Stephen J. Schueler, M.D.

Overview Incidence Symptoms Evaluation Treatment specialist Home Care warning signs Prevention Outlook Complications Underlying Cause Anatomy

Keratosis Seborrheic Anatomy

To better understand seborrheic keratosis, it helps to understand the anatomy of the skin.

The skin contains three main layers:

  • Epidermis:
    • The superficial layer that makes up the surface of the skin
    • It is composed of skin cells and can be divided into 5 layers based on cell type.
    • The top layer of the epidermis, the stratum corneum, is made of dead, flat skin cells that shed about every 2 weeks.
    • The thickness of the epidermis varies, according to location: it is very thick over the soles of the feet, and very thin over the ears.
  • Dermis:
    • Lies beneath the epidermis
    • Also varies in thickness depending on the location of the skin. It is .3 mm on the eyelid and 3.0 mm on the back.
    • The dermis is composed of 2 layers that contain a connective tissue called collagen
    • The dermis contains blood vessels, nerves, sweat glands, and hair follicles.
    • The number of structures in the dermis varies, according to location.
    • The dermis under the arms contains more sweat glands and hair follicles than the dermis on the back.
  • Subcutaneous layer:
    • Mainly fat and connective tissue.
    • Contains blood vessels and nerves.

Last Updated: Jan 10, 2011 References
Authors: Stephen J. Schueler, MD; John H. Beckett, MD; D. Scott Gettings, MD
Copyright DSHI Systems, Inc. Powered by: FreeMD - Your Virtual Doctor

PubMed Keratosis Seborrheic References
  1. Cashmore RW, Perry HO. Differentiating seborrheic keratosis from skin neoplasm. Geriatrics. 1985 Jul;40(7):69-71, 74-5. [4007500]
  2. Eads TJ, Hood AF, Chuang TY, Faust HB, Farmer ER. The diagnostic yield of histologic examination of seborrheic keratoses. Arch Dermatol. 1997 Nov;133(11):1417-20. [9371026]
  3. Lindelof B, Sigurgeirsson B, Melander S. Seborrheic keratoses and cancer. J Am Acad Dermatol. 1992 Jun;26(6):947-50. [1535080]
  4. Winkelmann RK. Superficial spreading (and disappearing) seborrheic keratosis. Cutis. 1999 Apr;63(4):235-7. [10228754]
FreeMD is provided for information purposes only and should not be used as a substitute for evaluation and treatment by a physician. Please review our terms of use.