Pronator Quadratus Muscle Anatomy

Overview
Origin Distal anterior surface of ulna
Insertion Distal anterior surface of radius
Action Pronates forearm at radioulnar joint
Nerve Anterior interosseous nerve (C7, C8)
Artery Anterior interosseous artery

Location & Overview

In Latin, the word ‘pronator’ means ‘lying face downward’. This Latin word suggests how the pronator quadratus muscle gets its name. The pronator quadratus muscle is able to rotate the forearm (into a pronated position) with the palm facing down. It is also a quadrilateral shape. The pronator quadratus is short and flat and has parallel running fibers. It is the deepest muscle of the anterior forearm and unable to be palpated or observed superficially [1] [2].

pronator quadratus from an anterior view

Here we can see the pronator quadratus from an anterior view.

pronator quadratus supinated and pronated

Here we can see an anterior view of the pronator quadratus in both a supinated and a pronated position.

Origin & Insertion

The pronator quadratus originates from the anterior surface of the distal fourth of the ulna. It then inserts onto the lateral border and anterior surface of the distal one fourth of the radius[3] [4].

pronator quadratus origin and insertion

Here we can see the origin and insertion of the pronator quadratus. The origin is on the distal anterior surface of the ulna and the insertion is on the distal anterior surface of radius.

Actions

As the pronator quadratus muscle’s name suggests, its action is pronation of the forearm at the proximal radioulnar joint[5] [6].

Innervation

The pronator quadratus muscle is innervated by the anterior interosseous nerve (C7, C8). The anterior interosseous nerve supplies the deep muscles on the anterior of the forearm and it is a branch of the median nerve [7] [8] [9].

Blood Supply

Blood is supplied to the pronator quadratus via the anterior interosseous artery which is a branch of the common interosseous artery. The common interosseous artery arises from the ulnar artery in the cubital region of the forearm [10] [11].

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Pronator Quadratus Flashcards

References

References
1, 3, 5 Choung PW, Kim MY, Im HS, Kim KH, Rhyu IJ, Park BK, Kim DH. Anatomic Characteristics of Pronator Quadratus Muscle: A Cadaver Study. Ann Rehabil Med. 2016 Jun;40(3):496-501. doi: 10.5535/arm.2016.40.3.496. Epub 2016 Jun 29. PMID: 27446787; PMCID: PMC4951369.
2, 4, 6, 8, 11 Moore KL, Dalley AF, Agur AM. Clinically oriented anatomy. 7th ed. Philadelphia: Lippincott Williams & Wilkins; 2014.
7, 10 Thomas BP, Kiran SP, Tang M, Geddes CR, Morris SF. The Vascular Basis of the Pronator Quadratus Muscle Flap and Its Use in Clinical Cases. Indian J Plast Surg. 2021 Jan;54(1):63-68. doi: 10.1055/s-0040-1716421. Epub 2020 Sep 7. PMID: 33814744; PMCID: PMC8012782.
9 Svízenská I, Cizmár I, Visna P. An anatomical study of the anterior interosseous nerve and its innervation of the pronator quadratus muscle. J Hand Surg Br. 2005 Dec;30(6):635-7. doi: 10.1016/j.jhsb.2005.06.017. Epub 2005 Aug 22. PMID: 16115708.