| posterior cranial fossa | The internal base of the skull posterior to the crest of the petrous part of the temporal bones and the dorsum sellae and anterior to the grooves for the transverse sinuses, where the cerebellum, pons, and medulla oblongata rest. Synonym: fossa cranii posterior. (05 Mar 2000) |
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| posterior fossa tumours | <radiology> Midline, medulloblastoma (hyperdense, enhances), astrocytoma (hypodense, enhances), 4th ventricle, ependymoma (most common, slow-growing, expands ventricle), medulloblastoma (usually obliterates ventricular cavity), choroid plexus papilloma (more common in lateral ventricles) (12 Dec 1998) |
| crural fossa | A depression on the peritoneal surface of the abdominal wall, inferior to the inguinal ligament, corresponding to the situation of the femoral ring. Synonym: crural fossa, fovea femoralis. (05 Mar 2000) |
| Cruveilhier's fossa | A boat-shaped hollow. A longitudinal hollow on the posterior surface of the superior portion (root) of the medial pterygoid plate; it gives origin to the tensor veli palati muscle. Synonym: fossa scaphoidea ossis sphenoidalis, Cruveilhier's fossa, fossa navicularis Cruveilhier, scaphoid fossa of sphenoid bone. Synonym: scapha. (05 Mar 2000) |
| cubital fossa | The fossa in front of the elbow, bounded laterally and medially by the humeral origins of the extensors and flexors of the forearm, respectively, and superiorly by an imaginary line connecting the humeral condyles. Synonym: fossa cubitalis, antecubital space, chelidon, triangle of elbow. (05 Mar 2000) |
| pterygoid fossa | The fossa formed by the divergence posteriorly of the plates of the pterygoid process of the sphenoid bone; it lodges the origin of medial pterygoid and the tensor palati muscles. Synonym: fossa pterygoidea. (05 Mar 2000) |
| pterygomaxillary fossa | Sphenomaxillary fossa, a small pyramidal space, housing the pterygopalatine ganglion, between the pterygoid process, the maxilla, and the palatine bone. Synonym: fossa pterygopalatina, Bichat's fossa, pterygomaxillary fossa, sphenomaxillary fossa. (05 Mar 2000) |
| pterygopalatine fossa | Sphenomaxillary fossa, a small pyramidal space, housing the pterygopalatine ganglion, between the pterygoid process, the maxilla, and the palatine bone. Synonym: fossa pterygopalatina, Bichat's fossa, pterygomaxillary fossa, sphenomaxillary fossa. (05 Mar 2000) |
| hyaloid fossa | A depression on the anterior surface of the vitreous body in which lies the lens. Synonym: fossa hyaloidea, lenticular fossa, patellar fossa of vitreous. (05 Mar 2000) |
| sigmoid fossa | A broad groove in the posterior cranial fossa, first situated on the lateral portion of the occipital bone, then curving around the jugular process on to the mastoid portion of the temporal bone, and finally turning sharply on the posterior inferior angle of the parietal bone and becoming continuous with the transverse groove; it lodges the transverse sinus. Synonym: sulcus sinus sigmoidei, sigmoid fossa, sigmoid groove, sigmoid sulcus. (05 Mar 2000) |
| hypophysial fossa | Fossa of the sphenoid bone housing the pituitary gland. See: sella turcica. Synonym: fossa hypophysialis, pituitary fossa. (05 Mar 2000) |
| sphenomaxillary fossa | Sphenomaxillary fossa, a small pyramidal space, housing the pterygopalatine ganglion, between the pterygoid process, the maxilla, and the palatine bone. Synonym: fossa pterygopalatina, Bichat's fossa, pterygomaxillary fossa, sphenomaxillary fossa. (05 Mar 2000) |
| navicular fossa of urethra | The terminal dilated portion of the urethra in the glans penis. Synonym: fossa navicularis urethrae, fossa terminalis urethrae, Morgagni's fossa, Morgagni's fovea. (05 Mar 2000) |
| subarcuate fossa | An irregular depression on the posterior surface of the petrous portion of the temporal bone just below its crest and above and lateral to the internal acoustic meatus. In the foetus, the flocculus of the cerebellum rests here; in the adult, a small vein enters the bone here. Synonym: fossa subarcuata, floccular fossa, hiatus subarcuatus. (05 Mar 2000) |
| subcaecal fossa | An inconstant depression in the peritoneum extending posterior to the caecum. Synonym: Treitz's fossa. (05 Mar 2000) |