Injuries of the upper limb are commonly due to falls on the outstretched arm; the resultant fractures vary with age. The clavicle may be fractured at any age, the common site is at the junction of the middle and lateral thirds. Young adults, undertaking rigorous sporting and other activities, fracture the neck of the humerus, endangering the axillary nerve: severe trauma may also produce a spiral fracture of the humerus, with damage to the radial nerve.
In childhood, falls may produce a supracondylar fracture, through the thin transverse layer of bone above the condyles of the humerus. A serious complication of this injury is entrapment of the brachial artery during reduction. Great care must be taken to monitor the radial pulse, the perfusion of the hand and the sensation of the median nerve, in these children. Forearm fractures in the child (figure 24) may be of the greenstick variety, where only one side of a bone breaks, the other side bending, with angulation of the forearm: this may occur in one or both forearm bones.
Upper limb falls may also produce wrist fractures. In children, they produce fracture of the radial epiphysis. In young adults, fracture of the scaphoid (figure 25) is more common, and must be identified, as the bone is prone to non-union giving long-standing wrist weakness. Persistent tenderness over the proximal scaphoid, in the anatomical snuffbox, is a useful diagnostic sign. In the elderly, falling on the wrist characteristically produces a Colles’ fracture (figure 26). This is through the distal radius, with posterolateral angulation, posterolateral displacement and impaction of the distal fragment.
Dislocations in the upper limb include the shoulder joint, this occurs with the arm abducted; the displacement is through the unsupported inferior capsule and the axillary nerve is at risk. Dislocation of the radial head occurs in children, before the conical shape of the radial head has expanded to fit the annular ligament. In the hand, the lunate may be dislocated, and dislocations of the phalanges are common sporting injuries.
The initial application of a few simple tests may serve to localise upper limb abnormalities. These may for example include picking up objects, writing, asking the patient to put their hands together, as in praying, or to comb their hair. Functional limitation and problems then usually become apparent, and direct the subsequent examination. A full regional examination includes inspection, palpation and movement of all joints, and examination of periarticular structures. Assessment of muscle power and neurological function should also be carried out.