INTRODUCTION

Although the number of diseases that affect the elbow with any degree of frequency is small, examining the joint often provides clues to diagnosis of specific neuromuscular disease. Pain is the symptom that focuses attention on this joint and prompts the patient to visit the physician. Although it usually reflects a localized process at the elbow, the pain may be referred from the hand and wrist or from the shoulder and neck. Most abnormal actions of the elbow can be compensated by the shoulder; therefore, even moderate compromises of motion, provided they are painless, do not result in disability. Subtle flexion contractures may develop over years without the patient even being aware of the changes or range-of-motion losses. In contrast, significant pain at the elbow incapacitates the entire arm. Sleeves of clothing often cover the elbows; thus, swellings and deformities become cosmetically important only when they are exaggerated. The examiner should note whether swelling is intracapsular or extracapsular, intramuscular or intermuscular. The earliest sign of joint effusion is induration of the capsule around the olecranon or epicondyles. In the flexed position, the hollows of the indurated synovium are totally filled.

When the elbow is extended, the epicondyles and the tip of the olecranon should be at the same level. In normal elbow configuration, when a line is drawn between the epicondyles, the olecranon should bisect and be on the center of the line. When the normal elbow is flexed to an angle of 90 degrees, the tip of the olecranon should be directly below to the line joining the epicondyles. If a line from the olecranon is drawn to each epicondyle, the three prominences and line should form an isosceles triangle.

TABLE 5-2 ELBOW JOINT CROSS-REFERENCE TABLE BY SYNDROME

If the triangle is normal but abnormal in relation to the shaft of the humerus, the patient may have a supracondylar fracture in which the three bony landmarks are displaced posteriorly.

The examination of the elbow must be preceded by a precise history to allow emphasis to be placed on particular areas. Complaints usually consist of pain, loss of movement, weakness, clicking, or locking.

The patient may complain of sharply localized pain, typical of an extraarticular abnormality, deep joint pain, or the poorly localized pain of ulnar neuropathy with or without typical paresthesia extending to the hand. The functional interplay among the elbow, shoulder, and wrist means that examination of all of these joints may be necessary (Table 5-3). Referred pain in the elbow, especially from the neck or shoulder, is usually diffuse. Examination must include comparison of right and left arms.

TABLE 5-3 FUNCTIONAL ARC MEASUREMENTS FOR SELECTED ACTIVITIES OF DAILY LIVING

From Kelley WN, et al: Textbook of rheumatology, ed 5, Philadelphia, 1997, WB Saunders.

Pain of lateral elbow origin is usually diagnosed as radiohumeral bursitis, epicondylitis, or tennis elbow. All of these problems involve the origin of the wrist extensors (tendinopathy) or, occasionally, radial nerve impingement by musculotendinous structures crossing the elbow joint.

A similar problem may occur on the medial elbow epicondyle because all of the wrist flexors and pronators originate from the medial epicondyle. Affected individuals use flexor-pronator muscle groups repetitively, isometrically or isokinetically. This circumstance is unusual because forceful wrist flexor power is seldom used. Most of powerful hand grasping is accomplished in the dorsiflexed wrist position.

Intraarticular abnormalities such as osteochondritis dissecans of the capitellum result in lateral elbow pain.

Osteochondritis dissecans of the elbow is an idiopathic disorder that affects the capitellum of the humerus, with ensuing avascular necrosis. It is usually seen in the dominant arm of adolescent boys, especially those involved in throwing sports. Panner disease is a condition of unclear origin in which osteochondrosis of the capitellum occurs. It is seen most often in young boys who complain of tenderness and swelling over the lateral aspect of the elbow with limited extension. Direct trauma or inadequate circulation through the elbow joint has been associated with osteochondritis of the capitellum.

An extremely minor fracture of the radial head (chisel fracture) may cause pain that can be confused with tennis elbow. An injury occurring in children and adolescents in whom the medial epicondyle is inflamed with partial separation of the apophysis is little leaguer’s elbow.

Boxer’s elbow (also called hyperextension overload syndrome or olecranon impingement syndrome) is caused by repetitive valgus extension of the elbow in the boxer’s jab or in sports involving throwing. Elbow joint hyperextension injuries usually result from falling on an outstretched arm. The elbow is extended and the forearm supinated.

Pain in the elbow, particularly extending along the entire arm, in the absence of objective findings at the joint suggests psychogenic origins. Other diseases referring pain to the elbow include myocardial infarction, cervical root lesions, thoracic outlet syndromes, and subdeltoid bursitis. Psychogenic origins are further supported with a history of neurosis, strange behavior, or a bizarre and inconsistent complaint history; diagnostic imaging and laboratory tests are as unimpressive as the physical findings. Carpal tunnel syndrome may cause retrograde radiation of pain to the elbow.

Elbow joint complaints usually consist of pain, loss of movement, weakness, clicking, or locking. The patient may complain of sharply localized pain (typical of an extraarticular abnormality), deep joint pain, or poorly localized pain of ulnar neuropathy with or without typical paresthesias extending to the hand. The functional interplay among the elbow, shoulder, and wrist means that examination of all these joints is necessary. Referred pain in the elbow, especially from the neck or shoulder, is usually diffuse (Table 5-4).

TABLE 5-4 UPPER EXTREMITY PERIARTICULAR SYNDROME DIFFERENTIAL DIAGNOSTIC LIST

Modified from Kelley WN, et al: Textbook of rheumatology, ed 5, Philadelphia, 1997, WB Saunders.

True elbow pain can be related to joint disease; however, it is more commonly caused by lesions of the periarticular tissues. Inflammation of the olecranon bursa (draftsman’s elbow) may be secondary to several conditions, including repetitive or acute trauma, rheumatoid arthritis, gout, and pseudogout. It is also known as student’s elbow or miner’s elbow.

The olecranon bursa is prone to injury by friction or a blow. Additionally, because of its position, swelling occurs easily and is readily visible. It is also a common site involved in crystal arthropathies (gout, or rarely, calcium pyrophosphate arthritis) or in generalized inflammatory arthritis, especially rheumatoid arthritis in which swelling of the olecranon bursa may be seen in association with rheumatoid nodules on the ulnar border of the forearm.

Traumatic or repetitive-motion osteochondritis of the radial head occurs in some sports that involve throwing, especially evident in the preadolescent and adolescent athletes. The radioulnar joint is affected by loose bodies and synovial osteochondromatosis. Traumatic partial subluxation of the radial head through the annular ligament occurs in children younger than 8 years.

A pushed elbow describes subluxation of the radial head in a proximal direction, which is often seen after a child falls on an outstretched hand. A pulled elbow is subluxation of the radial head in a distal direction, which may follow a forceful traction to the forearm.

ESSENTIAL ANATOMY

The elbow acts as a lever system that, along with the other joints, changes the direction of the upper extremity to put the hand in the most effective functional position. The elbow consists of three bones: the distal end of the humerus and the proximal ends of the radius and the ulna. The three articulating surfaces are enclosed in a single synovial cavity. The olecranon bursa is the largest bursa of the elbow, although several smaller bursae are present.

The three major deep nerves of the forearm are the radial, medial, and ulnar nerves. The radial nerve lies anterior to the lateral epicondyle in the arm in its anterior compartment.

Arterial supply to the forearm depends entirely on branches of the brachial artery. The radial artery courses to the lateral side of the forearm and aligns itself with the radius. The ulnar artery is the larger of the two branches of the brachial artery.

ESSENTIAL MOTION ASSESSMENT

Tissue approximation limits elbow flexion to 140 to 150 degrees. Retained flexion motion of 130 degrees or less is impairment in the activities of daily living (Fig. 5-1).

FIG. 5-1 Tissue approximation limits elbow flexion to 140 to 150 degrees.

Elbow extension is 0 degrees. Up to 10 degrees of hyperextension is still within normal limits if the patient has no history of trauma to the joint. The inability to return the elbow to within 10 degrees of the neutral position is impairment in the activities of daily living (Fig. 5-2).

FIG. 5-2 Elbow extension is 0 degrees. Ten degrees of hyperextension is within normal limits if equal bilaterally and in the absence of injury.

Supination of the elbow is limited by tissue stretch to 90 degrees. Retained supination motion of 60 degrees or less is impairment in the activities of daily living (Fig. 5-3).

FIG. 5-3 Supination of the elbow is limited, by tissue stretch, to 90 degrees.

Elbow pronation is the same as supination, 80 to 90 degrees. Retained pronation motion of 70 degrees or less is impairment in the activities of daily living (Fig. 5-4).

FIG. 5-4 Elbow pronation, 80 to 90 degrees, is the same as supination.

ESSENTIAL MUSCLE FUNCTION ASSESSMENT

The prime movers in flexion of the elbow are the biceps brachii (musculocutaneous nerve, C5, and C6), brachialis (musculocutaneous nerve, C5, and C6), and brachioradialis (radial nerve, C5, and C6) muscles. The flexor muscles of the forearm arising from the medial epicondyle of the humerus are the accessory muscles (Fig. 5-5).

FIG. 5-5 The patient is instructed to flex the elbow through its range of motion against graded resistance applied by the examiner. The examiner’s other hand is just proximal to the patient’s wrist.

The prime mover in extension of the elbow is the triceps brachii muscle (radial nerve, C7, and C8); the anconeus muscle is an accessory. When the arm is horizontally abducted, the long head of the triceps is shortened over the shoulder joint. When the shoulder is flexed, the long head of the triceps is shortened over the elbow joint and elongated over the shoulder joint (Fig. 5-6).

FIG. 5-6 The examiner fixes the patient’s arm as described for flexion and instructs the patient to move the elbow through the range of extension motion while providing graded resistance with the other hand just proximal to the patient’s wrist.

Although the triceps and anconeus act together in extending the elbow joint, the two muscles can be differentiated. The belly of the anconeus muscle is below the elbow joint and is easily distinguished from the triceps by palpation. Paralysis of the anconeus materially reduces the strength of elbow extension (Fig. 5-7).

FIG. 5-7 Paralysis of the anconeus materially reduces the strength of elbow extension. The muscle grade of good in-elbow extension strength is actually the result of a normal triceps and a zero anconeus function.

The primary supinators are the biceps brachii and the supinator. The accessory muscle in this movement is the brachioradialis. In addition to its role in supination, the biceps also functions as an elbow flexor. Its total biceps function is well illustrated in the act of twisting a corkscrew into the cork of a bottle and then pulling the cork out of the bottle (Fig. 5-8).

FIG. 5-8 The thenar eminence of the examiner’s resisting hand is placed on the dorsal surface of the patient’s hand and wrist. The patient begins supination from a position of pronation, and as the arm is moved into supination, the resistance is gradually increased.

The primary pronators are the pronator teres and the pronator quadratus. The accessory muscle in this movement is the flexor carpi radialis. Pronation and supination are complex movements (Fig. 5-9) that occur simultaneously around an axis best described as an imaginary line between the head of the radius proximally and the medial end of the triangular articular disc distally. In the proximal radioulnar joint, the head of the radius can rotate within the perimeter created by the annular ligament.

FIG. 5-9 The patient begins forearm pronation from a position of supination. As the patient moves into pronation, the resistance is increased.

ESSENTIAL IMAGING

The elbow position of function is 90 degrees of flexion with the forearm midway between supination and pronation. In this position, the olecranon process of the ulna and the medial and lateral epicondyles of the humerus normally form an isosceles triangle when viewed posteriorly; this sign is known as the triangle sign. If a fracture, dislocation, or degeneration exists leading to loss of bone or cartilage or both, the distance between the apex and base decreases, and the isosceles triangle no longer exists.

COZEN TEST

PROCEDURE

FIG. 5-10

ELBOW FLEXION TEST (WADSWORTH ELBOW FLEXION TEST)

PROCEDURE

FIG. 5-11

GOLFER ELBOW TEST

PROCEDURE

FIG. 5-12

KAPLAN SIGN

PROCEDURE

FIG. 5-13

LIGAMENTOUS INSTABILITY TEST

PROCEDURE

FIG. 5-14

FIG. 5-15

MILLS TEST (ALSO KNOWN AS MILLS MANEUVER)

PROCEDURE

FIG. 5-16

TINEL SIGN AT THE ELBOW (ALSO KNOWN AS FORMICATION SIGN, DISTAL TINGLING ON PERCUSSION [DTP] SIGN, AND HOFFMAN-TINEL SIGN)

PROCEDURE

FIG. 5-17