Introduction to Regional Anatomy

The epidermis is derived from the mesoderm.

The dermis is primarily composed of elastin fibres.

The classification of skin as thick or thin is determined by the depth of the combined epidermis and dermis.

In thick skin, such as on the sole of the foot, the dermis is characteristically thick.

Skin is fundamentally composed of epithelium and muscle tissue.

Sebaceous glands secrete a watery substance that moisturizes the horny layer of the skin.

Maceration of keratin due to prolonged water exposure results in it becoming thin, stiff and white.

The medial epicondyle is less prominent than the lateral epicondyle.

Pronator teres arises from the medial supracondylar ridge.

The ulnar nerve is lodged in a groove between the lateral epicondyle and the trochlea.

The lateral epicondyle has an undulating smooth facet for the common extensor origin of forearm muscles.

The medial epicondyle fuses with the other centers around the elbow at about 18 years.

The panniculus adiposus, also known as subcutaneous fat, contains flat sheets of muscle called the panniculus carnosus.

The panniculus carnosus is typically absent in domestic quadrupeds such as sheep and horses.

One end of each muscle fibre in the panniculus carnosus is attached to the skin.

Tension lines and wrinkle lines of skin are due to the patterns of muscle bundles.

The panniculus carnosus can be seen in action when a horse twitches the skin over its withers.

The subcutaneous tissue is also known as the deep fasciae.

In a butcher's shop, the panniculus carnosus is generally incised in parallel slits to make an attractive pattern.

Panniculus adiposus is a type of muscle found under the skin.

In humans, the recognition of tension lines and wrinkle lines in the dermis is important for understanding skin movement.

The lateral border extends from the glenoid cavity to the clavicular facet.

The infraglenoid tubercle is located just below the glenoid fossa.

The tendon of trapezius passes over the deltoid tubercle which is lubricated by a bursa.

The deltoid muscle originates along the inferior margin of the acromion.

Supraspinatus is covered by a strong fascia attached to the upper margin of the spine.

The most lateral part of the shoulder region is formed by the acromion.

The supraspinous fossa lodges subscapularis.

The acromion has four or more vertical ridges along its lateral border for the attachment of septa in the deltoid muscle.

The medial end of the spine is triangular and smooth.

The junction of lateral and anterior borders of the acromion forms the prominent bony 'tip of the shoulder' 2 cm lateral to the acromioclavicular joint.

The claw hand is caused by the unopposed action of extensors and flexor digitorum profundus.

Wasting of the interossei muscles gives the appearance of guttering between the metacarpals.

Sensory loss in ulnar nerve damage is often greater than might be expected.

Injury at the elbow affects the distal interphalangeal joints of the ring and little fingers.

The abductor pollicis brevis is tested for lesions at the wrist level.

The median nerve is exposed by incising along the lateral border of biceps in the arm.

To relieve compression in the carpal tunnel, the flexor retinaculum is incised longitudinally.

Testing for the action of the ulnar half of flexor digitorum profundus is performed by observing flexion of the distal interphalangeal joint of the index finger.

The first dorsal interosseous muscle is used to test for abduction of the index finger.

Detaching the radial head of flexor digitorum superficialis displays the median nerve in the forearm.