II. Definitions

  1. Parietal Lobe
    1. Parietal Lobe receives sensory input and performs language processing
    2. As with motor centers in the Frontal Lobe, the Parietal Lobe is organized in the form of the cortical humunculus
      1. Disproportionately large region devoted to the face and hands, in contrast with the torso and legs
    3. Sensory functionality is primarily contained in Brodmann Areas 3,1,2
      1. Also in adjacent seconday somatic area (for pain and TemperatureSensation)
    4. Brain Lesions result in Receptive Aphasia, sensory loss, hemianopia and and spatial Disorientation.

III. Anatomy: Brodmann Areas of Parietal Lobe

  1. Images
    1. neuroBrodmannMedial.png
    2. neuroBrodmannLateral.png
  2. Primary Somatosensory Cortex or Somesthetic Area (Area 3,1,2)
    1. Lesions in this region affect contralateral sensory loss in light touch, pressure and proprioception
    2. Pain and Temperature sense are received in a region inferior to Area 3,1,2, known as the Secondary Somesthetic Area.
  3. Secondary Somatosensory Cortex or Somesthetic Area (Area S2)
    1. Lesions in this region affect pain and Temperature sense
    2. These fibers are inferior to Primary Somesthetic Area (Area 3,1,2)
  4. Superior Parietal Lobule (Anterior, Area 5)
    1. Involved in spatial orientation
  5. Visuo-Motor Coordination (Posterior, Area 7)
    1. Involved in spatial orientation
  6. Angular Gyrus (Area 39)
    1. When in the dominant hemisphere, a lesion in the Angular Gyrus affects the ability to read (alexia) and write (agraphia).
  7. Supramarginal Gyrus (Area 40)
    1. Dominant hemisphere lesions in the Supramarginal Gyrus cause Agnosia of tactile Sensation and proprioception
    2. The patient may have difficulty with left-right discrimination and Apraxia (difficulty with skilled movement)
    3. It also affects the interpretation of gestures made by other people.

IV. Physiology: Homunculus

  1. Homunculus is a graphical representation of sensory and motor control
  2. Man standing at the midline between the two Cerebral Hemispheres
    1. Legs are above the falx cerebri at the medial Parietal Lobe (Anterior Cerebral Artery)
    2. Legs are relatively small compared to arms and head
      1. Represents fewer overall Neurons dedicated to leg motor and sensory control
  3. Man is bending at the waist over the top of the Parietal Lobe
    1. Legs and head extend over the lateral Parietal Lobe (Middle Cerebral Artery)
    2. Arms and head are relatively large
      1. Represents greater overall Neurons dedicated to arm/head motor and sensory control

V. Signs: Brain Lesions

  1. Receptive Aphasia (Area 39)
  2. Sensory loss (Area 3,1,2 and Area S2 following Homunculus distribution)
  3. Spatial Disorientation (Area 5, 7)
  4. Hemianopia (loss of half of Visual Field in each eye)
  5. Agnosia of tactile Sensation and proprioception (Area 40, dominant hemisphere)
  6. Apraxia (difficulty with skilled movement) and altered left-right discrimination (Area 40)

VI. Exam

  1. Cognitive Dominant
    1. Names fingers
    2. Knows left and right
    3. Performs calculations on paper
    4. Reading
  2. Cognitive Non-Dominant
    1. Constructs copy of matchstick figure made by examiner

Images: Related links to external sites (from Bing)

Related Studies

Ontology: Parietal Lobe (C0030560)

Definition (FMA) Parietal lobe is the one of five lobes of the cerebral hemisphere which occupies the dorsal-posterior portion of the hemisphere. It is bounded by the central sulcus on its anterior border and and by the longitudinal cerebral fissure on its medial border. Posteriorly it shares an arbitrary border with the occipital lobe.
Definition (NCI_CDISC) One of the lobes of the cerebral hemisphere located superiorly to the occipital lobe and posteriorly to the frontal lobe. Cognition and visuospatial processing are its main function. (NCI)
Definition (NCI) One of the lobes of the cerebral hemisphere located superiorly to the occipital lobe and posteriorly to the frontal lobe. Cognition and visuospatial processing are its main functions.
Definition (MSH) Upper central part of the cerebral hemisphere. It is located posterior to central sulcus, anterior to the OCCIPITAL LOBE, and superior to the TEMPORAL LOBES.
Concepts Body Part, Organ, or Organ Component (T023)
MSH D010296
SnomedCT 16630005
English Parietal Lobes, Lobe, Parietal, Lobes, Parietal, Parietal Lobe, Tissue of parietal lobe brain, Tissue of parietal lobe of brain, Parietal cortex, Regio parietalis, Parietal region, parietal lobes, lobe parietal, parietal region, parietal cortex, parietal lobe, PL, Lobus parietalis, Parietal lobes, PARIETAL LOBE, Parietal Regions, Parietal Cortex, Cortex, Parietal, Parietal Region, Regions, Parietal, Parietal Cortices, Region, Parietal, Cortices, Parietal, Parietal lobe, Parietal lobe structure (body structure), Parietal lobe structure, Parietal lobe, NOS, Parietal Lobe of the Brain, lobus parietalis
Swedish Hjässlob
Czech parietální lalok
Finnish Päälakilohko
Russian TEMENNAIA DOLIA, ТЕМЕННАЯ ДОЛЯ
Croatian Not Translated[Parietal Lobe]
Polish Płat ciemieniowy
Norwegian Lobus parietalis, Parietallapp, Isselapp
Spanish estructura del lóbulo parietal (estructura corporal), estructura del lóbulo parietal, lóbulo parietal, Lóbulo Parietal
French Lobe pariétal
German Parietallappen, Scheitellappen
Italian Lobo parietale
Dutch Lobus parietalis (cerebri), Kwab, pariëtaal-, Pariëtaalkwab
Portuguese Lobo Parietal

Ontology: Structure of postcentral gyrus (C0152302)

Concepts Body Part, Organ, or Organ Component (T023)
MSH D013003
SnomedCT 56884009
English Posterior central gyrus, Postrolandic gyrus, Postcentral convolution, postcentral convolution, postrolandic gyrus, post central gyrus, PoG, posterior central gyrus, postcentral gyrus, Gyrus postcentralis, Gyrus centralis posterior, Gyrus, Postcentral, Postcentralis, Gyrus, Gyrus, Post Central, Gyrus Postcentrali, Postcentrali, Gyrus, Postcentral Gyrus, Gyrus Postcentralis, Post Central Gyrus, Central Gyrus, Post, Postcentral gyrus, Structure of postcentral gyrus (body structure), Structure of postcentral gyrus
Spanish circunvolución poscentral, circunvolución postcentral, estructura de la circunvolución poscentral (estructura corporal), estructura de la circunvolución poscentral

Ontology: Structure of angular gyrus (C0152305)

Definition (NCI) The portion of the brain located in the parietal lobe that plays a role in intersensory processing, language comprehension, and cognition.
Concepts Body Part, Organ, or Organ Component (T023)
MSH D010296
SnomedCT 59024009
English Middle part of inferior parietal lobule, Preoccipital gyrus, gyrus angularis, middle part of inferior parietal lobule, AnG, angular gyrus, prelunate gyrus, preoccipital gyrus, Gyrus angularis, Gyrus parietalis inferior, Angularis, Gyrus, Angular Gyrus, Gyrus, Angular, Gyrus Angulari, Prelunate Gyrus, Gyrus, Prelunate, Gyrus Angularis, Angulari, Gyrus, Angular gyrus, Structure of angular gyrus (body structure), Structure of angular gyrus
Spanish circunvolución angular, estructura de la circunvolución angular (estructura corporal), estructura de la circunvolución angular

Ontology: Structure of precuneus (C0152306)

Definition (NCI) The medial aspect of the posterior parietal lobe, which is bounded anteriorly by the marginal branch of the cingulate sulcus, posteriorly by the medial portion of the parieto-occipital fissure and inferiorly by the subparietal sulcus. It is involved in a wide range of higher-order cognitive function, such as episodic memory, visuospatial processing, reflections upon self, and aspects of consciousness.
Definition (NCI_CDISC) The posteromedial region of the parietal lobe bounded by the marginal branch of the cingulate sulcus anteriorly, by the medial portion of the parieto-occipital fissure posteriorly and by the subparietal sulcus inferiorly.
Concepts Body Part, Organ, or Organ Component (T023)
MSH D010296
SnomedCT 17292004
English Precuneate lobule, medial area of the superior parietal cortex, precuneus, PCu, quadrate lobule, precuneate lobule, PRECUNEUS, Cortices, Precuneus, Cortex, Precuneus, Praecuneus, Precuneus Cortex, Precuneus Cortices, Precuneus, Quadrate lobule, Structure of precuneus (body structure), Structure of precuneus
Spanish estructura del precúneo (estructura corporal), estructura del precúneo, lóbulo cuadrado, precúneo

Ontology: posterior paracentral gyrus (C2327483)

Concepts Body Part, Organ, or Organ Component (T023)
English Posterior paracentral gyrus, Gyrus paracentralis posterior, posterior paracentral gyrus

Ontology: Segment of supramarginal gyrus (C2331116)

Concepts Body Location or Region (T029)
English Supramarginal gyrus subdivision, Segment of supramarginal gyrus

Ontology: Sulcal segment of superior parietal lobule (C2950304)

Concepts Body Location or Region (T029)
English Sulcal segment of superior parietal lobule