Paralysis of opponens muscle leads to loss of following function of thumb?
**Core Concept**
The opponens pollicis muscle plays a crucial role in thumb opposition, allowing the thumb to move toward the palmar surface of the other fingers. This movement enables the thumb to grasp and manipulate objects.
**Why the Correct Answer is Right**
The opponens pollicis muscle is responsible for the opposition movement of the thumb, which is essential for fine motor functions and grasping. This muscle is innervated by the median nerve, specifically the recurrent branch, and receives input from the ulnar nerve for coordinated movement. The opponens pollicis muscle acts in conjunction with the flexor pollicis brevis and abductor pollicis brevis muscles to facilitate thumb opposition.
**Why Each Wrong Option is Incorrect**
**Option A:** Flexion of the thumb is primarily a function of the flexor pollicis longus and flexor pollicis brevis muscles, not the opponens pollicis muscle.
**Option B:** Extension of the thumb is primarily a function of the extensor pollicis brevis and extensor pollicis longus muscles, not the opponens pollicis muscle.
**Option C:** Abduction of the thumb is primarily a function of the abductor pollicis longus and abductor pollicis brevis muscles, not the opponens pollicis muscle.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that the opponens pollicis muscle is responsible for thumb opposition, which is essential for fine motor functions and grasping. Damage to this muscle can lead to significant impairment in hand function.
**Correct Answer: A. Loss of opposition of the thumb.**