Talk:Pronator quadratus muscle

Anatomy: Gross Mid‑importance

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A doubt

Why the contraction of pronator quadratus produces pronation, and not supination? Think of it, unlike pronator teres, it is not attached to a more proximal fixed point like the medial border of the humerus. This muscle runs absolutely perpendicular to the radius and the ulna.

I have thought about it, and feel that when the forearm is supine, there's no further margin for supination, so the muscle acts to bring the radius closer to the ulna, and not vice versa. And, when the forearm is pronated fully, the muscle must be getting so much relaxed (consequently, also shortened) that its contraction cannot further shorten the fibers, hence no movement occurs in this position.

Well, this is just a guess. It'd be nice if someone approves of it, or corrects my ideas. Regards.

Ketan Panchal, MBBS (talk) 19:37, 5 May 2008 (UTC)[reply]