Brodmann area 4 993486 222731754 2008-06-30T20:58:04Z Tkgd2007 2934677 svg brain {{Infobox Brain| Name = {{PAGENAME}} | Latin = | GraySubject = | GrayPage = | Image = ba4.png | Caption = Brodmann area 4 of human brain. | Image2 = Gray726-Brodman.svg | Caption2 = Lateral surface. | IsPartOf = [[Precentral gyrus]]| Components = | Artery = | Vein = | BrainInfoType = ancil | BrainInfoNumber = 1043 | MeshName = | MeshNumber = | }} '''Brodmann area 4''' comprises the [[primary motor cortex]] of the human [[brain]]. Brodmann area 4 is about the same as the [[precentral gyrus]]. The borders of this area are: the [[precentral sulcus]] in front ([[anterior]]ly), the [[medial longitudinal fissure]] at the top ([[medial]]ly), the [[central sulcus]] in back ([[posterior]]ly), and the [[lateral sulcus]] along the bottom ([[Human anatomical terms#Anatomical directions|lateral]]ly). This area of cortex, as shown by [[Wilder Penfield]] and others, has the pattern of a [[homunculus]]. That is, the legs and trunk fold over the midline; the arms and hands are along the middle of the area shown here; and the face is near the bottom of the figure. Because Brodmann area 4 is in the same general location as [[primary motor cortex]], the [[homunculus]] here is called the [[motor homunculus]]. The term '''area 4 of Brodmann-1909''' refers to a [[cytoarchitecture|cytoarchitecturally]] defined portion of the [[frontal lobe]] of the [[guenon]]. It is located predominantly in the [[precentral gyrus]]. [[Brodmann]]-1909 regarded it as topographically and cytoarchitecturally homologous to the human gigantopyramidal area 4 and noted that it occupies a much greater fraction of the frontal lobe in the monkey than in the human. Distinctive features (Brodmann-1905): the cortex is unusually thick; the layers are not distinct; the cells are relatively sparsely distributed; [[pyramidal cell|giant pyramidal (Betz) cell]]s are present in the internal [[pyramidal layer]] (V); lack of an internal [[granular layer]] (IV) such that the boundary between the external pyramidal layer (III) and the internal pyramidal layer (V) is indistinct; lack of a distinct external granular layer (II); a gradual transition from the [[multiform layer]] (VI) to the subcortical [[white matter]]. ==See also== * [[Brodmann area]] * [[List of regions in the human brain]] {{neuroanatomy-stub}} {{Prosencephalon}} [[Category:Brodmann areas|04]]