Fig. 2.
The Upper-part of the First Vertebra of the Neck.
A, The Inside of the Back-part of the First Vertebra of the Neck next the Medulla Spinalis.
B, The Outside and Fore-part of the same Vertebra:
C C, Two Process's whose Two Shallow Cavities are Ar∣ticulated with Two somewhat•• Convext Prominencies of the Os Occipitis, Tab. 92, Fig. 2. O O; in which Articulation the Head is Mov'd in Nodding Fore-wards, Back-wards and Side-ways.
D, A Sinus in the Upper-part of this Vertebra, in which the Contorted Trunk of One of the Cervical Artery, passes towards the Great Foramen of the Os Occipitis.
N. B. It is Necessary the Great Foramen of this First Ver∣tebra of the Neck should be much Larger than any of the Infe∣rior, least the Beginning of the Medulla Spinalis should be In∣commoded in Turning the Head to One Side; in which Action, this First Vertebra Moves with the Head on the Axis or Tooth∣like Process of the Second Vertebra of the Neck.