File:Velociraptor quills1.jpeg

Summary
(A) View of right ulna of Velociraptor IGM 100/981. (B) Detail from cast of red box in (A), with arrows showing six evenly spaced feather quill knobs. (C) View of right ulna of a turkey vulture (Cathartes). (D) Same view of Cathartes as in (C) but with soft tissue dissected to reveal placement of the secondary feathers relative to the quill knobs. (E) Detail of Cathartes, with one quill completely removed to reveal quill knob. (F) Same view as in (E) but with quill moved to the left to show placement of quill, knob, and follicular ligament. Follicular ligament indicated with arrow. (Credit: Mick Ellison)