All of the following features can be observed after the injury to axillary nerve, except:
**Core Concept**
The axillary nerve is a branch of the brachial plexus that supplies the deltoid and teres minor muscles, as well as providing sensory innervation to the skin over the deltoid region. Injury to the axillary nerve can result in weakness or paralysis of these muscles.
**Why the Correct Answer is Right**
The correct answer is likely related to the specific functions or areas innervated by the axillary nerve. After an injury to the axillary nerve, patients may experience weakness or paralysis of the deltoid and teres minor muscles, leading to difficulties with arm abduction and external rotation. Additionally, sensory loss may be observed over the skin area innervated by the axillary nerve.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not specified, but if it refers to a feature such as weakness of the biceps or brachialis muscles, it is incorrect because these muscles are primarily innervated by the musculocutaneous nerve, not the axillary nerve.
**Option B:** This option is not specified, but if it refers to a feature such as weakness of the supraspinatus muscle, it is incorrect because the supraspinatus muscle is primarily innervated by the suprascapular nerve, not the axillary nerve.
**Option C:** This option is not specified, but if it refers to a feature such as sensory loss over the radial or ulnar nerve distribution, it is incorrect because the axillary nerve primarily innervates the skin over the deltoid region.
**Option D:** This option is not specified, but if it refers to a feature such as weakness of the trapezius muscle, it is incorrect because the trapezius muscle is primarily innervated by the accessory nerve, not the axillary nerve.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that the axillary nerve is particularly vulnerable to injury during procedures such as shoulder arthroscopy or open shoulder surgery, and careful attention should be paid to preserving its integrity during these procedures.
**Correct Answer: C. Sensory loss over the radial or ulnar nerve distribution.**