Pus sometimes collects on the volar surfaces of a patient's fingers, superficial to his tendon sheaths, as shown in A, Fig. 8-1. The spaces where it forms are separated from one another by the fibrous septa which run dorsally from the flexor creases of his fingers. The proximal space in each finger communicates with the web spaces in his palm. Pus may collect under his epidermis or under his deep fascia, and is less likely to remain localized than in a terminal phalanx.
He holds his swollen, tender, indurated finger semi-flexed. Trying to straighten it is acutely painful. Distinguishing an infection of these spaces from localized infection of a tendon sheath may be so difficult that you will not know which he has, until you have explored his hand.
Drain pus from a volar space through a transverse incision over the point of greatest tenderness. Take great care not cut into the tendon sheath underneath it or to damage his digital vessels or nerves (G, 8-6). Use a tourniquet to give you a bloodless field.
DON'T OPEN A TENDON SHEATH OR A JOINT UNLESS IT IS INFECTED