What impairments might you expect in a patient with an axillary nerve neuropraxia following shoulder dislocation?

• A. Weakness in shoulder flexion and internal rotation
• B. Weakness in shoulder abduction and decreased sensation over the lateral arm
• C. Weakness in elbow flexion and wrist extension
• D. Decreased grip strength and shoulder extension

Answer: (B)

The correct choice highlights the characteristic functional impairments associated with axillary nerve neuropraxia, particularly following a shoulder dislocation. The axillary nerve innervates the deltoid and teres minor muscles, which are crucial for shoulder abduction and external rotation. Therefore, weakness in shoulder abduction is expected as the deltoid muscle, which is primarily responsible for this action, can be affected.

Additionally, the axillary nerve also provides sensory innervation to the skin over the lateral aspect of the shoulder and the upper arm, often referred to as the "regimental badge" area. As a result, a patient with axillary nerve involvement may experience decreased sensation over this area.

Overall, the combination of weakness in shoulder abduction and altered sensation over the lateral arm is a direct manifestation of the axillary nerve's role and its pathway, leading to the symptoms described in the correct answer. The other options do not properly align with the expected motor and sensory deficits resulting from axillary nerve injury, emphasizing the importance of understanding the specific anatomical and functional implications of nerve injuries in the upper extremity.