Velociraptor was small for a dromaeosaurid, with adults
measuring up to 1.8 meters (6 ft) long, 0.6 meters (2 ft)
high at the hip, and weighing 20 kilograms (45 lb). The
skull, which grew up to 250 millimeters (10 in) long, was
uniquely up-curved, concave on the upper surface and convex
on the lower. The jaws were lined with 26–28 widely-spaced
teeth on each side, each more strongly serrated on the back
edge than the front — possibly an adaptation that improved
its ability to catch and hold fast-moving prey.
Velociraptor,
like other dromaeosaurids, had a large manus ('hand') with
three strongly-curved claws, which were similar in construction
and flexibility to the wing bones of modern birds. The second
digit was the longest of the three digits present, while
the first was shortest. The structure of the carpal (wrist)
bones prevented pronation of the wrist and forced the 'hands'
to be held with the palmar surface facing inwards (medially),
not downwards. The first digit of the foot, as in other
theropods, was a small dewclaw. However, whereas most theropods
had feet with three digits contacting the ground, dromaeosaurids
like Velociraptor walked on only their third and fourth
digits. The second digit, for which Velociraptor is most
famous, was highly modified and held retracted off of the
ground. It bore a relatively large, sickle-shaped claw,
typical of dromaeosaurid and troodontid dinosaurs. This
enlarged claw, which could be over 65 millimeters (2.5 in)
long around its outer edge, was most likely a predatory
device used to tear into prey, possibly delivering a fatal
blow.