Pronator Quadratus is a deep-seated,short, flat and quadrilateral muscle with fibres running in a parallel direction. The pronator quadratus muscle is compacted in a small closed compartment, covered by the interosseous membrane dorsally and distally and by its own fascia on the volarly. In the anatomical and functional literature, the muscle has been neglected to a high extend.A study shows that the muscle consist of two different heads. The superficial head which is the prime mover in forearm pronation, and the deep head which is dynamic stabilizer of radioulnar joint.
The action of the pronator teres and pronator quadratus muscle result in the pronation of radioulnar joint.Contraction of this muscle pulls the distal end of radius over the ulna, resulting in pronation of the radioulna joint.
The mean length of the muscle is 6 cm.
Mean width of the muscle is 3.5cm.
It can neither be palpated nor be observed as it is the deepest muscle of the forearm.
Myofascial Trigger point (TrP)
Pronator Quadratus muscle has two main referred pain pattern of the TrP.Most commonly pain spreads into the medial aspect of the forearm both distally and proximally.In many cases, the pain is referred proximally to the medial epicondyle and distally to the fifth digit of the hand.Pain also spread distally to the third and fourth finger, which is the second most common pattern.
The electrophysiologic diagnosis of AIN lesions is done by using the Pronator Quadratus muscle which is the key muscle for this diagnosis procedure.
Distal Radius Fracture
Volar plating is the most popular method for the treatment of this fracture and the complication of this method is flexor tendon rupture which can be protected by repairing the pronator quadratus muscle during the surgery.Fixing the distal radius fracture with preserving the pronator quadratus muscle can account for better pronation movement, better stability of radioulnar joint,good grip,reduce pain which all result in better wrist function in early post operative period.
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- Pronator Quadratus stretch
- Pronator Quadratus Strengthening