In cervical radiculopathy, which muscle is primarily affected by the C5 nerve root?

Cervical radiculopathy involves the compression or irritation of a nerve root in the cervical spine, leading to specific muscle weakness, sensory loss, or pain in the areas supplied by the affected nerve. The C5 nerve root primarily innervates muscles that control shoulder abduction and elbow flexion.

Among the muscles listed, the deltoids are indeed the primary muscle affected by the C5 nerve root. The deltoids are responsible for shoulder abduction, and their strength can be compromised when the C5 nerve root is involved. Additionally, the biceps are also innervated by the C5 nerve root, specifically for elbow flexion, but the deltoids have a more direct connection in terms of shoulder function impacted by C5.

The triceps primarily receive innervation from the C7 nerve root, making them less relevant in the context of C5 radiculopathy. The gastroc-soleus muscle is innervated by nerves from the lumbosacral region, so it does not relate to cervical radiculopathy at all.

Therefore, the association of the deltoids with the C5 nerve root makes this muscle the correct answer in the context of cervical radiculopathy.