This chapter discusses soft tissue injuries distal to the volar
wrist crease and fractures distal to the carpal bones.
The hand consists of 27 bones: 14 phalangeal bones, 5 metacarpal
bones, and 8 carpal bones arranged in five rays of metacarpals and
phalanges having its base at the carpometacarpal (CMC) articulation (Figure 265-1).
Bones of the hand and wrist.
The carpal bones are made up of two rows, each with four bones.
The bones are concave volar and are bridged by the flexor retinaculum.
This forms the carpal tunnel through which the median nerve and
the nine long flexor tendons of the fingers pass. The bases of the
second and third CMC articulation are fixed, whereas the thumb,
ring, and little finger have mobility at the CMC joint, allowing
motion that enables grasp and adaptive movement of the hand. Multiple
soft tissue structures support these bones and joints: capsular
ligamentous structures provide stability, whereas the intrinsic
muscles of the hand and their associated tendinous structures generate
mobility. The collateral ligaments of the metacarpophalangeal joints are
tightest in flexion (Figure 265-2). The interphalangeal
collaterals are tight throughout the entire range of motion. The intrinsic muscles of the
hand are those that have both their origins and insertions within
the hand. They consist of the muscle of the thenar and hypothenar
eminences, adductor pollicis, the interossei, and the lumbricals
Ligament attachments of the metacarpophalangeal and interphalangeal
A. Palmar (volar) view of the hand showing
relationship of muscles and tendon sheaths, and flexor zones of
the hand. B. Dorsal view of the hand showing tendons
and extensor zones of the hand. Extensor tendons of the hand and
extensor retinaculum. The extrinsic extensor tendons include the
following: extensor carpi radialis longus, extensor carpi radialis
brevis, extensor carpi ulnaris, extensor digitorum communis, extensor
digiti minimi, extensor indicis proprius, abductor pollicis longus,
extensor pollicis brevis, and extensor pollicis longus.
The thenar muscles (abductor pollicis brevis, opponens pollicis,
and flexor pollicis brevis) originate in the flexor retinaculum
and carpal bones and insert at the base of the first metacarpal
and first proximal phalanx, thus covering the thumb metacarpal.
The median nerve innervates all three muscles. The adductor
pollicis is innervated by the ulnar nerve and originates
from the second and third metacarpals and inserts in the first proximal
phalanx. The hypothenar muscles include the opponens digiti minimi,
the flexor digiti minimi, and the abductor digiti minimi. These muscles,
innervated by the ulnar nerve, originate in the flexor retinaculum ...