What condition is known as proximal intersection syndrome?

Proximal intersection syndrome is characterized by tenosynovitis of the second dorsal compartment, which involves the extensor carpi radialis longus and the extensor carpi radialis brevis tendons. These tendons cross under the first dorsal compartment, where the abductor pollicis longus (APL) and the extensor pollicis brevis (EPB) tendons are located. This anatomical arrangement can lead to friction and irritation between the tendons, especially during repetitive wrist and finger movements.

In this condition, the symptoms typically include pain and swelling in the distal forearm, specifically when performing activities that involve wrist extension and thumb movement. The inflammation occurs due to the mechanical stress on the tendons when they cross over one another, resulting in tenosynovitis in the second dorsal compartment. The clinical presentation and the mechanics of the condition distinctively define proximal intersection syndrome, making the identification of it as related to the second dorsal compartment pivotal in understanding its pathology.