Morphological study of lumbricals - a cadaveric study

The apparently simple human function of closing the hand to grasp an object or opening the palm to release it are in reality tasks of considerable mechanical complexity requiring the contraction of many individual muscles Lumbricals are important part of intrinsic musculature of hand. Though several deviations from normal have been described in standard textbooks of anatomy, a review of basic anatomy of lumbricals will be helpful.

Proper knowledge about anatomy and variaitions prevalent in intrinsic musculature of hand is mandatory for various surgical procedure like cleft hand surgery, pollicization & other digital transposition procedures Present study was conducted to study morphology & variations prevalent in this region. The results were compiled and tried to find out commonest variations Phylogenetical & ontogenetical basis and clinical applications related to variations encountered were tried to know by correlating it with available literature.

For this study 50 hands of formalin embalmed cadavers were dissected The limbs were labelled R OR L for right or left, M or F for male or female. Cunnigham's manual for dissection was followed for dissection.

Origin and nerve supply of lumbricals was normal in all hands. The variations were encountered in insertion of the 3rd lumbrical (32%) and 4th lumbrical (24%) were more confined to the right hand. Variations encountered commonly were split and misplaced insertion of third & fourth lumbricals. These variations are critically analyzed in the light of accessible literature.

Lumbricals are more variable in the insertion rather than the origin & nerve supply. The variation commonly seen were split & misplaced insertion Split insertion was common in the third lumbrical whereas misplaced insertion is more common in the fourth lumbrical Variations are more common on right hands.