GENERAL INFORMATION
The posterior compartment of the arm consists of several muscles responsible for extending the elbow joint, forearm supination, and wrist extension. These muscles are primarily located on the posterior aspect of the arm.
ORIGIN
Significantly, the muscles in the posterior compartment of the arm originate from various points along the humerus (upper arm bone) and the scapula (shoulder blade).
INSERTION POINT
Posterior compartment are inserted into different sites on the radius (forearm bone) and ulna (one of the two forearm bones).
MAJOR ARTERIES
Moreover, the posterior compartment of the arm receives its blood supply primarily from the deep brachial artery, a branch of the brachial artery.
NEURAL INNERVATION
Additionally, the muscles in the posterior compartment of the arm are innervated by the radial nerve, which originates from the posterior cord of the brachial plexus.
TRIGGER POINT
Trigger points in the muscles of the posterior compartment of the arm are relatively rare but may cause localised pain and referred pain to the posterior shoulder or forearm.
CONCENTRIC FUNCTION
Furthermore, the concentric function of the muscles in the posterior compartment of the arm involves the contraction of the muscle fibres, resulting in the extension of the elbow joint and forearm supination. This action is essential for movements such as pushing, pulling, and throwing.
ECCENTRIC FUNCTION
Conversely, the eccentric function of these muscles occurs when the muscle fibres lengthen under tension. It aids in controlling the flexion of the elbow joint and the descent of a loaded weight.
ISOMETRIC FUNCTION
Similarly, the isometric function of the muscles in the posterior compartment of the arm involves contracting and generating tension without changing their length. This function helps maintain stability and control during activities that require a static hold or resistance.
RELATED MUSCLE SCIENTIFIC NAMES
- Triceps Brachii: It is responsible for elbow extension. It is located at the back of the upper arm and is composed of three heads: long, lateral, and medial.
- Anconeus: A small muscle at the posterior aspect of the elbow, aiding in elbow extension and stabilising the elbow joint.
ANTAGONIST MUSCLES
- Biceps Brachii: this muscle is responsible for elbow flexion and supination of the forearm. It is found in the anterior compartment of the arm.
- Brachialis: Also in the anterior compartment, it assists in elbow flexion, providing stability and control during flexion movements.
COMMON INJURIES
- Strains or tears: Overstretching or excessive contraction of the muscles in the posterior compartment of the arm may lead to muscle fibre damage, causing pain and weakness.
- Tennis Elbow (Lateral Epicondylitis): Overuse injury affecting the tendons in the posterior compartment, resulting in pain and inflammation on the outer side of the elbow.
- Triceps Tendinitis: Inflammation or irritation of the triceps tendon, commonly at the insertion point on the olecranon process of the ulna, often due to repetitive strain.
EXERCISES FOR POSTERIOR COMPARTMENT
- Tricep pushdowns: Use a cable machine to perform pushdowns, targeting the triceps for strength and endurance.
- Overhead tricep extensions: Hold a weight overhead and lower it behind the head. Then extend the arms to work the triceps.
- Close-grip bench press: Perform a bench press with hands closer together to emphasise tricep engagement.
- Skull crushers: Lie on a bench and lower a barbell or dumbbell to the forehead. Then extend the arms to target the triceps.
- Hammer curls: Hold dumbbells with a neutral grip and curl them towards the shoulders, targeting both the triceps and forearms.
STRETCHES
- Tricep stretch: Raise one arm overhead, bend the elbow, and use the opposite hand to push the elbow back, stretching the triceps gently.
- Wrist flexor stretch: Extend the arm with the palm facing up and gently pull back on the fingers to stretch the wrist flexors and forearm.
- Wrist extensor stretch: Extend the arm with the palm facing down and gently pull back on the fingers to stretch the wrist extensors and forearm.
- Pronator stretch: Rotate the forearm palm down and gently apply pressure to stretch the pronator muscles, relieving tension.
- Supinator stretch: Rotate the forearm palm up and gently apply pressure to stretch the supinator muscles, improving flexibility.
