Basal ganglia
Updates to Article Attributes
The basal ganglia are a group of grey matter nuclei in the deep aspects of the brain that is interconnected with the cerebral cortex, thalami and brainstem.
Terminology
Whilst very widely used in English, the term 'basal ganglia' is actually a misnomer, as a ganglion is a collection of nerve cell bodies outside of the central nervous system. The equivalent within the central nervous system is termed 'nucleus', as reflected in the official term for the basal ganglia in the Terminologia Anatomica, 'nuclei basales', the English translation of which is 'basal nuclei'.
This is also illustrated by the name of each individual basal nucleus, e.g. caudate nucleus, lentiform nucleus, subthalamic nuclei, etc.
Anatomy
In a strict anatomical sense, it contains three paired nuclei that together comprise the corpus striatum:
Functionally, two additional nuclei are also part of the basal ganglia:
The caudate nucleus is located at the superomedial part of the internal capsule, while putamen and globus pallidus are located at the inferolateral part. The anterior part of the caudate nucleus indents medially into the floor of the lateral ventricle. The inferior part of the caudate nucleus limits the roof of the temporal horn of the lateral ventricle. Medial to the caudate nucleus is the thalamus. Superior to the caudate nucleus lies the corpus callosum. The tail of caudate nucleus extends under the internal capsule behind the thalamus forming a roof with the inferior horn of lateral ventricle 4.
Blood Supply
Arterial Supply
AlthoughThe precise vascular anatomy of the basal ganglia can vary among individuals, nevertheless, the majority of the basal ganglia receives arterial supply from medialthe the middle cerebral artery and lateral lenticulostriate arteries, and theanterior cerebral artery branches.
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Caudate:
Head: Recurrent artery of
Heubner, there is rich arterial supply from all major vesselsheubner (branch of theCircle of Willis:MCA).Terminal ICATail: Anteriorchoroidalcoroidal arterysupplies the tail(branch of thecaudateACA or the terminal ICA)
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Lentiform nucleus:
Putamen: lenticulostriate arteries.
ACAGlobus pallidus:Medial lenticulostriate arteries,artery ofHeubner supplytheglobus pallidus, putamenhuebner andhead of caudate.anterior choroid artery perforatorsMCA: lateral lenticulostriate arteries primarily supply the putamen.
PCA: Lateral posterior choroidal branch supplies the tail of the caudate.
Radiographic features
Ultrasound
Basal ganglia is isoechoic in head ultrasound 6. Hyperechoic basal ganglia would indicate oedema, ischaemia, or haemorrhage 7.
CT
Basal ganglia appears isodense to the cortex 5.
MRI
The basal ganglia are normally isointense to the cortex. As the globus pallidus has more myelin content and calcium deposition compared with the putamen, it usually appears slightly more T1 hyperintense 5. When calcification exceeds 30%, there is signal loss in all sequences 5.
Iron are particularly deposited within the globus pallidus, greater than putamen and caudate nucleus 3. This contributes to hypointensity of globus pallidus when compared to putamen and caudate nucleus on T2 an FLAIR weighted images 5. Ageing with consequent iron deposition in the putamen results in a gradual decrease of T2/T2*/SWI signal intensity in the putamen. This is more pronounced in the 8th or 9th decade of life.
Related pathology
See also
-</ul><p>The caudate nucleus is located at the superomedial part of the internal capsule, while putamen and globus pallidus are located at the inferolateral part. The anterior part of the caudate nucleus indents medially into the floor of the lateral ventricle. The inferior part of the caudate nucleus limits the roof of the temporal horn of the lateral ventricle. Medial to the caudate nucleus is the thalamus. Superior to the caudate nucleus lies the corpus callosum. The tail of caudate nucleus extends under the internal capsule behind the thalamus forming a roof with the inferior horn of lateral ventricle <sup>4</sup>.</p><h4>Blood Supply</h4><h5>Arterial Supply</h5><p>Although majority of the basal ganglia receives arterial supply from medial and lateral lenticulostriate arteries, and the artery of Heubner, there is rich arterial supply from all major vessels of the Circle of Willis:</p><ul>-<li><p>Terminal ICA: Anterior choroidal artery supplies the tail of the caudate.</p></li>-<li><p>ACA: Medial lenticulostriate arteries, artery of Heubner supply the globus pallidus, putamen and head of caudate.</p></li>-<li><p>MCA: lateral lenticulostriate arteries primarily supply the putamen.</p></li>-<li><p>PCA: Lateral posterior choroidal branch supplies the tail of the caudate.</p></li>- +</ul><p>The caudate nucleus is located at the superomedial part of the internal capsule, while putamen and globus pallidus are located at the inferolateral part. The anterior part of the caudate nucleus indents medially into the floor of the lateral ventricle. The inferior part of the caudate nucleus limits the roof of the temporal horn of the lateral ventricle. Medial to the caudate nucleus is the thalamus. Superior to the caudate nucleus lies the corpus callosum. The tail of caudate nucleus extends under the internal capsule behind the thalamus forming a roof with the inferior horn of lateral ventricle <sup>4</sup>.</p><h4>Blood Supply</h4><h5>Arterial Supply</h5><p>The precise vascular anatomy of the basal ganglia can vary among individuals, nevertheless, the majority of the basal ganglia receives arterial supply from the the middle cerebral artery and anterior cerebral artery branches. </p><ul>
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- +<p>Caudate: </p>
- +<ul>
- +<li><p>Head: Recurrent artery of heubner (branch of the MCA). </p></li>
- +<li><p>Tail: Anterior coroidal artery (branch of the ACA or the terminal ICA) </p></li>
- +</ul>
- +</li>
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- +<p>Lentiform nucleus: </p>
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- +<li><p>Putamen: lenticulostriate arteries.</p></li>
- +<li><p>Globus pallidus: artery of the huebner and anterior choroid artery perforators</p></li>
- +</ul>
- +</li>