What is the agonist for flexion and the antagonist for extension in the elbow?

The biceps brachii serves as the agonist for flexion at the elbow joint, which is the muscle primarily responsible for this movement. When the biceps contracts, it pulls the forearm towards the shoulder, allowing for bending of the elbow. This action exemplifies the role of the agonist in a movement pattern.

Conversely, the triceps brachii functions as the antagonist during this flexion movement. The triceps is responsible for extension at the elbow; when the biceps are active, the triceps must relax to allow for the smooth and coordinated flexion of the elbow. The relationship between these two muscles is a classic example of agonist and antagonist interaction in muscular movements.

This anatomical and functional relationship is crucial in understanding how muscles work together in opposing actions, allowing for controlled movement and stability at the joint.