Ulna
Except in mature individuals, the radius and ulna are commonly fused near their distal ends. This “articulation”, or lack of it, is ignored for the purpose of analysis and each element is analyzed separately. An individual radius is still considered complete even if the distal one-half is broken off.
Elements where the proximal and/or distal epiphyses are un-fused and not with the specimen are coded as though the epiphyses are missing.
Elements where the proximal or distal epiphyses are un-fused but are present during coding, the un-fused epiphyses are grouped together for coding and cataloguing and are not counted as separated pieces.
For an un-fused epiphysis unassociated with the rest of the element it is assigned an appropriate BU number.
For the Fincastle Project, Bone Units 21 to 23 were added.
BU 1
SC A
Complete element. Distal ½ or less of shaft usually broken off.
BU 9
SC B
All of semilunar notch. Three articular facets immediately below notch present. Virtually all of shaft absent. All or most of proximal end of ulna present. Extreme posterior margin may or may not be present.
BU 6
SC C
Proximal end of element with line of fracture at essentially a right angle to the long axis of the element and running through the semilunar notch.
BU 17
SC D
Element missing extreme distal end and semilunar notch with articular facets. (WU)
BU 5
SC E
Consists of proximal portion of ulna located above and posterior to semilunar notch. Usually includes most of anterior margin above semilunar notch. Line of fracture runs obliquely across long axis of element from upper anterior to lower posterior.
BU 7
SC F
Proximal end of ulna broken above semilunar notch. Line of fracture essentially at a right angle to the long axis of the element.
BU 12
SC G
Unfused proximal epiphyses or olecranon detached and not associated with rest of element. Condition coded as "weathered".
BU 15
SC H
Proximal portion of ulna with cap removed by crushing and gnawing. Distal ½ - 2/3 of shaft missing. (KK)
BU 10
SC I
Consists of complete distal portion of ulna with entire olecranon removed. Includes approximately half of anterior margin above semilunar notch. Line of fracture runs obliquely across long axis of element. Similar to BU 18.
BU 18
SC J
Similar to BU 10. Element consists of ½ of distal end and most of the semilunar notch and entire medial articular facet. Only ½ of distal end and entire olecranon are removed, as well as the anconaeus process and the process bearing the lateral articular facet. (WU)
BU 2
SC K
Consists of all of semilunar notch and three articular facets located immediately below. All of olecranon and almost all of posterior margin gone. Small portion of posterior margin located behind and below the three articular facets may occasionally be present.
BU 14
SC L
Consists of all of semilunar notch and medial 2 of the 3 articular facets. Lateral articular facet or sustentaculum missing. All of olecranon and much of posterior margin gone. None to limited portion of shaft present. Similar to BU 2, but lacks lateral articular facet or sustentaculum. (TH)
BU 8
SC M
Moderate sized portion or all of semilunar notch. Three articular facets immediately below notch absent. Small portion of anterior margin immediately above notch usually present.
BU 11
SC N
Proximal processus anocnaeus; and a small portion of the proximal end before the olecranon.
BU 4
SC O
Consists of three articular facets below semilunar notch. Moderate portion to none of semilunar notch present. Posterior margin absent.
BU 13
SC P
Lateral articular facet or sustentaculum detached from rest of element. (TH)
BU 19
SC Q
Unit consists of entire shaft and portion of the articular facets (either 2 or 3). However, portions of the lateral articular facets are missing. This is the opposite of BU 6. (WU)
BU 20
SC R
Unit consists of the lateral articular facet and ¾ of the distal shaft. Similar to BU 13. (TVH)
BU 3
SC S
Medial to distal portion of shaft of ulna. Frequency simply indicates number of pieces represented.
BU 16
SC T
Unfused distal epiphysis only. Unfused both to shaft of ulna and to radius. Coded as ‘weathered’. (GL)
BU 21
SC U
Missing the proximal end, with most of the shaft intact. Similar to BU 15. (SB)
BU 22
SC V
Portion of ulna characterized by curvature and shape. (SB)
BU 23
SC W
Complete juvenile missing proximal epiphysis. Opposite BU 12. (SB)