The Upper Limb

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Chapter 673 The Upper Limb

Shoulder

The shoulder is a ball-and-socket joint that is similar to the hip; however, the shoulder has a greater range of motion than the hip. This is due to the size of the humeral head relative to the glenoid, as well as to the presence of scapulothoracic motion. The shoulder positions the hand along the surface of a theoretical sphere in space, with its center at the glenohumeral joint.

Brachial Plexus Birth Palsy

Injuries to the brachial plexus can occur in the peripartum time, usually as a result of a stretching mechanism. This palsy is often associated with large fetal size and shoulder dystocia. The incidence is 1-3/1,000 live births. The injury can range in severity from neurapraxia to complete rupture of the nerve root or avulsion of the nerve root from the spinal cord. More often, the upper roots (C5 and C6) are affected rather than a complete brachial plexus palsy. Rarely, in isolation, a lower plexus injury (C8 and T1) is observed. The clinical appearance of a C5-6 brachial plexus birth palsy is the waiter’s tip position. The arm is held in a position of shoulder adduction and internal rotation, elbow extension, and wrist flexion. This is the classic Erb’s palsy.

Elbow

The elbow is the most congruent joint in the body. The stability of the elbow is imparted via this bony congruity as well as through the medial and radial collateral ligaments. Where the shoulder positions the hand along the surface of a theoretical sphere, the elbow positions the hand within that sphere. The elbow allows extension and flexion through the ulnohumeral articulation and pronation and supination through the radiocapitellar articulation.

Radial Longitudinal Deficiency

Radial longitudinal deficiency of the forearm comprises a spectrum of conditions and diseases that have resulted in hypoplasia or absence of the radius (Table 673-1). This process was formerly referred to as radial club hand, but the name has been changed to radial longitudinal deficiency, which better characterizes the condition. Clinical characteristics consist of a small, shortened limb with the hand and wrist in excessive radial deviation.

Table 673-1 SYNDROMES COMMONLY ASSOCIATED WITH RADIAL DEFICIENCY

SYNDROME CHARACTERISTICS
Holt-Oram syndomre Heart defects, most commonly atrial septal defects
Thrombocytopenia absent radius Thrombocytopenia present at birth but improves over time
VACTERL association Vertebral abnormalities, anal atresia, cardiac abnormalities, tracheoesophageal fistula, esophageal atresia, renal defects, radial dysplasia, lower limb abnormalities
Fanconi anemia Aplastic anemia not present at birth, develops about 6 yr of age; fatal without bone marrow transplant; chromosomal breakage challenge test available for early diagnosis

From Trumble T, Budoff J, Cornwall R, editors: Core knowledge in orthopedics: hand, elbow, shoulder, Philadelphia, 2005, Elsevier, p 425.

Radial longitudinal deficiency can range in severity from mild to severe and has been classified into four types according to Bayne and Klug (Table 673-2). Radial longitudinal deficiency can be associated with other syndromes such as Holt-Oram and Fanconi’s anemia.

Table 673-2 CLASSIFICATION OF RADIAL LONGITUDINAL DEFICIENCY

TYPE CHARACTERISTICS
I Short radius
Minor radial deviation of the hand
II Hypoplastic radius with abnormal growth at proximal and distal ends
Moderate radial deviation of the hand
III Partial absence of the radius
Severe radial deviation of the hand
IV Complete absence of the radius
The most common type

Adapted from Bayne LG, Klug MS: Long-term review of the surgical treatment of radial deficiencies, J Hand Surg Am 12(2):169–179, 1987.