Central sulcus

At a glance

English

Central sulcus

Latin (TA2)

Sulcus centralis

System

Brain and spinal cord

Region

Head

Side

Paired, left and right

About the central sulcus

The central sulcus is one of the main landmarks on the outer surface of the brain. It is also known as the fissure of Rolando, after the Italian anatomist Luigi Rolando, and should not be confused with the longitudinal fissure that separates the two hemispheres. It begins on the upper margin of the hemisphere, a little behind the midpoint between the front and back poles, usually notching onto the medial surface, and runs downwards and forwards across the lateral surface. It stops just short of the lateral sulcus, and its lower end is usually separated from it by a small bridge of cortex.

Its course is wavy rather than straight, with two main bends. The upper bend, convex backwards, forms the hand knob, an omega-shaped fold of the precentral gyrus that bulges into the sulcus and contains the motor area for the hand. This feature is easily found on MRI and helps identify the sulcus. The sulcus first appears in the fetus as a small dimple near the top of the hemisphere and lengthens towards both margins; by about three years of age its depth profile resembles that of an adult.

Its two banks hold the main motor and touch areas. In front lies the precentral gyrus, the primary motor cortex (Brodmann area 4), and behind it the postcentral gyrus, the primary somatosensory cortex (areas 3, 1 and 2), whose area 3 lines the back wall of the sulcus. Both carry a map of the opposite half of the body, upside down: the leg near the top and on the medial surface, then the trunk and arm, then the hand, and the face at the lower end. The hand and face have unusually large areas because of their fine control and sensitivity.

Because the sulcus divides motor from sensory function, surgeons locate it before removing tumours or epileptic foci nearby, using imaging, electrical stimulation and recordings of responses from the skin. Strokes in the middle and anterior cerebral artery territories affect the cortex on its banks, causing weakness and loss of feeling on the opposite side. Differences in its depth and length are reported in ADHD and Williams syndrome.

Function and supply

Function

Marks the boundary between the primary motor cortex in front and the primary somatosensory cortex behind, each mapping the opposite side of the body.

Blood supply

The lateral part is supplied by the central (Rolandic) branches of the middle cerebral artery; the upper end and medial part by branches of the anterior cerebral artery.