Canalis basilaris medianus
Updates to Article Attributes
The inferior median clival canal also known as thecanalis basilaris medianus is a rare anatomical variant of the clivus, which passes in the sagittal plane from the intracranial surface of the clivus to its retropharyngeal surface. It is generally thought to represent a remnant of the notocord.
It should not be confused with a horizontal groove or canal which is sometimes seen thought to represent a venous channel between the inferior petrosal sinuses or a remnant of the first true somite 4.
Radiographic features
The canal is a well defined corticated structure, usually less than 2 mm in diameter which passes in the sagittal plane from the intracranial surface of the clivus (above the anterior rim of the foramen magnum) forwards and usually downwards to the nasopharyngeal surface (not surprisingly to the location of Tornwaldt cysts, also of notochord origin) 3. A co-existing cystic structure at its nasopharyngeal end has been reported, which may or may not represent a Tornwaldt cyst, depending on definition etc... 3.
Amazingly enough for a usually asymptomatic and rare anatomical variant, 6 subtypes have been described, divided into two groups 6-7:
-
complete
- superior
- inferior
- bifurcated (bifurcatus)
- a long channel running through the basiocciput and posterior sphenoid
- a superior recess within the basiocciput (blind ending recess on the intracranial surface)
- an inferior foveola pharyngica recess (blind ending recess on the nasopharyngeal surface)
EtymologyHistory and tymology
First described byGruber in 1880 3,5.
-<p>The <strong>inferior median clival canal</strong> also known as the <strong>canalis basilaris medianus</strong> is a rare anatomical variant of the <a href="/articles/clivus" title="clivus">clivus</a>, which passes in the sagittal plane from the intracranial surface of the clivus to its retropharyngeal surface. It is generally thought to represent a remnant of the <a href="/articles/notocord" title="notocord">notocord</a>. </p><p>It should not be confused with a horizontal groove or canal which is sometimes seen thought to represent a venous channel between the <a href="/articles/inferior-petrosal-sinus" title="Inferior petrosal sinus">inferior petrosal sinuses</a> or a remnant of the first true somite <sup>4</sup>. </p><h4>Radiographic features</h4><p>The canal is a well defined corticated structure, usually less than 2 mm in diameter which passes in the sagittal plane from the intracranial surface of the clivus (above the anterior rim of the foramen magnum) forwards and usually downwards to the nasopharyngeal surface (not surprisingly to the location of <a href="/articles/thornwaldt_cyst" title="Tornwaldt cysts">Tornwaldt cysts</a>, also of notochord origin) <sup>3</sup>. A co-existing cystic structure at its nasopharyngeal end has been reported, which may or may not represent a Tornwaldt cyst, depending on definition etc... <sup>3</sup>.</p><p>Amazingly enough for a usually asymptomatic and rare anatomical variant, 6 subtypes have been described, divided into two groups <sup>6-7</sup>: </p><ol>-<li>complete<ol>-<li>superior</li>-<li>inferior</li>-<li>bifurcated (bifurcatus)</li>-</ol>-</li>-<li>incomplete<ol>-<li>a long channel running through the basiocciput and posterior sphenoid</li>-<li>a superior recess within the basiocciput (blind ending recess on the intracranial surface)</li>-<li>an inferior <a href="/articles/foveola-pharyngica-recess" title="foveola pharyngica recess">foveola pharyngica recess</a> (blind ending recess on the nasopharyngeal surface)</li>-</ol>-</li>-</ol><h4>Etymology</h4><p>First described by <strong>Gruber</strong> in 1880 <sup>3,5</sup>. </p>- +<p>The <strong>inferior median clival canal</strong> also known as the <strong>canalis basilaris medianus</strong> is a rare anatomical variant of the <a href="/articles/clivus">clivus</a>, which passes in the sagittal plane from the intracranial surface of the clivus to its retropharyngeal surface. It is generally thought to represent a remnant of the <a href="/articles/notocord">notocord</a>. </p><p>It should not be confused with a horizontal groove or canal which is sometimes seen thought to represent a venous channel between the <a href="/articles/inferior-petrosal-sinus">inferior petrosal sinuses</a> or a remnant of the first true somite <sup>4</sup>. </p><h4>Radiographic features</h4><p>The canal is a well defined corticated structure, usually less than 2 mm in diameter which passes in the sagittal plane from the intracranial surface of the clivus (above the anterior rim of the foramen magnum) forwards and usually downwards to the nasopharyngeal surface (not surprisingly to the location of <a href="/articles/tornwaldt-cyst-3">Tornwaldt cysts</a>, also of notochord origin) <sup>3</sup>. A co-existing cystic structure at its nasopharyngeal end has been reported, which may or may not represent a Tornwaldt cyst, depending on definition etc... <sup>3</sup>.</p><p>Amazingly enough for a usually asymptomatic and rare anatomical variant, 6 subtypes have been described, divided into two groups <sup>6-7</sup>: </p><ul>
- +<li>
- +<strong>complete</strong><ul>
- +<li>superior</li>
- +<li>inferior</li>
- +<li>bifurcated (bifurcatus)</li>
- +</ul>
- +</li>
- +<li>
- +<strong>incomplete</strong><ul>
- +<li>a long channel running through the basiocciput and posterior sphenoid</li>
- +<li>a superior recess within the basiocciput (blind ending recess on the intracranial surface)</li>
- +<li>an inferior <a href="/articles/foveola-pharyngica-recess">foveola pharyngica recess</a> (blind ending recess on the nasopharyngeal surface)</li>
- +</ul>
- +</li>
- +</ul><h4>History and tymology</h4><p>First described by <strong>Gruber</strong> in 1880 <sup>3,5</sup>. </p>
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