Introduction to Anatomy

• Introduction to Anatomy presented by Dr. Sayed Mostafa, Modified by Dr. Eid Nassar Ali

Human Anatomy

• Anatomy is to cut (Greek)
• Anatomy is to Dissect (Latin)
• There are three levels of studying anatomy: macroscopic, microscopic and radiological.
• Macroscopic or gross anatomy relates to Anatomy
• Microscopic anatomy relates to Histology
• Radiological anatomy is the use of radiology in the study of anatomy

Anatomical Planes and Terms

• Standard reference position is used for accurate description of different parts and regions of the body
• Other body positions include: supine, prone, right lateral and left lateral positions.
• Directional terms indicates where body parts are located with reference to the body in anatomical position.

Anatomical terms of position

• Anterior (ventral) is the front
• Posterior (dorsal) is the back
• Superior refers to above
• Inferior refers to below
• Medial means towards the midline
• Lateral is to the side
• Proximal means closer
• Distal means further away
• Superficial refers to near the surface
• Deep means away from the surface

Anatomical Planes

• The median plane divides body into right and left halves.
• The paramedian plane is parallel to median
• A midsagittal plane is the body midline
• A frontal (coronal) plane divides the body into anterior and posterior parts
• A transverse plane divides the body into upper and lower parts.

Common Anatomical Terms of Movements

• Flexion is to bend
• Extension is to straighten
• Abduction is to move away from the midline
• Adduction is to move towards the midline
• Pronation is to turn palms down
• Supination is to turn palms up
• Elevation is to raise
• Depression is to lower
• Protraction is to move forward
• Retraction is to move backward
• Hyperextension is excessive straightening
• Rotation is to turn

Body Coverings

• Coverings of the body are: skin and the fascia.

The Skin

• The functions of the skin include: protecting the underlying tissues, defending the body against microorganisms, regulating the body temperature and forming vitamin D.
• The skin can absorb certain substances
• The skin can also gives an idea about the external environment (heat, cold, pain and pressure)
• The structure of the skin is separated into the superficial layer (epidermis) and deep connective layer (dermis).
• Deep to the dermis lies the superficial fascia or the hypodermis.
• The epidermis is the most superficial layer that is formed of 4 to 5 layers (strata) of cell
• The epidermis superficial layer is formed of flat cells filled with keratin (Keratinized stratified squamous epithelium)
• Keratin is a water-insoluble protein
• Epidermis has no blood vessels
• Epidermis deep layer has the capacity for regeneration (by mitotic division)
• The epidermis is generally thin except in the palms of the hand and the soles of the feet.
• This protects these parts and withstand friction, tear and rubbing that occurs in these regions
• The dermis lies deep to the epidermis
• It is formed of connective tissue of blood vessels, lymph vessels, sensory nerve endings, smooth muscles ,hair follicles, sweat & sebaceous glands.

Appendages of the skin:

• Hairs cover most of the body surfaces except some areas as palms,soles and the red margin of the lip
• Hairs can be moved by a band of smooth muscle called arector pili
• These muscles are supplied by sympathetic nerve fibers
• Sebaceous glands lie within the dermis with ducts open into the side of a hair
• Sebaceous glands secrete sebum to lubricate hair and skin
• There are no sebaceous glands on the palms or soles.
• Sweat glands are long tubular glands that extend through the full thickness of the dermis.
• Sweat glands present all over the body except: the red margins of the lips, the nail beds ,the glans penis and clitoris.
• A nail is a flat horny plate on the dorsal surface of the distal phalanx of the fingers and toes with a root, body, nail fold and a bed.

Clinical Applications

• Pathogenic organisms (usually staphylococci) can enter to the tissue through: Nail Folds, Hair Follicles and Sebaceous Glands
• Infections of skin that happen between the nail and the nail fold is called paronychia.

The Fascia

• Connective tissue between the skin and the underlying muscles and bones.
• It is divided into superficial & deep layers.
• Superficial fascia: is found immediately under the skin, uniting the skin to the underlying tissues.
• It consists of a layer of loose connective tissue containing a variable amount of fat, blood vessels and nerves of the skin.
• Superficial fascia is extremely thin in the eyelids, external ear, penis and scrotum.
• The function of superficial fascia: keeps the body temperature, gives the body a rounded contour especially in females, stores fat, contains blood vessels, lymphatics and nerves of the skin.
• Superficial Fascia allows free mobility of the skin on the underlying structures.
• The muscles found in the superficial fascia include: muscles of facial expressions (in the face) and platysma (in the neck).
• Deep fascia is a dense, inelastic fibrous membrane that divides the superficial fascia from the deeper structures.
• Deep fascia covers most of the body, however, it is absent in certain regions like the face, scalp and anterior abdominal wall.

Functions of Deep Fascia

• It invests the muscles to separate the different muscle groups.
• In the distal joints it is thickened for protection forming retinaculae and in the palm of the hand and sole of the foot forming aponeuroses.
• It serves as pulleys, or retinaculae, around which tendons can move
• It surrounds blood vessels and nerves forming sheath as carotid sheath in the neck

Anatomy is the study of the structure of the human body. It can be studied at macroscopic, microscopic, and radiological levels. Standard anatomical terms of position, such as anterior, posterior, superior and inferior, are used for accurate description of body parts.