Lateral sulcus Lateral sulcus The lateral sulcus (also called Sylvian fissure or lateral fissure) is one of the most prominent features of the human brain. The lateral sulcus is a deep fissure in each hemisphere that separates the frontal and parietal lobes from the temporal lobe. The insular cortex lies deep within the lateral sulcus. The lateral sulcus divides both the frontal lobe and parietal lobe above from the temporal lobe below. It is in both hemispheres of the brain. The lateral sulcus is one of the earliest-developing sulci of the human brain. It first appears around the fourteenth gestational week. The
Choroidal fissure Choroidal fissure The choroid is the middle, vascular coat of the eye which resides between the sclera and the retina. Early in development the choroidal fissure is a groove that extends along the ventral aspect of the optic stalk. In effect, it is a continuation of the invagination that forms the optic cup during early development in amniotes. For a period of time this groove extends to the closing lips of the optic cup. During development it is through the choroidal fissure that the retinal vessels enter and leave the eye. While optic neural components (e.g. axons arising from retinal