Detailed anatomy of the motor and sensory roots of the trigeminal nerve and their neurovascular relationships: a magnetic resonance imaging study.
OBJECTIVE
The trigeminal nerve conducts both sensory and motor impulses. Separate superior and inferior motor roots typically emerge from the pons just anterosuperomedial to the entry point of the sensory root, but to date these two motor roots have not been adequately displayed on magnetic resonance (MR) images. The specific aims of this study, therefore, were to identify the superior and inferior motor roots, to describe their exact relationship to the sensory root, and to assess the neurovascular relationships among all three roots of the trigeminal nerve.


METHODS
Thirty-three patients and seven cadaveric specimens (80 sides) were studied using three-dimensional (3D) Fourier transform constructive interference in steady-state (CISS) imaging. The 33 patients were also studied by obtaining complementary time-of-flight (TOF) MR angiography sequences with and without contrast enhancement. At least one motor root was identified in all sides examined: in 51.2% of the sides a single motor root, in 37.5% two motor roots, and in 11.2% three motor roots. The superior cerebellar artery (SCA) and the anterior inferior cerebellar artery (AICA) contacted the sensory root in 45.5% of patients and 42.9% of specimens. The SCA often contacted the superior motor root (48.5% of patients and 50% of specimens) and less frequently the inferior motor root (26.5% of patients and 20% of specimens).


CONCLUSIONS
Three-dimensional CISS and complementary 3D TOF MR angiography sequences reliably display sensory, superior motor, and inferior motor roots of the trigeminal nerve and their relationships to the SCA and AICA.
Yousry
Indra
I
Department of Neuroradiology, Klinikum Grosshadern, Ludwig-Maximilians Universität, Munich, Germany. iyousry@ikra.med.uni-muenchen.de
Moriggl
Bernhard
B
Holtmannspoetter
Markus
M
Schmid
Urs D
UD
Naidich
Thomas P
TP
Yousry
Tarek A
TA
D000328:Adult; D000368:Aged; D001158:Arteries / Q000033:anatomy & histology; D002531:Cerebellum / Q000033:anatomy & histology / Q000098:blood supply; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000648:ultrastructure*; D011149:Pons / Q000033:anatomy & histology / Q000098:blood supply; D012016:Reference Values; D011984:Sensory Receptor Cells / Q000033:anatomy & histology* / Q000098:blood supply*; D013126:Spinal Nerve Roots / Q000033:anatomy & histology* / Q000098:blood supply*; D014276:Trigeminal Nerve / Q000033:anatomy & histology* / Q000098:blood supply*; D014680:Veins / Q000033:anatomy & histology
D003287:Contrast Media; D019786:Gadolinium DTPA