title: Microanatomical architecture of Dorello's canal and its clinical implications.
abstract: OBJECTIVE
  We investigated the membranous architecture of the abducens nerve at the petroclival region and describe the characteristics of this area in cadaveric specimen and two children with hydrocephalus and sixth nerve palsy using magnetic resonance imaging (MRI).
  
  
  METHODS
  Five adult cadaver heads were used to investigate the petroclival part of the abducens nerve. The heads were injected with colored latex for microsurgical dissection, and the length of the dural sleeve of the abducens nerve and its width at the apex were measured. In one cadaver head, the area between the petroclival entrance porus of the abducens nerve and the cavernous sinus was histologically studied under light microscopy. In two patients with hydrocephalus and abducens nerve palsy, the petroclival area was screened by using the MRI fat suppression technique.
  
  
  RESULTS
  In the cadavers, the arachnoid membrane on the clivus extended within the dural sleeve as far as the petrous apex, as an extension of the subarachnoid space. The average length of the dural sleeve was 9.5 mm and the average width was 1.5 mm at the apex, where the nerve entered the cavernous sinus. MRI scans showed that the cerebrospinal fluid distance of the petroclival region was 5 mm in the first patient and 7 mm in the second.
  
  
  CONCLUSIONS
  The subarachnoid space inside the dural sleeve of the abducens nerve can be defined by using thin-slice MRI scans. Enlargement of the dural sleeve at the petroclival region may coexist with the abducens nerve palsy. It has been documented in this study that the arachnoid membrane forms a membraneous barrier between the subarachnoid and subdural spaces within Dorello's canal.
authors.affiliation: Department of Neurosurgery, Ataturk Training and Research Hospital, Ankara, Turkey. fozveren@yahoo.com
authors.forename: Mehmet Faik
authors.initials: MF
authors.lastname: Ozveren
authors.forename: Fatih Serhat
authors.initials: FS
authors.lastname: Erol
authors.forename: Alpay
authors.initials: A
authors.lastname: Alkan
authors.forename: Ayhan
authors.initials: A
authors.lastname: Kocak
authors.forename: Cagatay
authors.initials: C
authors.lastname: Onal
authors.forename: Uğur
authors.initials: U
authors.lastname: Türe
mesh_terms: D000010:Abducens Nerve / Q000033:anatomy & histology*; D020434:Abducens Nerve Diseases / Q000473:pathology*; D000328:Adult; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000150:complications / Q000473:pathology; D007223:Infant; D008279:Magnetic Resonance Imaging