Hand injuries account for up to 15% of all trauma cases seen in the emergency department (ED). Their complex anatomy, ability to perform fine movements, and importance in daily life make missing these injuries potentially devastating.
The hand has a dorsal and a volar surface and the same terms are used when discussing the digits. In addition, each digit has a radial and an ulnar border. The muscle mass at the base of the thumb is called the thenar eminence and the muscle mass along the ulnar border of the hand is the hypothenar eminence.
The motions of the wrist include radial and ulnar deviation and extension and flexion. Motions of the thumb include flexion and extension, abduction and adduction, and opposition (Fig. 11–1). The digits are named the thumb, index, long, ring, and little fingers, respectively. The thumb is the first digit and the little finger is the fifth digit.
Terms used to describe motion of the hand and the digits.
When a patient presents to the ED with a hand complaint, the physician should first ascertain if there is any history of trauma. The approach and differential diagnosis of a traumatized hand are quite different from that of a nontraumatized hand. Important historical points to be elicited in evaluating traumatic hand injuries include:
The time elapsed since the injury
The environment in which the injury occurred (contamination)
The mechanism of injury (crush, laceration, etc.)
In the nontraumatized hand, the most important historical questions are:
When did the symptoms begin?
What functional impairment has been experienced?
What activities worsen the symptoms?
The design and versatility of the human hand has impressed anatomists and authors for centuries. Anatomically, the hand is a group of highly mobile gliding bones connected by tendons and ligaments to a “fixed center.” This fixed center consists of the second and third metacarpal bones. The remainder of the hand is suspended from these two relatively immobile bones. All of the intrinsic movements of the hand are relative to and dependent on the stability and immobility of these two bones.
The skin of the volar hand and fingers is fixed to the underlying bone by fibrous septa. This helps with grip, limits movement, and does not allow significant swelling. The dorsal hand has looser, thinner skin. This allows a fairly extensive space for swelling from trauma or infection. The clinician treating hand injuries should be aware that the venous and lymphatic drainage takes place on the dorsum of the hand. Any condition that causes inflammation and swelling in the hand can lead to lymphatic congestion and nonpitting edema over the dorsal aspect of the hand.