Golfer’s elbow and tennis elbow are both musculoskeletal pathologies that are hallmarked by elbow pain, hence their names. However, even though these conditions cause elbow pain, they are not conditions of the actual elbow joint; rather, they are overuse syndromes of musculature of the hand and/or the fingers (Images 1A and 1B). Pain is experienced at the elbow because these muscles have their proximal tendinous attachments there.

Biomechanics

The biomechanics of golfer’s and tennis elbow can be nicely compared and contrasted because they are extremely similar, although they are somewhat mirror opposites of each other. The muscles of golfer’s elbow have their proximal attachments on the medial epicondyle of the humerus, so golfer’s elbow causes medial elbow pain; whereas the muscles of tennis elbow attach onto the lateral epicondyle of the humerus, so tennis elbow causes lateral elbow pain.

Golfer’s elbow is an overuse condition of excessive flexion of the hand at the wrist joint and flexion of the fingers at the metacarpophalangeal (MCP) and interphalangeal (IP) joints, resulting in overuse of the anterior flexor compartment of the forearm musculature. In contrast, tennis elbow is primarily an overuse syndrome of excessive extension of the hand at the wrist joint and extension of the fingers at the MCP and IP joints, resulting in overuse of the posterior extensor compartment of the forearm musculature.

Elbow Pains by Different Names

Golfer’s and tennis elbow have classically been described as medial epicondylitis and lateral epicondylitis, respectively, because pain experienced with these conditions is usually situated at, or near, the medial or lateral epicondyle of the humerus.

Pain from tennis elbow occurs primarily at the lateral epicondyle because backhand strokes require wrist joint extension. This extension stresses the musculature of the common extensor belly/tendon that attaches at the lateral epicondyle of the elbow.

Pain from golfer’s elbow occurs primarily at the medial epicondyle because gripping and swinging a golf club (and a forehand stroke in tennis) requires wrist and finger joint flexion. This flexion stresses the musculature of the common flexor belly/tendon that attaches at the medial epicondyle of the humerus.

Because inflammation often accompanies these conditions, the suffix itis is part of the names. However, in recent years, it has become understood that the inflammation is often only present when the condition is acute. When the condition becomes chronic, the inflammation recedes or disappears; therefore, the more general terms, medial epicondylosis and lateral epicondylosis, are applied instead. The suffix osis simply means condition of and does not imply inflammation.

New terms have recently gained favor, including medial elbow tendinopathy for golfer’s elbow and lateral elbow tendinopathy for tennis elbow. These terms are likely better because they capture both the acute inflamed phase and the chronic noninflamed phase.

Golfer’s Elbow

Golfer’s elbow involves five muscles that all attach to the medial epicondyle of the humerus and along the medial supracondylar ridge of the humerus. These five muscles are the pronator teres, the three muscles of the wrist flexor group (the flexor carpi radialis, palmaris longus, and flexor carpi ulnaris), and the flexor digitorum superficialis (Image 2). These muscles attach to the medial epicondyle via what is known as the common flexor tendon because the proximal tendons of these muscles blend into each other. Perhaps a better name might be the common flexor belly/tendon because their bellies blend together before their tendons merge.

As the name common flexor implies, these muscles are involved with flexion. The three muscles of the wrist flexor group all cross the wrist joint anteriorly, so they flex the hand at the wrist joint. The flexor digitorum superficialis crosses the wrist joint anteriorly and the MCP and proximal IP joints of fingers 2–5 (index, middle, ring, and little) anteriorly, so it flexes the hand and fingers. The pronator teres pronates the forearm at the radioulnar joints. And all five golfer’s elbow muscles cross the elbow joint anteriorly, so they all flex the elbow joint as well (Image 3).

Common Tendons

The common flexor tendon is sometimes referred to as the common flexor/pronator tendon because the pronator teres is one of the involved muscles and is not involved in wrist or finger flexion; but does do forearm pronation at the radioulnar joints. In fact, even the flexor carpi radialis crosses the radioulnar joints and can pronate the forearm, so including the word pronation in the name of this common tendon is even more justified.

Similarly, the common extensor tendon can be referred to as the common extensor/supinator tendon because the extensor carpi radialis brevis can assist forearm supination. Also, although the supinator is not technically part of this common tendon, it also attaches to the lateral epicondyle of the humerus, immediately adjacent to the attachment of the common extensor/supinator tendon.

And given the possible inclusion of the word belly to these terms, we would have the common flexor/pronator belly/tendon and the common extensor/supinator belly/tendon!

Any of these joint actions of flexion of the wrist, fingers, and forearm—and pronation of the forearm—places a stress on the myofascial tissue of the musculature of this group, as well as its attachment onto the medial epicondyle of the humerus, where all their common tendinous attachment is located. Even though golfer’s elbow was originally described for its periosteal inflammation of the humeral attachment, before the humeral inflammation occurred, golfer’s elbow involved common flexor tendinopathy. And before the tendinopathy occurred, golfer’s elbow began as an overuse and tightness of the muscular tissue of the muscles involved. So, what was originally named as a condition of the bone, was before that a condition of the tendon, and before that, an overuse condition of musculature. This factor is often missed in allopathic treatment of this condition.

Tennis Elbow

Tennis elbow is nearly a mirror opposite of golfer’s elbow. Whereas golfer’s elbow involves five muscles that all attach to the medial epicondyle of the humerus, tennis elbow involves four muscles that all attach to the lateral epicondyle of the numerus.

The four muscles of the tennis elbow group are the extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, and the extensor carpi radialis brevis (Image 4). The extensor carpi radialis brevis and extensor carpi ulnaris are members of the wrist extensor group. These muscles attach to the lateral epicondyle via what is known as the common extensor tendon because the proximal tendons of these muscles blend into each other. A better name for this group would be the common extensor belly/tendon because, as with the musculature of golfer’s elbow, the bellies of the muscles of the common extensor tendon also blend together before their tendons do.

As the name common extensor implies, these muscles are involved with extension. The two extensor carpi muscles cross the wrist joint posteriorly, so they extend the hand at the wrist joint. The extensor digitorum crosses the wrist joint posteriorly and the MCP and proximal and distal IP joints of fingers 2–5 posteriorly, so it extends the hand and fingers. The extensor digiti minimi crosses the wrist and the MCP and IP joints of the little finger, so it extends those joints.

Only at the elbow joint does some of the mirror symmetry between the common flexor and common extensor groups disappear. The extensor carpi radialis brevis of the common extensor group actually flexes the elbow joint because it crosses it anteriorly (Image 5). All other wrist extensor muscles of the tennis elbow group cross the elbow joint posteriorly, so they extend the elbow joint as they extend the wrist and finger joints that they cross. All of these joint actions place a stress on the musculature of this group, as well as on its attachment onto the lateral epicondyle of the humerus.

Even though tennis elbow was originally described for its periosteal inflammation of the lateral epicondylar humeral attachment, before the humeral inflammation occurred, tennis elbow involved common extensor tendinopathy; and before the tendinopathy occurred, it began as an overuse and tightness of the myofascial tissue of the muscles involved.

In addition to the stress of the joint motions just described, tennis elbow has another cause. Whenever the fingers flex to grip an object, the finger flexor muscles (flexor digitorum superficialis and flexor digitorum profundus) also cause the hand to flex at the wrist joint. To keep the wrist joint in a neutral anatomic position so that grip strength is optimal, the wrist joint must be stabilized. This is primarily accomplished with isometric contraction of the extensor carpi radialis brevis of the tennis elbow group (Image 6). For this reason, in addition to extension motions of the wrist and hand, tennis elbow is also caused by finger flexion whenever we grip an object. This is another asymmetry between golfer’s and tennis elbow. Whereas golfer’s elbow is caused solely by flexion, tennis elbow is often thought of as being caused solely by extension, but is also caused by activities of life that involve finger flexion.

This may account for why tennis elbow tends to occur more often than golfer’s elbow. Another reason might be that the size of the tennis elbow lateral epicondylar attachment is so much smaller than the golfer’s elbow medial epicondylar attachment. Therefore, the force of the contraction of the tennis elbow musculature is more concentrated over a smaller surface area of bone (Image 7).

Keep in mind, tennis elbow is not necessarily caused by playing tennis, nor is golfer’s elbow caused only by playing golf. Indeed, any of the joint actions or joint stabilizations mentioned here could cause these conditions. Lifting a container of milk or holding a steering wheel or pen for prolonged periods of time could result in golfer’s and/or tennis elbow. In fact, when we look at the long periods of time we spend gripping and holding a smartphone, we can see that the predisposition to develop these conditions is tremendous. Also, repetitive flexion or extension motions of the hand at the wrist joint (such as working as a cashier or performing manual labor carpentry) could cause golfer’s or tennis elbow.

Indeed, most every daily activity places physical stresses into the upper extremity that could contribute to the incidence of these conditions. This is why golfer’s and tennis elbow are so prevalent.

The Myth of Proper Form

It is often claimed that if a tennis player develops tennis elbow, then their form must be poor. This is simply not true. Proper tennis form minimizes the risk of the player developing golfer’s or tennis elbow but does not completely negate the risk.

When executing a backhand, the hand is gripping the handle of the racquet, which can contribute to the development of either golfer’s or tennis elbow. This is because of the isometric contraction of the finger flexor muscles (flexor digitorum superficialis of the golfer’s elbow group), as well as isometric contraction of the wrist extensor musculature to stabilize the wrist (primarily extensor carpi radialis brevis of the tennis elbow group). During the backhand stroke, the hand should remain stable and not move into extension as the stroke is performed.

Certainly, if the player does have poor form and does break the wrist into extension, then they are placing an additional stress force into the wrist extensor musculature of the tennis elbow group. But, even if the wrist joint is held perfectly stable—as it should be—the force of the ball hitting the face of the racquet would cause the wrist joint to collapse into flexion if it were not for the isometric stabilization of the wrist extensor musculature of the tennis elbow group.

When we look at the distance from the ball striking the racquet strings to where the hand grips the handle, we see that there is a tremendous leverage force that multiplies many times over the contraction force that is required of this musculature. If the speed of the ball is great, the force increases even more.

What often causes a tennis player to develop tennis elbow is a sudden increase in play (such as seasonal changes in activity) or playing an opponent who hits the ball harder than they are accustomed to. Similarly, these concepts apply to the development of golfer’s elbow when playing tennis, although this usually involves the forehand stroke and/or serve.

Images

<Image 1a>Golfer’s elbow causes pain at the medial elbow. Anterior view of the right upper extremity.

<Image 1b>Tennis elbow causes pain at the lateral elbow. Posterior view of the right upper extremity.

(Permission: Dr. Joe Muscolino, The Muscular System Manual, 4th edition, Elsevier, 2015.)

<Image 2>The muscles of golfer’s elbow common flexor belly/tendon group. Anterior view of the right upper extremity. (Permission: Dr. Joe Muscolino, The Muscular System Manual, 4th edition, Elsevier, 2015.)

<Image 3>Bones and joints of the upper extremity, right side. (Permission: Dr. Joe Muscolino, Kinesiology: The Skeletal System and Muscle Function, 3rd edition, Elsevier, 2015.)

<Image 4>The muscles of tennis elbow common extensor belly/tendon group. (Permission: Dr. Joe Muscolino, The Muscular System Manual, 4th edition, Elsevier, 2015.)

<Image 5>The extensor carpi radialis brevis of the common extensor muscle group actually crosses the elbow joint anteriorly, so it flexes the forearm at the elbow joint. Lateral view of the right upper extremity. (Permission: Dr. Joe Muscolino, The Muscular System Manual, 4th edition, Elsevier, 2015.)

<Image 6>Contraction of flexor digitorum superficialis and/or profundus to flex the fingers and grip an object would also cause the hand to flex at the wrist joint. To prevent this, wrist extensor musculature must isometrically contract to stabilize the wrist joint. (Permission: Dr. Joe Muscolino.)

<Figure 7>Anterior view of the lateral and medial epicondyles of the humerus on the right side of the body. Note how much smaller the lateral epicondyle is than the medial epicondyle. (Permission: Dr. Joe Muscolino.)