Illustrated Encyclopedia of Human Anatomic Variation: Opus I: Muscular System: Alphabetical Listing of Muscles: L

Lumbricals (Pedis)

Ronald A. Bergman, PhD
Adel K. Afifi, MD, MS
Ryosuke Miyauchi, MD
Peer Review Status: Internally Peer Reviewed

Various attachments have been noted: the second, third, or fourth lumbrical may arise from the short instead of the long flexor tendon, and the first may arise from the tendon of tibialis posterior.

A frequent observation is the contribution of fleshy or tendinous fibers to the lumbricals from flexor digitorum longus and flexor hallucis longus.

Macalister reported the variations of the lumbricals of the foot as follows:

1. All may be absent but the third;
2. Absence of the second reported by Petsche and by Macalister;
3. Absence of the two middle muscles by Behrends, 1661 (via Sömmerring);
4. Absence of the third reported by Rudolphi via Gantzer;
5. Absence of the fourth is described by Heschl, Rudolphi, and by Wood;
6. The third has been found arising from the perforated, instead of the perforating tendon (Wood);
7. The fourth has been found doubled;
8. Or bifurcated at its insertion;
9. And the third has been found doubled by Mr. Wood;
10. The first may arise from the tibial side of the deep tendon for the second toe after the junction of the communicaling slip from flexor hallucis, and sometimes from the tibial side of this slip itself;
11. It may have two heads, one from each tendon;
12. There may be no first and two second lumbricals;
13. The second, third, and fourth may arise from special slips of the tendons;
14. The fourth may get a slip from the accessorius.

References

Macalister, A. (1866) On muscular anomalies in human anatomy, and their bearing on homotypical myology. Proc. Roy. Irish Acad. Sci. 10:126-164.

Macalister, A. (1875) Observations on muscular anomalies in the human anatomy. Third series with a catalogue of the principal muscular variations hitherto published. Trans. Roy. Irish Acad. Sci. (1875) 25:1-130.

Schmidt, R., Reissig, D. und H.-J. Heinrichs. (1963) Die Mn. lumbricales am fuss des Menschen. Anat. Anz. 113:450-453.

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