ABSTRACT
The heads of the second to the fifth metacarpal bones are connected by superficial and deep transverse metacarpal ligaments near the metacarpophalangeal joints. These ligaments form tunnels through which the digital nerves, the common palmar digital arteries and veins, and the tendon of the lumbrical muscles pass (Figure 28.1). The digitorum palmaris communis nerves (the branches of the ulnar and the median nerves) branch before or within the tunnels to provide terminal branches (the digitorum palmaris proprius nerves) to neighboring surfaces of corresponding fingers. The branches provide innervation to the lumbricals proximal to the tunnels. The third digital branch, a branch of the median nerve, anastomoses with the ulnar nerve via a ramus communicans. Variations in and overlapping areas of innervation exist; therefore, few areas of the hand can be assessed as being innervated solely by the median, ulnar, or even radial nerve.
