pathology: pronator teres syndrome PTS

yogabook / pathology / pronator teres syndrom

Definition

Pronator teres syndrome is a comparatively rare nerve compression syndrome of the median nerve in the area of the pronator teres in the forearm. This nerve usually runs between the two heads of the pronator teres (origin at the humerus and origin at the ulna). In between, it may be subjected to compression by the muscle, but also by fibrous structures of the flexor digitorum superficialis. Another possibility is that an accessory tendon of the brachialis or the lacertus fibrosus (aponeurosis bicipitalis) exerts pressure on the nerve. The demand-responsive hypertrophy of the above muscles is an important pathomechanism. However, acute pressure damage can also occur in practice, e.g. as a result of a head being placed on the head, such as that of a partner: „honeymoon paralysis“ or a baby during breastfeeding.

After carpal tunnel syndrome, this is the second most common lesion of the median nerve. The pronator-teres syndrome is often a cumulative trauma disorder.

Predisposing

  1. Frequent alternation between pronation and supination of the forearm.

Cause

  1. Exposure of the nerve to pressure from neighbouring structures
  2. proximal forearm fracture
  3. neurinoma
  4. Haematoma

Diagnosis

  1. EMG, can also be O.B.
  2. Nerve conduction velocity, may also be O.B.
  3. Tests and signs: Pressure tenderness des Pronator teres, Schmerzprovokation durch resisted pronation, positives Hoffmann-Tinel-Zeichen des proximal N. medianus
  4. possibly weakness of the finger flexors with bottle sign (grasping a bottle is incomplete or not strong on the thumb side – disruption of abductor pollicis brevis and opponens pollicis)

Symptoms

  1. Pressive pain in the area of the pronator teres
  2. Paresis of the radial three and a half fingers as in carpal tunnel syndrome and the abductor pollicis brevis, if the anterior interosseous nerve is also affected flexor pollicis longus, pronator quadratus
  3. Paraesthesia in the supply area of the median nerve

Therapy

  1. Conservative: stress reduction, immobilisation, anti-inflammatory drugs if necessary
  2. Only if conservative therapy fails: surgery (neurolysis)

DD

  1. Carpal tunnel syndrome (Flexor pollicis longus nicht betroffen)

external links