Phalanx bone and far phalanges of the fourth and fifth toes are often fused together (symphalangism). The phalanges of the hand are commonly known as the finger bones. The phalanges of the foot differ from the hand in that they are often shorter and more compressed, especially in the proximal phalanges, those closest to the body. A phalanx is named according to whether is are proximal, middle, or distal and its associated finger or toe. The proximal phalanges are those that are closest to the hand or foot. In the hand, the prominent, knobby ends of the phalanges are known as knuckles.
Ostromia addition, the ungual (claw) of the first digit of the hand is smaller than the corresponding first metacarpal, while in "Archaeopteryx" the claw is larger. The Haarlem specimen's metatarsals are also estimated to be proportionally longer than those of "Archaeopteryx" specimens. In addition, the Haarlem specimen shares several features with "Anchiornis". Most notably, they both have longitudinal furrows on the top and bottom sides of their manual phalanges (finger bones). While such structures can be a result of collapsed or broken bones (as is the case in several "Archaeopteryx" specimens), the straight, smooth edges of the furrows in "Ostromia" and