Collateral sulcus
Sulcus collateralis
A long groove on the underside of the temporal and occipital lobes, running from near the occipital pole towards the temporal pole.
At a glance
- English
- Collateral sulcus
- Latin (TA2)
- Sulcus collateralis
- System
- Brain and spinal cord
- Region
- Head
- Side
- Paired, left and right
About the collateral sulcus
The collateral sulcus is one of the main furrows on the inferior, or tentorial, surface of the cerebral hemisphere, the face that rests on the tentorium cerebelli and the floor of the middle cranial fossa. It runs forward roughly parallel to the midline, starting near the occipital pole and stopping short of the temporal pole. It is deep enough to bulge into the lateral ventricle, raising a ridge called the collateral eminence in the floor of its temporal horn and the collateral trigone near the atrium.
Its relations change along its length. At the back it lies below and to the side of the calcarine sulcus, and the lingual gyrus sits between the two. Further forward it separates the parahippocampal gyrus on its medial side from the fusiform gyrus (lateral occipitotemporal gyrus) on its lateral side. At its front end it is often continuous with, or lies just behind, the rhinal sulcus, which marks off the entorhinal area at the front of the parahippocampal gyrus.
The cortex lining the sulcus belongs to the ventral visual stream and to the medial temporal lobe memory system. Its banks include the perirhinal and parahippocampal cortex, which pass information about objects and places to the entorhinal cortex and on to the hippocampus. The neighbouring fusiform region is used in recognising faces, words and objects, and the parahippocampal side responds strongly to scenes and places.
Because the sulcus forms the lateral edge of the parahippocampal gyrus, it is a guide on coronal MRI to measuring the entorhinal and perirhinal cortex, regions that shrink early in Alzheimer's disease. It is also a route surgeons use to reach the temporal horn and medial temporal structures from below.
Function and supply
- Function
- Bounds cortex of the medial temporal memory system and the ventral visual stream, involved in object and scene recognition and in passing information to the hippocampus.
- Blood supply
- Temporal and occipital branches of the posterior cerebral artery.
Anthromica
See the collateral sulcus where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
