Because many of today’s careers require constant motion of isolated muscle groups, repetitive motion injuries are one of the most common problems faced by healthcare workers. When such an injury involves the forearm, median nerve compression is a likely consequence. If entrapment of the median nerve is found to be responsible for arm or hand pain, tingling or numbness, a hypertonic pronator teres muscle could be the culprit. By applying several of Doug Alexander’s nerve mobilization techniques, bodyworkers can bring surprisingly swift and effective relief to someone with a pronator teres overuse injury.
Pronator Teres Syndrome
Pronator teres syndrome (PTS) is a painful nerve entrapment condition where the median nerve is placed under abnormal pressure by the pronator teres muscle. Functioning to pronate the forearm, the pronator teres muscle attaches to both the humerus and ulna bones near the elbow and then diagonally cross to the radius bone. When stressed, this muscle’s hypertonicity can apply pressure on the median nerve, especially where the nerve passes between the pronator teres’ two heads.
Pain elicited from a tight pronator teres is usually located in the forearm, wrist and the thenar side of the palmar aspect of the hand. Similar to carpal tunnel syndrome (CTS), pronator teres syndrome typically squeezes the median nerve producing numbness or tingling in the palm, thumb, forefinger and middle finger. Since the well-known condition of CTS also involves compression of the median nerve, many cases of PTS are mistakenly diagnosed as carpal tunnel syndrome. Also occurring from median nerve compression, CTS results from compression of the carpal tunnel – the wrist’s fibrous sheath that forms a passageway for the median nerve and hand tendons.
Since PTS typically results from repetitive motions that cause hypertonicity in the pronator teres, activities involving recurring pronation are often behind this problem. Some examples of these motions include:
- Cleaning fish
- Prolonged use of screw drivers or other hand tools
- Overhand motions in racquet sports
While PTS and CTS both affect the median nerve and have similar symptoms, there are several differences:
- PTS pain is exacerbated by repetitive elbow flexion, and symptoms arise in the forearm as well as the hand.
- CTS is aggravated by wrist movements, and pain is not experienced as much in the forearm.
- Due to prolonged wrist flexion during sleep, CTS often causes pain at night, while PTS usually does not. (Wrist flexion does not recruit the pronator teres muscle.)
Bodywork Techniques for the Pronator Teres
Overuse injuries from forearm or wrist pronation cause the pronator teres to shorten and become denser, thus increasing the likelihood of compressing the median nerve. Therefore, releasing and lengthening the pronator teres can ease median nerve pressure and relieve PTS symptoms.
In the Institute for Integrative Healthcare’s Nerve Mobilization home study course, Doug Alexander cautions bodyworkers that treating the pronator teres can further aggravate an already irritated median nerve. To prevent this, Alexander advises putting the median nerve on slack in two ways:
- proximally via shoulder girdle elevation and slight elbow flexion
- distally via neutral wrist posture
After giving the median nerve some slack, several techniques can release the pronator teres. While step-by-step instructions are included in the Institute’s Nerve Mobilization workbook, Alexander says the following three techniques usually unravel pronator teres tension:
- Contact Inhibition – Inhibitory contact with the hypertonic parts of the muscle can drain pronator teres tension.
- Post-Isometric Relaxation – Post-isometric relaxation further challenges stubborn pronator teres hypertonicity.
- Sustained Stretching – Sustained stretching helps to lengthen a previously shortened pronator teres.
Nerve pain can be frustrating, especially for those misdiagnosed with carpal tunnel syndrome. By taking a little extra time to evaluate the pronator teres’ involvement in median nerve compression, bodyworkers can provide more targeted, therapeutic treatment. If the pronator teres is hypertonic, protecting the median nerve while combining contact inhibition, post-isometric relaxation and sustained stretching will relieve a majority of PTS cases.