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. 2017 Jan 25;12(1):e0170315. doi: 10.1371/journal.pone.0170315

Fig 1. 24 measurements used to map the hindbrain and craniocervical junction on T1w mid-sagittal MRIs of a CKCS without SM.

Fig 1

Key. (a) dorsum of spheno-occipital synchondrosis. (b) basion of basioccipital bone. (c) rostral edge of the dorsal lamina of the atlas. (d) junction between the supraoccipital bone and the occipital crest. (e) most dorsal point of intersection of the cerebellum with the occipital lobe circle. (f) centre of occipital lobe circle placed on the baseline at the level of the basioccipital bone (ab) and extending to encompass the occipital lobes. Diameter of circle = f-diam. (g) point at which the optic nerve deviates into the optic canal. (h) rostral edge of supra-occipital bone. (i) intersection point with ventrally extended line dc with the caudally extended ab baseline (forms angle 3 dib). (j) most rostral aspect of the dens of the axis bone. (k) extended line from point b along the best fit line of the ventral medulla oblongata to where it changes angle to the spinal cord. (l) rostral extension of baseline abi (hence becoming baseline labi). 11 angles measured are (1) lae, (2) fac, (3) dib, (4) fae (5) aeb (6) abd (7) bdi (8) ebd (9) jcb (10) afg (11) dbk. * significant for CM in the Griffon Bruxellois [24].