Origin: Flexor digitorum profundus
Insertion: Extensor expansion
Artery: 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
The Lumbricales are four small fleshy fasciculi, associated with the tendons of the Flexor digitorum profundus. The first and second arise from the radial sides and volar surfaces of the tendons of the index and middle fingers respectively; the third, from the contiguous sides of the tendons of the middle and ring fingers; and the fourth, from the contiguous sides of the tendons of the ring and little fingers. Each passes to the radial side of the corresponding finger, and opposite the metacarpophalangeal articulation is inserted into the tendinous expansion of the Extensor digitorum communis covering the dorsal aspect of the finger.
Variations.—The Lumbricales vary in number from two to five or six and there is considerable variation in insertions.