Elbow Muscles - Horse Anatomy

Extensors

Triceps brachii

Innervation: Radial n. from the brachial plexus

It has three heads:

Origin:

Long head: Caudal margin of the scapula

Lateral and Medial heads: Shaft of the humerus (lateral and medial aspects, respectively)

Insertion: Olecranon, proteced by the tricipital bursa against the bone, and subcutaneous bursa against the skin

Action: Extends and stabilizes the elbow

Tensor fasciae antebrachii

Innervation: Radial n. from the brachial plexus

Overlies the triceps extending from the scapula to the olecranon

Origin: Caudal border of the scapula

Insertion:Antebrachial fascia

Action: Tenses antibrachial fascia and extends the elbow

Anconeus

Innervation: Radial n. from the brachial plexus

Origin: Distal humerus and olecranon fossa,deep to the triceps

Insertion: Lateral olecranon, joining the lateral head of the triceps

Action: Extends the elbow

Flexors

Biceps brachii

Innervation: Musculocutaneous n. from the brachial plexus

Origin: Supraglenoid tubercle of the scapula

Insertion: Distally, the muscle divides into a medial and lateral portion.

Medial - Medial tuberosity on the proximal radius

Lateral - Proximal radius and ulna

It runs through the intertubercular groove of the humerus facilitated by the bicipital bursa.

Action: Flexes the elbow, extends and stabilises the shoulder during the stance phase

Brachialis

Innervation: Musculocutaneous n. from the brachial plexus

Origin: Proximocaudal humerus

Insertion: Spirals to insert next to biceps on the medial radius

Action: Flexes the elbow