The anatomy of the subarcuate canaliculus (SAC), subarcuate fossa (SAF) and subarcuate artery (SAA) was studied in 12 cadavers and 35 dry temporal bones. Each cadaver was scanned with high resolution CT (HRCT) prior to microdissection. The SAC was always found to be a single canal located between the two arcs of the anterior semicircular canal in both microdissections and HRCT scans and the internal acoustic meatus was observed to be located just inferior to the SAC. The SAC was on average of 9.2 mm in length and 1 mm in width. The SAF was situated at a distance of 4.2 mm from the internal acoustic meatus, 3.5 mm from the groove for the superior petrosal sinus, 6.7 mm from the opening of the vestibular canaliculus and 11.5 mm from the most superior part of the jugular foramen. The SAA was found to originate from the anterior inferior cerebellar artery in 9 cadavers and from the internal auditory artery in 3 cadavers. The SAA always emerged from the main artery outside the internal acoustic meatus. It ran through the SAC as a single artery. This study investigated CT correlated anatomical aspects of the subarcuate canaliculus and its artery which is claimed to be responsible for the blood supply of the mastoid antrum, facial canal and bony labyrinth.
"As the petrous bone grows, the SAF progressively narrows during early life to form a so-called 'canaliculus' shape  . Most publications of the appearance of the PMC are of adults     , with only 2 publications of the high resolution computed tomography (HRCT) features of the PMC in a large number of children  . However, these studies do not describe the year-by-year change in the width and shape of the PMC during the first years of life, despite this being described in anatomical studies  . "
[Show abstract][Hide abstract] ABSTRACT: Objective:
The adult petromastoid canal (PMC) is a thin anatomical structure, but in young children, it can be wide on high resolution CT (HRCT) scans. We performed this study to evaluate the year-by-year change in width and shape of the PMC in the young child.
Materials and methods:
We retrospectively reviewed temporal bone HRCT scans, performed between 2007 and 2012. Eighty children were included (age range: 0.3-6.9 years; median age: 3.1 years; 56% male). All scans had a slice thickness of ≤ 1 mm.
The average width of the PMC was 1.95 mm in children < 2 years, compared to 0.83 mm in children ≥ 2 (p < 0.001). We categorized the PMC into 4 subtypes. A bulky (type III) PMC was predominant < 2 years. A thin curvilinear (type I) PMC was more prevalent in the older children. Type II and IV PMC were found infrequently. The PMC width correlated inversely with the degree of pericapsular ossification (p<0.001), and mastoid pneumatisation (p < 0.001).
A wide PMC (≥ 1 mm) is a common finding in children < 2 years. As children grow older, the PMC progressively narrows. This correlates to increased temporal bone pneumatisation and ossification of the otic capsule.
International journal of pediatric otorhinolaryngology 03/2013; 77(5). DOI:10.1016/j.ijporl.2013.02.015 · 1.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The small structures in the temporal bone are surrounded by bone and air. The objectives of this study were (a) to compare contrast-enhanced T1-weighted images acquired by fast spin-echo-based three-dimensional real inversion recovery (3D rIR) against those acquired by gradient echo-based 3D SPGR in the visualization of the enhancement of small structures in the temporal bone, and (b) to determine whether either 3D rIR or 3D SPGR is useful for visualizing enhancement of the cochlear lymph fluid. Seven healthy men (age range 27-46 years) volunteered to participate in this study. All MR imaging was performed using a dedicated bilateral quadrature surface phased-array coil for temporal bone imaging at 1.5 T (Visart EX, Toshiba, Tokyo, Japan). The 3D rIR images (TR/TE/TI: 1800 ms/10 ms/500 ms) and flow-compensated 3D SPGR images (TR/TE/FA: 23 ms/10 ms/25 degrees) were obtained with a reconstructed voxel size of 0.6 x 0.7 x 0.8 mm3. Images were acquired before and 1, 90, 180, and 270 min after the administration of triple-dose Gd-DTPA-BMA (0.3 mmol/kg). In post-contrast MR images, the degree of enhancement of the cochlear aqueduct, endolymphatic sac, subarcuate artery, geniculate ganglion of the facial nerve, and cochlear lymph fluid space was assessed by two radiologists. The degree of enhancement was scored as follows: 0 (no enhancement); 1 (slight enhancement); 2 (intermediate between 1 and 3); and 3 (enhancement similar to that of vessels). Enhancement scores for the endolymphatic sac, subarcuate artery, and geniculate ganglion were higher in 3D rIR than in 3D SPGR. Washout of enhancement in the endolymphatic sac appeared to be delayed compared with that in the subarcuate artery, suggesting that the enhancement in the endolymphatic sac may have been due in part to non-vascular tissue enhancement. Enhancement of the cochlear lymph space was not observed in any of the subjects in 3D rIR and 3D SPGR. The 3D rIR sequence may be more sensitive than the 3D SPGR sequence in visualizing the enhancement of small structures in the temporal bone; however, enhancement of the cochlear fluid space could not be visualized even with 3D rIR, triple-dose contrast, and dedicated coils at 1.5 T.
European Radiology 01/2004; 13(12):2650-8. DOI:10.1007/s00330-003-1922-8 · 4.01 Impact Factor
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