The patella is a large sesamoid bone located in the tendon of the insertion of the quadriceps muscle of the pelvic limb.
The patella is roughly triangular, presenting:
A base proximally, roughened for muscular attachment
An apex distally
A lateral and a medial border (this one extended medially in horse, ox and cows by the fibrocartilage process)
An articular surface caudally (divided in horses by a sagittal ridge that occupied the groove between the two rides of the trochlea)
A cranial surface palpable under the skin
Text by Antoine Micheau, MD - Copyright IMAIOS Veterinary Anatomy of Domestic Mammals: Textbook and Colour Atlas, Sixth Edition - Horst Erich König, Hans-Georg Liebich - Schattauer - ISBN-13: 978-3794528332 Anatomy of the Horse - Sixth Edition - Klaus Dieter Budras - Schlütersche