Palmar interossei muscles

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Palmar interossei muscles
The Interossei volares of left hand.
Latin	musculi interossei palmares
Gray's	subject #126 465
Origin	metacarpals
Insertion	proximal phalange
Artery
Nerve	deep branch of ulnar nerve
Actions	adduction
Antagonist	Dorsal interossei of the hand

The palmar interossei (interossei volares) are small muscles in the hand that lie on the anterior aspect of the metacarpals. They are smaller than the dorsal interossei of the hand, which lie between the metacarpals.

Contents 1 Structure 2 Innervation 3 Actions 4 Pollical Palmar Interosseous Muscle (of Henle, PPIM) 5 See also 6 References 7 External links

[edit] Structure

Each palmar interosseous muscle arises from the entire length of the metacarpal bone of one finger, and is inserted into the side of the base of the proximal phalanx and extensor expansion of the extensor digitorum tendon to the same finger.

There are three palmar interossei:

#	Origin	Insertion
first	from the ulnar side of the second metacarpal bone	into the same side of the proximal phalanx of the index finger
second	from the radial side of the fourth metacarpal bone	into the same side of the ring finger
third	from the radial side of the fifth metacarpal bone	into the same side of the little finger

The palmar interossei are unipennate.

From this account it may be seen that each finger is provided with two interossei, with the exception of the little finger, in which the abductor digiti minimi muscle takes the place of one of the pair.

Some texts consider the medial head of the flexor pollicis brevis to be a palmar interosseous muscle. This muscle would then be considered the first palmar interosseous muscle, and the total number of palmar interosseous muscles in the hand would be four.

[edit] Innervation

All of the interosseous muscles of the hand are innervated by the deep branch of the ulnar nerve.

[edit] Actions

The palmar interosseous muscles adduct the fingers towards the middle finger. This is in contrast to the dorsal interossei, which abduct the fingers away from the middle finger. In addition (like dorsal interossei) they flex the finger at the metacarpo-phalangeal joint and extend the finger at the interphalangeal joint and thus assist the lumbricals.^[1]

[edit] Pollical Palmar Interosseous Muscle (of Henle, PPIM)

It is currently accepted that more than 80% of individuals present a pollical palmar interosseous muscle (of the thumb) as suggested by Henle's description in 1858 and verified by numerous investigations such as those carried out by Randall S. Susman, Lukhanyo Nyati, and Mandeep S. Jassal.^[2]

[edit] See also

• Plantar interossei muscles
• Dorsal interossei of the foot
• Dorsal interossei of the hand

[edit] References

[edit] External links

• UWASH interossei
• LUC pih
• -33161139 at GPnotebook
• palmar+interosseous+muscle at eMedicine Dictionary
• Mnemonic at medicalmnemonics.com 293 96
• PTCentral

v • d • e List of muscles of upper limbs Vertebral column trapezius · latissimus dorsi · rhomboid (major, minor) · levator scapulae Thoracic cavity pectoralis major · pectoralis minor · subclavius · serratus anterior Shoulder deltoid · rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis) · teres major Arm Anterior coracobrachialis · biceps brachii · brachialis Posterior triceps brachii · anconeus Forearm Anterior superficial: pronator teres · palmaris longus · flexor carpi radialis · flexor carpi ulnaris · flexor digitorum superficialis deep: pronator quadratus · flexor digitorum profundus · flexor pollicis longus Posterior superficial: mobile wad (brachioradialis, extensor carpi radialis longus and brevis) · extensor digitorum · extensor digiti minimi · extensor carpi ulnaris deep: supinator · anatomical snuff box (abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus) · extensor indicis Hand Lateral volar thenar (opponens pollicis, flexor pollicis brevis, abductor pollicis brevis) · adductor pollicis Medial volar hypothenar (opponens digiti minimi, flexor digiti minimi brevis, abductor minimi digiti) · palmaris brevis Intermediate lumbrical · interossei (dorsal, palmar)