Origin: The scapula at the supraglenoid fossa.
Insertion: into the radial tuberosity of the radius.
Function: The muscle is responsible for extension of the shoulder joint, flexion of the elbow joint, adduction of the forelimb and stabilisation of the shoulder. This muscle works as an antagonist with the triceps brachii muscle. The biceps brachii, alongside the pectoral muscles, aid in supporting the shoulder during lateral movements and producing a smooth quality of movement. This muscle also acts as a catapult to help reduce muscular effort to pull the forelimb forward.
Soreness: Discomfort and tightness in this muscle may affect the horses co-ordination and the horse may struggle with lateral movements. You may also find that the horse becomes difficult to shoe as the muscle is aggravated with the limb is in flexion for a long period of time.
Massage would help to relieve tension in the muscle and restore the fluidity of the gait. Forelimb retraction stretches will aid in improving range of movement and reduce build up of tension.