Atlas
The atlas is the first cervical vertebra.
For the Fincastle Project, Bone Unit 14 was added.
BU 1
SC A
Complete element.
BU 5
SC B
Element complete except for limited to extensive crushing of margins of one or both wings. Articular surfaces not damaged. (DS)
BU 6
SC C
Element complete except for dorsal tubercle which is absent. Articular processes present but may be damaged by crushing. (DS)
BU 9
SC D
Unit is complete, with the exception of the ventral portion of the element. The area surrounding the neural arch is missing entirely. (WU)
BU 10
SC E
Unit consists of only the dorsal portion of the body and possibly one of the wings (optional). Portions missing from the unit include the entire ventral portion of the body and one or both wings. Similar to BU 11.
BU 11
SC F
Unit consists of one half of the element only. (The dorsal and ventral surfaces from one side) Similar to BU 10. (WU)
BU 8
SC G
All or most of either left or right wing of atlas. Anterior and posterior surface totally or largely absent. (KK)
BU 3
SC H
All or major portion. (greater than ¾ of either the left or right anterior articular surface). (JB)
BU 12
SC I
Unit consists of dorsal tubercle and dorsal portions of anterior articular surfaces (anterior dorsal portion). Ventral anterior portions are absent, as well as all posterior portions. (WU)
BU 4
SC J
Portion of dorsal arch of Atlas consisting of all or major portion of dorsal tubercle. Lacks any articular surfaces. (TH)
BU 2
SC K
Small to medium sized fragment containing a portion of one posterior articular surface.
BU 7
SC L
Portion of ventral area of arch including one or both posterior, and one or both anterior articular processes. Wings of atlas and dorsal portion of arch absent. (KK)
BU 13
SC M
Unit consists only of ventral anterior portion. Similar to BU 7. (WU)
BU 14
SC N
Posterior sub-articular surface. (SB)