Ganglion Cyst Carpal Tunnel

Ganglion Cysts Pressure Motor Branch of Median Nerve

After passing through the carpal tunnel, the median nerve gives a branch on the radial side called the recurrent motor branch. The recurrent motor branch innervates the abductor pollicis brevis, the flexor pollicis brevis (superficial head), and the opponens pollicis muscles.

The recurrent motor branch of the median nerve has multiple variations of the nerve. 50% are extraligamentous with recurrent innervation. 30% are subligamentous with recurrent innervation. 20% are transligamentous with recurrent innervation. When you release the carpal tunnel, it is important to cut the transverse carpal ligament far ulnarly to avoid cutting the recurrent motor branch of the median nerve. These are the patients that will get motor symptoms after you do carpal tunnel release. There is another entity similar to this entity, and these are the patients that have symptoms similar to carpal tunnel syndrome, but their presentation is not classic. These are the patients that you may need to get an MRI or ultrasound to check the carpal tunnel area. Pain symptoms of carpal tunnel syndrome occur more at night. Self-administered hand diagram is extremely helpful (most specific test for carpal tunnel syndrome). The patient should highlight the areas where they are experiencing the symptoms. The patient may complain of thenar atrophy, weakness, or clumsiness of the hand. The positive compression test (Durkan’s test) is the most sensitive test. You can see the Tinel’s Sign, do the Phalen’s test, or the Semmes Weinstein test. Some physicians believe that EMG doesn’t really increase the diagnostic value of these tests (if you have a combination of these test), and you will proceed with surgery even if the EMG is normal. The problem is, that you will find a group of patients that have weakness and atrophy of the thumb muscles, and the provocative and sensory tests for carpal tunnel syndrome are negative. These are the patients that you will get an MRI to rule out pressure on the motor branch of the median nerve. These are the patients that you will probably find a ganglion cyst pressuring the motor branch of the median nerve.