selves. To pinpoint this tenderness, the examiner should palpate very carefully with one finger while the patient's elbow is flexed to 90° and the forearm muscles are relaxed (Fig. 3-30). Resisted wrist extension may exacerbate the pain of palpation.
MEDIAL ASPECT
Medial Epicondyle. The most prominent structure of the medial elbow is the medial epicondyle, the site of ori- gin of the flexor-pronator muscle group. The medial epi- condyle has a separate apophyseal growth center and may be avulsed in children or adolescents, either in association with an elbow dislocation or as an isolated injury. In preadolescent or adolescent athletes who throw, repeated traction from the flexor pronator muscle group can cause an overuse injury known as medial epicondyle apophysitis or Little Leaguer's elbow. In the presence of this condition, firm palpation of the medial epicondyle is painful. Because the epicondyle is so prominent, the examiner can actually grasp it between the t h u m b and the index finger and attempt to move it back and forth. Although no motion with respect to the rest of the humerus is detectable, this manipulation is usually quite painful if Little Leaguer's elbow is present (Fig. 3-31).
In older patients, the flexor-pronator tendon origin is subject to a tendinitis similar to that seen on the lateral Figure 3-28. Prorated forearm, palpating the distal radius.
86 CHAPTER 3 Elbow and Forearm
Figure 3-29. A and B, Palpating the radial head while rotating the forearm.
Figure 3-30. Palpation for lateral epicondylitis.
side of the elbow. This flexor-pronator origin tendinitis is referred to by many names: medial epicondylitis, golfer's
elbow, reverse tennis elbow, medial tennis elbow. To screen for flexor pronator origin tendinitis, the examiner
firmly palpates with one index finger just distal to the medial epicondyle with the patient's elbow flexed and forearm relaxed (Fig. 3-32). If the patient's response is equivocal, the tenderness may be accentuated by palpat- ing the tendon while the patient pronates the forearm against resistance.
Ulnar Nerve. The ulnar nerve can usually be palpated
as a fairly soft longitudinal structure slightly thicker than a sneaker shoelace. Palpation of the ulnar nerve should be very gentle because it can be quite sensitive. Sensitivity of the nerve is reflected in its common names: crazy bone or
funny bone. If an ulnar neuropathy is suspected, the
examiner should attempt to elicit Tinel's sign by tapping gently on the exposed portion of the nerve with the tip of the long finger (Fig. 3-33). In a normal patient, such tap-
Figure 3-33. Tinel's test of the ulnar nerve.
ping may be mildly uncomfortable. If the tapping pro- duces a feeling of paresthesias or dysesthesias radiating distally from the point of impact into the forearm, Tinel's sign is said to be present. Tinel's sign reflects irritation of the ulnar nerve. C o m m o n causes of ulnar nerve irritation at the elbow include compression where the ulnar nerve enters the flexor carpi ulnaris muscle, external compres- sion from leaning on the elbow, irritation owing to habit- ual subluxation of the nerve over the medial epicondyle, and traction due to cubitus valgus or valgus instability of the elbow.
To screen for ulnar nerve instability, the examiner should gently palpate the nerve between the medial epi- condyle and the olecranon while passively flexing and extending the patient's elbow (Fig. 3-34). If nerve insta- bility is present, the examiner feels the nerve pass anteri- orly over the epicondyle when the elbow is flexed, usually with a soft palpable snap. When ulnar nerve injury at the elbow is detected in an athlete who throws, the elbow should be examined carefully for valgus instability as the underlying cause of the neuropathy.
Medial (Ulnar) Collateral Ligament. The most impor-
tant ligamentous stabilizer of the elbow is the medial col-
lateral ligament (ulnar collateral ligament). This
ligament is triangular with two main limbs. The more important anterior limb arises from the medial epi- condyle deep to the flexor pronator origin and inserts on a small tubercle on the medial border of the coronoid process of the ulna. The posterior limb arises from the medial epicondyle behind the anterior limb and inserts into the medial border of the olecranon, forming the floor of the cubital tunnel. The posterior portion of the ligament is thus covered by the ulnar nerve, but the ante- rior portion is more exposed and can be palpated just anterior to the nerve with the elbow flexed from 30° to 60° (Fig. 3-35). The goal of palpation is to elicit tenderness because the outlines of the ligament cannot be clearly discerned. Because the act of throwing places a valgus stress on the elbow, this ligament is subject to overuse injury in athletes who throw. Such an injury is manifested by tenderness of the medial collateral ligament and, in more severe cases, abnormal valgus laxity of the elbow.
• MANIPULATION
Muscle Testing
ELBOW FLEXORSThe biceps brachii is the principal elbow flexor and an important supinator of the forearm. The biceps is inner- vated by the musculocutaneous nerve. To test for biceps strength in elbow flexion, the examiner faces the patient and asks him or her to flex the elbow. The examiner sta- bilizes the patient's arm by grasping it at the posterior elbow and holds the patients forearm just proximal to the wrist. The examiner then attempts to passively extend the elbow while the patient resists maximally (Fig. 3-36). In a normal patient, the examiner is able to extend the elbow
88 CHAPTER 3 Elbow and Forearm
Figure 3-35. Palpation of the ulnar collateral ligament. only with difficulty; a strong patient may be able to over- come the examiner's resistance and flex the elbow further. Because there is wide variation in biceps strength, it is important to compare both arms. The brachialis muscle also assists in elbow flexion. It is not easy to isolate from the biceps brachii and is tested along with it.
The brachioradialis is a unique elbow flexor. Unlike the other flexor muscles, it arises close to the elbow from the lateral epicondylar ridge and inserts close to the wrist in the distal radius. Although brachioradialis strength cannot be isolated from that of the other elbow flexors, the muscle can be demonstrated to its best advantage by testing with the forearm in the position of neutral rota- tion. The patient is instructed to flex the elbow to 90°. The
Figure 3-36. Assessing biceps strength (elbow flexion).
examiner then pushes downward on the patient's wrist while the patient provides maximal upward resistance. The brachioradialis stands out distinctively from the other forearm muscles and its function, thus, is easily confirmed (Fig. 3-37).
The brachioradialis is innervated by the radial nerve. Injury to the radial nerve in the upper arm, such as might occur in association with a fracture of the humerus, denervates the brachioradialis along with the other wrist and finger extensors that are innervated fur- ther distally.
ELBOW EXTENDERS
The triceps brachii is the principal extender of the elbow and is innervated by the radial nerve. It is tested in a manner analogous to that of testing elbow flexion. The examiner stabilizes the patient's arm at the elbow in the same manner as used to test the biceps but this time pro- vides resistance against the ulna as the patient is instructed to extend the elbow as forcefully as possible (Fig. 3-38). As with the biceps, triceps strength varies considerably and should always be compared with the opposite side. The examiner should be able to overcome the normal triceps only with difficulty and may indeed be unable to resist the force of extension in a strong patient.
FOREARM ROTATORS
Supination Strength. Supination strength is provided
primarily by the biceps brachii, innervated by the muscu-
locutaneous nerve, and the supinator muscle, innervated
by the radial nerve. To test supination strength, the patient sits or stands with the elbow flexed 90° and the upper arm held snugly against the body. This ensures that the shoul- der muscles are not being used to supplement the strength of forearm supination. The test begins with the patient's forearm fully pronated. Both of the examiner's hands then firmly grasp the patient's hand. The patient is instructed to attempt to turn the hand over with as much force as
Figure 3-38. Assessing triceps strength.
possible (Fig. 3-39). Normally, the examiner's two hands should be able to prevent this motion, although strong patients may be able to overcome the examiner. Rupture of the long head biceps tendon at the shoulder, a common occurrence, normally produces only a mild decrease in supination strength. Rupture of the distal biceps tendon at the elbow, however, produces a dramatic loss of supina- tion strength. Denervation of the biceps owing to cervical radiculopathy or musculocutaneous nerve injury or of the supinator due to radial nerve injury also produces a diminution of supination strength.
Figure 3-39. Assessing supination strength.
Supination strength is normally about 15% greater than pronation strength. The dominant extremity is nor- mally about 5% to 10% stronger than the nondominant side, but this difference may be more marked in certain individuals, such as manual laborers.
Pronation Strength. Pronation strength is provided by
the pronator teres and pronator quadratus, both inner- vated by the median nerve. To test the strength of prona- tion, the patient is asked to assume the same general position as that used for testing supination strength. This time, the test is begun with the patient's forearm fully supinated. The examiner grasps the patient's hand in this position and instructs the patient to attempt to turn the hand over as forcefully as possible (Fig. 3-40). In most cases, the strength of the examiner's two hands is suffi- cient to prevent the patient's forearm from pronating. Testing with the elbow fully flexed puts the pronator teres at a disadvantage and thus is a way of relatively isolating the pronator quadratus.
OTHER FOREARM MUSCLES
The other forearm muscles are primarily motors of the wrist and hand. Strength testing of these muscles is described in Chapter 4, Hand and Wrist.
Sensation Testing
Nerve injuries at the elbow and forearm can result in sen- sory deficits in the hand and wrist. Sensation of the fin- gertips is best evaluated by testing for two-point discrimination. In other parts of the hand, light touch or pinprick testing may be used.
With any median nerve injury, there is potential for loss of sensation in the median nerve distribution, which includes the palmar surface of the thumb, the index fin- ger, the long finger, and the radial aspect of the ring finger. If the injury takes place in the proximal portion of
90 CHAPTER 3 Elbow and Forearm
the forearm, sensation to the palmar aspect of the base of the t h u m b is also affected. If a more distal injury occurs, such as a carpal tunnel syndrome, sensation is preserved on the palmar aspect of the base of the t h u m b because the palmar cutaneous branch of the median nerve is given off before the median nerve enters the carpal tun- nel (Fig. 3-41).
Anterior interosseous nerve syndrome has no asso-
ciated sensory deficit.
The ulnar nerve supplies sensation to the little finger and the ulnar aspect of the ring finger. Any injury to the ulnar nerve at the level of the wrist or more proximally results in the loss of sensation in this distribution. Injuries that occur more proximally, such as at the elbow, also affect sensation over the dorsal ulnar part of the hand (Fig. 3-42).
The radial nerve supplies sensation to the dorsum of the hand, particularly over the first web space. An injury to the radial nerve at the level of the elbow or above affects sensation in this area (Fig. 3-43).
Special Tests
NERVE COMPRESSION SYNDROMES
Cubital Tunnel S y n d r o m e . The most common nerve compression syndrome occurring about the elbow is the
cubital tunnel syndrome involving the ulnar nerve. This syndrome can occur spontaneously or in association with many other factors, such as activities requiring repetitive elbow movements, osteoarthritis, rheumatoid arthritis, fractures and dislocations, cubitus valgus, and instability of the ulnar nerve. Rarely, an anomalous muscle known as the anconeus epitrochlearus crosses the ulnar nerve in the region of the medial epicondyle and may also cause this syndrome. Typical symptoms of cubital tunnel syndrome include achy pain in the medial forearm and paresthesias in the sensory distribution of the ulnar nerve in the hand. The most common screening test for cubital tunnel syndrome is described in the Palpation section, under Medial Aspect, Ulnar Nerve: percussion of the ulnar nerve between the medial epicondyle and the olecranon process to elicit Tine's sign. The elbow flexion test is another provocative test for ulnar nerve compression at the elbow. To perform the elbow flexion test, the examiner passively flexes the patient's elbow to the maximal degree possible and holds it in this position for a minute or more (Fig. 3-44). In the presence of cubital tunnel syndrome, the patient often reports the gradual development of pares- thesias in the small finger and the ring finger. These symp- toms may be further accentuated by applying digital pressure directly over the ulnar nerve as it runs through the cubital tunnel. This combination of prolonged passive