the posterior arch is the most posterior structure of the atlas c1 vertebra.
the posterior arch is the most posterior structure of the atlas c1 vertebra.
what is the most posterior structure of the atlas c1 vertebra?
posterior arch
within the cns, nerve cell bodies are generally organized into functional clusters, called nuclei. axons within the cns are grouped into tracts.









































there are 33 spinal cord nerve segments in a human spinal cord:









































8 cervical segments forming 8 pairs of cervical nerves (c1 spinal nerves exit spinal column between occiput and c1 vertebra; c2 nerves exit between posterior arch of c1 vertebra and lamina of c2 vertebra; c3-c8 spinal nerves through ivf above corresponding cervica vertebra, with the exception of c8 pair which exit via ivf between c7 and t1 vertebra)
neuromere
embryonic analysis of weberian apparatuses of the taxon "brycon" has shed some light on the development of the structure itself. the weberian apparatus elements form from the fully distinguishable first five vertebrae of the individual. the supraneural starts as an element of the skull. the claustra and the scaphia develop from expanded elements of the neural arch of the first vertebra (v1). from the second vertebra (v2), the intercalarum and the vertebra's lateral process are reduced and clump together. the plural rib (r1) of the third vertebra (v3) shrinks and moves somewhat ventrally, forming the tripus from a vertebral parapophysis fusing with the pleural rib. the os suspensorium bone of the fourth vertebra (v4) somewhat retains its shape, developing from the pleural rib of the vertebra (r2). the remaining elements of the fifth vertebra (v5), the parapophysis and the articulating rib (r3), including the vertebra itself form the posterior structure of the weberian apparatus. the neural spines of the first four vertebrae fuse and compress, forming one of the major structures of the apparatus.
weberian apparatus