Base of phalanx - Basis phalangis
Proximal extremities of phalanges :
The proximal extremities of the bones of the first row present oval, concave articular surfaces, broader from side to side than from before backward.
The proximal extremity of each of the bones of the second and third rows presents a double concavity separated by a median ridge.
This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).