By Johnny Barthel, OTR, CHT
What is Intersection Syndrome?
When one thinks of an intersection, one may correlate this with a place of crossing. In the radial aspect (thumb side) of the distal forearm, there is a place of crossing as well. In an individual’s distal forearm, there is a location where two muscle bellies groups cross or “intersect.” These muscle bellies/tendons are housed in different sections in the forearm that are referred to as compartments.
By being located on the back or the dorsal (posterior) aspect of the forearm these compartments are referred to as dorsal compartments. These compartments contain the extensors of the digits and of the wrist. There are six dorsal extensor compartments. Within these six compartments, two of them cross or “intersect.” The two compartments that cross or “intersect” are known as the first dorsal extensor compartment (extensor pollicis brevis (EPB)/ abductor pollicis longus (APL)) and second dorsal extensor compartment (extensor carpi radialis longus (ECRL)/ extensor carpi radialis brevis (ECRB)).
At the location of intersection, an individual may experience inflammation or irritation. These symptoms may result in a great deal of discomfort or pain. If an individual consult his or her physician with these symptoms in this particular region, he or she may be diagnosed with what has been coined as intersection syndrome.
Intersection Syndrome Defined
Intersection syndrome is defined as the friction at the point where the muscle bellies of the EPB and the APL cross over the radial wrist extensors tendons proximal to the wrist joint approximately 4-5 cms., resulting in an inflammatory (swelling/irritation) peritendonitis.
This syndrome or condition may result from activities that involves a clenched fist with the thumb abducted. This may be seen in activities such as rowing, weight lifting, hammering, fishing, or any other behaviors that requires grasping an object in this fashion. This may also be associated with other activities requiring frequent or repetitive motions of the second dorsal extensor compartment (ECRL and ECRB).
The symptoms of intersection syndrome may include pain and swelling about the muscle bellies of the EBP and APL. In some severe cases, redness and crepitus (a clicking or crackling sound often heard in movements) maybe present.
It has also been reported that the basic pathology to be a tendon entrapment of the second dorsal extensor compartment (ECRL and ECRB). Nonoperative treatment may consist of the modification of activities, wrist splints, and in some patients an injection into the second dorsal extensor compartment maybe warranted. Furthermore, for persistent pain, a surgery maybe indicated.
Therefore, if an individual encounter these signs and symptoms, he or she should not have to live with the discomfort. It is recommended that the individual seek medical attention to relieve the pain. The treatment that an individual receive should assist in allowing the individual to returning to his or her everyday activities and hobbies with decreased pain. The treatment should also assist an individual in enhancing his or her quality of life painfree.