Ribs
The extreme distal articular surface on ribs is often absent or not clearly defined. This may be the result of light weathering, the original cartilaginous nature of many such articulations, or of butchering. Because of the problem in differentiating these and other possibilities, the distal 0 to 5 cm of rib shaft is normally not considered in bone unit definition. Un-fused proximal epiphyses have not been given a BU definition and are coded as “weathered” and undifferentiated BU. Calcified costal cartilage is coded as undifferentiated scrap, weathered condition.
For the Fincastle Project, Bone Units 21-25 were added.
BU 1
SC A
Complete element. Distal articular surface or up to 5cm of distal end may be absent. Similar to BU 5 and BU 20.
BU 20
SC B
Complete proximal end with from ½ to ¾ of total shaft length represented. Similar to BU 1 and BU 5.
BU 5
SC C
Complete proximal end of element with ¼ - ½ of shaft represented. Similar to BU 2, BU 8, and BU 20.
BU 8
SC D
Complete proximal end of rib with 5-10cm of shaft included. Similar to BU 2 and BU 5.
BU 2
SC E
Unit consists of proximal end of rib including head, neck, tubercle and 0-5cm of shaft. Similar to BU 5 and BU 8.
BU 12
SC F
Rib complete except tubercle removed. Head and distal articular surface present.
BU 14
SC G
Essentially complete proximal end of rib with 5-10cm of shaft included. Small area immediately distal to tubercle crushed or removed. Similar to BU 2, BU 5 and BU 8.
BU 3
SC H
Unit consists of proximal end including head, neck, and 0-5cm of shaft. Tubercle removed. Similar to BU 2 and BU 9.
BU 9
SC I
Head of rib detached from rest of element. None of tubercle or shaft included. Similar to BU 3.
BU 19
SC J
Unfused epiphyseal head. Condition coded as weathered. (GL)
BU 13
SC K
Rib complete except head removed. Tubercle and distal articular surface present. Distal articular surface, or up to 5cm of distal end may be absent.
BU 17
SC L
Proximal end with tubercle present but missing head. Retains more then 5 and less than 20cm of adjoining shaft. Similar to BU 6. (TH)
BU 6
SC M
Proximal portion of element consisting of tubercle and 0-5cm of shaft. Head absent. Similar to BU 2.
BU 10
SC N
Essentially complete shaft or rib with only extreme proximal end including head and tubercle removed and possibly the extreme distal articular surface.
BU 4
SC O
Long to short section of shaft severed just below proximal end as evidenced by pronounced deepening of costal groove or sharp curvature present on fragmentation. Similar to BU 10 but with less of shaft present.
BU 18
SC P
Medium to short section of rib with proximal end characterized by removal or crushing of top of head and articular surface of tubercle. Removal by either crushing or carnivore gnawing. Similar to BU 4. (KK)
BU 7
SC Q
Small to medium sized section of shaft characterized by an easily discernible constriction along the posterior border near the distal end. May or may not include distal articular surface.
BU 11
SC R
Small to medium sized section of shaft characterized by presence of distal articular surface. Note: Does not include constriction along the posterior border as BU 7 does.
BU 16
SC S
Greater than 10cm long medial section of rib. Piece may split open, exposing internal cancellous tissue. Frequency indicates number of pieces only. Particular care should be taken to ensure whether BU 5 and BU 16 pieces reflect fragmentation resulting from weathering.
BU 15
SC T
0-10cm long medial section of rib. Frequency indicates number of pieces only.
BU 21
SC U
Portion of neck only; head, shaft and tubercle removed, with 0-20cm of shaft present. (SB)
BU 22
SC V
Small portion of tubercle only. Similar to BU 6. (SB)
BU 23
SC W
Small portion of head only. Similar to BU 9. (SB)
BU 24
SC X
Head and tubercle only. Neck and shaft missing. (SB)
BU 25
SC Y
Distal epiphysis. (SB)