The clinical course of most hand infections is affected by anatomic, local, and systemic factors, in addition to bacterial virulence and the size of the inoculum. Anatomic factors that to some extent determine the ease of penetration, localization, and spread of infection include: (1) the thin layer of skin and subcutaneous tissue over the tendons, bones, and joints; (2) the closed space of the distal digital pulp; (3) the proximity of the flexor tendon sheath to bone and joint; (4) the proximal extent of the flexor sheath into the palm, connecting with the radial and ulnar bursae; and (5) the location of the thenar and midpalmar spaces in the hand and the space of Parona proximal to the wrist near the flexor tendon sheaths.
