Lumbricals of the hand

Muscle infobox
Name = PAGENAME
Latin = musculi lumbricales manus
GraySubject = 126
GrayPage = 464


Caption = The muscles of the left hand. Palmar surface. (1st lumbricalis labeled at bottom right of muscular group.)
Origin = flexor digitorum profundus
Insertion = extensor expansion
Blood = superficial palmar arch, common palmar digital arteries, deep palmar arch, dorsal digital artery
Nerve = deep branch of ulnar nerve, median nerve
Action = flex metacarpophalangeal joints, extend interphalangeal joints
MeshName =
MeshNumber =
DorlandsPre = m_22
DorlandsSuf = 12549749
The lumbrical muscles are intrinsic muscles in the fingers that allow flexion at the metacarpophalangeal joints, while maintaining extension at the interphalangeal joints.

tructure

There are four of these small, worm-like muscles on each hand. These muscles are unusual in that they do not attach to bone. Instead they attach proximally to the tendons of flexor digitorum profundus and distally to extensor expansions on the dorsal surface (back) of the hand.

Innervation

The first and second lumbricals (i.e. the two that are most lateral) are innervated by the median nerve.The third and fourth lumbricals (i.e. the most medial two) are innervated by the deep branch of the ulnar nerve.

Blood supply

There are four separate sources of blood supply for these muscles: the superficial palmar arch, the common palmar digital artery, the deep palmar arch, and the dorsal digital artery.

Actions

The lumbrical muscles, with the help of the interosseous muscles, simultaneously flex the metacarpophalangeal joints while extending both interphalangeal joints of the digit on which it inserts.

Other lumbricals

There are also lumbrical muscles of the foot that have a similar action, though these are of less clinical concern.

=Additional

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