Most common nerve injured in anterior shoulder dislocation: March 2011, March 2013 (c, e)
**Core Concept**
The question is testing the knowledge of the anatomy and common complications of anterior shoulder dislocation. In anterior shoulder dislocation, the humeral head is displaced anteriorly and inferiorly, which can lead to compression or injury of the surrounding nerves.
**Why the Correct Answer is Right**
The axillary nerve is the most commonly injured nerve in anterior shoulder dislocation due to its close proximity to the shoulder joint. The axillary nerve arises from the posterior cord of the brachial plexus and innervates the deltoid muscle and the teres minor muscle. It also provides sensory innervation to the skin over the lateral aspect of the shoulder. The compression or injury of the axillary nerve can lead to weakness or paralysis of the deltoid muscle, resulting in a drooping shoulder or winged shoulder appearance.
**Why Each Wrong Option is Incorrect**
**Option A:** The suprascapular nerve is also a nerve that can be injured in shoulder dislocations, but it is not the most commonly injured nerve. The suprascapular nerve innervates the supraspinatus and infraspinatus muscles.
**Option B:** The musculocutaneous nerve is not typically injured in anterior shoulder dislocations. It innervates the biceps brachii, brachialis, and coracobrachialis muscles.
**Option C:** The radial nerve is not commonly injured in shoulder dislocations. It is more commonly injured in fractures of the humerus or in conditions such as radial tunnel syndrome.
**Clinical Pearl / High-Yield Fact**
It is essential to examine patients with anterior shoulder dislocations for signs of axillary nerve injury, such as weakness of the deltoid muscle or a drooping shoulder. Early recognition and treatment of axillary nerve injury can help prevent long-term morbidity.
**Correct Answer:** C. Axillary nerve