Dermatology

Anatomy

Region: Beneath the epidermis.
Key Structures: Collagen/elastin matrix; hair follicles, sebaceous & sweat glands, vessels, and sensory nerves (Meissner, Pacinian corpuscles).
Clinical Correlation: Pilosebaceous plugging → acne; burns reaching the dermis blister & scar; dermal vessels regulate temperature.

High-Yield Pearl

Acne begins at the pilosebaceous unit — follicular plugging plus Cutibacterium acnes.

Region: Outermost, avascular layer of skin.
Key Structures: Deep → superficial: stratum basale, spinosum, granulosum, (lucidum), corneum; keratinocytes, melanocytes, Langerhans cells.
Clinical Correlation: Basale holds stem cells & melanocytes (melanoma origin); the corneum is the barrier; desmosome attack → pemphigus vulgaris.

High-Yield Pearl

“Come, Let’s Get Sun Burned” — Corneum, Lucidum, Granulosum, Spinosum, Basale (top → bottom).

Region: Dorsal distal digits.
Key Structures: Nail matrix (growth), nail plate, nail bed, lunula, cuticle/eponychium, hyponychium.
Clinical Correlation: Matrix damage → nail dystrophy; nails mirror systemic disease — clubbing, pitting, splinter hemorrhages.

High-Yield Pearl

Nail clues: clubbing → hypoxia, pitting → psoriasis, splinter hemorrhages → endocarditis.