A patient's thenar space (B, and C, Fig. 8-1) is sometimes infected by a penetrating wound. It lies underneath his palmar fascia, and is bounded dorsally by the transverse head of his adductor pollicis. On its ulnar side a fibrous septum divides it from his middle palmar space.
His thenar eminence is grossly swollen, and his thumb is abducted.
THENAR SPACE. For the general method for a hand infection, see Section 8.1.
Drain the patient's thenar space over the point of greatest tenderness through a curved incision in the web between his thumb and index finger, parallel to the border of his first dorsal interosseous muscle, on the dorsal edge of his hand (incision 4). Or, drain it in an incision along his thenar crease in his palm (incision 5). Insert a haemostat deep into the abscess, and open it. You will usually find that it is walled off from the muscles of his thumb.
CAUTION ! Remember the course of the sensory and motor branches of his median nerve which lies within his thenar muscles. These are in less danger from incision (4) than from incision (5).