Anatomy Introduction Anatomy is the scientific discipline that investigates the body’s

structure. For example, the shape and size of the bones can be described.

In addition, anatomy examines the relationship between the structure of

a body part and its function. the structure of a specific body part allows

it to perform a particular function effectively. For example, bones can

provide strength and support because bone cells surround themselves

with a hard, mineralized substance.

Anatomy can be considered at many different levels. Some structures are

so small that they are best studied using a microscope. Cytology

examines the structural features of cells, and Histology is the study of

tissues, which are cells and the materials surrounding them. Gross

anatomy, the study of structures that can be examined without the aid of

a microscope, can be approached from either a systemic of regional

perspective. In Systemic anatomy the body is studied by systems, a

system is a group of structures that have one or more common functions.

Examples are the circulatory, nervous, respiratory, skeletal, and

muscular systems. In Regional anatomy the body is studied by areas,

within each region such as the head, abdomen, or arm, all systems are

studied simultaneously. Surface anatomy is the study of the external

form of the body and its relation to deeper structures. For example, the

sternum (breastbone) and parts of the ribs can be seen and felt on the

front of the chest. These structures can be used as landmarks to identify

regions of the heart and points on the chest at which certain heart sounds

can best be heard. Anatomic imaging involves the use of radiographs

(x-rays), ultrasound, magnetic resonance imaging (MRI), and other

technologies to create pictures of internal structures. Both surface

anatomy and anatomic imaging provide important information in

diagnosing disease.

Anatomical Terms:

The terms used to describe locations and positions reference a person in

the standard anatomical position.

Superior and Inferior: Superior means above, inferior means

below. The elbow is superior (above) to the hand. The foot is

inferior (below) to the knee.

Anterior and Posterior: Anterior means toward the front (chest

side) of the body, posterior means toward the back.

Medial and Lateral: Medial means toward the midline of the body,

lateral means away from the midline. Ipsilateral means on the

same side—the left arm is ipsilateral (on the same side) to the left

leg.

Proximal and Distal: Proximal means closest to the point of origin

or trunk of the body, distal means farthest away. Proximal and

distal are often used when describing arms and legs. If you were

describing the shin bone, the proximal end would be the end close

to the knee and the distal end would be the end close to the foot. In

the fingers of the hand, a proximal joint is closest to the wrist and a

distal joint is farthest from the wrist.

Superficial and Deep. Superficial means toward the body surface,

deep means farthest from the body surface.

Ventral and dorsal, may be used instead of anterior and posterior

in the trunk.

In the hand, dorsal commonly replaces posterior, and palmar

replaces anterior. In the foot, the corresponding surfaces are

superior and inferior in the anatomical position, but these terms are

usually replaced by dorsal (dorsum of the foot) and plantar (the

planta = the sole)

Middle or its Latin equivalent medius, is the usual adjective

indicating a position between superior and inferior or between

anterior and posterior

Intermediate, commonly used for a position between lateral and

medial

Anatomical Reference Planes

A plane is a two-dimensional surface — its dimensions are length and width. The

body reference planes are used to locate or describe the location of structures in the

body.

Main Reference Planes

Sagittal plane (median) — this vertical (top to bottom) plane divides the body

into equel left and right sides.

Coronal (vertical, frontal) plane — a vertical plane that divides the body into

front (anterior or ventral) and back (posterior or dorsal)

Transverse (horizontal, table) plane — this horizontal plane is parallel to the

ground and divides the body into up (toward the head) and down (toward the

feet)

Anatomical movements of body

Flexion: refers to a movement that decreases the angle between two

body parts. Flexion at the elbow is decreasing the angle between the ulna

and the humerus. When the knee flexes, the ankle moves closer to the

buttock, and the angle between the femur and tibia gets smaller.

Extension: refers to a movement that increases the angle between two

body parts. Extension at the elbow is increasing the angle between the

ulna and the humerus. Extension of the knee straightens the lower limb.

Abduction: is a movement away from the midline – just as abducting

someone is to take them away. For example, abduction of the shoulder

raises the arms out to the sides of the body.

Adduction: is a movement towards the midline. Adduction of the hip

squeezes the legs together.

In fingers and toes, the midline used is not the midline of the body, but

of the hand and foot respectively. Therefore, abducting the fingers

spreads them out.

Medial rotation: is a rotational movement towards the midline. It is

sometimes referred to as internal rotation. To understand this, we have

two scenarios to imagine. Firstly, with a straight leg, rotate it to point the

toes inward. This is medial rotation of the hip. Secondly, imagine you

are carrying a tea tray in front of you, with elbow at 90 degrees. Now

rotate the arm, bringing your hand towards your opposite hip (elbow still

at 90 degrees). This is internal rotation of the shoulder.

Lateral rotation: is a rotating movement away from the midline. This is

in the opposite direction to the movements described above.

Elevation refers to movement in a superior direction (e.g. shoulder

shrug),

depression refers to movement in an inferior direction.

Pronation and Supination

This is easily confused with medial and lateral rotation, but the

difference is subtle. With your hand resting on a table in front of you,

and keeping your shoulder and elbow still, turn your hand into its back,

palm up. This is the supine position, and so this movement

is supination.

Again, keeping the elbow and shoulder still, flip your hand into its front,

palm down. This is the prone position, and so this movement is

named pronation.

These terms also apply to the whole body – when lying flat on the back,

the body is supine. When lying flat on the front, the body is prone.

Dorsiflexion: refers to flexion at the ankle, so that the foot points more

superiorly. Dorsiflexion of the hand is a confusing term, and so is rarely

used. The dorsum of the hand is the posterior surface, and so movement

in that direction is extension. Therefore we can say that dorsiflexion of

the wrist is the same as extension.

Plantarflexion: refers extension at the ankle, so that the foot points

inferiorly. Similarly there is a term for the hand, which is palmarflexion.

Inversion: involves the movement of the sole towards the median plane

so that the sole faces in a medial direction.

Eversion: involves the movement of the sole away from the median

plane – so that the sole faces in a lateral direction.

Opposition: brings the thumb and little finger together.

Reposition: is a movement that moves the thumb and the little finger

away from each other, effectively reversing opposition.

Circumduction: can be defined as a conical movement of a limb

extending from the joint at which the movement is controlled.

It is sometimes talked about as a circular motion, but is more accurately

conical due to the ‘cone’ formed by the moving limb.

Protraction: describes the anterolateral movement of the scapula on the

thoracic wall that allows the shoulder to move anteriorly. In practice,

this is the movement of ‘reaching out’ to something.

Retraction: refers to the posteromedial movement of the scapula on the

thoracic wall, which causes the shoulder region to move posteriorly i.e.

picking something up.

Descriptive Anatomy

The Skin The skin is the outer covering of living tissue of an animal. It is the

largest organ of the integumentary system made up of multiple layers of

epithelial tissues, and guards the underlying muscles, bones, ligaments,

internal organs. Because it interfaces with the environment, skin plays a

very important role in protecting (the body) against pathogens.

skin is composed of two primary layers:

the epidermis, which provides waterproofing and serves as a barrier

to infection.

the dermis, which serves as a location for the appendages of skin;

1.Epidermis

The epidermis is composed of the outermost layers of the skin. It forms

a protective barrier over the body's surface, responsible for keeping

water in the body and preventing pathogens from entering, and is a

stratified squamous epithelium, composed of proliferating basal

and differentiated suprabasal keratinocytes.

Keratinocytes are the major cells, constituting 95% of

the epidermis, while Merkel cells, melanocytes and Langerhans cells are

also present.

The epidermis contains no blood vessels, and cells in the deepest layers

are nourished by diffusion from blood capillaries extending to the upper

layers of the dermis.

2. Dermis

The dermis is the layer of skin beneath the epidermis that consists

of connective tissue and cushions the body from stress and strain.

The dermis provides tensile strength and elasticity to the skin through

an extracellular matrix composed of collagen fibrils, microfibrils,

and elastic fibers, embedded in hyaluronan and proteoglycans. Dermis

have many mechanoreceptors (nerve endings) that provide the sense

of touch and heat through nociceptors and thermoreceptors. It also

contains the hair follicles, sweat glands, sebaceous glands, apocrine

glands, lymphatic vessels and blood vessels. The blood vessels in

the dermis provide nourishment and waste removal from its own cells as

well as for the epidermis.

The dermis is tightly connected to the epidermis through a basement

membrane

Bursae (from L. bursa, a purse), like synovial tendon sheaths, are connective

tissue sacs with a slippery inner surface and are filled with synovial

fluid. Bursae are present where tendons rub against bone, ligaments, or

other tendons, or where skin moves over a bony prominence. They may

develop in response to friction. Bursae facilitate movement by

minimizing friction.

Tendons and aponeuroses The attachment of muscle to bone (or other tissue) is usually by a long,

cord-like tendon or sinew or by a broad, relatively thin aponeurosis.

Tendons and aponeuroses are both composed of more or less parallel

bundles of collagenous fibers. Tendons and aponeuroses are surrounded

by a thin sheath of looser connective tissue. Where tendons are attached

to bone, the bundles of collagenous fibers fan out in the periosteum.

Tendons are supplied by sensory fibers that reach them from nerves to

muscles. They also receive sensory fibers from nearby superficial or

deep nerves.

Bone is a type of C.T. in which the intercellular matrix is highly specialized

for rigidity and strength. It is a highly dynamic tissue. Bony tissue is

classified as either spongy (trabecular, cancellous) or compact bone,

depending on the relative proportions of mineralized and soft tissue;

most bones contain both spongy and compact regions. Compact bone

and the larger trabeculae of spongy bone contain lamellae. In compact

bone, however, the predominant structural unit is the osteon, or

Haversian system. In the osteon, lamellae are arranged as concentric

cylinders surrounding a central Haversian canal. This canal contains

nerves, connective tissue and blood vessels. The long axis of an osteon

is approximately parallel to the major axis of stress, usually the long axis

of the bone.

Types of bone: 1. Compact bone

2. Spongy bone

3. Pnomatic bone ( the bone that contain cavity inside it like nasal bone)

Bone Function: Support (eg) pelvic bowl, legs

Protect (eg) skull, vertebrae

Mineral storage (eg) calcium, phosphate, inorganic component

Movement (eg) walk, grasp objects

Blood-cell formation (eg) red bone marrow

Bone shape Individual bones can be classified according to their shape as long,

short, flat, or irregular. Long bones are longer than they are wide; most

of the bones of the upper and lower limbs are long bones. Short bones

are about as broad as they are long; they are nearly cube- shape or round

and are exemplified by the bones of the wrist (carpals) and ankle

(tarsals). Flat bones have a relatively thin, flattened shape and are

usually curved, for example certain skull bones, the ribs, the breastbone

(sternum), and the shoulder blades (scapula). Irregular bones are those

such as the vertebrae and facial bones, with shapes that do not fit readily

into the other three categories.

Muscles Muscle (from Latin musculus, diminutive of mus "mouse"[1]) is

contractile tissue of the body, muscle cells contain contractile filaments

that move past each other and change the size of the cell. Most skeletal

muscles extend from one bone to another and cross at least one joint.

Muscular System Functions • Body movement

• Maintenance of posture

• Respiration

• Production of body heat

• Communication

• Constriction of organs and vessels

• Heart beat

Muscle Tissue Types • Skeletal

– Attached to bones

– Nuclei multiple and peripherally located

– Striated, Voluntary and involuntary (reflexes)

• Smooth

– Walls of hollow organs, blood vessels, eye, glands, skin

– Single nucleus centrally located

– Not striated, involuntary, gap junctions in visceral smooth

• Cardiac

– Heart

– Single nucleus centrally located

– Striations, involuntary, intercalated disks

General Principles • Tendons: Attach muscles to bones

– Aponeurosis: A very broad tendon

• Muscles

– Origin or head: Muscle end attached to more stationary of two bones

– Insertion: Muscle end attached to bone with greatest movement

– Belly: Largest portion of the muscle between origin and insertion

– Synergists: Muscles that work together to cause a movement

ROLE OF MUSCLES Agonist: prime mover

Antagonist: action opposite to the agonist

Stabilizers: fixate or stabilize the joint

Synergists: assist or guiding

Joints A joint (articulation) is a union or junction between two or more bones

or rigid parts of the skeleton. Joints exhibit a variety of forms and

functions. Some joints have no movement; others allow only slight

movement, and some are freely movable, such as the glenohumeral

(shoulder) joint.

Function:

Synarthroses = no/little movement

Amphiarthroses = slight movement

Diarthroses = great movement

Joints by Functional Classification

Joint Classification

Structure

1. Cartilagenous a. Synchondrosis: connected by hyaline cartilage (synarthroses)

b. Symphysis: connected by fibrocartilage (amphiarthroses)

2. Fibrous a. Sutures: connected by short strands of dense CT (synarthroses)

b. Syndesmoses: connected by ligaments (varies)

c. Gomphosis: peg in socket w/short ligament (synarthroses)

3. Synovial (diarthroses)

Joint Shapes Hinge: cylindrical end of 1 bone fits into trough shape of other

- angular movement-1 plane (eg) elbow, ankle,

interphalangal

Plane: articular surface in flat plane

- Short gliding movement

- (eg) intertarsal, articular processes of vertebrae

Condyloid: egg-shape articular surface + oval concavity

- side-to-side, back+forth movement

- (eg) metacarpophalangeal (knuckle)

Pivot: round end fits into ring of bone + ligament

- rotation on long axis

- (eg) prox. radius/ulna, atlas/dens

Saddle: articular surface both concave + convex

- side-to-side, back-forth movement

- (eg) carpometacarpal joint of thumb

Ball + Socket: spherical head + round socket

- multiaxial movement

- (eg) shoulder, femur

Arteries Which carry the blood from the heart to the body, the arteries have

special names like axillary artery and brachial artery. And the arteries

have fixed patterns in all persons.

Veins Are carry the blood from the body to the heart, it have variable pattern

and its small tributaries are different from one person to another.

Arteries Veins

Lymphatics Lymph vessels collect the lymph from the body and it consists of lymph

vessels and lymph nodes. (The lymphatic vessels are very important

medically, because they are road for infection and cancer).

The lymphatic system has multiple interrelated functions:[23]

It is responsible for the removal of interstitial fluid from tissues

It absorbs and transports fatty acids and fats as chyle from the

digestive system

It transports white blood cells to and from the lymph nodes into the

bones

The lymph transports antigen-presenting cells, such as dendritic cells,

to the lymph nodes where an immune response is stimulated.

Nervous system 1. Central nervous system CNS a. Brain

b. Spinal cord

2. Peripheral nervous system PNS

Consists of all nervous tissue outside the CNS

(Nerves): - 12 pairs of cranial nerves from brain.

- 31 pairs of spinal nerves from spinal cord (8 cervical S.N., 12 thoracic

S. N., 5 lumbar S. N., 5 sacral S.N., 1 coccygeal S.N.)

3. Autonomic nervous system ANS a. sympathetic .

b. parasympathetic.

Radiological & Cross sectional Anatomy

Medical imaging refers to techniques and procedures used to create

images of the human body. Various types of medical imaging allow

visualization of structures inside our bodies and are increasingly helpful

for precise diagnosis of a wide range of anatomical and physiological

disorders. The grandparent of all medical imaging techniques is

conventional radiography (x-rays), in medical use since the late 1940s.

The newer imaging technologies not only contribute to diagnosis of

disease, but they also are advancing our understanding of normal

physiology.

RADIOGRAPHY Procedure: a single barrage of x-ray passes through the body, producing

an image of interior structures on x-ray-sensitive film. The resulting

two-dimensional image is a radiograph, commonly called an x-ray.

Comments: radiographs are relatively inexpensive, quick, and simple to

perform, and usually provide sufficient information for diagnosis. X-

rays do not easily pass through dense structures so bones appear white.

Hollow structures, such as the lungs, appear black. Structures of

intermediate density, such as skin, fat, and muscle, appear as varying

shades of gray. At low doses, x-rays are useful for examining soft tissues

such as the breast (mammography) and bone density (bone

densitometry). It is necessary to use a substance called a contrast

medium to make hollow or fluid-filled structures visible in radiographs.

X-rays make structures that contain contrast media appear white. The

medium may be introduced by injection, orally, or rectally depending on

the structure to be imaged. Contrast x-rays are used to image blood

vessels (angiography), the urinary system (intravenous urography), and

the gastrointestinal tract (barium contrast x-ray).

X-Ray gives picture have two dimensional, and the quality not very

good.

MAGNETIC RESONANCE IMAGING (MRI)

Procedure: the body is exposed to a high energy magnetic field, which

causes protons (small positive particles within atoms, such as hydrogen)

in body fluids and tissues to arrange themselves in relation to the field.

Then a pulse of radiowaves “reads” these ion patterns, and a color-coded

image is assembled on a video monitor. The result is a two- or- three-

dimensional blueprint of cellular chemistry.

Comments, relatively safe, but can’t be used on patients with metal in

their bodies. Shows fine details for soft tissues but not for bones. Most

useful for differentiating between normal and abnormal tissues. Used to

detect tumors and artery-clogging fatty plaques, reveal brain

abnormalities, measure blood flow, and detect a variety of

musculoskeletal, liver, and kidney disorders.

COMPUTED TOMOGRAPHY (CT)

[Formerly called computerized axial tomography (CAT) scanning]

Procedure: Computer-assisted radiography in which an x-ray beam

traces an arc at multiple angles around a section of the body. The

resulting transverse section of the body, called a CT scan, is shown on a

video monitor.

Comments: Visualizes soft tissues and organs with much more detail

than conventional radiographs. Differing tissue densities show up as

various shades of gray. Multiple scans can be assembled to build three-

dimensional views of structures. In recent years, whole-body CT

scanning has emerged. Typically, such scans actually target the torso.

Whole-body CT scanning appears to provide the most benefit in

screening for lung cancers, coronary artery disease, and kidney cancers.

ULTRASOUND SCANNING

Procedure: High-frequency sound waves produced by a handheld wand

reflect off body tissues and are detected by the same instrument. The

image, which may be still or moving, is called a sonogram (SON-o¯-

gram) and is shown on a video monitor.

Comments: Safe, noninvasive, painless, and uses no dyes. Most

commonly used to visualize the fetus during pregnancy. Also used to

observe the size, location, and actions of organs and blood flow through

blood vessels (doppler ultrasound).

ENDOSCOPY Procedure: The visual examination of the inside of body organs or

cavities using a lighted instrument with lenses called an endoscope. The

image is viewed through an eyepiece on the endoscope or projected onto

a monitor.

Comments: Examples of endoscopy include colonoscopy, laparoscopy,

and arthroscopy.

Colonoscopy is used to examine the interior of the colon, which is part

of the large intestine.

Laparoscopy is used to examine the organs within the abdominopelvic

cavity. Arthroscopy is used to examine the interior of a joint, usually the

knee.