Anomalous contrahentes muscles in human feet.

Anomalous muscles were found in the third layer of plantar musculature in 2 human feet. Although they occupied the approximate position of m. adductor hallucis caput obliquum , they were larger than that muscle and showed more extensive insertions. In one specimen the muscle inserted into the areas of the metatarsophalangeal joint capsules of the first and second toes. In the second specimen the insertion was into the metatarsophalangeal joint capsules of the 4 medial toes. The m. adductor hallucis caput transversum was missing in both feet. Both muscles were supplied by ramus profundus n. plantaris lateralis. The location and innervation of these unusual muscles indicates that they are contrahentes .