INTRODUCTION TO

ANATOMY

. الحبيطي. الجبار عبد د أ

Anatomy is the science of structure& function of the body that can be seen grossly(with out the aid of magnification) & microscopically(with aid of magnification).Typically when used by itself,the term tends to mean gross or Macroscopic Anatomy.

Clinical Anatomy is the study of macroscopic structure & function of the body as relates to the practice of medicine and other health sciences.

Basic Anatomy is the study of the minimal amount of Anatomy consistent with the understanding of the overall structure & function of the body.

Physiology: is the study of the function of the body's structural machinery .

Regional Anatomy to study all structures in one part of the body as head,neck& abdomen.

Systemic Anatomy is a gross Anatomy of the body studied by system

Surface Anatomy to study internal structures as they relate to the overlying skin.

Gross Anatomy

Cytology to study the structure of cells.

Histology to study the tissues ( Tissue is group of cells having same function ).

Cytochemistry to study the chemical activity in the cells.

Histochemistry to study the chemical activity in the tissues.

Microscopic Anatomy

Pathological Anatomy: study of structural chamges caused by diseases.

Radiographic Anatomy:Study of internal structure visualized by X—ray.

Molecular Biology: study of anatomical structures at a sub-cellular level.

Neuro-anatomy: Specialized type og Gross Anatomy deals with the Nervous system.

Embryology:Study developmental changes of the body before birth.

Developmental Anatomy: Tracing structural changes throughout life

Specialized Branches of Anatomy

The accurate use of anatomic terms by medical personnels enables them to communicate with their colleagues both nationally & internationally.

Without Anatomic terms ,one cannot accurately discuss or record the abnormal functions of joints,action of muscles,alteration of position of organs,or the exact location of swellings or tumors.

Descriptive Anatomic Terms

All description of the human body are based on the assumption that the person is standing erect,with the upper limbs by the sides and the face & palms of the hands are directed forward.This is the so called Anatomical position.The varous parts of the body are then described in relation to certain imaginary planes.

In Anatomical position the body is erect with the feet slightly a parts,palm facing forward& thumbs pointed a way from body.

Terms related to position

This is a vertical plane passing through the centre of the body dividing it into right & left halves which are mirror to each other.Any term situated to one or the other side of the median plane and parallel to it are termed paramidiam or sagittal plane.

Any structure situated nearer to the median plane of the body than another is said to be related to the other.Similarly a structure that lies farther away from the median plane than another is said to be lateral to the other.

The Coronal planes: these are planes which are imaginary vertical planes at right angles to the median plane.

Horizontal or Transverse planes: are planes at right angles to both the median & coronal plane.

The terms Anterior & posterior indicate the front & back of the body respectively.

Median Sagittal plane

To describe the relationship of two structures,one is said to be anterior or posterior to the other in so far as it is closer to the anterior or posterior body surface,but in describing the hand ,the terms palmar& dorsal surfaces are used in stead of anterior & posterior.In describing the foot ,the terms planter & dorsal are used instead of lower & upper surfaces

The terms proximal & distal describe the relative distances from the roots of the limbs,for example ,the arm is proximal to the forearm & the hands distal to forearm.

The terms superficial & deep denote the relative distances from the surface of the body.

The terms superior & inferior denote levels relatively high or low with reference to the upper & lower ends of the body.

The terms internal & external are used to describe the relative distance of structure from the center of an organ or body cavity,for example,the internal carotid artery is found inside the cranial cavity & the external carotid artery is found outside cranial cavity.

Superior ( Cranial) : it means toward the head or upper part of the body e.g the head is superior to the neck region,thorax & abdomen.

Inferior ( caudal): it means away from head or toward the lower part of the body e.g abdomen is inferior to the thorax, neck is inferior to the neck.

Lateral: away from the mid line of the body e.g arms are lateral to the chest.

Intermediate: between amore medial & a more lateral structures.

Ipsilateral: refers to the same side of the body(left hand & left foot are ipsilateral).

Contralateral: refers to opposite side of the body (left lobe of brain controls contralateral half of the body).

Supine position of the body is lying on the back,while prone position is lying face downward.

A joint is a site where 2 or more bones come together and movement take place here.

Some joints have no movement at all e.g sutures between the skull bones.

Some joints have slight movement e.g superior Tibio—fibular joint.

Some joints are freely movable e.g shoulder joint.

Flexion is a movement that takes place in sagittal plane e.g flexion of Elbow joint( approximates anterior surface of the forearm to anterior surface of the arm

Extension means straightening the joint & usually takes place in a posterior direction.

Abduction is a movement of a limb away from the midline of the body in the coronal plane.

Adduction is a movement of a limb toward the body in in the coronal plane.

In the fingers & toes abduction means spreading of fingers or toes,while Adduction means drawing together the fingers or toes.

The movements of the Thumb are a little more complicated e.g Circumbduction of thumb.

Circumduction is combination in sequence of the movements of flexion,extension ,abduction & adduction as of the thumb & the limb( at shoulder joint).

Rotation is movement of a part of the body around a long axis.

Medial rotation is movement results in the anterior surface of the part facing medially.

Lateral rotation movement result in the anterior surface of the part facing laterally.

Lateral flexion is a movement of the trunk in coronal plane .

Pronation of the forearm is a medial rotation of F.A in such amanner that the palm of the hand faces posteriorly.

Supination of the F.A is a lateral rotation of the F.A from the pronated position so that the palm of the hand comes to face anteriorly.

Inversion is movement of the foot so that the sole faces in a medial direction.

Eversion is the opposite movement of the foot so that the sole faces in a lateral direction.

Axial means the head,neck & trunk regions .

Appendicular means appendages or limbs .

Dorsal cavity protect the Nervous system & is divided into Cranial cavity ( the skull which houses the brain) and the Vertebral cavity( within the vertebral column & houses the spinal cord).

Ventral cavity houses the internal organs ( viscera) .Is divided into 2 subdivisions: Thoracic ( contains pleural cavities,lungs & heart) & Abdominal cavity ( contains the peritoneal cavity and its viscera).

Cavities of the body

Bone is a living tissue capable of changing its structure as the result of stresses to which it is subjected.Like other tissue bone consists of cells,fibers & intercellular matrix.It is hard because of the calcification of its extracellular matrix& possesses a degree of elasticity because of the presence of organic fibers..The main functions of bones are the followings:

1-Protective function e.g skull( for brain ),vertebral column ( spinal cord),the sternum & ribs protect the thoracic & upper abdominal viscera.

2- It serves as a lever as seen in the long bones of the limbs.

3-Main storage area for calcium salts.

4-It houses & protects within its cavities the delicate blood—forming bone marrow.

The Bones

The bone exists in two forms: a compact & cancellous

The compact bone appears as a solid mass.

The cancellous bone consists of a branching network of trabeculae.The trabeculae are arranged in such a manner as to resists the stress & strains to which the bone is exposed.

The bones can be classified as follows based on their general shape: Long bones,short bones,Flat bones,irregular bones & sesamoid bones

The long bones are found in the limbs e.g the humerus& femur.Their length are greater than their breadth.The ends of long bones are composed of cancellous bone surrounded by a thin layer of compact bone& the articular surfaces of the ends of the bones are covered by hyaline cartilage.

The short bones are found in the hand & foot as carpal & tarsal bones. They are roughly cuboidal in shape& composed of cancellous bone surrounded by a thin layer of compact bone.The short bones are covered by periosteum & the articular surfaces are covered by hyaline cartilage.

The flat bonesare seen in the vault of the skull ( the frontal & parietal bones).The sternum & scapula although irregular are included in this group..

The irregular bones are composed of a thin shell of compact bone with an interior made up of cancellous bone,they include those bones not assigned to the previous groups(e.g some skull bones,vertebrae& the pelvic bones).

The sesamoid bones are small nodules of bone that are seen in certain tendons.The largest sesamoid bone is the patella,which is found in the tendon of Quadriceps femoris muscle.The function of sesamoid bone is to reduce friction on the tendon.

The regional classification of bones are Axial & Appendicular skeleton

The Axial Skeleton include Skull bones ( 22) cranium of 8 & face bones 14 in number.

The auditory ossicles (6 in number )

Hyoid bone ( 1 ).

Vertebrae including sacrum & coccyx ( 26 in number).

Sternum ( 1)

Ribs ( 24 in number)

Shoulder girdile ( 2 clavicles & 2 scapulae)

Upper extrimities

Humerus ( 2 ), Radius ( 2 ),Ulna ( 2) ,carpal ( 16) ,metacarpal ( 10),phalanges(28).

Pelvic girdle( 2 hip bones)

Lower extrimities includes:

Femur (2),patella (2),fibula (2),tibia (2),tarsals (14),metatarsals (10),phalanges (28)

Total 206 bones .

There are three types of muscles: skeletal ( attached to bones & having somatic nerve supply),Smooth muscles( related to wall of viscera & other involuntary structures ,being innervated by autonomic nervous system) & Cardiac muscles related to the heart also are innervated by autonomic nervous system..

The Skelatal muscles are attached to bones ( origin & insertion) and produce movement of the skeleton.They are known as voluntary muscles & are made up of striped muscle fibers.

THE MUSCLES

A skeletal muscle has 2 or more attachments.The fixed attachment is the ORIGIN & the movable attachment is the INSERTION of the muscle,while the fleshy part is its belly.The ends of the muscles are attached to bones, cartilage & ligaments.Occasionally flattened muscles are attached by a thin sheet( strong fibrous)known as Aponeurosis(Abdominal Ms)

A raphe is an interdigitation of the tendinous ends of fibers of flat M.Each single M.F is surrounded by Endomysium,group of fibers ( bundle) are surrounded by Perimysium,while all the bundles are surrounded by Epimysium.M.Fs may be arranges as Pennate along the line of pull for e.g Unippenate ( Palmar interosei),Bippenate ( Dorsal interossei) & multipennate ( Deltoid M).

1-Excitability( irritability) i.e its stimulation leads to impulses that generates action potential

2-Conductibility i.e the action potential is conducted along the plasma membrane.

3-Contractility i.e the ability to contract & becomes shorter.

4-Extensibility i.e extended or stretched e.g Biceps & Triceps.

5-Elasticity i.e tends to return to its original position after contraction.

The characteristics of muscle tissue

The skeletal M work in the following 4 ways:

A-Prim mover e.g Quadriceps Femoris in the movement of extending the knee joint.

B-Antagonist: any M opposes the action of the prim move is considered as Antagonist e.g Biceps femoris opposes the action of Quadriceps femoris when knee joint is extended.

C- Fixator: A fixator M contracts isometrically to stabilizes the origin of the prim mover so that it can acts efficiency for e.g the Ms attaching the shoulder girdle to the trunk contract as fixator to allow the Deltoid M to act on the shoulder joint.

D-Synergist: in many locations in the body the prim mover M crosses several joints before it reaches the joint at which its main action takes place.In order to prevent movements of these intermediate joints a group of Ms ( Synergistics)contract & stabilizes the intermediate joints. E.g flexors & extensors of fingers.

Naming of the muscles are according to the following points:

1-Shape of the Muscle e.g Teres ( round) major & minor.

2-Size of the Muscle e.g Gluteus Maximus.

3-Number of heads the muscle have e.g Biceps & Triceps.

4-Position of the Muscle e.g Supraspinatous,Infraspinatous & Subscapularis.

5-Depth e.g Obturator internus & Externous.

6-Attachment e.g Sternocleidomastoid muscle.

7-Actions of the muscle or group of muscles as e.g Flexors & Extensors.

The nervous system can be divided in to Central & Peripheral nervous system.

The Central nervous system ( C.N.S) includes the brain + the spinal cord & Peripheral nervous system ( P.N.S) includes 12 pairs of cranial nerves + 31 pairs of spinal nerves.

Functionally the nervous system can be subdivided into Somatic( controle voluntary structures) & Autonomic N.S ( Sympathetic & parasympathetic) which controls involuntary activities as Respiratory,cardiovascular systems ..

The Nervous System

On dissection ,the cranial & spinal nerves are seen as grayish white cords.They are made up of bundles of N.Fs( axons)supported by delicate areolar tissue.

Total of 31 pairs of spinal nerves leave the spinal cord & pass through the intervertebral foramina in the vertebral column.They includes 8 pairs of cervical nerves, 12 pairs of thoracic , 5 lumbars , 5 sacral & 1 coccygeal.Each spinal nerve is connected to the S.C by 2 roots ,anterior ( ventral) & posterior ( dorsal ) roots.The anterior root contains motor fibers ( Efferent) ,while posterior root contains sensory ( Afferent ) fibers.The motor fibers goes to skeletal muscle fibers & cause them to contract& their cells of origin are located in anterior horn of the S.C ( lower motor neurons) .

The posterior root contains bundles of sensory fiberscarrying impulses ( sensations to the C.N.S) and are called Afferent & the cell bodies of these N.Fs are situated in a swelling on the posterior root ganglion.At the intervertebral foramen both roots unite together forming the spinal nerve proper( mixture of N.Fs),after emerging from the intervertebral foramen ,the spinal nerve divides in to 2 rami ( contains sensory & motor fibers) a ventral & dorsal rami to supply skin & muscles.

At the root of the limbs ,the ventral rami join together forming Plexuses as Cervica & Brachial Plexuses at the root of the neck,and Lumbar & Sacral Plexuses at the root of the lower limbs..

A-Superficial fascia,is a general coating of the body beneath the skin made up of loose areolar tissue with varying amount of fat,.It function to conserve body temperature & it fasciltate movement of the skin.

B-Deep fascia which is a fibrous sheet investing the body beneath the superficial fascia & is devoid of fat.It function in keeping the underlying structures in position & in providing extra surface for attachment of some muscles.It has the following modifications :

The Fasciae in the body

1-aponeurosis as for e.g Bicepital aponeurosis& aponeurosis of anterior abdominal wall.

2-Retinaculum as for e.g Flexor & extensor retinaculae at junction of F.A & hand.

3-Bursa as between the sking & underlying bones or related to some Ms tendons.

4-Sheeth around some arteries as Carotid sheeth.

5-Capsules of joints.

The Bursa is a closed sac of synovial membrane containing little amount of synovial fluid,it reduces friction & permits complete freedom of movement within limited range e.g subacromial & subdeltoid bursa.

A-Fibrous joints which are immovable joints ( no movement) as for e.g Sutures of the skull.

B-Cartilagenous joints,which could be primary one where the bones are connected by hyaline cartilage & the joint is temporary as for e .g Spheno-occipital joint ,or could be secondary cartilaginous joint united by a disc of fibrocartilage e.g Symphysis pubis.

C-Synovial joint where there are articular cartilages covering the opposed ends of 2 bones,capsule to cross the gap of the joint & connecting the 2 bones in addition there is synovial membrane & cavity in side the joint to reduces friction completely & allow freedom of movements at the joint>The synovial joint are classified as follows:

1-Uniaxial synovial joint as for e.g Hing (elbow joint) & Pivot (upper radioulnar joint).

2-Biaxial as for e.g Condylar(temporomandibular) & Ellipsoid (Wrist joint).

3-Multiaxial e.g Saddle (Carpometacarpal joint) & Ball and socket ( Shoulder joint ).

Types of joints

The characteristics of synovial joints are :

1-Articular ends covered by hyaline cartilage.

2-the presence of synovial membrane.

3- The joint contains synovial fluids.

4- The joint is strengthened by some ligaments .

5-Some degree of movent always present till complete freedom of movement.

The smooth muscles : each single muscle is spindle –shaped with centrally placed nuceus,smooth muscles are arranged in bundles or sheets.They lack striations & are under the controle of Autonomic nervous system & they are present in the followings:

1-In the iris.

2- In the wall of all blood vessels.

3-In the walls of the Gastro-intestinal tract.

4-In the walls of the respiratory passages ( Trachea & bronchii).

5-In the waals & tubes of the Genitourinary system.

6-In the erector pilli muscles.

The Cardiac muscles: are striated muscles that branched & unite together & found within the wall of the heart namely in the nyocardium.They show an intercalated discs& have the ability for spontaneous &rhythmical contraction .The specialized cardiac muscle fibers form the conducting system of the heart.The cardiac Ms resemble the striated as having striations & also resemble smooth muscles as under the controle of autonomic N.S.

Are tubes concerened with the conduction & storage of the blood.They includes arteries which conduct the oxygenated blood from the heart to all tissues and organs in the body(except the pulmonary arteries) & veins which store non –oxygenated blood & return it to the heart( except the pulmonary veins contains oxygenated blood).The vessels are classified as follows:

1-Conducting (Elastic) or big arteries as the Aorta.

THE BLOOD VESSELS

2-Distributing ( muscular or medium sized) as the Brachial artery.

3-Resistance vessels as the arterioles.

4-Exchange vessels as Capillaries.

5-Capacitance vessels (storage) as veins.

It covers the body surface & consists of 2 layes outer Epidermis ( stratified squamous epithelium which is keratinized at some places) & inner layer known as Dermis>Under the skin we can see superficial fascia & subcutaneous tissue .The skin is rich in sensory nerve endings>The skin has the following Appendages :

a-The nails. B-Sweat glands c-Sebacous glands d-Hair follicles.

 

THE SKIN

Consists of Lymphatic tissues ( thymus,spleen,lymphatic nodules & lymph nodes) & lymphatic vessels.They collect the lymph & bring it back to the circulatory system.

The lymphatic System

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