This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
In a patient with erb's palsy, paralysis of which of the following muscles results in medial rotation of the arm? 
Select and explain. 
A. Supraspinatus and deltoid, B. Teres major and biceps brachii, C. Infraspinatus and teres minor, D. Biceps brachii, brachialis and brachioradialis
C: Infraspinatus and teres minor
Answer: C: Infraspinatus and teres minor 
Explanation: In a patient with Erb's palsy there is involvement of C5, 6 nerve root. In this condition, the arm is held in adduction and internal rotation at the shoulder, extension at the elbow, pronation of the forearm and flexion at the wrist. Paralysis of the teres minor and infraspinatus result in medial rotation of the arm. Paralysis of Biceps brachii, brachialis and brachioradialis result in extended forearm. Paralysis of Supraspinatus and deltoid result in adducted arm.