From the case:
Pencil-in-cup deformity (illustrations)
{"current_user":null,"step_through_annotations":true,"access":{"can_edit":false,"can_download":true,"can_toggle_annotations":true,"can_feature":false,"can_pin":false},"extraPropsURL":"/studies/60637/annotated_viewer_json?iframe=true\u0026lang=us"}
Simplified illustration of the pencil-in-cup deformity evident at the proximal interphalangeal joint of the digit.
Case Discussion
The pencil-in-cup deformity is a common radiographic feature of psoriatic arthritis. See article for more information.