Carpal tunnel syndrome is the most common upper limb peripheral neuropathy, and it’s characterized by pain, numbness, tingling, and weakness in the parts of the hand innervated by the median nerve, namely the thumb and index, middle, and half the ring finger. Because it’s such a common diagnosis for these symptoms, it’s not unusual for carpal tunnel syndrome to be misdiagnosed in place of another condition: pronator teres syndrome.
The median nerve runs down the center of the forearm on the palm side and passes through multiple narrow openings and tight spaces enroute to the hand, including near the pronator teres muscle in the forearm. If the mobility of the median nerve is restricted at this site, then it can produce many of the same symptoms as carpal tunnel syndrome with some differences we’ll cover shortly. If a healthcare provider assumes compression at the wrist is to blame, then they may prescribe treatment that fails to provide lasting relief for the patient, if at all. In fact, a third of misdiagnosed pronator teres syndrome cases are initially thought to be carpal tunnel syndrome, and about one-in-sixteen carpal tunnel syndrome patients have co-occurring pronator teres syndrome. One study looked at surgical outcomes of patients with both conditions who underwent carpal tunnel release and found a third continued to experience ongoing symptoms.
The clinical history and exam are most helpful to differentiate the conditions. In the case of pronator teres syndrome, symptoms may be more apparent in the forearm, especially when rotating the palm downward or during gripping activities. Pronator teres symptoms are also more present during the day and less so at night (sleep problems are more common with carpal tunnel syndrome). The palmar cutaneous branch of the median nerve splits off before the carpal tunnel and enters the hand via a different route. If compression of the median nerve occurs before the split (at the pronator teres, in this case), then the patient may also experience diminished sensation in the palm—an uncommon finding with carpal tunnel syndrome. A chiropractor will also perform compression tests over the pronator teres muscle to see how quickly symptoms are provoked (faster suggests compression is already occurring there).
Pronator teres syndrome serves as an excellent reminder on the importance of approaching musculoskeletal disorders like carpal tunnel syndrome from a holistic perspective as the symptoms associated with the condition may not always be the result of an issue exclusive to the area of chief complaint. That’s why doctors of chiropractic check the entire course of the median nerve when examining a patient. While the carpal tunnel is the likely culprit, it’s not always the case and there may also be compression at both the wrist and elsewhere on the nerve’s course, like the pronator teres muscle. The good news is that chiropractic also offers an excellent non-surgical approach for managing pronator teres syndrome!
