Animal Chiropractic Extremities Practice Exam 2026 – Complete Study Resource

Suprascapular nerve. This nerve travels across the cranial border of the scapula at the suprascapular notch and supplies both the supraspinatus and infraspinatus muscles. When it is injured at that location, motor input to both muscles is lost, leading to atrophy. The supraspinatus initiates the first part of shoulder abduction and the infraspinatus enables external rotation, so damage here produces weakness and wasting in those movements. The other nerves listed do not innervate these two rotator cuff muscles, so they wouldn’t cause this specific pattern of atrophy.