Subfalcine herniation

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Subfalcine herniation, also known as midline shift or cingulate hernia, is the most common cerebral herniation pattern. It is generally caused by unilateral frontal, parietal or temporal lobe disease that creates a mass effect with medial direction of the ipsilateral cingulate gyrus beneath the free edge of the falx cerebri due to raised intracranial pressure

Radiographic features

CT

The easiest method of evaluating for subfalcine shift is a straight line drawn in the axial plane, at the level of the foramen of Monro, and measuring the distance between this line and the displaced septum pellucidum. Shift of the septum pellucidum from this midline can be measured in millimetres and compared over time to determine any change.

In more severe hernias, the displaced tissue may compress the corpus callosum and contralateral cingulate gyrus as well as the ipsilateral lateral ventricleforamen of Monro, causing dilation of the contralateral lateral ventricle

Subfalcine hernias occur anteriorly, as the anterior falx (although rigid) is displaced, secondary to mass effect. The posterior falx on the other hand is more rigid and will resist the displacement. 

MRI

Findings are best visualised on coronal MR imaging. Unilateral mass effect from pathology in the frontal, parietal or temporal region, such as intracranial haemorrhage or tumour, causes displacement of the brain away from the mass. 

Treatment and prognosis

Complications

ACA infarction occurs as the cingulate sulcus extends under the falx dragging the ipsilateral anterior cerebral artery with it. If this becomes compressed against the falx, distal anterior cerebral artery infarction can occur, the most common clinical manifestation being contralateral leg weakness. 

In subfalcine herniation, the degree of midline shift correlates with the prognosis; less than 5mm deviation has a good prognosis, whereas a shift of more than 15mm15 mm is related to a poor outcome 4

  • -<p><strong>Subfalcine herniation</strong>, also known as <a href="/articles/midline-shift">midline shift </a>or <a href="/articles/cingulate-hernia">cingulate hernia,</a> is the most common <a href="/articles/cerebral-herniation">cerebral herniation</a> pattern. It is generally caused by unilateral frontal, parietal or temporal lobe disease that creates a mass effect with medial direction of the ipsilateral <a href="/articles/cingulate-gyrus">cingulate gyrus</a> beneath the free edge of the <a href="/articles/falx-cerebri">falx cerebri</a> due to <a href="/articles/raised-intracranial-pressure">raised intracranial pressure</a>. </p><h4>Radiographic features</h4><h5>CT</h5><p>The easiest method of evaluating for subfalcine shift is a straight line drawn in the axial plane, at the level of the <a title="foramen of Monro" href="/articles/foramen-of-monroe">foramen of Monro</a>, and measuring the distance between this line and the displaced <a href="/articles/septum-pellucidum">septum pellucidum</a>. Shift of the septum pellucidum from this midline can be measured in millimetres and compared over time to determine any change.</p><p>In more severe hernias, the displaced tissue may compress the <a href="/articles/corpus-callosum">corpus callosum</a> and contralateral <a href="/articles/cingulate-gyrus">cingulate gyrus</a> as well as the ipsilateral <a href="/articles/lateral-ventricle">lateral ventricle</a>, <a title="foramen of Monro" href="/articles/foramina-of-monroe">foramen of Monro</a>, causing dilation of the contralateral <a href="/articles/lateral-ventricle">lateral ventricle</a>. </p><p>Subfalcine hernias occur anteriorly, as the <a href="/articles/anterior-falx">anterior falx</a> (although rigid) is displaced, secondary to mass effect. The <a href="/articles/posterior-falx">posterior falx</a> on the other hand is more rigid and will resist the displacement. </p><h5>MRI</h5><p>Findings are best visualised on coronal MR imaging. Unilateral mass effect from pathology in the frontal, parietal or temporal region, such as <a href="/articles/intracranial-haemorrhage">intracranial haemorrhage</a> or <a href="/articles/intracranial-tumour">tumour</a>, causes displacement of the brain away from the mass. </p><h4>Treatment and prognosis</h4><h5>Complications</h5><ul>
  • +<p><strong>Subfalcine herniation</strong>, also known as <a href="/articles/midline-shift">midline shift </a>or <a href="/articles/cingulate-hernia">cingulate hernia,</a> is the most common <a href="/articles/cerebral-herniation">cerebral herniation</a> pattern. It is generally caused by unilateral frontal, parietal or temporal lobe disease that creates a mass effect with medial direction of the ipsilateral <a href="/articles/cingulate-gyrus">cingulate gyrus</a> beneath the free edge of the <a href="/articles/falx-cerebri">falx cerebri</a> due to <a href="/articles/raised-intracranial-pressure">raised intracranial pressure</a>. </p><h4>Radiographic features</h4><h5>CT</h5><p>The easiest method of evaluating for subfalcine shift is a straight line drawn in the axial plane, at the level of the <a href="/articles/foramen-of-monroe">foramen of Monro</a>, and measuring the distance between this line and the displaced <a href="/articles/septum-pellucidum">septum pellucidum</a>. Shift of the septum pellucidum from this midline can be measured in millimetres and compared over time to determine any change.</p><p>In more severe hernias, the displaced tissue may compress the <a href="/articles/corpus-callosum">corpus callosum</a> and contralateral <a href="/articles/cingulate-gyrus">cingulate gyrus</a> as well as the ipsilateral <a href="/articles/lateral-ventricle">lateral ventricle</a>, <a href="/articles/foramina-of-monroe">foramen of Monro</a>, causing dilation of the contralateral <a href="/articles/lateral-ventricle">lateral ventricle</a>. </p><p>Subfalcine hernias occur anteriorly, as the <a href="/articles/anterior-falx">anterior falx</a> (although rigid) is displaced, secondary to mass effect. The <a href="/articles/posterior-falx">posterior falx</a> on the other hand is more rigid and will resist the displacement. </p><h5>MRI</h5><p>Findings are best visualised on coronal MR imaging. Unilateral mass effect from pathology in the frontal, parietal or temporal region, such as <a href="/articles/intracranial-haemorrhage">intracranial haemorrhage</a> or <a href="/articles/intracranial-tumour">tumour</a>, causes displacement of the brain away from the mass. </p><h4>Treatment and prognosis</h4><h5>Complications</h5><ul>
  • -</ul><p>ACA infarction occurs as the <a href="/articles/cingulate-sulcus">cingulate sulcus</a> extends under the falx dragging the ipsilateral <a href="/articles/anterior-cerebral-artery">anterior cerebral artery</a> with it. If this becomes compressed against the falx, distal anterior cerebral artery infarction can occur, the most common clinical manifestation being contralateral leg weakness. </p><p>In subfalcine herniation, the degree of <a href="/articles/midline-shift">midline shift </a>correlates with the prognosis; less than 5mm deviation has a good prognosis, whereas a shift of more than 15mm is related to a poor outcome <sup>4</sup>. </p><p> </p><p> </p>
  • +</ul><p>ACA infarction occurs as the <a href="/articles/cingulate-sulcus">cingulate sulcus</a> extends under the falx dragging the ipsilateral <a href="/articles/anterior-cerebral-artery">anterior cerebral artery</a> with it. If this becomes compressed against the falx, distal anterior cerebral artery infarction can occur, the most common clinical manifestation being contralateral leg weakness. </p><p>In subfalcine herniation, the degree of <a href="/articles/midline-shift">midline shift </a>correlates with the prognosis; less than 5mm deviation has a good prognosis, whereas a shift of more than 15 mm is related to a poor outcome <sup>4</sup>. </p>

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