Final answer:
The C7 myotome is tested by assessing muscle strength and tone through exercises such as elbow extension and flexion, and wrist extension while observing for lateral strength differences. These tests, combined with additional resistance and resting position tests like the pronator drift, help determine the integrity of both upper and lower motor neuron functions associated with the C7 spinal level.
Step-by-step explanation:
When assessing the C7 myotome, it is important to evaluate the muscle strength and tone associated with this level of the spinal cord, as it innervates key muscles in the arm and neck. The patient would typically be asked to perform elbow extension and flexion, which involves muscles like the triceps brachii, to test the muscle strength against resistance. Additionally, the patient’s ability to perform wrist extension also provides information about the integrity of the C7 myotome. Observing for any lateral differences in strength (such as being stronger on one side compared to the other) can help identify potential damage or neurological issues.
When muscle tone is being evaluated, the resting tension or slight contraction of muscle fibers is checked for, and the absence of such tone might suggest underlying issues with lower motor neuron (LMN) pathways. During resistance testing for strength, if there is a notable difference in capacity to resist on either side, it may point to a corticospinal tract deficit. An inability to maintain positions such as with the pronator drift test could also indicate an upper motor neuron (UMN) lesion. Collectively, these motor exams contribute to a comprehensive assessment of the motor function and integrity of the C7 myotome.