Fractures of the Humeral Shaft

I. Overview—Humeral shaft fractures represent approximately 3% of all fractures. Multiple treatment options are available and include both operative and nonoperative management. The majority of humeral shaft fractures may be treated via nonsurgical means with a high success rate. Most low-energy fractures may be amenable to closed treatment because of internal soft-tissue splinting and the biologic potential of the humerus. In high-energy fractures, soft-tissue disruption and extensive fracture comminution are frequently observed rendering closed treatment less predictable.

II. Anatomy

A. Osteology—The humeral shaft can be defined as extending from the pectoralis major insertion proximally to the supracondylar ridge distally. The shaft of the humerus assumes a more triangular shape distally. The anterolateral surface of the humerus contains the deltoid tuberosity as well as the sulcus for the profunda brachii artery and the radial nerve. The spiral groove located on the posterior humeral shaft contains the radial nerve as it passes distally.

B. Musculature—The humeral musculature is divided by medial and lateral intermuscular septa into anterior and posterior compartments. The triceps brachii muscle fills the posterior compartment. The anterior compartment contains the biceps brachii, the coracobrachialis, and the brachialis muscles. Deforming muscle forces often lead to predictable patterns of fracture displacement. Fractures that occur between the pectoralis major insertion and the deltoid insertion display adduction of the proximal fragment and lateral displacement of the distal fragment. Humeral shaft fractures distal to the deltoid muscle insertion often result in abduction of the proximal fragment.

C. Nerves

1. Musculocutaneous nerve—The musculocutaneous nerve pierces the coracobrachialis muscle 5 to 8 cm distal to the coracoid process and then branches to supply the coracobrachialis, the biceps brachii, and the brachialis muscles. It continues distally and becomes the lateral antebrachial cutaneous nerve.

2. Median nerve—The median nerve accompanies the brachial artery medial to the humeral shaft and crosses lateral to medial (in relation to the artery) in the distal arm. It lies medial to the artery in the antecubital fossa.

3. Radial nerve—The radial nerve, formed from the posterior cord of the brachial plexus, spirals around the humerus in a medial to lateral direction. It supplies the triceps as well as innervation to the lateral portion of the brachialis muscle. It emerges through the intermuscular septum between the brachialis and the brachioradialis muscles.

4. Ulnar nerve—The ulnar nerve travels down the arm medial to the brachial artery. It traverses behind the medial epicondyle of the humerus.

D. Vasculature—The endosteal blood supply of the humeral shaft comes from branches of the brachial artery. Periosteal branches may arise from the brachial artery, the profunda brachii artery, and the posterior humeral circumflex artery. In addition, numerous small muscular branches contribute to the periosteal circulation.

III. Clinical Examination—The majority of patients with humeral shaft fractures have the common signs and symptoms of fracture, including swelling, pain, deformity, and crepitation. Motor-vehicle accidents, direct blows, and falls on the upper extremity are common mechanisms of injury. The humeral shaft also concentrates rotational force applied to the upper extremity and is subject to fracture under these loading conditions. A complete physical examination is performed before concentrating on the upper extremity.
A complete neurovascular examination of the entire upper extremity is performed. Because of the high incidence of injury, the function of the radial nerve must be documented before any reduction maneuver or surgical intervention. The joints above and below the humerus, as well as the ipsilateral wrist, are examined to exclude other injuries. The skin should be examined for abrasions, lacerations, contusions or a combination thereof. The compartments of the arm should be palpated to assess for the possibility of a compartment syndrome.

IV. Radiographic Evaluation—A complete radiographic evaluation is mandatory in the workup of a humeral shaft fracture. An anteroposterior radiograph and a lateral radiograph that includes both the elbow joint and the glenohumeral joint are essential. While obtaining radiographs, the examining physician should place the X-ray cassette in various positions about the upper extremity rather than manipulating the patient’s fractured limb. Simple limb rotation does not provide orthogonal views of the proximal humeral shaft and results in an incomplete radiographic analysis. Pathologic fractures may require other imaging studies, before definitive treatment, to evaluate a neoplasm and exclude occult lesions.

A. Fracture Classification—There are numerous classification strategies for describing and reporting on humeral shaft fractures. Most fracture classification schemes are based on plain radiography and rely on fracture geometry. In practice, treatment for humeral shaft fractures frequently depends on other variables, including bone quality, concomitant injuries, soft-tissue injuries, or neurovascular insult. Simple fracture patterns include those of transverse, oblique, and spiral geometry. More complex patterns include segmental fractures, severely comminuted fractures, open fractures, and humeral shaft fractures with dislocation of either the shoulder or the elbow. The Holstein-Lewis fracture is a spiral fracture in the distal third of the humeral shaft that typically presents with a lateral spike on the distal fragment. This pattern has been associated with a radial nerve injury because of proximity and tethering of the nerve adjacent to this lateral spike. Open fractures should be evaluated according to the Gustilo and Anderson Classification. Moreover, pathologic conditions such as osteoporosis, metastatic or primary tumors, and other associated conditions are important in regards to fracture description.

V. Treatment

A. Closed Treatment—The majority of fractures of the humeral shaft are treated adequately via closed methods. The fracture character, the patient’s age and occupation, and the presence of associated injuries all influence fracture management. Transverse and oblique humeral shaft fractures are commonly best treated closed. Options for closed treatment include hanging arm cast, shoulder spica cast, Velpeau dressing, coaptation splint, and a functional brace

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