| herniation | <anatomy> Bulging of tissue through an opening in a membrane, muscle or bone. (16 Dec 1997) |
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| herniation of nucleus pulposus | <radiology> Focal protrusion of disc material secondary to rupture of annulus fibrosus confined within the posterior longitudinal ligament location: L4/5 (35%); L5/S1 (27%); L3/4 (19%); L2/3 (14%); L1/2 (5%); thoracic spine affected in 3:1000 disc operations, posterolateral (49%): weakest point (posterior longitudinal ligament tightly adherent to posterior margin of disc), posterocentral (8%), lateral/foraminal (less than10%), intraosseous/vertical (14%): Schmorl node, extraforaminal/anterior (29%): commonly overlooked, bilateral: on both sided of the posterior ligament findings: disc (low T1) displaces posterior ligament/epidural fat (high T1), enlarged (edematous) nerve root: trumpet sign, see: degenerative disc disease extradural mass (12 Dec 1998) |
| sphenoidal herniation | Displacement of ventral frontal lobar tissue over the sphenoid ridge. (05 Mar 2000) |
| subfalcial herniation | Herniation beneath the falx cerebri; usually of the cingulate gyrus. (05 Mar 2000) |
| transtentorial herniation | <neurology> A condition that occurs when the brain is under abnormally increased pressure. The increased intracranial pressure forces the brain downward inside the skull. This results in typical neurologic manifestations (coma, paralysis and a unilateral dilated pupil). May occur secondary to head injury, primary or metastatic brain tumour, bacterial meningitis and brain abscess. Brain herniations may involve different portions of the brain such as the cerebellum (cerebellar herniation), uncus (uncal herniation) and transtentorial herniation of the cerebrum. (19 Jan 1998) |
| uncal herniation | <neurology> A condition that occurs when the brain is under abnormally increased pressure. The increased intracranial pressure forces the brain downward inside the skull. This results in typical neurologic manifestations (coma, paralysis and a unilateral dilated pupil). May occur secondary to head injury, primary or metastatic brain tumour, bacterial meningitis and brain abscess. Brain herniations may involve different portions of the brain such as the cerebellum (cerebellar herniation), uncus (uncal herniation) and transtentorial herniation of the cerebrum. (27 Sep 1997) |
| foraminal herniation | <radiology> Displacement of cerebellar tonsils through the foramen magnum. (05 Mar 2000) |