| cranial dystonia | <neurology> A term used to describe dystonia that affects the muscles of the head, face, and neck. Oromandibular dystonia affects the muscles of the jaw, lips, and tongue. The jaw may be pulled either open or shut, and speech and swallowing can be difficult. Spasmodic dysphonia involves the muscles of the throat that control speech. Also called spastic dysphonia or laryngeal dystonia, it causes strained and difficult speaking or breathy and effortful speech. Meige's syndrome is the combination of blepharospasm and oromandibular dystonia and sometimes spasmodic dysphonia. Spasmodic torticollis can be classified as a type of cranial dystonia. (12 Dec 1998) |
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| cranial epidural space | The intracranial dura mater, consisting of two layers: the outer periosteal layer which normally always adheres to the periosteum of the bones of the cranial vault; and the inner meningeal layer which in most places is fused with the outer. The two layers separate to accommodate meningeal vessels and large venous (dural) sinuses. The meningeal layer is also involved in the formation of the various dural folds, such as the falx cerebri and tentorium cerebelli and is comparable to and continuous with the dural mater of the spinal cord. The cranial epidural space is then a potential space between the bone and the combined periosteum/periosteal layer of the dura mater realised only pathologically and is neither continuous with or comparable to the vertebral epidural space. Synonym: dura mater cranialis, dura mater encephali, cerebral part of dura mater, cranial epidural space. (05 Mar 2000) |
| cranial flexure | The sharp, ventrally concave bend in the developing midbrain of the embryo. Synonym: cerebral flexure, cranial flexure, mesencephalic flexure. (05 Mar 2000) |
| cranial fontanels | <anatomy> The membranous intervals between the angles of the cranial bones in the infant; they include the midline anterior fontanel and posterior fontanel, and the paired sphenoidal fontanel and mastoid fontanel. Synonym: fonticuli cranii. (05 Mar 2000) |
| cranial fossa, posterior | The posterior subdivision of the floor of the cranial cavity, lodging the cerebellum, pons, and medulla oblongata. It is formed by portions of the sphenoid, temporal, parietal, and occipital bones. (12 Dec 1998) |
| cranial index | The ratio of the maximal breadth to the maximal length of the skull, obtained by the formula: (breadth × 100)/length. (05 Mar 2000) |
| cranial irradiation | The exposure of the head to roentgen rays or other forms of radioactivity for therapeutic or preventive purposes. (12 Dec 1998) |
| cranial mononeuropathy III | (compression type) A disorder involving vision changes and eyelid drooping associated with a decreased functioning of cranial nerve III. Damage is usually caused by compression of the nerves from localised lesions or a swelling in the area of the nerve. Examples include cerebral aneurysms and tumours Symptoms include a drooping eyelid and double vision. (diabetic type) A disorder involving vision changes and eyelid drooping associated with a decreased functioning of cranial nerve III as a complication of diabetes. Symptoms include a drooping eyelid and double vision. Good control of blood sugars can reduce the incidence of this complication. (27 Sep 1997) |
| cranial mononeuropathy vi | A disorder involving vision changes that are associated with the decreased function of cranial nerve VI. Often this form of nerve damage is associated with diabetes, tumours of the VI nerve or increased intracranial pressure. Trauma and stroke may also damage the VI cranial nerve. Symptoms include double vision when looking to one side. (27 Sep 1997) |
| cranial mononeuropathy vii | A disorder which involves drooping of the face and the decreased ability to move one side of the face. Causes include isolated damage to the facial nerve, HIV infection, sarcoidosis and Lyme disease. Bell's palsy is a dysfunction of the facial nerve for reason unknown. (27 Sep 1997) |
| cranial nerve I | <anatomy, nerve> The olfactory nerve carries impulses for the sense of smell. Synonym: cranial nerve I. (27 Sep 1997) |
| cranial nerve II | <anatomy, nerve> The optic nerve. The nerve carrying impulses for the sense of sight. Projection from the vertebrate retina to the midbrain. Embryologically, a CNS tract rather than a peripheral nerve. Popular experimental preparation for studies of regeneration of retino tectal projections in lower vertebrates and also for studies of glial cell lineage in CNS. Synonym: cranial nerve II. (18 Nov 1997) |
| cranial nerve III | <anatomy, nerve> The occulomotor nerve is responsible for motor enervation of upper eyelid muscle, extraocular muscle and pupillary muscle. Lesions of the oculomotor nerve results in ptosis (dropping eyelid), deviation of the eyeball outward, double vision and a dilated pupil. Synonym: cranial nerve III. (27 Sep 1997) |
| cranial nerve IV | <anatomy, nerve> The trochlear nerve controls an extraocular muscle. Lesions of this nerve will result in rotation of the eyeball upward and outward (and double vision). Synonym: cranial nerve IV. (27 Sep 1997) |
| cranial nerve IX | <anatomy, nerve> The glossopharyngeal nerve enervates muscles involved in swallowing and taste. Lesions of the ninth nerve result in difficulty swallowing and disturbance of taste. Synonym: cranial nerve IX. (27 Sep 1997) |