Upper Limb | Arm

Rupture of the biceps tendon.

A complete rupture of any tendon in the body is rare. However, the long head of the biceps is one of the more common tendons to rupture. This produces a characteristic signs on flexing the elbow - a buldge where the muscle belly is calle the "Popeye Sign". The patient would not notice much weakness in the upper limb due to the action of brachialis and supinator muscles.

Muscles of the anterior compartment of the arm.

Biceps brachii Coracobrachialis Brachialis

Which muscles are involved in lateral rotation of the arm?

Infraspinatus and teres minor.

What is the origin, insertion, innervation, and action of tricep brachii?

Origin: Long head - infraglenoid tubercle. Lateral head - humerus, superior to the radial groove. Medial head - humerus, inferior to the radial groove. Insertion: The heads converge onto one tendon and insert into the olecranon of the ulna. Innervation: Radial nerve. A tap on the triceps tendon tests spinal segment C7. Actions: Extension of the arm at the elbow joint. Note: In some individuals, the long head of the triceps brachii is innervated by the axillary nerve.

Which rotator cuff muscle abducts the arm initially before the action of the deltoid takes over?

Supraspinatus

What is the origin, insertion, innervation, and action of biceps brachii?

The biceps brachii is a two-headed muscle. Although the majority of the muscle mass is located anteriorly to the humerus, it has no attachment to the bone itself. As the tendon of biceps brachii enters the forearm, a connective tissue sheet is given off - the bicipital aponeurosis. This forms the roof of the cubital fossa and blends with the deep fascia of the anterior forearm. Origin: Long head - supraglenoid tubercle of the scapula Short head - coracoid process of the scapula. Insertion: Radial tuberosity and the fascia of the forearm via the bicipital aponeurosis. Innervation: Musculocutaneous nerve. The bicep tendon reflex tests spinal cord segment C6. Actions: Supination of the forearm. It also flexes the arm at the elbow joint and at the shoulder joint.

What is the origin, insertion, innervation, and action of brachialis?

The brachialis muscle lies deep to the biceps brachii, and is found more distally than the other muscles of the arm. It forms the floor of the cubital fossa. Origin: Medial and lateral surfaces of the humeral shaft Insertion: Ulna tuberosity, distal to the elbow joint. Innervation: Musculocutaneous nerve, with contributions from the radial nerve. Actions: Flexion at the elbow joint.

What is the origin, insertion, innervation, and action of coracobrachialis?

The coracobrachialis muscle lies deep to the biceps brachii in the arm. Origin: Coracoid process of the scapula. The muscle passes through the axilla. Insertion: Medial side of the humeral shaft, at the level of the deltoid tubercle. Innervation: Musculocutaneous nerve. Actions: Flexion of the arm at the shoulder joint, and weak adduction.

Muscle of the posterior compartment of the arm.

Triceps brachii The posterior compartment of the upper arm contains the triceps brachii muscle, which has three heads. The medial head lies deeper than the other two, which cover it. Arterial supply to the posterior compartment of the upper arm is via the profunda brachii artery.