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Bell RingerName 10 bones of the human body.
Turn your bell ringers into the tray.
Skeletal System
Skeletal SystemSkeleton: from Greek for “dried-up body” Infant backbone begins as an arch (C-
shape); changes to a swayback, then quickly forms the common S-shape of the adult spine
Two divisions: Axial Skeleton Appendicular Skeleton
Also includes: joints, cartilage, and ligaments
FunctionsSupportProtection
Of soft body organsMovement
Assisted by muscles and tendonsStorage
Fat inside the cavitiesMineral storage (calcium, phosphorous, etc)
Blood cell formation (Hematopoiesis)Occurs in the marrow cavities
Classification of BonesTypes of bone tissue
Compact boneDense, looks smooth
Spongy boneMade of small needlelike pieces of bone (lots of
open space)Shapes of bones
Long (shaft with a head at each end; mostly compact)
Short (generally cube shaped; mostly spongy)Sesamoid bones – form within tendons
Flat (thin, flat, usually curved; two thin layers of compact bone with spongy bone inbetween)
Irregular
Structure of a Long BoneGross Anatomy
Diaphysis (shaft)Composed of
compact boneCovered by
periosteumHeld by Sharpey’s
fibersEpiphysis (ends)
Spongy bone covered with compact bone
Covered by articular cartilage (hyaline cartilage)
Epiphyseal plate (childhood) becomes epiphyseal line (adult) – hyaline cartilage as the bone grows
Structure of a Long BoneGross Anatomy
Medullary cavity In the shaftHolds the yellow
marrow (fat tissue)
Holds red marrow in infants (blood formation)
Red marrow in adults in cavities of spongy bone of the flat bones and the epiphyses of some long bone
Bone MarkingsProjections or
processesDepressions or
cavities
Bony LandmarksProjections that are sites of muscle and
ligament attachmentTubercle: small rounded projection or processTuberosity: large rounded projection; may be
roughenedTrochanter: very large, blunt, irregularly
shaped processCrest: narrow ridge of bone; usually
prominentLine: narrow ridge of bone; less prominent
than a crestSpine: sharp, slender, often pointed
projectionEpicondyle: raised area on or above a
condyleRamus: armlike bar of bone
Projections that help to form jointsHead: bony expansion carried on a narrow
neckFacet: smooth, nearly flat articular surfaceCondyle: rounded articular projection
Bony LandmarksDepressions and openings allowing blood
vessels and nerves to passMeatus: canal-like passagewaySinus: cavity within a bone, filled with air and
lined with mucous membraneFossa: shallow, basinlike depression in a
bone, often serving as an articular surfaceGroove: slitlike furrowFissure: narrow, slitlike openingForamen: round or oval opening through a
bone
Structure of a Long BoneMicroscopic Anatomy
Osteocytes (mature bone cells)Lacunae (cavity within the bone matrix)
Arranged in concentric circles – lamellae; around a Haversian (central) canal
Haversian system (osteon)Run lengthwise Contains a central canal, a matrix of rings, and a
blood vesselCanaliculi
Tiny canals that radiate outward from the central canals
Volkmann’s (perforating) canalCommunication pathway from the outside of the
bone to its interior Run at right angles to the shaft
Microscopic Anatomy
Bone Formation, Growth & RemodelingSkeleton made of cartilage and bone
As an embryo – skeleton of hyaline cartilageYoung child – most cartilage replaced by
boneMost bones develop using hyaline cartilage
as the model (flat bones use fibrous membranes)Ossification – bone formationOsteoblasts (bone forming cells) cover
hyaline with boneEnclosed hyaline digested to leave medullary
cavityTwo regions left as hyaline cartilage
Articular cartilageEpiphyiseal plates
Bone Formation, Growth & RemodelingBones grow in length by adding hyaline
cartilage at the epiphyseal plateBones grow in width by osteoblasts in the
periosteum adding osteocytes to the external surface of the diaphysis & osteoclasts remove bone from the inner surface of the diaphysis
Appositional growthProcess of bones increasing in diameterControlled by growth hormones and sex
hormones (during puberty)
Bone Formation, Growth & RemodelingBones are not static – continually changing
in response to body changesCalcium levels in the blood
Levels drop, parathyroid glands stimulated to release PTH
PTH activates osteoclasts to break down bone matrix and release calcium ions into the blood
Levels rise, calcium is deposited in the bone matrix as calcium salts
Pull of gravity and muscles on the skeletonIncrease pull will influence where calcium is
deposited
Bone FracturesClosed (simple) fracture – does not
penetrate the skinOpen (compound) fracture – does
penetrate the skinCorrection:
Closed reduction: physician guides the bone into realignment
Open reduction: realignment achieved during surgery
Healing:Simple fracture – healing time 6-8 weeksLonger healing time for larger bones and for
elderly
Repair of Bone Fractures1. Hematoma forms
Blood filled swellingBones deprived of
nutrition die2. Fibrocartilage callus
formsNew capillaries grow
into the clotted bloodDead tissue removed
by phagocytesConnective tissue forms
a mass (callus) containing cartilage matrix, bony matrix, and collagen fibers
Closes the gap in the broken bone
Repair of Bone Fractures3. Bony callus forms
As osteoblasts and osteoclasts move into the area and multiply
Made of spongy bone4. Bone remodeling
Occurs over the next few months to form a permanent patch
Bell RingerDefine fracture. Which fracture types are
most common in the elderly? Why are greenstick fractures more common in children?
Axial SkeletonSkull
CraniumFacial bonesSkull bones held together by sutures
(immovable); except for the mandibleVertebral column (spine)
From the skull to the pelvis26 irregular bones protecting the spinal cordPlus the sacrum and coccyx
Bony thorax (thoracic cage)Consists of the sternum, ribs, & thoracic
vertebraeProtects heart, lungs, and major blood
vessels
SkullCranium (eight large,
flat bones)Frontal boneParietal bonesTemporal bonesOccipital boneSphenoid boneEthmoid bone
Facial BonesMaxillae (Maxillary
bones)Palatine bonesZygomatic bonesLacrimal bonesNasal bonesVomer boneInferior ConchaeMandible
Hyoid bone
CraniumFrontal Bone
Forehead, bony projections under eyebrows, superior part of the orbit
Bony marking: Glabella, supraorbital marginParietal Bones (2)
Most superior and lateral walls of craniumMeet at the midline to form the sagittal sutureMeets the frontal bone to form the coronal sutureBony markings: Parietal eminence, temporal line
Occipital BoneMost posterior – forms the floor and back wall of the
skullMeets the parietal bone to form the lambdoid sutureForamen magnum – large opening in the base for the
extension of the spinal cord from the brainOccipital condyles allow the occiput to rest on the first
vertebra
CraniumTemporal Bones (2)
Inferior to parietal bonesMeets parietal bones to form squamous
suturesBony Markings:
External auditory meatus – canal leading to the ear drum
Styloid process – sharp, projection inferior to external auditory meatus; attachment point for many neck muscles
Zygomatic process – bridge of bone meeting the zygomatic bone (cheek)
Mastoid process – posterior and inferior to external auditory meatus, full of mastoid sinuses (air); attachment site for some neck muscles
Jugular foramen – at junction of occipital and temporal bone; allows passage of jugular vein (drains the brain)
Carotid canal – anterior to jugular foramen; allows passage of internal carotid artery
CraniumSphenoid Bone
Butterfly shapedSpans width of skull and forms part of the
floor of the cranial cavityAlso forms part of the eye orbits and the
lateral surface of the skullBone markings:
Sella turcica (Turk’s saddle)Small depression at the midline; holds the
pituitary glandForamen ovale
Large oval opening for the passage of cranial nerve V to supply the masseter muscle
Sphenoid sinuses (air cavities)
CraniumEthmoid Bone
Anterior to sphenoidIrregularly shapedForms roof of nasal cavity and medial walls of
orbitsBone Markings:
Crista galli (Cock’s comb)Projects from superior sufaceAllows for attachment of dura matter
Cribriform platesHoles on either side of crisa galliAllow nerve fibers from olfactory receptors to
reach the brain
Facial BonesMade of fourteen bones (twelve are paired)Maxillae (maxillary bones)
Fuse to form the upper jawAll facial bones (except mandible) join the
maxillaeBone Markings:
Alveolar margin – location of teethPalatine processes
Extensions that form the anterior part of the hard palate
Paranasal sinusesPalatine Bones
Posterior to palatine process of maxillaeForm posterior part of hard palateCleft palate: failure of the palatine or the
palatine processes to fuse
Facial BonesZygomatic Bones
Cheekbones; also form part of lateral walls of orbitsBony Markings: zygomatic arch; temporal process
Lacrimal BonesForm medial walls of orbitHas a groove that serves as the passageway for tears
(lacrima = tears)Nasal Bones
Form the bridge of the noseVomer Bone
Single bone in the median of the nasal cavity Inferior Conchae
Thin curved bones projecting from lateral walls of nasal cavity
Superior and middle conchae part of ethmoid bone
Facial BonesMandible
Lower jawLargest and strongest bone of the faceOnly freely movable joints in the skull (joins
temporal bones)Bone Markings:
Body – horizontal part of mandibleRami – upright bars extended from bodyAlveoli (sockets) for the teethAlveolar margin – superior edge of mandibular bodyMental foramen
Hyoid BoneHyoid Bone
Not technically part of the skullOnly bone that does not articulate directly
with another boneSuspended above the laynx, anchored by
ligamentsServes as a movable base for the tongue and
an attachment point for neck musclesBone Markings:
BodyHorns (Cornua)
Fetal SkullNot fully formed at birth – spaces in-
between the bones (fontanels)Fontanels are covered with a fibrous
membraneAllow the skull to collapse slightly during
birth and for additional growth of the brain after birth
Completely closed by 24 months of ageAnterior (largest) – diamond-shapedPosterior – triangularSphenoidal Mastoid
Vertebral Column (Spine)26 irregular bones33 bones before birth (9 fuse to form the sacrum
and coccyx)7 cervical vertebrae12 thoracic vertebrae5 lumbar vertebraeSeparated by intervertebral disc
Flexible fibrocartilage90% water in a young person; decreases with age –
causing less compressibilityCurvatures
Primary curvatures – present at birthSecondary curvature – develop later (with raising head
and walking)
Vertebral ColumnStructures of Vertebrae
Body (centrum)Weight-bearing partAnterior
Vertebral archFormed by joining all
posterior extensions Laminae – posterior
portion Pedicle – anterior
portionVertebral foramen
Canal for spinal cord
Transverse processesLateral projections from
vertebral archSpinous process
Fused laminae forming a single projection to the posterior
Superior and inferior articular processPaired projections,
lateral to vertebral foramen
Allow vertebra to form joints with adjacent vertebrae
Also unique characteristics based on region
Cervical VertebraeC1 – C7
C1 – atlasNo bodyDepressions to receive the occipital condylesAllow for “yes” nodding
C2 – axisOdontoid process (dens) – acts as a pivot pointJoint between C1 & C2 allow for “no” movement
C3 – C7 (typical cervical vertebrae)Smallest, lightest vertebraeSpinous processes short and generally split in two
(bifurcated)Transverse processes contain foramina for the
vertebral arteries to pass through
Thoracic & Lumbar VertebraeThoracic Vertebrae
T1 – T12Larger than cervical vertebraeBody somewhat heart shaped with two costal
demifacets to receive the heads of the ribsSpinous process long and hooks sharply
downwardLumbar Vertebrae
L1 – L5Massive, block-like bodiesSpinous process is short and hatchet-shaped
Sacrum & CoccyxSacrum
Formed by fusion of 5 vertebraeForms the posterior wall of pelvisAlae: lateral winglike portion that articulates
with the hip bones to form sacroiliac jointMedian sacral crest: dorsal midline surface
Fused spinous processesSacral Foramina: holes for nerves to enter
the legsSacral canal: continuation of vertebral canal
CoccyxFormed by fusion of 3-5 tiny vertebraeHuman “tailbone”
Bony ThoraxSternum
Flat boneSternal puncture: process of obtaining
hematopoietic tissue for the diagnosis of blood diseases (use the sternum because of proximity to body surface)
Created by fusion of three bonesManubriumBodyXiphoid Process
Attached to first seven pairs of ribsBony landmarks
Jugular notch – concave, superior border of manubrium
Sternal angle – slight angle where manubrium and body meet
Xiphisternal joint
Bony ThoraxRibs
Twelve pairsAll ribs articulate with the vertebral column,
then curve downward and toward the anterior body surface
True ribs – first 7 pairs, attach directly to the sternum
False ribs – next 5 pairs either attach indirectly to the sternum or not at allFloating Ribs – the last 2 pairs (lack sternal
attachments)
Intercostal spaces – filled with intercostal muscles to assist in breathing
Bell RingerWhich bones have the following landmarks:
A. Manubrium, body, xiphoid processB. Body, rami, mental foramenC. Condyles, foramen magnumD. Crista galli, cribiform platesE. Odontoid process, transverse foramen
Appendicular SkeletonComposed of 126 bonesIncludes: appendages (limbs), pectoral and
pelvic girdlesBones of the Pectoral (shoulder) Girdle
Clavicle (collarbone)Slender, double curved boneAttaches to manubrium medially and scapula
laterally Acts as a brace to hold the arm away from the top of
the thorax and helps prevent shoulder dislocationBony Processes: Costal tuberosity, Conoid tubercle,
Subclavian groveBroken clavicle: shoulder region caves in medially
Scapulae (shoulder blades); wings
Bones of the Shoulder GirdleScapulae
Bony Processes:Acromion: enlarged end of the spine of the scapulaCoracoid process: beaklike, points over the top of the
shoulderAcromioclavicular jointSuprascapular notch: medial to coracoid process, serves
as a nerve passagewayBorders:
Superior Medial (vertebral) Lateral (axillary)
Angles Superior Inferior Lateral
Glenoid Cavity: shallow socket that receives that head of the humerus
Bones of the Shoulder GirdleShoulder Girdle is very light and allows for
exceptionally free movement because:1. Shoulder girdle attaches to axial skeleton
at one point – sternoclavicular joint2. Loose attachment of scapula allows for
sliding against thorax as muscles act3. Glenoid cavity is shallow, shoulder joint
reinforced by ligamentsAll this extra movement leads to the
shoulder being easy to move and easy to dislocate
Bones of the Upper LimbsArm, forearm, and hand – 30 bonesHumerus (arm)
Head: proximal end, fits into glenoid cavityGreater and lesser tubercles: also on proximal end,
sites for muscle attachmentDeltoid tuberosity: roughened area in the midpoint of
the shaft; allows attachment of the deltoid muscleRadial groove: runs obliquely down the posterior shaft;
makes the course for the radial nerveTrochlea: distal end, medialCapitulum: distal end, lateralCoronoid fossa: depression superior to trochlea on the
anterior sideOlecranon fossa: depression superior to trochlea on
the posterior sideMedial and lateral epicondyle: on either side of the
olecranon fossa
Bones of the Upper LimbsForearm: Two bones – Radius and Ulna
Radiculoulnar joints (proximal and distal)Interosseous membrane: connects along the
entire lengthRadius – lateral in anatomical position
Head: proximal Radial tuberosity: inferior to head;
connection point for biceps tendonUlna – medial in anatomic position
Coronoid process: anterior on the proximal end
Olecranon process: posterior on the proximal end
Trochlear notch: separates the coronoid and olecranon processes
Bones of the Upper LimbsHand: Carpals,
Metacarpals, and Phalanges
Carpal bones Form the carpus
(wrist) Two bands of four
bones each (8 total)TrapeziumTrapezoidCapitateHamateScaphoidLunateTriquetralPisiform
Bound together by ligaments
MetacarpalsForm the palmHeads of metacarpals –
knucklesNumbered 1 -5 starting at
the thumbPhalanges
Bones of the fingers3 per finger
ProximalMiddleDistal
2 per thumbProximal and Distal
Stop Letting Those PeopleTouch The Cadaver’s Hand
Bones of the Pelvic GirdleFormed by the Coxal bones (ossa coxae)Commonly called the hip bones
Together with the sacrum, forms the bony pelvis
Inside the bony pelvis: reproductive organs, urinary bladder, and part of the large intestine
Each Ossa Coxae is actually three fused bonesIliumIschiumPubis
Ossa Coxae Ilium
Connects with sacrum to form sacroiliac joint
Makes most of the hip bone
Alae: winglike portionIliac crest: upper edge
of alaeAnterior superior iliac
spine: anterior end of iliac crest
Posterior superior iliac spine: posterior end of iliac crest
Anterior/Posterior inferior iliac spine
Ischium“Sitdown bone”Most inferior part of
coxal boneIschial tuberosity:
Rough area that receives body weight while sitting
Ischial spine: superior to tuberosity (narrows the outlet that a baby must pass through)
Greater sciatic notch: allows blood vessels and the sciatic nerve to pass from the pelvis posteriorly to the thigh
Ossa CoxaePubis
Most anterior part of coxal boneRami: bony bar reaching back to ischiumObturator foramen: anterior rami of pubis
meets posterior ischial ramus to create an opening; allows blood vessels and nerves to go into the anterior part of thigh
Pubic symphysis: pubic bones fuse anteriorly to form a cartilaginous joint
Acetabulum: deep socket that receives the head of the femur; fusion of ilium, ischium, and pubis
Ossa CoxaeBony pelvis divided into two regionsFalse pelvis
Superior to true pelvisArea medial to the flaring ilia
True pelvisSurrounded by bone; inferior to false pelvisInlet: superior openingOutlet: inferior opening
Male vs. Female PelvisFemale inlet larger and more circularFemale pelvis shallowerFemale pelvis bones are lighter and thinnerFemale ilia flare more laterallyFemale sacrum is shorter and less curvedFemale ischial spines are shorter and
farther apart (larger outlet)Female pubic arch is more rounded
because the angle of the pubic arch is greater
Bones of the Lower LimbsFemur (thigh)Heaviest and strongest bone in the body
Proximal MarkingsHead: ball like, fits into acetabulumNeck: narrow portion inferior to the headGreater and lesser trochanters: muscle attachment Intertrochanteric line: anterior Intertrochanteric crest: posterior; muscle attachmentGluteal tuberosity: muscle attachment
Distal MarkingsLateral and Medial Condyles: articulate with tibia Intercondylar notch: posteriorPatellar surface: anterior; forms joint with patella
Slant medially to the knees
Bones of the Lower LimbsLeg: 2 bones – Tibia & Fibula
Interosseous membrane: connects the two bones along their length
Tibia (shinbone)Larger & MedialProximal end
Medial and lateral condyles: make a joint with the femur Intercondylar eminence: separates the condylesTibial tuberosity: rough area on the anterior surface for the
patella tendon attachmentDistal end
Medial malleolus: inner bulge of ankleAnterior crest: anterior surface of the tibia; sharp ridge
FibulaHead: proximal endLateral malleolus: distal end; outer part of ankle
Bones of the Lower LimbsFoot – Tarsals, metatarsals, & phalanges
Tarsus (seven tarsal bones)Calcaneus (heelbone)Talus (ankle): between tibia and calcaneusNavicularCuboidMedial, Intermdiate, and Lateral Cuneiform
Metatarsals (5): sole of footPhalanges (14): toes (similar layout as
fingers)Forms 3 arches
Medial and lateral longitudinal archTransverse arch
Bell Ringer
Describe how to differentiate between a male and female pelvis.
JointsEvery bone in the body forms at least one joint with
another bone (except the hyoid bone) Joints also called articulationsTwo functions:
Hold bones togetherProvide mobility
Classification methods:Functional
Synarthrosis (immovable)Amphiarthroses (slightly movable)Diarthroses (freely movable)
StructuralFibrous (most are immovable)Cartilaginous (mostly amphiarthrotic)Synovial (freely movable)
JointsFibrous Joints
Sutures of the skullIrregular edges of the bones interlock; bound tightly
together by connective tissue fibersSyndesmoses: type of fibrous joint where the fibers
are longer allowing more give; found in the distal end of the tibia and fibula
Cartilaginous JointsBone ends connected by cartilageAmphiarthrotic examples: pubic symphysis and
intervertebral jointsSynarthrotic examples: the hyaline cartilage
epiphyseal plates of growing bones and the cartilaginous joints between the ribs and the sternum
JointsSynovial Joints
Articulating bone ends separated by a joint cavity containing synovial fluid
Four distinct features:1. Articular cartilage: covers the ends of the bones2. Fibrous articular capsule: Joint surface enclosed
by a capsule of fibrous connective tissue; lined with a smooth synovial membrane
3. Joint cavity: contains the synovial fluid4. Reinforcing ligaments: ligaments that reinforce
the fibrous capsuleBursa: flattened fibrous sacs filled with
synovial fluid; common where ligaments, muscles, skin, tendons, or bones rub together
Tendon sheath: an elongated bursa that wraps around a tendon subjected to friction
Types of Synovial Joints (Shape) Shape of joint determines the movements allowed
(Structure determines function) Plane (Gliding) Joint: essentially flat; nonaxial movement
Ex: intercarpal joints Hinge Joint: cylindrical end of one bone into a trough-
shaped surface of another; uniaxial movement – around one axisEx: elbow
Pivot Joint: rounded end of one bone fits into a sleeve or ring of bone; uniaxial movement – rotate around the long axisEx: Proximal radioulnar joint
Condyloid (Ellipsoidal) Joint: egg shaped end of one bone fits into an oval concavity of another; biaxial – side to side movement and back and forth movementEx: Metacarpophalangeal joints
Saddle Joint: each articular surface has both a convex and concave area; biaxialEx: Thumb
Ball-and-Socket Joint: Spherical head of one bone fits into a round socket of another; multiaxial – movements in all axes, including rotationEx: Shoulder
Inflammatory Disorders of JointsBursitis: swollen bursa due to injurySprains: ligaments or tendons damaged by
excessive stretching, or torn away from the bone; heal slowly because of lack of blood supply
Arthritis: joint inflammation; encompasses over 100 different inflammatory or degenerative diseasesAcute forms of arthritis: usually due to an
infectionChronic forms of arthritis: Osteoarthritis (OA),
Rheumatoid (RA), and Gouty arthritis
Chronic ArthritisOsteoarthritis (OA)
Most common formSoftening, fraying, and breakdown of
articular cartilageExposed bone thickens and extra bone tissue
(bone spurs) formSpurs may protrude into the joint space
limiting movementCommonly affects: fingers, cervical and
lumbar joints, knees and hipsSlow and irreversible progressionTreatment: analgesics, capsaicin (hot pepper
extract) rubbed on the skin, or glucosamine-chondroitin sulfate (nutritional supplement)
Chronic ArthritisRheumatoid arthritis (RA)
Chronic inflammatory disorder; more common in women
Commonly affects: fingers, wrists, ankles, and feet (usually symmetrical)
Marked by remissions and flare-upsAn autoimmune diseaseBegins with inflammation of the synovial membranes,
membranes thicken and joints swellWhite blood cells enter the joint cavity and produce
pannus (abnormal tissue that clings to and erodes articular cartilage)
Scar tissue forms and connects the bone ends; tissue eventually ossifies and fuse the joint (ankylosis)
Tx: Methotrexate and cyclosporin – drugs to neutralize the inflammatory chemicals; exercise is recommended for joint mobility; cold packs to relieve swelling; heat to reduce morning stiffness
Chronic ArthritisGouty Arthritis (Gout)
Uric acid accumulates in the blood and may be deposited (as needle-shaped crystals) in the soft tissues of joints
Very painful – usually only affecting one joint (most often the big toe)
More common in malesUntreated gout can be very destructive
(fusing the bone ends together)Tx: Colchicine, Ibuprofen; weight loss if
obese; avoid liver, kidneys, sardines, and alcohol
Developmental ConsiderationsFetal skeleton – cartilage; bones ossify after
birthFontanels allow for continued brain growth
Spinal curvature: starts as a “C” at birth and progresses to an “S” shape
Osteoporosis: bone thinning diseaseLinked to inactivity, poor diet, estrogen
deficiency, & smokingMay lease to pathologic fractures
(spontaneous breaks without injury)