MUSCLES OF THE ELBOW JOINT Flashcards
MUSCLES OF THE ELBOW JOINT
These muscles are arranged around the humerus. They originate from the scapula or humerus and insert on the proximal radius and ulna; some of the muscles therefore span two joints. They function mainly as extensors or flexors, but also play an important role in stabilizing
the shoulder, and elbow joints, and the limb as a whole when bearing weight.
M. biceps brachii
This very strong, spindle-shaped muscle lies deep to the M. cleidobrachialis on the cranio-medial surface of the humerus. Although its name suggests that it has two heads, it has only one in all the domestic species
M. biceps brachii origin?
Tub. supraglenoidale of the scapula. The long tendon of origin runs in the Sulcus intertubercularis of the humerus where it is surrounded by the sheath-like Bursa intertubercularis; the bursa is an extension of the shoulder joint capsule. The tendon is held in the sulcus by the so-called transverse humeral ligament, which passes between the major and minor tubercules. The biceps is also held in position by the deep pectoral muscle’s insertion on the Tub. majus
M. biceps brachii funcion?
Flexion of the elbow joint; extension and stabilization of the shoulder joint.
M. biceps brachii insertion?
At the elbow, the tendon of insertion divides into two parts. The stronger part inserts medially on the ulna, just distal to the medial coronoid process. The weaker part inserts on the Tuberositas radii, together with a fleshy insertion of the brachialis muscle.
M. triceps brachii
The triceps is the most powerful muscle of the thoracic limb. It fills the triangular space between
the scapula, humerus and olecranon, and its caudal edge forms the Margo tricipitalis. While the biceps has only one head, the triceps has four: Caput longum/laterale/mediale/accessorium.
The accessory head lies between the other heads, on the caudal surface of the M. brachialis.
M. triceps brachii origin?
Long head: Tub. infraglenoidale and the caudal margin of the scapula.
Lateral head: Linea m. tricipitis of the humerus.
Medial head: Crista tuberculi minoris of the humerus, caudal to the Tuberositas
teres major and cranial to the insertion of the M. coracobrachialis.
Accessory head: Caudal surface of the humeral neck.
M. triceps brachii insertion?
Olecranon. A synovial bursa, the Bursa subtendinea m. tricipitis brachii, lies between the tendon of insertion and the olecranon. An acquired subcutaneous
bursa, the B. subcutanea olecrani, often lies between the tendon and the skin on the point of the elbow.
M. triceps brachii function?
Extension of the elbow joint; the long head is a powerful flexor of the shoulder.
M. tensor fasciae antebrachii
This is a thin, flat muscle. The proximal portion of the muscle lies lateral to the distal part of the
M. latissimus dorsi, while its distal portion lies on the medial surface of the triceps (long head).
M. tensor fasciae antebrachii origin insertion and function?
Origin: Epimysium of the lateral aspect of the M. latissimus dorsi.
Insertion: Olecranon (together with the triceps) and the antebrachial fascia.
Function: Tensing of the antebrachial fascia; extension of the elbow joint.
M. anconeus
This well-developed muscle covers the Fossa olecrani and can be seen along the ventral margin
of the triceps’ lateral head. The muscle lies on the elbow joint capsule
M. anconeus origin insertion and function?
Origin: Lateral epicondyle and supracondylar crest, and the proximo-medial rim of the
Fossa olecrani
Insertion: Laterally on the Olecranon, just distal to the insertion of the triceps.
Function: Extension of the elbow joint; tensing of the elbow joint capsule.
M. brachialis
This fleshy muscle occupies the musculospiral groove (Sulcus M. brachialis) and is largely covered by the triceps. On the cranio-distal surface of the humerus, it is separated from the M. biceps brachii by the insertions of the superficial pectoral muscles and the M.cleidobrachialis. The M. brachialis is unusual in that it receives its innervation distally; just proximal to where the
muscle narrows to form its tendon of insertion (it is far more common for the nerve to enter a muscle proximally).
M. brachialis origin?
Caudo-lateral surface of the proximal humerus, just distal to the origin of the triceps’ accessory head and caudo-distal to the Tuberositas teres minor.
