Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «C»:
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 to...
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...
Cranial nerve, seventh
Cranial nerve, seventh: The
seventh cranial nerve is the facial nerve, a mixed nerve that has fibers both
going out and coming in (both efferent and afferent fibers). It supplies the muscles of facial expression.
Paralysis of the facial
nerve causes a characteristic picture with drooping of one s...
Cranial nerve, sixth
Cranial nerve, sixth: The sixth cranial nerve is the abducent nerve. It is a small motor nerve that has one task: to supply a muscle called the lateral rectus muscle that moves the eye outward.
Paralysis of the abducent nerve causes inward turning of the eye (internal strabismus) leading to double ...
Cranial nerve, tenth
Cranial nerve, tenth: The tenth cranial nerve, and one of the most important, is the vagus nerve. All twelve of the cranial nerves, the vagus nerve included, emerge from or enter the skull (the cranium), as opposed to the spinal nerves which emerge from the vertebral column. The vagus nerve origin...
Cranial nerve, third
Cranial nerve, third: The third cranial nerve is the
oculomotor nerve. 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 oculomotor nerve is responsible for the nerve suppl...
Cranial nerve, twelfth
Cranial nerve, twelfth: See: Twelfth cranial nerve....
Cranial nerves: Nerves that emerge from or enter the skull (the cranium), as opposed to the spinal nerves which emerge from the vertebral column. Cranial nerves come directly from the brain through the skull.
There are 12 cranial nerves each of which is accorded a Roman numeral and a name:
Cranio-: Referring to the cranium, the top portion of the skull, the bony vault that protects the brain. As in craniocleidodysostosis,
craniology, craniopharyngioma, craniotomy, etc....
A genetic (inherited) disorder of bone development characterized by:
Typical cranial and facial abnormalities with square
skull, late closure of the sutures of the skull, late closure of the fontanels
(the soft spots), low nasal bridge, delayed eruption of the teeth, a...
Craniology: The study of variations in size, shape, and proportion of the skull (cranium). Also known as phrenology, it was a pseudoscience of the 18th and 19th centuries based on the belief that a person's character could be learned by looking with care at the shape of their head and noting each an...
Craniometaphyseal dysplasia: An inherited skeletal condition that involves abnormal bone formation and abnormal mineralization of the skull as well as the long bones. There is increased density of craniofacial bones beginning at the base of the skull during early childhood. The progressive thickenin...
Craniopagus: Conjoined twins whose heads are fused together. From cranio-, relating to the cranium + the Greek pagos, referring to something fixed. See also: Syncephaly; Janiceps....
Craniopagus parasiticus: Conjoined twins joined at the head (craniopagus) in which a rudimentary head (with little or no body) is attached to the head of the larger and usually more normal twin. The rudimentary head was thought to be parasitic....
Craniopharyngioma: A type of benign brain tumor that emerges develops from embryonic tissue that forms part of the pituitary gland. Pressure on the pituitary by the tumor reduces the availability of the hormone vasopressin, raising the pressure within the cranium. A craniopharyngioma usually include...