Straight gyrus (Gyrus rectus)
The narrow, straight convolution along the medial edge of the underside of the frontal lobe, beside the longitudinal fissure.
At a glance
- English
- Straight gyrus (Gyrus rectus)
- System
- Brain and spinal cord
- Region
- Head
- Side
- Paired, left and right
About the straight gyrus (gyrus rectus)
The gyrus rectus, or straight gyrus, runs from front to back on the orbital (inferior) surface of the frontal lobe. It forms the most medial strip of that surface, bordered on its inner side by the longitudinal fissure and on its outer side by the olfactory sulcus, in which the olfactory bulb and tract lie. Lateral to the olfactory sulcus come the orbital gyri, the nearest being the medial orbital gyrus. At the front it curves up onto the medial surface of the hemisphere, where it runs on into the superior frontal gyrus.
Unlike the irregular orbital gyri, which are broken up by an H-shaped pattern of sulci, the gyrus rectus is a simple unbranched ridge, which is how it gets its name. At its back end it reaches the anterior perforated substance and the subcallosal area. Its cortex forms part of the medial orbitofrontal and ventromedial prefrontal cortex, and the two straight gyri face each other across the fissure, above the cribriform plate and the planum of the sphenoid bone.
No function belongs to the gyrus alone, but as part of ventromedial prefrontal cortex it takes part in weighing rewards and punishments, in emotional regulation and in decisions guided by social and personal consequences. It is connected with the amygdala, hypothalamus, anterior cingulate cortex and other orbital areas.
The gyrus lies just above the anterior communicating artery. Surgeons often remove a small part of it to reach aneurysms of that artery, and bleeding from such aneurysms can track into it. It is also a typical site for contusion when the frontal lobes strike the floor of the anterior cranial fossa in head injury, and for meningiomas of the olfactory groove pressing from below.
Function and supply
- Function
- Part of the ventromedial prefrontal cortex, involved in valuing outcomes, emotional regulation and socially guided decision making.
- Blood supply
- The medial orbitofrontal branch of the anterior cerebral artery, with small twigs from the anterior communicating artery.
Anthromica
See the straight gyrus (gyrus rectus) 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.
