Lumbrical muscles (hand)
| Musculi lumbricales manus 1 to 4 |
|---|
.png)
|
| origin |
| Tendons of the flexor digitorum profundus muscle |
| approach |
| Radial side of each finger in the area of the dorsal aponeurosis |
| function |
| Flexion of the metacarpophalangeal joints with simultaneous extension of the median and end joints |
| Innervation |
| Median nerve (lumbrical muscles 1 and 2), ulnar nerve , deep ramus (lumbrical muscles 3 (variable) and 4) |
| Spinal segments |
| C8, Th1 |
The lumbricales manus muscles ( Latin for "worm-shaped hand muscles") are delicate skeletal muscles on the palm side of the metacarpal bones . There are four of these narrow muscles on both hands.
These muscles are unusual because they don't connect directly to a bone; rather, they arise from the tendons of the flexor digitorum profundus muscle and attach to the dorsal aponeuroses of the fingers in the area of the metatarsophalangeal joints.
The lumbrical muscles flex the metatarsophalangeal joints when the finger joints are stretched (especially the middle of the fingers). They are important for precision handles, e.g. B. when writing or holding a sheet of paper.
The first and second lumbrical muscles on the spoke side are innervated by the median nerve. The fourth and usually also the third lumbrical muscle (lumbrical muscle on the elliptical side) are innervated by the deep branch of the ulnar nerve. This pattern occurs in 60% of the population. But there are also deviating innervation patterns. In 20% of people, only the first lumbrical muscle is innervated by the median nerve or only the fourth by the ulnar nerve, the rest by the other nerve. The innervation of the lumbrical muscle always follows the innervation pattern of the associated muscle unit of the flexor digitorum profundus muscle (i.e. if the muscle units supplying the tendon of the middle finger are innervated by the median nerve, the second lumbricalis muscle is also innervated by the median nerve).
There are four different sources of blood supply for these muscles: the superficial palmar arch ( superficial palmar arch ), the communal digital arteries , the deep palm arch ( archus palmaris profundus ) and the digital dorsal artery .
See also
Individual evidence
- ^ Last's Anatomy - Regional and Applied . 10th edition. Chummy S. Sinnatamby, p. 64 and p. 82.