Question

A patient presents with muscle wasting, reduced tone, and weakness in the left hand. Fine motor movements like dough kneading are impaired. Which of the following structure is most likely affected?

• A. Right anterior horn cells in spinal cord
• B. Pyramidal lesion
• C. Internal capsule
• D. Left corticospinal tract in the cervical cord

Hint:

Lower motor neuron lesion causes wasting, fasciculations, weakness and reduced tone. Upper motor neuron lesion causes increased tone and exaggerated reflexes.

Answer 1

The Correct Option is A

Concept: Muscle wasting, reduced tone and weakness suggest a lower motor neuron lesion. Anterior horn cells are lower motor neurons.

Step 1: Identify clinical signs.
The findings are: \[ \text{Muscle wasting + reduced tone + weakness} \] These indicate lower motor neuron involvement.

Step 2: Recall lower motor neuron location.
The anterior horn cells of the spinal cord are lower motor neurons supplying skeletal muscles.

Step 3: Choose the best answer.
Among the options, anterior horn cell involvement best explains wasting and reduced tone. Therefore, the correct answer is: \[ \text{Right anterior horn cells in spinal cord} \]