> as lemmas
proatlas
proatlas n.
Brit. 
/prəʊˈatləs/
, /prəʊˈatləs/U.S. /proʊˈætləs/
Zoology and Anatomy a vertebral element located between the base of the skull and the atlas vertebra which fuses with the skull during embryonic development in most vertebrates, but persists as a distinct element in some, esp. as a pair of small, V-shaped bones anterior to the neural arch of the atlas in certain reptiles (e.g. chameleons and tuataras)./proʊˈætləs/ΚΠ
1884 Amer. Naturalist 18 434 The skeleton examined (an adult [tuatara]) had, besides the pro-atlas, 8 cervical, 17 dorso-lumbar, 2 sacral, and 15 caudal vertebræ.
1968 Brain 91 661 This extra vertebra is termed the pro-atlas, but should, more correctly, be termed the occipital vertebra.
1986 A. S. Romer & T. S. Parsons Vertebr. Body (ed. 6) vii. 187 In many reptiles there may be, incidentally, a small, extra neural arch in advance of that of the atlas—a proatlas.
2002 Clin. Anat. 15 150/1 In man, the neural arch of the proatlas divides into anterior and posterior segments.
<
as lemmas