lymph node

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Characteristics

discrete structures surrounded by a capsule composed of connective tissue surrounded by a few elastic fibrils
the capsule is perforated by afferent lymphatics that empty into the peripheral sinus subadjacent to the capsule

lymph nodes are dynamic organs, the size & morphology of which are modified by immunologic responses.
lymph nodes are secondary lines of immunological defense, responding to antigenic stimuli in the absence of clinical disease
superficial chains of lymph nodes drain the skin into 3 large areas.
- cervical lymph nodes
  - scalp
  - face
  - top of neck
- axillary lymph nodes
  - upper extremities
  - lower neck
  - trunk above the umbilicus
- inguinal lymph nodes
  - lower extremities
  - perineum
  - genitals
  - trunk below the umbilicus

residual scarring may occur after enlargement.
- enlargement of a lymph node (> 1 cm) is lymphadenopathy

↑ Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
↑ Cotran et al Robbins Pathologic Basis of Disease, 5th ed. W.B. Saunders Co, Philadelphia, PA 1994 pg 629