BU 1

SC A

Complete element.

BU 2

SC B

One-third or less of anterior portion of element removed. BU consists of posterior 2/3 or more of element.

BU 4

SC C

Posterior/lateral portion of element with portion of lateral and posterior edges of element present. No anterior or medial borders present. (TH)

BU 3

SC D

Small extreme anterior piece of element removed to form BU 2. Unless BU 3 is found together with BU 2, there is little likelihood of its being identifiable.

BU 5

SC E

Medial 2/3 of the element. (SB)