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Pronator Teres, Rx, Hx, PE
This is a draft cheat sheet. It is a work in progress and is not finished yet.
Pronator Teres
- Compression of median nerve by pronator teres
- Median nerve innervates most of the flexor muscles of the forearm and hand
- Sensation to volar forearm and first 3 and a half digits
Path
- Median nerve passes through cubital fossa at forearm |
- Passes beneath bicipital aponeurosis and arch of the FDS |
- Passes between superficial and deep heads of the pronator teres |
Causes
- Prolonged/repetitive forearm pronation and finger flexion (gripping with palm down) |
- More common in dominant arm |
- Usually in fifth decade |
- Four times more common in women |
- Diabetes, alcoholism or hypothyroidism increases risk |
Hx
- Aching discomfort in volar forearm |
- Paresthesia in first three and a half digits |
- Can present similar to CTS (noctural pain usually absent and symptoms increase in repetitive/resisted forearm supination/pronation in PTS) |
PE
- TTP over pronator teres, medial epicondyle |
- +ve Tinel sign (proximal anterior forearm) |
- -ve Phalans/Tinels at carpal tunnel |
- +ve Pronator Teres test |
- Weakness of FPL, FDP, Pronator Quad - grip |
- Assess for Cx radiculopathy - weakness of wrist extensors and triceps |
- Assess for other areas of entrapment (see below) |
Sites of entrapment
Ligament of Struthers - Anatomical variant (1%)
Ligament attaches from supracondylar process to the medial episcondyle
Palpate distal humerus (5cm proximal to medial epicondyle) |
Thickened bicipital aponeurosis - Occurs in resisted elbow flexion (120-130 degrees) with the forearm in maximal supination |
Thickened proximal edge of the arch of the FDS - Resisted flexion of middle finger |
AINS Anterior interosseous nerve - branch of the median nerve gets entrapped purely motor unable to do "ok" sign |
DDx
- Double crush |
- Cx arthropathy |
- Cx disc |
- Brachial plexus neuritis |
- TOS |
- CTS |
- Cubital tunnel entrapment |
Imaging
Above image shows supracondylar process on x-ray
- X-ray if supracondylar process , deformity, f#, neoplasm
- MRI - tumours, cysts, osseous spurs, anatomical varients
- US
Management
- Rest |
- Nerve gliding exercises |
- Avoid repetitive/forceful gripping |
- Splint if severe for two weeks |
- Night splint |
- Cryotherapy over pronator teres |
- US (15 mins 1MHz, 1 watt 25% duty cycle) and elec stim |
- Stretching and myofascial release of hypertonic pronator teres and wrist flexors |
- Sx if failure to respond to conservative care within 4 months |
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