## Core Concept
The ansa cervicalis is a loop of nerves in the neck that provides motor innervation to infrahyoid muscles. It is a component of the cervical plexus and is formed by the union of the anterior roots of the C1-C3 spinal nerves. The infrahyoid muscles include the sternohyoid, sternothyroid, and omohyoid muscles.

## Why the Correct Answer is Right
The correct answer, , is the sternohyoid muscle. This muscle receives its nerve supply directly from the ansa cervicalis. The ansa cervicalis gives off branches to the sternohyoid and sternothyroid muscles. The omohyoid muscle also receives its supply from the ansa cervicalis but through a different arrangement.

## Why Each Wrong Option is Incorrect
* **Option A:** The digastric muscle receives its nerve supply from the facial nerve (cranial nerve VII), not from the ansa cervicalis.
* **Option B:** The sternocleidomastoid muscle is supplied by the accessory nerve (cranial nerve XI), not from the ansa cervicalis.
* **Option D:** The omohyoid muscle, while related, does not receive its nerve supply directly in the same straightforward manner as the sternohyoid and sternothyroid muscles from the ansa cervicalis; it is still associated but through a slightly different pathway.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the ansa cervicalis provides motor innervation specifically to the infrahyoid muscles (sternohyoid, sternothyroid, and omohyoid), which are crucial for the movement of the hyoid bone during swallowing.

## Correct Answer: C. sternohyoid.