Which nerve is responsible for innervating the infraspinatus muscle?

The infraspinatus muscle, which is one of the rotator cuff muscles, is primarily responsible for lateral rotation of the arm at the shoulder and stabilization of the shoulder joint. The nerve that innervates the infraspinatus muscle is the suprascapular nerve.

This nerve arises from the superior trunk of the brachial plexus, specifically from the roots of C5 and C6. It travels through the suprascapular notch and supplies not only the infraspinatus muscle but also the supraspinatus muscle, which is located above it and is responsible for initiating shoulder abduction. The proper function and strength of the infraspinatus are critical for shoulder stability and movement, and the suprascapular nerve's role in innervating this muscle is essential for normal shoulder mechanics.

The other nerves listed have different functions and innervate different muscles, thus not contributing to the innervation of the infraspinatus.