted to left atrium. Acyanotic. Can cause enlarged right atrium, right ventricle (causing convexity of normally slightly concave left auricle),& pulmonary trunk (obliterating distinction between aortic knuckle & pulmonary trunk)

Ebstein anomaly: some of right ventricle is incorporated into right atrium (atrialization dysfunction). Distorts normal architecture of tricuspid valve, resulting in severe tricuspid Valvular dysfunction. Right heart has to work harder. Called box-shaped heart

Perimembranous VSD: involves membranous ventricular septum because of active growth required to form it. Left heart pressure is higher than right; left to right shunt. Acyanotic

Tetralogy of Fallot:o Pulmonary infundibular stenosiso Right ventricular hypertrophyo Perimembranous VSDo Cyanotic (aorta overrides VSD & desaturated blood makes it to systemic circulation)o Patent ductus arteriosuso Boot-shaped heart

Persistent Truncus Arteriosus: failure of development of conotruncal septum & contribution to membranous interventricular septum. Cyanotic. Causes left tracheal deviation

Patent Ductus Arteriosus: seen in many cyanotic conditions because level of oxygen desaturation causes ductus to remain patent. Pulmonary stenosis & greater aortic pressure expands ductus retrograde into pulmonary artery, leading to enlargement of pulmonary artery. Left to right shunt.

Transposition of Great Arteries: arteries get hooked up to wrong ventricle. Cyanotic. Egg-on-string appearance. Tricuspid atresia: right atrioventricular orifice & valve fail to develop; patent foramen ovale & PDA. Cyanotic. Common Stenoses of Aorta & Pulmonary Artery & their Valves

o Isolated pulmonary Valvular & arterial stenosis: PDA provides flow to lungs for oxygenation. Acyanotico Aortic Valvular stenosis: acquired stenosis. Enlargement of left ventricle & left atrium because of

resistance of stenotic aortic valve. o Aortiic Valvular Atresia: no blood can go from left ventricle to aorta. Left ventricle is hypoplastic. Only

outflow is pulmonary artery supplying lungs & systemic circulation. When it returns to left atrium it is shunted to right atrium & mixing with venous blood. Cyanotic.

Anomalies of aortic saco Vascular Rings, Slings & Compressors: affect trachea, esophagus, or both. Airway obstruction

accompanied by stridor (especially expiratory). If esophagus is involved, there is dysphagia lusoria (dysphagia caused by act of nature)

o If dorsal aorta fails to degenerate: double aortic arch that forms vascular ring around esophagus & trachea

o Aberrant right subclavian artery: indentation of esophagus, trachea is displaced & compressedo Aberrant left pulmonary artery: courses between esophagus & trachea. Indents esophagus & trachea

airwayo Left aortic arch loses connection with descending aorta: double aortic arch with left one being

incomplete. Right gives off left common carotid, right common carotid, & right subclavian & forms main connection with descending thoracic aorta. Left arch is broken leaving a stump (Kommerell’s diverticulum). Horsehoe clamp around trachea

Displaced innominate artery: may be taught & over trachea such that it compresses tracheal rings. Can lead to gradual tracheomalacia, tracheal compression, & dyspnea.

Eisenmenger Syndrome: high flow through pulmonary artery persists, resulting in pulmonary arterial resistance increasing & pulmonary hypertension. Right ventricle begins to hypertrophy to such a point that shunt from left to right reverses. Body is supplied with deoxygenated blood. Cyanotic. Previous high pressure through lungs causes damage & scar tissue in lunges which reduces oxygen transfer & decreased oxygen saturation in blood. Leads to increased production of RBCs (polycythemia). More immature blood cells enter vasculature leading to hyperviscosity syndrome & formation of microthromboemboli in small vessels. Patients have uncontrolled bleeding & random clots

Persistent Hypoxia: cyanosis, clubbing of digits Manubriosternal joint: sternal angle, angle of Louis, T4/T5 ivd Inferior vena cava: T8/T9 ivd (+right phrenic nerve)

Xiphisternal junction: T9V Esophagus: T10 (+ vagal trunks) Descending aorta: T12 (+ thoracic duct) Burkell’s surgical classification:

o anterior & middle mediastina: separated by curvilinear line that passes anterior to heart shadow & then superiorly passes posteriorly to anterior surface of trachea, cutting off great vessels. Contains pulmonary artery & branches, superior vena cava, aortic arch & branches, thymus, anterior lymphatics & fatty areolar tissue

o middle mediastinum: separated from posterior by smooth curvilinear line posterior to trachea & heart shadow. Contains pericardial cavity & heart proper, pulmonary veins, inferior vena cava, trachea & bifurcation, main bronchi

o posterior mediastinum: contains osteoligamentous elements, pulmonary sulci, sympathetic trunk & splanchnic nerves, azygos & hemiazygos venous systems, esophagus, descending aorta, thoracic duct, paravertebral lymphatics & fatty areolar tissue

Osteoligamentous layer: thoracic vertebrae & disks, posterior ribs, pulmonary sulci, & assoc. ligaments (especially anterior longitudinal ligament)

Spinal arcuate lines: smooth imaginary lines drawn along contours of vertebral bodies & posterior elements of vertebrae

Anterior vertebral line: connects anterior surface of vertebral bodies. There should be uniformity in this line Enthesopathies: abnormalities where anterior longitudinal ligament attaches to vertebral body along anterior

spinal line. Enthesis: attachment point of a ligament or tendon onto a bone Osteophytes: (syndesmophytes) grow into ligaments & severe vertebral lipping of edges of vertebral bodies

occurs Posterior vertebral line: aligns posterior surface of vertebral bodies Spinolaminar line: spinolaminar junctions of vertebrae; junction of spinous process with laminae of vertebral

arch; posterior boundary of spinal canal Neurovascular layer

o Arterial Layer: descending thoracic aorta & posterior intercostal arteries Thoracic aortic aneurysm: abnormal dilatation of thoracic aorta. Can erode left anterior surface

vertebral bodies distorting anterior spinal line Aortic aneurysm with dissection: force of blood in true lumen can dissect along fracturing

tunica media, forming a false lumen Marfan’s Syndrome: patients prone to aortic dissection Aortic Isthmus: take-off of left subclavian artery & third pair of posterior intercostal arteries;

marked by ligamentum arteriosumo Venous Layer: azygos system & posterior intercostal veins

Superior Vena Cava Syndrome: trauma to superior vena cava or encroachment via metastasis causes this syndrome. Venous pressures in head & arm veins can approach 200-500 mm Hg. If it involves azygos arch thus curtains collateral routes, may be more serious & result in fatal cerebral edema. In pediatric setting SVC syndrome is a medical emergency

Gradual Superior Vena Cava Syndrome: if SVCS is gradual, collateral chest & abdominal veins can enlarge. Venous return from upper body gets back to right heart by flowing through femoral system & eventually inferior vena cava

o Lympathic Layer: thoracic duct

Chylomediastinum: injury to thoracic duct resulting in 1500 ml?day of chyle extravasating into mediastinum

Chylothorax: chyle seets into pleural space Chylopericardium: chyle seeps into pericardial space

o Nervous Layer Sympathetic trunk Greater splanchnic

Digestive Layer: esophagus & plexues; vagal trunkso Gastroesophageal venous plexus: in portal hypertension, this plexus can become varicose posing

danger of rupture. Normally smooth luminal contour demonstrates worm-like, space taking lesions which are the varices into the projecting lumen

o Sengstaken-Blakemore Tube: tube with 2 inflatable section to tamponade hemorrhage from ruptured gastroesophageal varicies above & below diaphragm

o Esophagus 4 Constricted Points: upper esophageal constrictor (cricopharyngeus muscle – 70% of obstructions by foreign objects), left of esophagus (aortic arch & left main bronchus- 15% of obstructions by foreign objects), anterior wall (left atrium, basis for fistula formation), esophagus through diaphragm (angle leftward to enter stomach – 15% of obstruction by foreign objects)

o Phrenic ampulla: normal manometric pause prior to relaxation of lower esophageal sphinctero Schatzki’s Ring: constriction at esophageal hiatus; B ring or congenital narrow mucosal ring that

develops at lower end of esophaguso Boerhaave’s Syndrome: tears in left wall of esophagus above diaphragm after severe case of vomiting;

tears can violate left pleural cavity causing pneumothorax/pyothoraxo Leiomyoma: benign smooth muscle neoplasm; displaces contrast in esophageal lumeno Diverticulum: outpouching of mucosa; covered with rest of wall layers is true diverticulum; just an

outpouching of mucosa without rest of wall is false diverticulum Respiratory Layer: trachea & bifurcation, lymphocenters

o Tracheoinnominate fistula: placement of endotracheal tube can erode anterior margin of trachea, ulcerate the innominate artery, & result in this

o Right paratrachael stripe: trachea is in contact with right mediastinal parietal pleura; with lung contrast in PA CXR this line shows up

o Pneumomediastinum: air in the mediastinumo Hamman’s Sign: crunching or clicking sound with heart beat; indication of air in the mediastinumo Lung Cancer: occurs in right lung = stays rightward. Occurs in left lung upper lobe = stays leftward, lower

lobe = crosses to right & tracks rightward Great Arterial Layer: proximal (ascending aorta), aortic arch, pulmonary trunk

o Pulmonary arterial embolism: can be iatrogenic air from misplacement of central line into right side of heart or a thromboembolism from dislodged thrombus. Most common is from deep venous thrombosis of lower limb.

o Economy class syndrome: susceptible patients that were seated for a long timeo Oligema: reduced blood flow to a tissue regiono Westermark’s Sign: vascular cut-off sign o Hampton’s Hump: wedge-shaped consolidation projection from parietal pleura into the lungo Melting sign: consolidation melts away from periphery towards center of consolidation when embolism

clears Great venous Layer: superior & inferior venae cavae

o Aortic nipple: the left superior intercostal vein can be large; as it crosses aortic arch it can show up as a small radiodense bump

o Azygos Lobe of Right Upper Lobe: azygos arch can loop more laterally & pinch off part of the right upper lobe producing a fissure

Glandular Layer: Thymus Glando Sail Sign: thymus gland that is considerably larger in newborn produces sail sign in pediatric PA or AP

CXRo Aberrant retrosternal thyroid tissue: thyroid tissue that extends inferiorly behind sternum; can become

goitrous o Pemberton’s Sign: symptoms of goiter compressing on trachea are aggravated when patient’s arms are

raised above head which draws more of goiter behind the sternum causing greater compression-related symptoms & faintness

Ovulatory Crypsis: hidden ovulation; important feature is breast of sexually mature female Nipple: resides over 4th intercostal space; important for sexual attraction. Uniquely human. Changes in

sympathetic tone increase relief of nipple & areola Montgomery Glands: frequent sites of staphylococcal infections; left untreated can result in mastitis &

subareolar abscess Cooper’s Ligaments: suspensory ligaments that run through the fascial layers from deep pectoral fascia to the

skin & nipple Lactiferous lobes: drain to a lactiferous duct that drains onto nipple Lactiferous lobules: several in each lobe; drain to several acini Terminal duct & its acini (alveoli) comprise terminal duct lobular unit Fibroglandular stroma: parenchyma is encased in stroma of more fibrous tissue that is continuous with

suspensory ligaments Keratinizing squamous epithelium: dips into orifices at nipple & then abruptly changes Double-layered cuboidal epithelium: lines ducts & their sinuses Terminal duct lobular unit: successive branch of large ducts eventually lead to this Terminal duct: branches into a grapelike cluster of small acini to form a lobule Axillary tail: ducts extend into subcutaneous tissue of chest wall & into axilla Myoepithelial cells: form meshlike pattern on basement membrane; assist in milk ejection during lactation &

provide structural support to lobules Luminal epithelial cells: only cells capable of producing milk Stem cells: postulated to give rise in both luminal myoepithelial cells Interlobular stroma: consists of dense fibrous connective tissue admixed with adipose tissue Intralobular stroma: envelopes acini of lobules & consists of breast-specific, hormonally-responsive fibroblast-

like cells admixed with scattered lymphocytes Colustrum: after delivery of baby luminal cells of lobules produce colostrum (high in protein) which changes to

milk (higher in fat & calories) over the next 10 days Breast: main endocrine regulator of calcium metabolism during lactation; releases large amounts of PTH-like

peptide & calcitonin; careful mobilization of calcium from trabecular bone while maintaining & expanding cortical component

Blood Supply:o Arteries: internal thoracic artery, lateral thoracic artery, intercostal arterieso Venous: axillary & subclavian veins, azygos system

Lymphatics: axillary chain has good sentinel nodeso Level 1: pectoral nodes

o Level 2: central nodeso Level 3: apical nodes

Venous drainage: go reverse of arterial supply; cancer cells can spread via these routes to vertebral column Sensory: Intercostal nerves T2-T6, with nipple at T4. Mastalgia/Mastodynia/Mammalgia: pain from breast Mammary ridges: epidermal band-like thickenings; milk lines; these degenerate except for the normal positions

in the thoracic region Polythelia: supernumerary nipples, usually in axillary region, that are often mistaken as moles Polymastia: additional functional breast tissue Amastia: breast fails to develop, or just nipple & areola are present Inverted nipple: nipple fails to evert Thelarche: breast development; precedes menarche by 2 years Breast Quadrants: upper outer, lower outer, upper inner, lower inner Fibrocystic Disease: mammary dysplasia Mediolateral Oblique View: observer is the detector looking at the breast; placed on right in right MLO and left

in left MLO; divides breast into upper & lower halves; in image, breast points toward direction it is name for (IE left breast image points left)

Craniocaudal View: detector is looking up at breast from underneath; image seen is rotated clockwise & placed on right for right CC or left for left CC. divides breast into outer & inner halves

Incidence of carcinoma: concentrated to upper outer quadrant Cancerous tumor: causes edema of lymphatics & pulls on Cooper’s ligaments, distorting the normal breast

contour. Veins may be more evident due to increased vascularity Spot Views: compression/close up views. Focuses in closer at lesion Other methods of Imaging

o X-ray mammogramo Contrast Enhanced MRI using gadolinium: detects tissue with high metabolic activityo Lymphoscintigraphy: Tc is bound to sulfur colloid which has avidity for lymphatics. Compound is

injected & sentinel nodes will light up. These can be found with a Geiger probe. Breast Cancer: favors lungs & spinal column for metastasis