Precentral gyrus
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At the time the article was created Chad Wong had no recorded disclosures.
View Chad Wong's current disclosuresAt the time the article was last revised Daniel J Bell had no financial relationships to ineligible companies to disclose.
View Daniel J Bell's current disclosures- Primary motor cortex
- Motor strip
- M1
- pre central gyrus
- pre-central gyrus
The precentral gyrus, also known as the primary motor cortex, is a very important structure involved in executing voluntary motor movements.
Gross anatomy
The precentral gyrus is a diagonally orientated cerebral convolution situated in the posterior portion of the frontal lobe. It is located immediately anterior to the central sulcus (fissure of Rolando), running parallel to it 1,2.
In the precentral gyrus, large neurones known as Betz cells send efferent axons that terminate on the contralateral motor cranial and spinal nuclei. The functional organisation of the precentral gyrus is such that clusters of Betz cells are somatotopically represented by an inverted homunculus. Therefore, head and face regions are innervated by the inferior portion of the precentral gyrus. Conversely, the lower limbs are innervated by the superior portion 4.
Relations
Anterior to the precentral gyrus, separated by the precentral sulcus, lie a set of areas composing the lateral premotor cortex and the supplemental motor area. Posteriorly, separated by the central sulcus, lies the primary somatosensory cortex.
Medially and inferiorly, it is bound by the cingulate gyrus. Laterally and inferiorly, it is bound by the Sylvian fissure 3.
The precentral gyrus is continuous with the postcentral gyrus on both the medial and superolateral aspects of each hemisphere. Medially, this occurs via the paracentral lobule, and superolaterally this connection is via the subcentral gyrus, which may be hidden within the operculum.
References
- 1. Encyclopedia of Clinical Neuropsychology. Springer. ISBN:0387799486. Read it at Google Books - Find it at Amazon
- 2. Encyclopedia of Autism Spectrum Disorders:5 volume set. Springer. ISBN:1441916970. Read it at Google Books - Find it at Amazon
- 3. Parent A, Carpenter MB. Carpenter's Human neuroanatomy. Williams & Wilkins. ISBN:0683067524. Read it at Google Books - Find it at Amazon
- 4. Rivara CB, Sherwood CC, Bouras C et-al. Stereologic characterization and spatial distribution patterns of Betz cells in the human primary motor cortex. Anat Rec A Discov Mol Cell Evol Biol. 2003;270 (2): 137-51. doi:10.1002/ar.a.10015 - Pubmed citation
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Related articles: Anatomy: Brain
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brain
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