title: ANATOMICAL STUDY OF CRANIAL NERVE EMERGENCE AND SKULL FORAMINA IN THE HORSE USING MAGNETIC RESONANCE IMAGING AND COMPUTED TOMOGRAPHY.
abstract: For accurate interpretation of magnetic resonance (MR) images of the equine brain, knowledge of the normal cross-sectional anatomy of the brain and associated structures (such as the cranial nerves) is essential. The purpose of this prospective cadaver study was to describe and compare MRI and computed tomography (CT) anatomy of cranial nerves' origins and associated skull foramina in a sample of five horses. All horses were presented for euthanasia for reasons unrelated to the head. Heads were collected posteuthanasia and T2-weighted MR images were obtained in the transverse, sagittal, and dorsal planes. Thin-slice MR sequences were also acquired using transverse 3D-CISS sequences that allowed mutliplanar reformatting. Transverse thin-slice CT images were acquired and multiplanar reformatting was used to create comparative images. Magnetic resonance imaging consistently allowed visualization of cranial nerves II, V, VII, VIII, and XII in all horses. The cranial nerves III, IV, and VI were identifiable as a group despite difficulties in identification of individual nerves. The group of cranial nerves IX, X, and XI were identified in 4/5 horses although the region where they exited the skull was identified in all cases. The course of nerves II and V could be followed on several slices and the main divisions of cranial nerve V could be distinguished in all cases. In conclusion, CT allowed clear visualization of the skull foramina and occasionally the nerves themselves, facilitating identification of the nerves for comparison with MRI images.
authors.affiliation: Department of Veterinary Science, Small Animal Teaching Hospital, University of Liverpool, Leahurst, Neston, CH64 7TE, UK.
authors.forename: Rita
authors.initials: R
authors.lastname: Gonçalves
authors.affiliation: Department of Veterinary Science, Philip Leverhulme Equine Hospital, University of Liverpool, Leahurst, Neston, CH64 7TE, UK.
authors.forename: Fernando
authors.initials: F
authors.lastname: Malalana
authors.affiliation: Department of Veterinary Science, Small Animal Teaching Hospital, University of Liverpool, Leahurst, Neston, CH64 7TE, UK.
authors.forename: James Fraser
authors.initials: JF
authors.lastname: McConnell
authors.affiliation: Department of Veterinary Science, Small Animal Teaching Hospital, University of Liverpool, Leahurst, Neston, CH64 7TE, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Maddox
mesh_terms: D000010:Abducens Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D000055:Accessory Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D019412:Anatomy, Cross-Sectional; D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D002102:Cadaver; D003391:Cranial Nerves / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D005154:Facial Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D005930:Glossopharyngeal Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D006736:Horses / Q000033:anatomy & histology*; D007002:Hypoglossal Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000662:veterinary*; D009802:Oculomotor Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D009900:Optic Nerve / Q000033:anatomy & histology / Q000528:radiation effects; D011446:Prospective Studies; D012886:Skull / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000662:veterinary*; D014276:Trigeminal Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D014321:Trochlear Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D014630:Vagus Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D000159:Vestibulocochlear Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging
keywords: CT; MRI; cranial nerves; horse