EPICONDYLE: CHARACTERISTICS, FUNCTIONS AND PATHOLOGIES - ANATOMY AND PHYSIOLOGY - 2025

Epicondyle is a bony eminence that is located above or on the condyle of some long bones and that allows the insertion of muscles and ligaments. The condyle is a bony protrusion where an articular surface meets. The term comes from the Greek "epi" which means "on" the condyle.

Epicondyles are described for the upper limb, in the humerus, and for the lower limb, in the femur. Formerly, in anatomical nomenclature the epicondyle referred exclusively to the lateral epicondyle of the humerus. Currently two epicondyles are described for the humerus and two for the femur.

Medial and lateral epicondyle of the humerus (Source: Doctor Jana via Wikimedia Commons)

The epicondyles are found at the distal ends of the humerus and femur. The lateral and medial epicondyle of the humerus and the medial and lateral epicondyle of the femur are described. Six muscles are inserted into the lateral epicondyle of the humerus, which are the anconeus muscle, the extensor carpi radialis brevis, the common extensor digitorum, the extensor digiti minimi, the extensor carpi ulnaris, and the short supinator.

The medial epicondyle of the humerus, which is also called the epicondyle or internal epicondyle of the humerus, is the seat of five muscle attachments that are: the pronator teres muscle, the palmar major, the palmar minor, the ulnar anterior and the superficial common flexor muscle of fingers.

The third adductor tubercle is located in the medial or medial epicondyle of the femur. The lateral epicondyle of the femur is smaller than the medial one and the peroneal collateral ligament of the knee joint attaches there.

The epicondyles can be subject to inflammation from traumatic injuries or from overuse in some sports. Fractures in the area are frequent, especially in children, and can be the object of any other pathological process such as any organ or body tissue.

Features and functions

The distal or inferior epiphysis of the humerus is made up of the trochlea, the condyle, the medial epicondyle or epicondyle, and the lateral epicondyle. The epicondyle is rough in its anterior part and gives rise to the flexors of the forearm. Behind is the epitrochleolecranian canal through which the ulnar or ulnar nerve passes.

The lateral epicondyle gives rise to the anconeus muscle, the short supinator, and the extensor muscles of the forearm. The humeral epicondyles are in the vicinity of the brachial artery and ulnar nerve pathways.

Because of this proximity to the epicondyle (medial epicondyle of the humerus), fractures of these epicondyles can cause injury to the ulnar nerve. Supracondylar humerus fractures, which are very common in children, can involve the brachial artery.

The functions of the epicondyle are to provide an insertion surface for the tendons that insert into the area. In the case of the epicondyles of the humerus, they represent the insertion of origin of the muscles inserted there, therefore, they are the point of support for muscular action.

Unlike the epicondyles of the humerus, which are the seat of the tendons of nine muscles, those of the femur are the site of insertion of only two muscles. However, the function of the femoral epicondyles is similar to that of the humeral ones.

Pathologies

The epicondyles can be subject to various traumatic, infectious, inflammatory or tumor injuries, however, fractures and injuries due to overuse in sports are the most frequent.

Humeral epicondylitis in sports practice

Epicondylitis is an inflammation of the tendon where it inserts into the bone, that is, the epicondyle. Tennis elbow or lateral epicondylitis is one of the most common epicondylitis associated with sports practice.

Tennis elbow (Source: Σχέδιο: Δρ. Χαράλαμπος Γκούβας (Harrygouvas) via Wikimedia Commons)

It is an elbow disease whose main cause is overuse. Tennis epicondylitis is usually due to irritation of the extensor carpi radialis tendon at its original insertion on the lateral epicondyle of the humerus.

In tendinitis, fluid accumulated due to inflammation causes edema (swelling) of the sheath covering the tendon. This results in a thickening of the tendon sheath that causes pain, limiting movement.

The injury can cause small local bleeding, edema and pain, affecting one tendon or spreading to the other tendons inserted in the corresponding epicondyle. If the process is repeated, after a while, calcium begins to deposit in the area of ​​origin of the tendon and calcific tendinitis occurs.

Tennis elbow pain is located locally in the lateral area of ​​the affected elbow, it increases with active movement but not with passive mobilization of the limb. The maximum pain peak is reached progressively and the movement of the joint is not mechanically limited.

Golfer's Elbow (Source: www.scientificaimations.com via Wikimedia Commons)

Another epicondylitis associated with sports is medial elbow epicondylitis called golfer's elbow, which causes inflammation of the medial epicondyle of the humerus. The symptomatology is similar to the previous one but affects the medial epicondyle.

Femoral epicondylitis in sports practice

Iliotibial band syndrome is the most common cause of lateral knee pain in runners, although it can occur with swimming, rowing, cycling, or hiking.

This iliotibial band is the tendon of the tensor fasciae lata muscle. This band originates in the greater trochanter of the femur due to the fusion of the tendon of the tensor fasciae latae with the tendon of the gluteus maximus and medius.

From its origin it descends through the knee joint through the lateral epicondyle of the femur and then inserts into the tibia. Permanent friction against the epicondyle during running can cause inflammation of both structures, causing pain in the area.

The use of acupuncture as an alternative treatment has been used successfully to alleviate the pain of epicondylitis.

Other causes of epicondylitis

Trauma to the epicondyles can cause tendonitis or epicondylitis, causing painful inflammation of the involved tendon (s). Other causes are crystal deposits, postural misalignments, and hypermobility of the joint.

Other common injuries are epicondyle fractures. Frankly displaced fractures of the medial epicondyle cause joint instability and must be resolved surgically.

20% of fractures in the elbow region in pediatric patients correspond to a fracture of the medial epicondyle of the humerus and, in these cases, 60% of patients present with a dislocation of the elbow.

References

1. Abush, S., & Katz, C. (1999). Iliotibial band friction syndrome. Diagnosis and treatment in running patients. Rev Mex Ortop Traumatol, 13 (2), 99-103.
2. Conesa, MV (2010). Incidence of sports injuries in the popular runner. Culture, science and sport, 5 (15), 32.
3. Gardner, ED, Gardner, ED, & O'Rahilly, R. (1986). Gardner-Gray-O'Rahilly Anatomy: A Regional Study of Human Structure Anatomy. WB Saunders.
4. Gottschalk, HP, Eisner, E., & Hosalkar, HS (2012). Medial epicondyle fractures in the pediatric population. JAAOS-Journal of the American Academy of Orthopedic Surgeons, 20 (4), 223-232.
5. McCance, KL, & Huether, SE (2002). Pathophysiology-Book: The Biologic Basis for Disease in Adults and Children. Elsevier Health Sciences.
6. Trinh, KV, Phillips, SD, Ho, E., & Damsma, K. (2004). Acupuncture for the alleviation of lateral epicondyle pain: a systematic review. Rheumatology, 43 (9), 1085-1090.
7. Wiener, CM, Brown, CD, Hemnes, AR, & Longo, DL (Eds.). (2012). Harrison's principles of internal medicine. McGraw-Hill Medical.