Musculus triceps brachii caput longum
The triceps brachii has three heads: the long head, the lateral head, and the medial head. The long head is the largest and most superficial, visible as the muscular mass behind the shoulder. It originates from the caudal border of the scapula. The lateral head originates from the deltoid tuberosity and lateral surface of the proximal humerus. The medial head originates from the medial surface of the humerus. All heads insert on the olecranon process of the ulna. Their primary action is to extend the elbow and bear weight during the stance phase. They are innervated by the radial nerve (roughly C7-T1).
Origin: Caudal border of the scapula
Insertion: Olecranon process of the ulna (point of the elbow)
Action: Extends the elbow; flexes the shoulder; major weight-bearing muscle
Innervation: Radial nerve (C7-T1)
Triceps dysfunction or atrophy can severely compromise elbow extension and weight bearing. Radial nerve damage can affect the triceps. Relevant in evaluations of elbow function and after trauma. Diagnosis is clinical and with ultrasound or electromyography.
## Overview Strain of the long head of the triceps occurs from overload during landing from jumps or intense collected work. It produces acute forelimb lameness, swelling behind the shoulder, pain on
## Overview Olecranon fracture is a break of the point of the elbow, usually from direct trauma such as a kick or fall. Because the triceps inserts on the olecranon, the horse cannot extend the elbow
Inability to bear weight on a forelimb or sudden swelling behind the shoulder after trauma should be evaluated immediately.
## Overview Strain of the long head of the triceps occurs from overload during landing from jumps or intense collected work. It produces acute forelimb lameness, swelling behind the shoulder, pain on palpation of the caudal arm, and reluctance to fully extend the elbow. A dropped-elbow appearance can occur with more severe injury. ## Causes Acute overload of the primary elbow extensor. ## Diagnosis Palpation, ultrasound of the triceps, and lameness examination. Radiographs rule out fracture. ## Treatment Rest, anti-inflammatories, and controlled rehabilitation. Severe tears require longer recovery. ## Recovery and Prognosis Good for most strains. Complete rupture is uncommon and has a more guarded outlook. ## Prevention Progressive conditioning for jumping and collected work. Signs include: acute forelimb lameness after jumping; swelling behind the shoulder; pain on caudal arm palpation; reluctance to extend the elbow
## Overview Olecranon fracture is a break of the point of the elbow, usually from direct trauma such as a kick or fall. Because the triceps inserts on the olecranon, the horse cannot extend the elbow and presents with a dropped elbow and non-weight-bearing lameness. Surgical repair with plates and screws is the treatment of choice for most displaced fractures and carries a generally good prognosis. ## Causes Direct trauma. In foals, excessive pull from the triceps can also cause fracture. ## Diagnosis Characteristic posture and radiographs of the elbow. ## Treatment Tension-band plating for displaced fractures. Some non-displaced fractures in foals may be managed conservatively. Prognosis is good with internal fixation. ## Recovery and Prognosis Good with appropriate surgical repair. ## Prevention Trauma avoidance. Signs include: dropped elbow; inability to bear weight; swelling at the point of the elbow; cannot extend the elbow
Triceps dysfunction or atrophy can severely compromise elbow extension and weight bearing. Radial nerve damage can affect the triceps. Relevant in evaluations of elbow function and after trauma. Diagnosis is clinical and with ultrasound or electromyography.
Inability to bear weight on a forelimb or sudden swelling behind the shoulder after trauma should be evaluated immediately.
See the Triceps Brachii (Long Head) on our interactive 3D horse model. Open 3D Model