Longitudinal fissure Longitudinal fissure The longitudinal fissure (or cerebral fissure, median longitudinal fissure, or interhemispheric fissure) is the deep groove that separates the two hemispheres of the vertebrate brain. The medial surfaces of the two hemispheres are as similarly convoluted by gyri and sulci as is the outer surface of the brain. It is thought that a majority of existing animals, including Homo sapiens, have evolved from a common wormlike ancestor that lived around 600 million years ago, called the urbilaterian. A bilaterian animal is one that has symmetrical left and right body halves. While it is still debated whether this species
Palpebral fissure be increased in vertical height in Graves' disease, which is manifested as Dalrymple's sign. Seen in disorders like cri-du-chat. Narrowing of the fissure can be a prominent indicator of myofascial trigger points in the ipsilateral sternocleidomastoid muscle's sternal division, a common cause of tension headaches, particularly those felt around the eyes and sinuses. In animal studies, using four times the therapeutic concentration of the ophthalmic solution Latanoprost, the size of the palpebral fissure can be increased. The condition is reversible. Latanoprost is a prostaglandin F receptor agonist. Palpebral fissure The palpebral fissure is the elliptic space between the medial and