Cranial nerve, eleventh: The eleventh cranial nerve is the accessory nerve. The twelve cranial nerves, the accessory nerve included, emerge from or enter the skull (the cranium) as opposed to the spinal nerves which emerge from the vertebral column. The accessory is so-called because, although it arises in the brain, it receives an additional (accessory) root from the upper part of the spinal cord.
The accessory nerve supplies the sternocleidomastoid and trapezius muscles. The sternocleidomastoid muscle is in the front of the neck and turns the head. The trapezius muscle moves the scapula (the wingbone), turns the face to the opposite side, and helps pull the head back.
Damage to the accessory nerve can be isolated (confined to the accessory nerve) or it may also involve the ninth and tenth cranial nerves which exit through the same opening (foramen) from the skull . Accessory neuropathy (nerve disease) can sometimes occur and recur for unknown reasons. Most patients recover.
Paralysis of the accessory nerve prevents rotation of the head away from that side and causes drooping of the shoulder.
- Cranial nerve, fifth
Cranial nerve, fifth: The fifth cranial nerve is the trigeminal nerve. The trigeminal nerve is quite complex. It functions both as the chief nerve of sensation for the face and the motor nerve controlling the muscles of mastication (chewing). Problems with the sensory part of the trigeminal nerve result in pain or loss of sensation […]
- Cranial nerve, first
Cranial nerve, first: The cranial nerves emerge from or enter the skull (the cranium), as opposed to the spinal nerves which emerge from the vertebral column. There are twelve cranial nerves. The first cranial nerve is the olfactory nerve which carries impulses for the sense of smell from the nose to the brain. The word […]
- Cranial nerve, fourth
Cranial nerve, fourth: The fourth cranial nerve, the trochlear nerve, is the nerve supply to the superior oblique muscle of the eye, one of the muscles that moves the eye. Paralysis of the trochlear nerve results in rotation of the eyeball upward and outward (and, therefore, double vision). The twelve cranial nerves, the trochlear nerve […]
- Cranial nerve, ninth
Cranial nerve, ninth: The ninth cranial nerve is the glossopharyngeal nerve. The 12 cranial nerves, the glossopharyngeal nerve included, emerge from or enter the skull (the cranium), as opposed to the spinal nerves which emerge from the vertebral column. The glossopharyngeal nerve supplies the tongue, throat, and one of the salivary glands (the parotid gland). […]
- Cranial nerve, second
Cranial nerve, second: The second cranial nerve is the optic nerve, the nerve that connects the eye to the brain and carries the impulses formed by the retina — the nerve layer that lines the back of the eye, senses light and creates the impulses — to the brain which interprets them as images. The […]