Ulnar collateral ligament anatomy and function

¶ … Ulnar Collateral Ligament. Discussed is how one can injure it and what can one do for it.

Ulnar collateral Ligament structure that holds bones together and aides in controlling movement of joints in a ligament. It is like a tether between the bones, "which gets too tight when the bones move...When a ligament is torn, the tether is too long and the bones move too much" (Eisner pg).

This causes pain and an instability and/or looseness. It can also lead to the inability to work at one's profession or activities, especially sports. "The ulnar collateral ligament complex (UCL) is lovated on the inside (or medial side) of the elbow (small finger of the arm)" (Eisner pg). The three bands or divisions that compose it are the anterior, posterior, and transverse bands. The ulnar collateral ligament "attaches on one side of the humerus (the bone of the upper arm) and on the other side to the coronoid process of the ulna (a bone in the forearm)" (Eisner pg).

The anterior band is the arm's primary restraint from elbow stress. The posterior and transverse bands work less to stabilize the elbow. "The largest stresses in the elbow are those forces that cause twisting and bending of the elbow, such as the throwing of a baseball or javelin" (Eisner pg). During certain parts of the motion, these throwing type motions put extreme stress on the ligament. Throwing athletes often complain of medial elbow pain. This pain is especially felt during an overhead throw. The pain is can be chronic or recurrent and "may lead to a slow erosion of throwing ability" (Kacprowicz pg). When athletes suffer acute pain over the medial elbow, they may associate it with a 'pop,' and this single throw will cause them to stop throwing immediately (Kacprowicz pg).

Most commonly, there is a gradual onset of medial elbow pain due to repetitive stresses on the ligament" (Eisner pg). For athletes engaging in an overhead or throwing sport, poor mechanics, inflexibility, or fatigue can lead to muscle strain which places even more stress on the ulnar collateral ligament. "These stresses create microscopic tears in the ligament, which can add up to one big tear over time" (Eisner pg). The ligament begins to stretch and becomes too long, thus it can no longer hold the bones tightly enough for throwing activities (Eisner pg). It is common for athletes to feel pain on the inside of the elbow after heavy throwing or some other overhead activity, or he or she may be unable to throw beyond fifty percent on successive attempts. The pain is most often felt during the phase of throwing when the arm accelerates forward, just before releasing the ball (Eisner pg). Sometimes an athlete may feel irritation of the ulnar nerve, or funny bone, on the medial side of the elbow. The is caused by stress on the nerve once the ligament is stretched. The athlete may experience tingling or numbness in the last two fingers, small and ring fingers, in the hand (Eisner pg). Although, the instability from the tear of the ulnar collateral ligament may inhibit participation in throwing sports, it is not likely to effect daily activities. "Interestingly, a tear of the UCL rarely prevent exercising, lifting weights, batting, running, or other non-throwing sports" (Eisner pg).

To diagnose a tear of the ulnar collateral ligament, a physician must complete a history and physical examination. "A valgus stress test, in which the physician tests the patient's elbow for instability, is the best way for the physician to assess the condition of the UCL" (Eisner pg). The most notable findings are medial elbow tenderness. "UCL tenderness may occasionally be difficult to differentiate from flexor pronator tendonitis, but the pain of flexor pronator tendinitis is aggraated by resisting forearm pronation" (Kacprowicz pg). Other symptoms may include loss of elbow range of motion, ecchymosis may be seen over the medial elbow with an acute rupture, and pain when making a clenched fist (Kacprowicz pg). An x-ray or an MRI, magnetic resonance scan, may also be used to "further assess the condition of the structures in the patient's elbow, but these tests are not the sole basis for a diagnosis" (Eisner pg). These tests will often indicate changes in the ligament indicating stress. Moreover, these tests may also show a definite ligament tear. The injection of dye, gadolinium, into the joint before an MRI may increase the accuracy of the test. "Arthroscopy is believed by some authors to be the most specific diagnostic procedure because it allows visualization of the medial compartment while valgus stress is applied" (Kacprowicz pg). However, when diagnosing a suspicious ulnar collateral ligament injury, a good history and physical examination are the most reliable (Kacprowicz pg). Because examinations are often inexact and tests are not 100% accurate, making a diagnosis is the most difficult part of treating a ulnar collateral ligament problem (Eisner pg).