Circular sulcus of insula
Sulcus circularis insulae
The groove that rings the insula deep inside the lateral sulcus, marking where the insular cortex meets the overlying opercula.
At a glance
- English
- Circular sulcus of insula
- Latin (TA2)
- Sulcus circularis insulae
- System
- Brain and spinal cord
- Region
- Head
- Side
- Paired, left and right
About the circular sulcus of insula
The insula is a lobe of cortex hidden at the floor of the lateral sulcus. During development the frontal, parietal and temporal lobes grow over it, and the parts that cover it are called the opercula, or lids. The circular sulcus of the insula, also named the sulcus of Reil, is the furrow that outlines the insula where its surface turns up into the inner face of these opercula. It is not quite a full circle: it runs round the front, the top and the back of the insula, and is open below at the limen insulae, where the insula meets the anterior perforated substance.
Atlases usually describe it in three limbs. The anterior limb separates the insula from the orbital part of the frontal operculum; the superior limb runs beneath the frontal and parietal opercula; and the inferior limb follows the upper surface of the temporal operculum. Inside the ring the insula itself is divided by its central sulcus into a front part with several short gyri and a back part with long gyri.
Branches of the middle cerebral artery run along the surface of the insula and turn sharply at the circular sulcus to climb out over the opercula, which is why the sulcus is a key landmark on angiograms and in surgery on this region. The insula it borders handles taste, signals from the internal organs, pain, temperature and the autonomic control of the heart and blood pressure, and it takes part in emotion and in speech articulation. Its front part is granular-poor and its back part granular.
Strokes in the middle cerebral territory often involve the insula. Damage to the left front insula has been linked with problems in planning the movements of speech, and insular injury in smokers has been followed by a striking loss of the urge to smoke. In surgery for tumours the circular sulcus is used as the outer limit of insular resection.
Function and supply
- Function
- Marks the boundary of the insular cortex, which processes taste and internal body signals, pain and temperature, and helps regulate heart rate, blood pressure, emotion and speech articulation.
- Blood supply
- Insular branches of the middle cerebral artery, which run in and turn at the sulcus before passing out over the opercula.
Anthromica
See the circular sulcus of insula 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.
