Central sulcus

Central Sulcus

Question 1. Name the sulci that help in demarcating the superolateral surface of the cerebral hemisphere into four lobes. Discuss the central sulcus in detail.

Answer. The sulci help in demarcating the superolateral surface of the cerebral hemisphere into four lobes:

• Central sulcus
• Lateral sulcus (posterior ramus)
• Parieto-occipital sulcus (terminal portion)

Central Sulcus (of Roland)

Features Of the Central Sulcus

Central sulcus

• Presents on the superolateral surface of the cerebral hemisphere
• Begins at the superomedial border of the cerebral hemisphere about 1 cm behind its midpoint
• Runs vertically downwards and slightly forward, and ends just above the lateral sulcus

Sulci of the cerebral hemisphere

Significance Of Central Sulcus

• Gyri lying in front and behind it are called the precentral gyrus and postcentral gyrus, respectively.
• The precentral gyrus is motor in function, and most of the fibres of the pyramidal tract arise in this gyrus to supply the opposite half of the body (i.e., contralateral half of the body).
• The postcentral gyrus is sensory in function and receives sensory impulses from the opposite half of the body (i.e. contralateral half of the body).
• The frontal branch of the middle meningeal artery ascends parallel and in front of the central sulcus, just deep into the pterion. The bone is thin here, and a fracture at this site causes haemorrhage from the artery and presses upon the precentral gyrus, leading to pressure symptoms like hemiplegia.