Nerve, fourth cranial
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 included, emerge from or enter the skull (the cranium), as opposed to the spinal nerves which emerge from the vertebral column.
The trochlear nerve is the only cranial nerve that arises from the back of the brain stem and it follows the longest course within the skull of any of the cranial nerves.
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The glossopharyngeal nerve is the ninth cranial 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). Problems with the […]
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The largest of the three major salivary glands, it is located in front and below the ear and behind the jaw bone. The other two glands are the submandibular (submaxillary) and sublingual.
- Nerve, hypoglossal
The hypoglossal nerve is the twelfth cranial nerve. The twelve cranial nerves, the hypoglossal nerve included, emerge from or enter the skull (the cranium), as opposed to the spinal nerves which emerge from the vertebral column. The hypoglossal nerve supplies the muscles of the tongue. (The Greek “hypo-“, under and “-glossal” from A”glossa”, the tongue […]
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The ninth cranial nerve is the glossopharyngeal nerve. All 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). Problems with the […]
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The upper eyelid muscle which raises the eyelid; The extraocular muscle which moves the eye inward; and The pupillary muscle which constricts the pupil. Paralysis of the oculomotor nerve results in drooping eyelid (ptosis), deviation of the eyeball outward (and therefore double vision) and a dilated (wide-open) pupil.