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From the external occipital protuberance, an often faintly marked ridge or crest, the median nuchal line, descends to the foramen magnum and affords attachment to the nuchal ligament. Running from the middle of this line across either half of the nuchal plane is the inferior nuchal line.
Only a comparatively small part of the head at term is represented by the face. The rest of the head is composed of the firm skull, which is made up of two frontal, two parietal, and two temporal bones, along with the upper portion of the occipital bone and the wings of the sphenoid. These bones are separated by membranous spaces, or sutures.
The occipital plane is said to be ossified from two centers and the basilar portion from one. About the fourth year the squamous part and the two lateral parts unite, and by about the sixth year the bone consists of a single piece. Between the 18th and 25th years the occipital and sphenoid bone become united, forming a single bone.
Occipital lesions can cause visual hallucinations. Lesions in the parietal-temporal-occipital association area are associated with color agnosia, movement agnosia, and agraphia. Lesions near the left occipital lobe can result in pure alexia (alexia without agraphia). Damage to the primary visual cortex, which is located on the surface of the ...
Brodmann area 18, or BA18, is part of the occipital cortex in the human brain.It accounts for the bulk of the volume of the occipital lobe. It is known as a "Visual Association Area" or V2 and is a first stage in processing or feature extraction of retinotopic images from V1.
Brodmann area 19, or BA 19, is part of the occipital lobe cortex in the human brain.Along with area 18, it comprises the extrastriate (or peristriate) cortex. In humans with normal sight, extrastriate cortex is a visual association area, with feature-extracting, shape recognition, attentional, and multimodal integrating functions.
The under surface of the jugular process is rough, and gives attachment to the Rectus capitis lateralis muscle and the lateral atlanto-occipital ligament; from this surface an eminence, the paramastoid process, sometimes projects downward, and may be of sufficient length to reach, and articulate with, the transverse process of the atlas.
In mammals, it is located in the posterior pole of the occipital lobe and is the simplest, earliest cortical visual area. It is highly specialized for processing information about static and moving objects and is excellent in pattern recognition. Moreover, V1 is characterized by a laminar organization, with six distinct layers, each playing a ...