19 julio, 2024

Epicondyle: concept, characteristics, functions and pathologies

What is the epicondyle?

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. In the past, in anatomical nomenclature the epicondyle referred exclusively to the lateral epicondyle of the humerus. Two epicondyles are currently described for the humerus and two for the femur.

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 attach to the lateral epicondyle of the humerus, namely the anconeus muscle, the extensor carpi radialis brevis, the extensor digitorum commonis, the extensor digitorum propria, the extensor carpi ulnaris, and the supinator brevis.

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

The medial or medial epicondyle of the femur houses the third adductor tubercle. The lateral epicondyle of the femur is smaller than the medial epicondyle, and it is here that the fibular collateral ligament of the knee joint attaches.

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 they can be the object of any other pathological process like any other organ or body tissue.

Characteristics and functions of the epicondyle

The distal or inferior epiphysis of the humerus is formed by the trochlea, the condyle, the epitrochlea or medial epicondyle, and the lateral epicondyle. The epitrochlea is rough in its anterior part and gives origin to the flexors of the forearm. Behind it is the epitrochleoolecranial canal through which the ulnar or ulnar nerve passes.

The lateral epicondyle gives rise to the anconeus muscle, the supinator brevis, and the extensor muscles of the forearm. The humeral epicondyles lie in close proximity to the course of the brachial artery and the ulnar nerve.

Because of its close proximity to the epitrochlea (medial epicondyle of the humerus), fractures of these epicondyles can cause ulnar nerve injury. Supracondylar humeral 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 are inserted in 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 support point 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 humerals.

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 at the site where it inserts into the bone, that is, at the epicondyle. Tennis elbow or lateral epicondylitis is one of the most frequent epicondylitis associated with sports practice.

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

In tendonitis, fluid accumulated due to inflammation causes edema (swelling) of the sheath that covers the tendon. This produces a thickening of the tendon sheath that causes pain, limiting movement.

The lesion can cause small local bleeding, edema and pain, affecting a tendon or spreading to the other tendons inserted in the corresponding epicondyle. If the process is repeated, after a while, calcium begins to be deposited 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 peak of pain is reached progressively and the movement of the joint is not mechanically limited.

Another epicondylitis associated with sports practice is medial epicondylitis of the elbow called golfer’s elbow, which produces inflammation of the medial epicondyle of the humerus. The symptoms are similar to the above but affect the medial epicondyle.

Femoral epicondylitis in sports practice

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

This iliotibial band is the tendon of the tensor fascia lata muscle. This band originates from the greater trochanter of the femur by fusion of the tendon of the tensor fascia lata 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 rubbing against the epicondyle during the race can cause inflammation of both structures, which causes pain in the area.

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

Other causes of epicondylitis

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

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

20% of the 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 the patients present elbow dislocation.

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