The muscles of the hand

The thenar muscles

Abductor pollicis brevis (m. abductor pollicis brevis/короткая мышца, отводящая большой палец кисти)

• Origin. From the flexor retinaculum and adjacent carpal bones.

• Insertion. To the base of the proximal phalanx of the thumb.

• Action. Abduction of the thumb.

• Nerve supply. Median nerve.

Flexor pollicis brevis (m. flexor pollicis brevis/короткий сгибатель большого пальца кисти)

• Origin. From the flexor retinaculum and adjacent carpal hones.

• Insertion. To the base of the proximal phalanx of the thumb. Its tendon contains a sesamoid bone.

• Action. Flexion of the proximal phalanx of the thumb.

• Nerve supply. Median nerve.

Adductor pollicis (m. adductor pollicis/мышца, приводящая большой палец кисти)

• Origin. Oblique head from the bases of metacarpals; transverse head from the shaft of the 3^rd metacarpal.

• Insertion. To the base of the medial side of the proximal phalanx of the thumb. The tendon contains a sesamoid bone.

• Action. Adduction of the thumb.

• Nerve supply. Deep branch of the ulnar nerve.

Opponens pollicis (m. opponens pollicis/мышца, противопоставляющая большой палец кисти)

• Origin. From the flexor retinaculum and adjacent carpal bones.

• Insertion. To the shaft of the 1^st metacarpal.

• Action. Produces opposition of the thumb.

• Nerve supply. Median nerve.

The hypothenar muscles

Palmaris brevis (m. palmaris brevis/короткая ладонная мышца)

• Origin. From the flexor retinaculum and palmar aponeurosis.

• Insertion. To the skin of the ulnar border of the palm.

• Action. Tenses the palmar aponeurosis.

• Nerve supply. Ulnar nerve.

Abductor digiti minimi (m. abductor digiti minimi/мышца, отводящая мизинец)

• Origin. From the pisiform bone.

• Insertion. To the base of the proximal phalanx of the little finger.

• Action. Abduction of the little finger.

• Nerve supply. Ulnar nerve.

Flexor digiti minimi brevis (m. flexor digiti minimi brevis/короткий сгибатель мизинца)

• Origin. From the flexor retinaculum and adjacent carpal bone.

• Insertion. To the base of the proximal phalanx of the little finger.

• Action. Flexes the proximal phalanx of the little finger.

• Nerve supply. Ulnar nerve.

Opponens digiti minimi (m. opponens digiti minimi/мышца, противопоставляющая мизинец)

• Origin. From the flexor retinaculum and adjacent carpal bones.

• Insertion. To the shaft of the fifth metacarpal.

• Action. Opposition of the little finger.

• Nerve supply. Ulnar nerve.

The middle muscles of the hand

The lumbrical muscles (mm. lumbricales/червеобразные мышцы)

• Origins. The four muscles arise from the sides of the tendons of the flexor digitorum profundus.

• Insertions. To the lateral sides of the dorsal extensor expansions of the extensor digitorum tendon.

• Actions. Flexion of the metacarpophalangeal joints and extension of the interphalangeal joints.

• Nerve supply. Medial two muscles by the ulnar nerve and lateral two by the median nerve.

The interossei (mm. interossei/межкостные мышцы)

• Origins. Dorsal from adjacent sides of four metacarpals and palmar from one side of each metacarpal.

• Insertions. Both dorsal and palmar are inserted into the sides of the proximal phalanges and the dorsal extensor expansions in such a way that the dorsal interossei abduct the fingers and the palmar adduct them.

• Actions. Adduction and abduction as above. Both sets of muscles pro­duce flexion of the metacarpophalangeal joints and extension of the interphalangeal joints, as in the ‘precision grip’.

• Nerve supply. All by the deep branch of the ulnar nerve.