Edexcel GCSE Biology · 1BI0
Specification 4.6B · Paper 1
Revise: Pentadactyl LimbOne upper-arm bone connects to two forearm bones, followed by wrist bones and the bones of the digits. This is the pentadactyl limb pattern, named for its five digits. The digits may be lengthened, shortened or less obvious in an adult animal, so the important comparison is the underlying arrangement rather than five clearly visible fingers.