Your elbow joint or shoulder joint is where three bones in your arm meet: your upper arm bone (humerus) and the two bones in your forearm (radius and ulna). It is a combination hinge and pivot joint. The hinge part of the joint lets the arm bend and straighten; the pivot part lets the lower arm twist and rotate.
At the upper end of the ulna is the olecranon, the bony point of the elbow that can easily be felt beneath the skin.
On the inner and outer sides of the elbow, thicker ligaments (collateral ligaments) hold the elbow joint together and prevent dislocation. The ligament on the inside of the elbow is the ulnar collateral ligament (UCL).
It runs from the inner side of the humerus to the inner side of the ulna, and must withstand extreme stresses as it stabilizes the elbow during overhand throwing.
Several muscles, nerves, and tendons (connective tissues between muscles and bones) cross at the elbow. The flexor/pronator muscles of the forearm and wrist begin at the elbow, and are also important stabilizers of the elbow during throwing.
The ulnar nerve crosses behind the elbow. It controls the muscles of the hand and provides sensation to the small and ring fingers.
Cause & Symptoms
Elbow and shoulder injuries in throwers are usually the result of overuse and repetitive high stresses. In many cases, pain will resolve when the athlete stops throwing. It is uncommon for many of these injuries to occur in non-throwers.
In baseball pitchers, rate of injury is highly related to the number of pitches thrown, the number of innings pitched, and the number of months spent pitching each year. Taller and heavier pitchers, pitchers who throw with higher velocity, and those who participate in showcases are also at higher risk of injury. Pitchers who throw with arm pain or while fatigued have the highest rate of injury.
Most of these conditions initially cause pain during or after throwing. They will often limit the ability to throw or decrease throwing velocity. In the case of ulnar neuritis, the athlete will frequently experience numbness and tingling of the elbow, forearm, or hand as described above.
The medical history portion of the initial doctor visit includes discussion about the athlete’s general medical health, symptoms and when they first began, and the nature and frequency of athletic participation.
During the physical examination, the doctor will check the range of motion, strength, and stability of the elbow. He or she may also evaluate the athlete’s shoulder.
The doctor will assess elbow range of motion, muscle bulk, and appearance, and will compare the injured elbow with the opposite side. In some cases, sensation and individual muscle strength will be assessed.
The doctor will ask the athlete to identify the area of greatest pain, and will frequently use direct pressure over several distinct areas to try to pinpoint the exact location of the pain.
To recreate the stresses placed on the elbow during throwing, the doctor will perform the valgus stress test. During this test, the doctor holds the arm still and applies pressure against the side of the elbow. If the elbow is loose or if this test causes pain, it is considered a positive test. Other specialized physical examination maneuvers may be necessary, as well.
The results of these tests help the WBJ physician decide if additional testing or imaging of the elbow is necessary.
X-rays. This imaging test creates clear pictures of dense structures, like bone. X-rays will often show stress fractures, bone spurs, and other abnormalities.
Computed tomography (CT) scans. These scans are not typically used to help diagnose problems in throwers’ elbows. CT scans provide a three-dimensional image of bony structures, and can be very helpful in defining bone spurs or other bony disorders that may limit motion or cause pain.
Magnetic resonance imaging (MRI) scans. This test provides an excellent view of the soft tissues of the elbow, and can help your doctor distinguish between ligament and tendon disorders that often cause the same symptoms and physical examination findings. MRI scans can also help determine the severity of an injury, such as whether a ligament is mildly damaged or completely torn. MRI is also useful in identifying a stress fracture that is not visible in an x-ray image.