AN4.1-5 | General features of skin and fascia — Glossary

Skin of the palms and soles with a thick epidermis (up to 1.5 mm), five distinct layers, no hair follicles, and abundant sweat glands

Skin covering the rest of the body with a thinner epidermis (about 0.1 mm), hair follicles, sebaceous glands, and fewer epidermal layers

Outermost avascular layer of skin composed of stratified squamous keratinised epithelium; receives nutrients by diffusion from the dermis

Inner layer of skin containing connective tissue, blood vessels, nerves, and appendages; divided into papillary (superficial) and reticular (deep) layers

Main cell type of the epidermis producing keratin protein that makes skin waterproof and resistant to wear

Pigment-producing cell in the stratum basale with dendritic processes that transfer melanosomes to surrounding keratinocytes for UV protection

Dendritic antigen-presenting immune cell in the stratum spinosum; the skin's first line of adaptive immune defence

Mechanoreceptor in the stratum basale that detects light touch and pressure; associated with Merkel's disc nerve endings

Area of skin supplied by a single spinal nerve root; used clinically to localise nerve injuries and interpret rash patterns like shingles

Outermost epidermal layer of dead, flat, keratinised cells that provides the main barrier against water loss and microbial invasion

Deepest epidermal layer of actively dividing stem cells on the basement membrane; contains melanocytes and Merkel cells

Subcutaneous tissue between the skin and deep fascia containing fat, cutaneous nerves, superficial veins, and lymph nodes

Dense fibrous connective tissue layer deep to superficial fascia; forms compartments, retinacula, and intermuscular septa; contains no fat

Lines of predominant collagen fibre orientation in the dermis; surgical incisions parallel to these lines produce thinner scars

Thickened band of deep fascia at joints that holds tendons in place, preventing bowstringing during movement

Triangular thickening of deep fascia in the palm continuous with the palmaris longus tendon; thickening causes Dupuytren's contracture

Superficial fatty layer of the anterior abdominal wall superficial fascia; thick over the abdomen

Deep membranous layer of abdominal superficial fascia; attached to the fascia lata below the inguinal ligament, limiting urinary extravasation to the anterior abdominal wall

Emergency condition where increased pressure within a closed fascial compartment compromises blood supply and nerve function; requires fasciotomy

Encapsulated nerve ending in dermal papillae detecting fine/discriminative touch; abundant in fingertips and lips

Large lamellated nerve ending deep in the dermis and hypodermis detecting deep pressure and vibration

Progressive fibrosis of the palmar aponeurosis causing fixed flexion of the ring and little fingers; more common in men

Thickened lateral band of deep fascia (fascia lata) from the iliac crest to the lateral tibial condyle; insertion for gluteus maximus and tensor fasciae latae