Pronator quadratus

A short bridge near the wrist

Pronator quadratus is a flat, deep muscle near the distal ends of the radius and ulna. Its compact outline contrasts with the longer muscles passing through the forearm.

Although easy to see in this reduced model set, it is not a superficial muscle exposed beneath the skin. Overlying structures have been omitted.

Sources: Anatomical study

Distal ulna to distal radius

The muscle starts on the anterior distal quarter of the ulna and attaches to the anterior and lateral distal radius. Its fibers run broadly across the space between the bones.

Use the neighboring bone surfaces as orientation guides, not the edge of the browser window. Camera rotation can make a transverse structure look oblique.

Sources: Anatomical study

Pronation from the distal forearm

Pronator quadratus contributes to pronation. Compare its distal position with pronator teres higher in the forearm.

The model is a static surface reconstruction. Front, Back and Oblique change the camera, not the position of the radius relative to the ulna; no muscle contraction is simulated.

The experimental cut tool on the regional page can expose a geometric section through this area. It does not show fiber shortening or the internal organization of the muscle.

Sources: Anatomical study

Anterior interosseous connections

The anterior interosseous nerve, a branch of the median nerve, supplies pronator quadratus. The anterior interosseous artery is its main arterial source; vascular contributions can vary.

Nerves and vessels are not loaded in this subset, so the text describes connections you cannot select in the viewer.

Sources: Nerve study · Vascular study

Read the model

Explore pronator quadratus in 3D

1. Inspect the isolated muscle. Rotate the selected quadratus mesh to see its broad faces and narrow edges. Gold means selected, not its natural tissue color.
2. Find both distal bones. Choose Show context, then select Radius and Ulna in turn. Return to Pronator quadratus and use Fade others to distinguish it from the rest of the set.
3. Compare the pronators. Choose either Pronator teres head in the structure list and compare where it lies along the same two bones.
4. Try a geometric section. Open the regional forearm study, enable Section, and move Cut position toward this muscle. The cut position is relative to the model bounds, not a clinical measurement. Open forearm section study →

Sources and editorial status

This guide uses independently written explanations with links to the evidence behind them. Source checking and specialist anatomical review are separate steps; the latter is still pending.

1. Anatomic Characteristics of Pronator Quadratus Muscle: A Cadaver Study (2016)

   Introduction and cadaveric observations: location, attachments and function. Procedural needle-placement recommendations are outside this guide.

2. The intra-muscular course and distribution of the anterior interosseous nerve within pronator quadratus: An anatomical study (2022)

   Anterior interosseous nerve supply and its origin from the median nerve; no operative safe-zone claim is made for the atlas.

3. Detailed morphometric analysis of the pronator quadratus muscle: a cadaveric study (2025)

   Reported main supply from the anterior interosseous artery and variable additional arterial branches.

3D geometry and its separate license are credited beneath the viewer. References do not imply endorsement of this site.