Human Anatomy - Kotsan I. Ya. 2009

Muscles and fascia of the upper limb
Anterior muscle group of the forearm
Fourth layer of the anterior forearm muscles

The pronator quadratus Muscle (m. pronator quadratus) is a flat, quadrilateral muscle with transversely oriented fiber bundles (Fig. 119). Located in the region of the distal ends of the forearm bones, it belongs to the deepest Muscles of the anterior surface of the forearm. It originates from the anterior border and anterior surface of the lower third of the ulnar shaft and inserts into the anterior surface of the lower third of the radial shaft. Function: pronates the forearm and hand.

Innervation: median nerve (CV–ThI).

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Fig. 119. Pronator teres and pronator quadratus muscles

1 — medial epicondyle, 2 — pronator teres muscle, 3 — ulna, 4 — interosseous membrane, 5 — pronator quadratus muscle, 6 — radius, 7 — supinator muscle, 8 — tendon of the biceps brachii, 9 — articular capsule



Last update: 08/08/2026

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