13) Your patient dislocated their glenohumeral joint. They n…

13) Your patient dislocated their glenohumeral joint. They now have total paralysis of the deltoid muscle but weak abduction movement of the arm is still possible. External rotation of the arm is slightly weakened. Elbow flexion and extension strength are normal. Numbness exists at skin over lateral aspect of upper arm. Sensation elsewhere is normal. Where is the lesion?