The parietal lobe is one of the four lobes of the brain (along with the frontal lobe, temporal lobe, and occipital lobe), located between the frontal and occipital lobes and underlying the parietal bone. It occupies about 19% of the cerebral hemispheres volume.
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Gross anatomy
The parietal lobe accounts for only 19% of the total neocortical volume, only marginally larger than the occipital lobe 3. The lobe extends from the central sulcus anteriorly, which separates it from the frontal lobe, to the parieto-occipital fissure posteriorly, which separates it from the occipital lobe. The lateral sulcus corresponds to its inferolateral boundary, separating it from the temporal lobe. Medially, it is confined by the medial longitudinal fissure which divides both cerebral hemispheres.
Gyri
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lateral surface
postcentral gyrus (primary sensory area)
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medial surface
Sulci
post central sulcus (separates post central and superior parietal lobules)
intraparietal sulcus (divides superior and inferior lobules)
marginal sulcus (separates the precuneus and paracentral lobule) 5
Relations
anterior: frontal lobe
posterior: occipital lobe
superior: parietal bone
inferior: temporal lobe
Blood supply
middle cerebral artery (MCA): lateral parietal lobe
anterior cerebral artery (ACA): medial parietal lobe
posterior cerebral artery (PCA): posterior medial parietal lobe
Neurological deficits
The following neurological deficits occur with unilateral or bilateral lesions of the parietal lobes 4:
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deficits arising from unilateral lesions involving the dominant hemisphere:
Gerstmann syndrome: right-left disorientation, finger agnosia, agraphia (without alexia), acalculia
contralateral hemianopia
sensory loss
contralateral neglect (less common than non-dominant)
bilateral astereognosis: inability to identify an object by touch alone
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deficits arising from unilateral lesions involving the non-dominant hemisphere:
contralateral sensory loss
contralateral neglect
contralateral hemianopia
topographic memory loss
anosognosia: impaired self-awareness
dressing apraxia
irritative lesions involving either lobe can give rise to focal seizures involving the contralateral limb, including with Jacksonian march (seizures spreading up/down the sensory strip (begins on one side; may begin with thumb/fingers and spread to the wrist, forearm, arm, face and leg; Todd's paresis may ensue))