What is a common name for the hypotarsal?

The hypotarsal is commonly referred to as the hock joint in birds. This joint is located between the tibiotarsus and the metatarsals, functioning similarly to the ankle joint in mammals. It plays a crucial role in the mobility and flexibility of a bird's leg. Understanding the terminology associated with avian anatomy helps in assessing and judging poultry as it allows for better comprehension of their structure and movement.

Considering the other options, the terms neck, phalanges, and knee cap refer to different parts of the anatomy. The neck corresponds to the area connecting a bird's head to its body, phalanges are the bones found in the toes, and the knee cap is typically a term used for the patella in mammals, which does not directly apply to bird anatomy. Therefore, hock joint stands out as the correct term associated with the hypotarsal.