Final answer:
The 11th cranial nerve is known as the accessory nerve and is a motor nerve that controls the muscles of the shoulder and neck. A common test for its function includes shoulder shrugging and head rotation against resistance.
Step-by-step explanation:
Cranial Nerve XI - The Accessory Nerve:
The 11th cranial nerve, also known as the accessory nerve, is primarily a motor nerve. It is tasked with controlling the muscles involved in shoulder and neck movements. The accessory nerve has a unique characteristic, owing its structure to both the cranial and the spinal components. It is responsible for motor functions such as the movement of the trapezius and sternocleidomastoid muscles that facilitate shoulder shrugging and head rotation respectively.
Function and Tests:
The clinical examination of this nerve includes a motor function test, in which the patient is asked to shrug their shoulders or turn their head side-to-side against resistance. This helps in assessing the strength and functionality of the muscles innervated by the accessory nerve. A deficit in these movements may suggest a lesion or damage to the nerve or its associated pathways.
Summary:
Therefore, to directly answer the student's question, the 11th cranial nerve is a motor nerve, also known as the accessory nerve, it controls certain shoulder and neck muscles, and it can be tested by shoulder shrugging and head-turning exercises against resistance.