Difference Between Sulcus and Fissure

The key difference between sulcus and fissure is that sulcus is a groove on the cerebral cortex that surrounds a gyrus while fissure is a deeper sulcus that separates the brain into functional lobes.

The brain is one of the two major components of our central nervous system. It works as the center of the nervous system in all vertebrate and most invertebrate animals. The cerebral cortex is the outer layer of neural tissue of the cerebrum of the brain. It is made up of grey matter. Sulcus and fissure are two types of grooves present on the cerebral cortex. They aid in the compact packing of the brain into the skull. Both sulcus and fissure contain several common features. However, this article focuses on the difference between sulcus and fissure.

1. Overview and Key Difference
2. What is Sulcus
3. What is Fissure
4. Similarities Between Population Sulcus and Fissure
5. Side by Side Comparison – Sulcus vs Fissure in Tabular Form
6. Summary

What is Sulcus?

A sulcus is a groove present on the brain surface. Moreover, the convoluted nature of the brain is due to the presence of sulci (plural). They increase the surface area of the brain. Sulci are important to pack the large cerebral cortex inside the skull. These grooves are not as deep as a fissure. Sulci appear after 05 months of embryonic development. They become fully developed after 12 months of birth. Furthermore, sulci are made up of grey matter.

Figure 01: Sulci

Sulci produce gyri. They are the ridges of the brain. Gyri contain dendrites, glial cells, cell bodies axons, and synapses. However, the pattern of sulci differs in each individual. But some sulci such as central sulcus of insula, central sulcus, calcarine sulcus, hippocampal sulcus, etc, are notable as common grooves.

What is Fissure?

A fissure is a deeper groove present on the brain surface. Similar to sulcus, a fissure is made up of grey matter. Moreover, they are long narrow splits that separate larger portions of the brain into lobes. The longitudinal fissure divides the brain into two cerebral hemispheres; the left and the right. In humans, the right hemisphere controls the left side of the body and vice versa.

The right cerebral hemisphere is responsible for activities such as music, drawing, emotions, visual-spatial activities, and parallel processing. In contrast, the left cerebral hemisphere is responsible for writing, language, speech, and linear sequential processing.

Figure 02: Fissure

Each cerebral hemisphere consists of four lobes. They are frontal lobe, parietal lobe, temporal lobe, and occipital lobe. The central fissure, Sylvian fissure, and the parieto-occipital Sylvian fissure are the three fissures that separate above mentioned four lobes.

What are the Similarities Between Sulcus and Fissure?

Sulcus and fissure are two types of grooves present on the surface of the brain.
Both grooves divide the cerebral cortex into different sections.
Moreover, they are responsible for the convoluted nature of the cerebral cortex.
Besides, both are made up of grey matter.
Also, they aid the compact packing of the large cerebral cortex inside the skull.

What is the Difference Between Sulcus and Fissure?

Sulcus and fissure are two grooves present on the brain surface. A sulcus is a less deep groove that provides a convoluted nature while fissure is a long narrow split that separates larger portions of the brain into lobes. Therefore, we can consider this as the key difference between sulcus and fissure. Furthermore, another difference between sulcus and fissure is that the sulci give rise to gyri while fissures give rise to lobes. Furthermore, sulci are lesser deep grooves while fissures are the deepest grooves in the cerebral cortex. Thus, this is an important structural difference between sulcus and fissure.

Moreover, a functional difference between sulcus and fissure is that the sulci increase the surface area of the brain while fissures divide the brain into functional lobes. Examples for sulci are superior frontal and inferior frontal sulci, superior and inferior temporal sulci, and central sulcus. Examples for fissures are longitudinal fissure, central fissure, Sylvian fissure, and parieto-occipital Sylvian fissure.

Summary – Sulcus vs Fissure

The brain is the main unit of the central nervous system. Sulcus and fissure are two grooves present on the brain cerebral cortex. Sulci are lesser deep grooves, but fissures are the deepest grooves present in the brain. The key difference between sulcus and fissure lies in their function. Sulci produce gyri whilst fissures separate the brain into functional lobes. Furthermore, sulci increase the surface area of the brain. Moreover, gyri are composed of cell bodies, dendrites, axons, etc. The four functional lobes in each cerebral hemisphere produced by fissures are frontal lobe, parietal lobe, temporal lobe, and occipital lobe.

Reference:

1. “Cerebral Fissure.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., Available here.
2. Manickam, Appukutty. “Cerebral Sulci and Fissures | Radiology Reference Article.” Radiopaedia Blog RSS, Available here.

Image Courtesy:

1. “LobesCaptsLateral” By Sebastian023 (CC BY-SA 3.0) via Commons Wikimedia
2. “Blausen 0103 Brain Sensory&Motor” By Blausen.com staff (2014). “Medical gallery of Blausen Medical 2014”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. – Own work (CC BY 3.0) via Commons Wikimedia