Olfactory sulcus
Sulcus olfactorius
A straight groove on the underside of each frontal lobe, parallel to the midline, in which the olfactory bulb and tract lie.
At a glance
- English
- Olfactory sulcus
- Latin (TA2)
- Sulcus olfactorius
- System
- Brain and spinal cord
- Region
- Head
- Side
- Paired, left and right
About the olfactory sulcus
The olfactory sulcus is a groove on the orbital (inferior) surface of the frontal lobe. It runs straight from front to back, close to and parallel with the midline. Medial to it lies the gyrus rectus, the straight gyrus, along the edge of the longitudinal fissure; lateral to it lies the medial orbital gyrus, the first of the orbital gyri. The sulcus therefore marks the border between these two strips of cortex.
It takes its name from what rests in it. The olfactory bulb sits in the front of the sulcus, above the cribriform plate of the ethmoid bone, and the olfactory tract runs backwards along it. The tract is a narrow white band carrying the axons of the bulb's mitral and tufted cells, triangular in cross-section with its apex fitting up into the groove. At the back end of the sulcus the tract widens into the olfactory trigone and splits into medial and lateral olfactory striae in front of the anterior perforated substance. From there its fibres reach the anterior olfactory nucleus, the olfactory tubercle, the piriform cortex, the cortical part of the amygdala and the entorhinal cortex.
The sulcus is a cortical landmark rather than a functional area; the gyri on either side belong to the orbitofrontal cortex, which is involved in judging reward, smell and taste and in social behaviour.
The depth of the sulcus matters clinically. In people born without a sense of smell, such as those with Kallmann syndrome, where development of the olfactory pathway is disturbed, the bulbs may be small or absent and the olfactory sulcus is shallow. Measuring its depth on MRI is a recognised sign of such congenital anosmia. Damage to the olfactory tract itself causes loss of smell on the same side.
Function and supply
- Function
- A groove that houses the olfactory bulb and tract and separates the gyrus rectus from the medial orbital gyrus.
- Blood supply
- Orbitofrontal branches of the anterior cerebral artery.
Anthromica
See the olfactory 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.
