Intersection syndrome is an uncommon overuse injury of the forearm.
Intersection syndrome is an uncommon overuse injury of the forearm. It is termed ‘intersection’ due the pathologic relationship at the intersection of the 1st dorsal compartment (containing the abductor pollicis longus [APL] and extensor pollicis brevis [EPB]) and the 2nd dorsal compartment (containing the ECRL, ECRB). This syndrome has also been referred to as crossover syndrome, peritendinitis crepitans, oarsmen's wrist, squeaker's wrist, Bugaboo forearm, adventitial bursitis, subcutaneous perimyositis, chronic synovial tendonitis, hydropsia of the tendon, and abductor pollicis longus syndrome.
Muscles of the 1st and 2nd extensor compartments Anatomy Understanding the anatomy of the dorsal forearm is critical to diagnosing and managing intersection syndrome. The abductor pollicis longus (APL) muscle originates along the mid-proximal radius, ulna and interosseous membrane and inserts on the 1st metacarpal. The extensor pollicis brevis (EPB) muscle originates along the same distribution and attaches at the proximal phalanx of the thumb.
Both muscles are innervated by the posterior interosseous nerve and are responsible for abduction and extension of the thumb. The two tendons form the first extensor compartment of the wrist. Note that these compartment can also cause de quervain’s tenosynovitis.
The two tendons form the lateral border of the anatomical snuff box. The extensor carpi radialis longus (ECRL) muscle originates at the lateral supracondylar ridge of the humerus and attaches distally to the 2nd metacarpal. The extensor carpi radialis brevis (ECRB) originates at the lateral epicondyle and helps form the common extensor tendon and attaches distally to the 3rd metacarpal.
Both muscles are innervated by the radial nerve and are responsible for abduction and extension of the hand. These two tendons form the second dorsal compartment of the wrist. Generally these two muscles share a common tendon sheath, although there is an anatomic variant where they each have their own tendon sheath.
If you are experiencing symptoms that may be related to intersection syndrome: a review, it is important to see a sports medicine physician. Early evaluation and treatment typically lead to better outcomes. Do not ignore pain or symptoms that are limiting your activity.
*This article is for educational purposes only and does not substitute for professional medical advice. Always consult a qualified healthcare provider.*
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