[TA] the large semicircular notch at the proximal extremity of the ulna between the olecranon and coronoid processes that articulates with the trochlea of the humerus. SYN: incisura trochlearis [TA], incisura semilunaris ulnae, semilunar notch (2).

The trochlear notch is a concave surface on the ulna bone, which is one of the two long bones in the forearm, the other being the radius. The trochlear notch is located at the distal end of the ulna, which is the end closest to the wrist.

The trochlear notch articulates with the trochlea, which is a structure on the humerus bone, the long bone in the upper arm. This articulation forms the elbow joint, which is a hinge joint that allows for flexion and extension of the forearm.

The trochlear notch is also important because it provides stability to the elbow joint, which is subjected to a lot of stress and strain during activities that involve the arms and hands. The shape and size of the trochlear notch are critical in determining the range of motion and stability of the elbow joint.

In addition to its role in the elbow joint, the trochlear notch is an important landmark for various medical procedures, such as joint injections and surgical interventions. Its location and features make it easily identifiable and useful in clinical practice.

Overall, the trochlear notch is an important anatomical structure that plays a critical role in the function and stability of the elbow joint, and is an important reference point for various medical procedures.