Thoracic Vertebra
Only the anterior and posterior epiphyses on the body of the element are considered when coding whether the element is fused or un-fused. Loose un-fused anterior or posterior epiphyses unassociated with the rest of the element are coded as being of weathered condition and given their appropriate BU. Epiphyses on the spinous process are ignored in considering element fusion. When isolated un-fused epiphyses from the spinous or transverse processes are identified, they are coded as “undifferentiated” BU.
For the Fincastle Project, Bone Units 33-40 were added.
Thoracic vertebra #14 is the transition bone between thoracic and lumbar vertebrae. It has characteristics of both, but is coded as a thoracic vertebra.
BU 1
SC A
Complete element.
BU 20
SC B
Body, complete spinous process, half of arch and one transverse process present. One transverse process and half of arch missing (EMA).
BU 21
SC C
Essentially complete element missing one or both transverse processes (EMA).
BU 30
SC D
Unit consists of all or most of the spinous process, one or both anterior articular surfaces and one or both posterior articular surfaces, as well as one or both sides of the neural arch. One or both sides of the facets for the tubercle of the rib are present. The unit is the same as BU 12, but possess all or most of the spinous process. (TVH)
BU 31
SC E
Unit consists of ½ of the spinous process (split sagittally) and one transverse process only, attached by a small portion of the neural arch. This unit is essentially one half of BU 12. (WU)
BU 5
SC F
Element with distal ½ or less of the spinous process removed. The rest of the element is intact.
BU 4
SC G
Element with all or most of the spinous process removed. The posterior articular processes are always intact. Similar to BU 5 and BU 15.
BU 15
SC H
Element with all or most of spinous process and one or both of tubercles of ribs removed. Anterior and posterior articular surfaces may or may not be intact. Similar to BU 4.
BU 10
SC I
Element with all or most of spinous process. And ventral 1/3 – 2/3 of body removed. Arch, articular processes, and facets for ribs intact.
BU 29
SC J
Anterior ½ - 2/3 of element and ½ or more of adjoining spinous process. Posterior ½ - 2/3 of body, posterior articular processes and some of spinous process absent. (WU)
BU 12
SC K
Unit consists of basal portion of spinous process including one or both posterior articular surfaces; and all or most or either or both sides of the arch. One or both facets for the tubercle of the ribs are present. The same as BU 11 but with one or both of the rib facets present.
BU 24
SC L
Vertebral arch with 0-5cm of adjoining shaft of spinous process; all anterior and posterior articulating processes; all or base of one transverse process, lateral ¼ - ½ of body with costal facet for head of one rib. (DS)
BU 11
SC M
Unit has little or no spinous process. At least one of the anterior or posterior articular surfaces is present, and the unit can have both or either side of the arch. The facets for the rib tubercles, and the body if the vertebrae are missing. Similar to BU 12.
BU 23
SC N
Half to all body with all to part of one transverse process present. Vertebral arch, spinous process, and one transverse process absent. (DS)
BU 9
SC O
Essentially complete body with rest of element removed. The facets for the tubercles of the ribs are absent.
BU 19
SC P
Lateral ½ of vertebral body slit lengthwise. Portions of both epiphyses, all or portion of transverse processes, base of arch and articular surface missing. (EMA)
BU 27
SC Q
Posterior ½ of body (centrum and arch) of vertebrae. Anterior ½ of body, rib tubercles and spine missing. (KK)
BU 26
SC R
Unit consists of anterior ½ - 2/3 of element. Posterior ½ - 2/3 of body, posterior articular processes, and all or most of spinous processes absent. (TH)
BU 6
SC S
Approximately ½ - 2/3 of the body with the arch, articular processes and spinous process removed.
BU 13
SC T
Small fragments characterized by all portion of facet of rib tubercles. Frequency indicates number of pieces only.
BU 32
SC U
Unit consists of a portion of the anterior section of the centrum, with an adjoining anterior section of the spinous process. One or both anterior articulating facets may also be present. This unit is the anterior opposite of BU 28. (WU)
BU 28
SC V
Posterior articular facets and posterior portion of spinous process near base. Anterior portion of the centrum, arch and spinous process missing. (WU)
BU 8
SC W
Essentially complete spinous process severed from rest of element. Either anterior and/or posterior articular processes present. Similar to BU 3. Facets for tubercles of rib absent.
BU 3
SC X
Unit consists of all or most of the spinous process severed near the base. Both articular processes are absent. The distal end of the spinous process is represented. The facets for the rib tubercles are absent.
BU 14
SC Y
Unit consists of fragment of spinous process characterized by presence of intact distal end. Size and shape of pieces suggest they represent 2/3 or less of spinous process.
BU 7
SC Z
Large (greater then 10cm) medial fragment of the spinous process with both proximal and distal portions removed. One or both of the anterior or posterior borders are represented. Frequency indicates number of pieces only. Similar to BU 18.
BU 18
SC AA
Small (less then 10cm) medial fragment of the spinous process with both proximal and distal portions missing. One or both anterior and posterior edges represented. No series of ridges for muscle attachment present. Similar to BU 7 and BU 25. (TH)
BU 25
SC BB
Small to medium sized fragment of spinous process characterized by distinct series of ridges for muscle attachment on posterior surface. No articular facets or surfaces present. (DS)
BU 2
SC CC
Basal portion of spinous process with one or both posterior articular processes. Frequency indicates minimum number of elements represented. Anterior articular processes and distal end of spinous process absent.
BU 16
SC DD
Unit consists of base of arch minus the spinous process, rib facets, and both the anterior and posterior articular processes. (TH)
BU 22
SC EE
One either anterior or posterior articular process detached from rest of element. (DS)
BU 17
SC FF
Both anterior articular processes connected to one another by nothing but the immediate portion of the arch. (TH)
BU 33
SC GG
Identifiable based on curve and/or shape. (SB)
BU 34
SC HH
Portion of one epiphysis, 1/4 of body only. Similar to BU 19. (SB)
BU 35
SC II
Less than 1/3 of the body only. (SB)
BU 36
SC JJ
Similar to BU 11 with a bigger portion of the spinous process present. (SB)
BU 37
SC KK
Posterior 1/2 - 2/3 of element and 1/2 or more of adjoining spinous process. Anterior 1/2 – 2/3 of body, anterior articular processes and some of the spinous process absent. (SB)
BU 38
SC LL
Epiphysis of the spinous process. (SB)
BU 39
SC MM
Anterior centrum. (SB)
BU 40
SC NN
Posterior centrum. (SB)