In Depth: Deep Muscles
Deep muscles of the elbow facilitate and perform many functions, such as twisting the wrist and moving the fingers. The larger exterior muscles of the arm provide the most profound movements. For example, these muscles bend the elbow and wrist.
The deep muscles around the elbow include:
- Supinator: This muscle near the elbow helps the biceps muscle to turn the hand palm-side up (this action is called ‘supination’).
- Anconeus: Also near the elbow, this small muscle aids in extending the elbow and stabilizes it.
- Flexor carpi radialis: This muscle travels down and across the forearm from the elbow to the wrist to pull the hand away from the body.
- Flexor digitorum profundis: This long forearm muscle flexes the wrist and fingers.
- Flexor digitorum superficialis: This muscle that begins at the elbow and ends in the forearm flexes the middle fingers via collaboration with the profundis.
- Pronator teres: This muscle crosses the forearm under the brachioradialis, another long muscle of the arm, and helps turn the palm downward (this action is referred to as ‘pronation’).
- Abductor pollicis longus: This forearm muscle helps abduct the wrist and the thumb. It is important for grasping small objects such as a pencil.
- Extensor pollicis brevis: Another important thumb muscle, this one acts in conjunction with the abductor pollicis longus to extend and abduct the thumb.
The deep muscles allow for fine-tuned movements; they give the elbow the ability to twist slightly and aid the wrist and fingers in their performance of fine motor tasks, such as holding a pencil or using a screwdriver. This also makes them prone to repetitive stress injuries that can lead to inflammation of the tendons that connect the muscles to the bone. This condition is known as repetitive stress tendonitis. If the tendon on the outside of the joint is affected, it is called “tennis elbow.” If it is on the inside of the elbow, the condition is known as “golfer’s elbow.”
Symptoms of tendonitis include a dull ache in the joint, tenderness, and mild swelling. Mild tendonitis can be treated with rest, ice, compression, and elevation. Corticosteroid medications may be used to relieve swelling and inflammation. If the damage to the tendon is serious enough, surgery may ultimately be needed.