Physical Therapy Assistant Practice Exam

What is the skeletal effect of myasthenia gravis on muscle function?

1. Proximal limb weakness

2. Distal weakness only

3. No effect on muscle function

4. Muscle hypertrophy

The correct answer is: Proximal limb weakness

Myasthenia gravis is an autoimmune disorder that primarily affects the communication between nerves and muscles, leading to muscle weakness. The condition is characterized by weakness that typically worsens with activity and improves with rest. Proximal limb weakness is a common manifestation of myasthenia gravis because the proximal muscles (those closer to the center of the body) are more commonly affected than the distal muscles (those farther from the center). This weakness can significantly impact activities involving the upper limbs, such as lifting objects or climbing stairs, where these proximal muscles are highly engaged. Understanding this, the correct response highlights the characteristic presentation of muscle weakness in myasthenia gravis. Individuals often experience more difficulty with tasks requiring sustained effort from proximal muscles, further emphasizing the nature of fatigue and weakness associated with this condition. This is why proximal limb weakness is the correct answer to the question about the skeletal effect of myasthenia gravis on muscle function.