| primary fissure of cerebellum | The deepest fissure of the cerebellum; demarcates the division of anterior and posterior lobes of the cerebellum; second to appear embryologically. Synonym: fissura prima cerebelli. (05 Mar 2000) |
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| hippocampal fissure | A shallow groove between the dentate gyrus and the parahippocampal gyrus; the remains of a fissure extending deep into the hippocampus between Ammon's horn and the dentate gyrus which becomes obliterated during foetal development. Synonym: sulcus hippocampi, dentate fissure, fissura dentata, fissura hippocampi, hippocampal fissure. (05 Mar 2000) |
| secondary fissure of cerebellum | A fissure that separates the uvula of the inferior vermis of the cerebellum from the pyramid. Synonym: fissura secunda cerebelli. (05 Mar 2000) |
| pterygoid fissure | The cleft between the medial and lateral laminae of the pterygoid process of the sphenoid bone into which the pyramidal process of the palatine bone is fitted. Synonym: incisura pterygoidea, fissura pterygoidea, pterygoid notch. (05 Mar 2000) |
| pterygomaxillary fissure | The narrow gap between the lateral pterygoid plate and the infratemporal surface of the maxilla through which the infratemporal fossa communicates with the pterygopalatine fossa; gives passage to the third part of the maxillary artery and the posterior superior alveolar arteries, veins and nerves. Synonym: fissura pterygomaxillaris, fissura pterygopalatina. (05 Mar 2000) |
| horizontal fissure of cerebellum | Horizontal fissure that divides the ansiform lobule into its major parts, crus I (superior semilunar lobule) and crus II (inferior semilunar lobule). Synonym: fissura horizontalis cerebelli, great horizontal fissure. (05 Mar 2000) |
| horizontal fissure of right lung | The deep fissure that separates the upper and middle lobes of the right lung. Synonym: fissura horizontalis pulmonis dextri, horizontal fissure of right lung, minor fissure. (05 Mar 2000) |
| simian fissure | A small, inconstant semilunar groove on the cortical convexity near the occipital pole, marking the anterior border of the striate cortex (area 17) and considered homologous with the major sulcus of the same name that is a more constant feature of the cerebral cortex in monkeys and apes. Synonym: sulcus lunatus cerebri, ape fissure, lunate fissure, lunate sulcus, simian fissure. (05 Mar 2000) |
| sphenoidal fissure | A cleft between the greater and the lesser wings of the sphenoid establishing a channel of communication between the middle cranial fossa and the orbit, through which pass the oculomotor and trochlear nerves, the ophthalmic division of the trigeminal nerve, the abducens nerve, and the ophthalmic veins. Synonym: fissura orbitalis superior, foramen lacerum anterius, sphenoidal fissure. (05 Mar 2000) |
| sphenomaxillary fissure | A cleft between the greater wing of the sphenoid and the orbital plate of the maxilla, through which pass the maxillary division and the orbital branch of the trigeminal nerve, fibres from the pterygopalatine (Meckel's) ganglion, and the infraorbital vessels. Synonym: fissura orbitalis inferior, sphenomaxillary fissure. (05 Mar 2000) |
| sphenopetrosal fissure | A narrow fissure between the undersurface of the greater wing of the sphenoid and the petrous portion of the temporal bone. Synonym: fissura sphenopetrosa. (05 Mar 2000) |
| squamotympanic fissure | The fissure separating the tympanic part of the temporal bone from the squamous part; it is continuous medially with the petrotympanic fissure and the petrosquamous fissure. Synonym: fissura tympanosquamosa, tympanosquamous fissure. (05 Mar 2000) |
| superior orbital fissure | A cleft between the greater and the lesser wings of the sphenoid establishing a channel of communication between the middle cranial fossa and the orbit, through which pass the oculomotor and trochlear nerves, the ophthalmic division of the trigeminal nerve, the abducens nerve, and the ophthalmic veins. Synonym: fissura orbitalis superior, foramen lacerum anterius, sphenoidal fissure. (05 Mar 2000) |
| decidual fissure | A cleft in the decidua basalis or placenta. (05 Mar 2000) |
| superior temporal fissure | The longitudinal sulcus that separates the superior and middle temporal gyri. Synonym: sulcus temporalis superior, superior temporal fissure. (05 Mar 2000) |