Understanding Radiological anatomy of the Temporal Bone
The temporal bone has one of the most complicated anatomies in the body. It appears even more complicated on an HRCT Temporal bone. Teamwork and regular dialogue with our Radiology colleagues are of paramount importance to understand this intricate anatomy. We have devised a few basic tenets or rules to help to understand this tricky easily. One of the fundamental rules is mastering the intriguing anatomy of the semicircular canals.
The complicated orientation of semicircular (SCC) canals make the understanding the Radiological anatomy of the temporal bone difficult. The three semicircular canals are situated tangential to each other and are at different vertical planes and different levels on horizontal sections.
First, the posterior semicircular canal (PSCC) is vertically oriented and situated at a lower level. The PSCC lies posteriorly and is parallel to the posterior surface of the petrous part of the temporal bone. While the dark green indicates the posterior surface of the temporal bone, the blue colored arrow indicates the plane of the PSCC.
The superior semicircular canal (SSCC) is precisely at the right angle or perpendicular to the PSCC and, therefore, perpendicular to the posterior surface of the petrous part of the temporal bone also. The PSCC is also vertically situated and is at a higher level of the three canals.
Whereas the lateral semicircular canal (LSCC) is horizontally situated, at right angles to the plane of the other two canals, and is at the middle level, between the other two canals.