WHWT - Part 4 - heads by Joan Graber
To balance the strong powerful jaws required to do its work the Westie
needs width of backskull. You want a good handful, between the zygomatic
arches, when you feel the backskull. To have this broad skull and powerful
jaws the dog must have sufficient bone, frequently referred to as 'having
bone'. The first place I check for correct bone is the backskull, and if
the head is not sufficiently broad the rest of the dog is probably lacking
enough bone. The standard asks for a skull that is broad and slightly
domed. (picture #18)