Introduction to Anatomy

• بسم الله الرحمن الرحيم translates to "In the name of God, the Most Gracious, the Most Merciful."
• Prepared by Dr Sayed Mostafa
• Modified by Dr. Eid Nassar Ali

Introduction to Anatomy

• Anatomy is the study of the structure of the body.
• Greek origin of the word anatomy means "to cut".
• Latin origin of the word anatomy means "to dissect".

Levels of Studying Anatomy

• Macroscopic/Gross Anatomy involves studying large structures visible to the naked eye.
• Microscopic Anatomy (Histology) involves studying structures at the microscopic level.
• Radiological Anatomy involves studying structures using imaging techniques.

Anatomical Position

• This position is a standard reference for describing the body.
• Whole Body - Standing erect
• Eyes - Looking forward
• Upper Limbs - At the sides
• Palm of Hand - Looking forward
• Thumbs - Looking outwards
• Legs - Close together
• Feet - Looking forwards

Other Positions of the Body

• Supine Position
• Prone Position
• Right Lateral Position
• Left Lateral Position

Anatomical Planes

• Median Plane: Divides the body into right and left halves.
• Paramedian Plane: Parallel to the median plane.
• Frontal (Coronal) Plane: Divides the body into anterior and posterior parts.
• Transverse Plane: Divides the body into upper and lower parts.

Common Anatomical Terms of Movements

• Flexion
• Abduction
• Extension
• Adduction
• Pronation
• Supination
• Elevation
• Depression
• Protraction
• Retraction
• Dorsiflexion
• Plantar Flexion
• Inversion
• Eversion

Coverings of the Body

• Covers include the skin and fascia.

The Skin

• Protects underlying tissues
• Defends the body against microorganisms
• Regulates body temperature
• Forms vitamin D
• Absorbs certain substances
• Provides sensory information about the external environment (heat, cold, pain, pressure)

Skin Structure

• Epidermis is the superficial layer.
• Dermis is the deep connective layer.
• Deep to the dermis is the superficial fascia or hypodermis.

Epidermis Structure

• The most superficial layer of the skin.
• It consists of 4 to 5 layers (strata) of cells.
• The superficial layer is formed of flat cells filled with keratin.
• Keratin is a water-insoluble protein.
• It lacks blood vessels.
• Deep layer cells have the capacity for regeneration via mitotic division.
• The epidermis is generally thin except in the palms of the hand and soles of the feet.
• This thickness protects these parts and withstands friction, tear, and rubbing.

Dermis Structure

• Lies deep to the epidermis.
• Formed of connective tissue containing blood vessels, lymph vessels, sensory nerve endings, smooth muscles, hair follicles, sweat & sebaceous glands.

Appendages of the Skin

• Hairs
• Sweat glands
• Sebaceous glands
• Nails

Hair

• Hair covers most body surfaces except palms, soles, and the red margin of the lip.
• Hair can be moved by a band of smooth muscle called arrector pili.
• Arrector pili muscles are supplied by sympathetic nerve fibers.

Sebaceous Glands

• Lie within the dermis.
• Their ducts open into the side of a hair.
• Secrete sebum to lubricate hair and skin.
• Sebaceous glands are absent on the palms or soles.

Sweat Glands

• Long tubular glands.
• Extend through the full thickness of the dermis.
• Present all over the body except the red margins of the lips, nail beds, glans penis, and clitoris.

Nails

• A flat horny plate on the dorsal surface of the distal phalanx of the fingers and toes.
• It has a root, body, nail fold, and a bed.

Infections of the Skin

• Pathogenic organisms (usually staphylococci) can enter the tissue through nail folds, hair follicles, or sebaceous glands.
• If the infection happens between the nail and the nail fold, it is called paronychia.

The Fascia

• Connective tissue between the skin and underlying muscles and bones.
• The fascia is divided into superficial and deep layers.
• Superficial Fascia: found immediately under the skin uniting it to the underlying tissues.
• It consists of a layer of loose connective tissue that contains variable amounts of fat, blood vessels, and nerves of the skin.
• It is extremely thin in the eyelids, external ear, penis, and scrotum.

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.
• Allows free mobility of the skin on the underlying structures.
• Contains muscles in the face (muscles of facial expressions) and neck (platysma).

Deep Fascia

• A dense, inelastic fibrous membrane that separates the superficial fascia from the deeper structures.
• It covers most of the body but is absent in certain regions, e.g., in 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.
• Serves as pulleys around which the tendons can move.
• Surrounds blood vessels and nerves, forming a sheath as a carotid sheath in the neck.