cutybo'u lujvo

b1 is a/the sternum/breastbone of body b3=c2.

From greece sternum=chest. See also cutne and srubo'u (=rib).

In notes:

cutygreku
g1=c1 is the ribcage of c2.
cutyti'e
t1 is the upper back [body-part] of c2.