Extensor Digiti Minimi Muscle

Extensor digiti minimi Muscle Anatomy

Extensor digiti minimi is a long, thin muscle found in the posterior forearm. It extends from the distal humerus to the fifth digit. Together with anconeus, brachioradialis, extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, and extensor carpi ulnaris, it is a member of the superficial forearm extensor group.

Origin

It originates from the lateral epicondylar of the humerus.

Insertion

It inserts on the extensor expansion of the little finger.

Nerve supply

It is innervated by the posterior interosseous nerve.

Blood supply

It is supplied by the Radial recurrent artery, anterior interosseous artery, and posterior interosseous artery.

Action

It extends the metacarpophalangeal joint of the little finger.

Function

Extensor digiti minimi functions primarily to extend the fifth digit at its metacarpophalangeal joint. It also contributes to the extension of the wrist and all the fifth finger joints from the ulnar side of the hand, via its attachment into the extensor expansion and by acting along with the extensor carpi ulnaris muscle.

Relations

The muscle known as the extensor digiti minimi is medial to the extensor digitorum and occasionally partly united with it. It is located lateral to the carpi ulnaris extensor.

The extensor retinaculum divides the superficial surface of the tendon of the extensor digiti minimi at the level of the extensor retinaculum, where the dorsal branches of the ulnar artery and ulnar nerve cross.

Variations

An extra fibrous slip originating from the epicondyle lateral to the It’s possible for the tendon of insertion to split or to transmit a slip to the ring finger.
While belly fusion with the extensor digitorum communis is relatively common, the absence of the muscle is rare.
The extensor digiti minimi goes via the fifth extensor compartment, and variations in this compartment may restrict the function of the extensor digiti minimi and result in tenosynovitis.
Bifurcation, or splitting, of the extensor digiti minimi can occur at several locations across the muscle.

Strengthening Exercise

1. Towel Wrings

• For this exercise, you‘ll need a towel—preferably a hand towel.
• Soak the towel in water so it’s completely damp.
• Roll the towel up so it’s a cylinder. Beginning with an overhand grip, grasp the towel with both hands.
• Wring the towel out by twisting it. Twist the towel with your left hand towards you and the right hand away from you.
• Complete the movement, switching directions alternatively for 30 seconds. Complete 3 sets with a break in between.

2. Finger Extension Exercise

• Wrap the rubber band around all your fingers, having it rest right above your knuckles. Have your elbow resting on a surface like the arm of a chair or a table.
• When you’re ready, open your hand against the resistance of the rubber band and then slowly turn back into the closed finger position.
• Hold your movement at the open position for a moment before retracting back. Repeat for 3 sets of 10 reps. Make sure to switch hands.

Stretching Exercise

1. Wrist Extensor Stretch

• Extend your right arm in front of you with your palm facing downward.
• Bend the wrist of your right arm, pointing your hand toward the ground.
• Using your left hand, bend your wrist in an even more downward direction.
• You should feel the stretch through the top of your forearm.
• Hold the stretch for 10-15 seconds, repeating as needed.

Related pathology

The conditions involving Extensor Digiti Minimi are Vaugh Jackson Syndrome and Tenosynovits.