title: Variations in zygapophyseal joint orientation and level of transition at the thoracolumbar junction. Preliminary survey using computed tomography.
abstract: Variation in zygapophyseal joint orientation at the thoracolumbar transitional junction was investigated using computed tomography (CT). The study population (N = 214) comprised 176 cases of abdominal scans, 9 thoracolumbar junction referrals and 29 cadaveric vertebral columns. Scans through the superior endplates of T11, T12, L1 and L2 were selected and joint angles calculated using a computer aided digitiser. Analysis revealed 29% of cases presented coronally oriented superior and sagittally orientated inferior joint processes at T12. This pattern occurred in 16% of cases at T11 and 0.5% at L1. A gradual transition occurred in 54% of cases and involved the adjacent inter-segmental joints of T11 and T12. Articular tropism (greater than 20 degrees) was most frequent at T11-12 (21%), followed by T12-L1 (9%).
authors.affiliation: Department of Anatomy and Human Biology, University of Western Australia, Nedlands.
authors.forename: K P
authors.initials: KP
authors.lastname: Singer
authors.forename: P D
authors.initials: PD
authors.lastname: Breidahl
authors.forename: R E
authors.initials: RE
authors.lastname: Day
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013904:Thoracic Vertebrae / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed