Where does the APL insert?

In human anatomy, the abductor pollicis longus ( APL ) is one of the extrinsic muscles of the hand. As the name implies, its major function is to abduct the thumb at the wrist.

Abductor pollicis longus muscle
Origin	ulna, radius, Interosseous membrane
Insertion	1st metacarpal
Artery	Posterior interosseous artery

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Where is the abductor pollicis longus?

Abductor pollicis longus is a muscle found in the posterior compartment of the forearm. It is one of the five deep extensors in the forearm, along with the supinator, extensor pollicis brevis, extensor pollicis longus and extensor indicis.

What is the APB muscle?

The median nerve supplies the abductor pollicis brevis ( APB ) muscle at the lateral border of the thenar eminence which abducts the thumb at right angles to the palm.

What nerve innervates the abductor pollicis longus?

Abductor Pollicis Longus

Origin	Posterior surfaces of ulna, radius and interosseous membrane
Insertion	Base of 1st metacarpal
Action	Abducts thumb and extends it at carpometacarpal joint
Innervation	Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve (C7, C8)

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What does APL muscle do?

The Abductor pollicis longus ( APL ) is one of a deep extensor of the forearm and is responsible for facilitating movement and stabilization of the thumb. Its tendon is present in the first extensor compartment of the wrist.

Where is the EPB tendon?

The tendons of the EPB and the Abductor Pollicis Longus (APL) are enclosed in a common sheath at the dorsum of the wrist.

Why does my abductor pollicis brevis hurt?

De Quervain’s Tendonitis is a condition caused by an inflammation of the tendons located at the thumb side of the wrist. Tendons are tissues that attach our muscles to our bones. They can become swollen and sore from over use. The two muscles are called the Extensor Pollicis Brevis and the Abductor Pollicis Longus.

What nerve extends the thumb?

Extensor pollicis longus muscle
Insertion	thumb, distal phalanx
Artery	posterior interosseous artery
Nerve	posterior interosseous nerve (branching from the radial nerve )
Actions	extension of the thumb (metacarpophalangeal and interphalangeal)

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What is the Froment’s sign?

The Froment sign is an observable sign that correlates with the complaint of a weakened ability to pinch normally between the first and second digits. This sign is sometimes elicited by asking the patient to grasp a piece of paper between the thumb and index finger.

How do you test APB?

The Abductor Pollicis Brevis ( APB ) muscle receives sole innervation from the median nerve. Function can be tested by providing resistance to abduction up and away from the plane of the palm.

What is split hand?

In medicine, split hand syndrome is a neurological syndrome in which the hand muscles on the side of the thumb (lateral, thenar eminence) appear wasted, whereas the muscles on the side of the little finger (medial, hypothenar eminence) are spared.

What is anatomical snuff box?

The anatomical snuffbox is a surface anatomy feature described as a triangular depression on the dorsum of the hand at the base of the thumb. The anatomical snuffbox is visible with ulnar deviation of the wrist and extension and abduction of the thumb.

What nerve causes thumb abduction?

The abductor pollicis brevis originates on the scaphoid tubercle and the flexor retinaculum. It inserts to the radial sesamoid bone and the proximal phalanx of the thumb. It is innervated by the median nerve (C8 and T1).

What muscles are innervated by the radial nerve?

The radial nerve and its branches provide innervation the following muscles (See Structure and Function for specific nerve branch innervations and muscle actions)[7]:

• Abductor pollicis longus.
• Anconeus.
• Brachioradialis.
• Extensor carpi radialis brevis.
• Extensor carpi radialis longus.
• Extensor carpi ulnaris.