Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : Sweeney or loose shoulder is a condition where scapula is held away from body.
Reason (R) : Radial nerve paralysis causes sweeney.
In light of the above statements, choose the correct answer from the options given below

• A. Both (A) and (R) are true and (R) is the correct explanation of (A).
• B. Both (A) and (R) are true but (R) is NOT the correct explanation of (A).
• C. (A) is true but (R) is false.
• D. (A) is false but (R) is true.

Hint:

- Suprascapular Nerve Injury $\rightarrow$ Sweeney (shoulder slip lateral subluxation of shoulder joint).
- Radial Nerve Injury $\rightarrow$ Dropped elbow, flexed joints, inability to extend the forelimb.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Peripheral nerve injuries in horses or cattle lead to characteristic gait abnormalities and muscular atrophy, which are diagnostic for specific nerve lesions.

Step 2: Detailed Explanation:
Let us analyze both statements:
- Assertion (A):
"Sweeney" or "loose shoulder" is a clinical condition in draft horses and other livestock characterized by the atrophy of the supraspinatus and infraspinatus muscles.
Since these muscles act as collateral ligaments to stabilize the shoulder joint, their severe atrophy causes the scapular spine to become prominent, and the shoulder joint pops outward (subluxates laterally) away from the thoracic wall when weight is borne.
Therefore, Assertion (A) is correct.
- Reason (R):
Sweeney is caused by damage or paralysis of the suprascapular nerve, which runs around the cranial neck of the scapula and is vulnerable to blunt trauma or pressure from collars.
The suprascapular nerve specifically innervates the supraspinatus and infraspinatus muscles.
Radial nerve paralysis, on the other hand, causes "dropped elbow", inability to extend the elbow, carpus, and digits, and non-weight-bearing on the affected limb, but does not cause sweeney.
Therefore, Reason (R) is false.
Thus, Assertion (A) is true, but Reason (R) is false.

Step 3: Final Answer:
The correct option is (C).