Variable patterns of cutaneous innervation on the dorsum of foot in fetuses.

BACKGROUND: The aim of this study was to classify the different patterns of cutaneous nerves found on the dorsum of foot in Indian fetuses and compare them with patterns found in other population groups.

METHODS: A total of 60 lower limbs from 30 fetuses (19 male, 11 female) were dissected and the branching patterns of nerves were sketched and specimens photographed.

RESULTS: Six main types and few subtypes of innervation patterns were found. Type 1 (53.3%): deep peroneal nerve supplied the 1st cleft, lateral dorsal cutaneous nerve supplied the lateral border of little toe and the remaining part of the dorsum of the foot is supplied by superficial peroneal nerve. Type 2 (28.3%): deep peroneal nerve supplied the 1st cleft, superficial peroneal nerve supplied the medial border of big toe, 2nd cleft and lateral 2(1/2) digits supplied by the lateral dorsal cutaneous nerve. Type 3 (8.3%): deep peroneal nerve supplied the 1st cleft, lateral 1(1/2) digits supplied by the lateral dorsal cutaneous nerve and the remaining dorsum by superficial peroneal nerve. Type 4 (3.3%): deep peroneal nerve supplied the 1st and 2nd clefts, superficial peroneal nerve supplied the medial border of great toe, lateral 2(1/2) digits were supplied by lateral dorsal cutaneous nerve. Type 5 (5%): deep peroneal nerve supplied 1st and 2nd clefts, lateral border of the little toe by lateral dorsal cutaneous nerve and remaining part of the dorsum of foot by superficial peroneal nerve. Type 6 (1.7%): deep peroneal nerve supplied 2nd cleft, lateral border of little toe supplied by the lateral dorsal cutaneous nerve and the remaining area by superficial peroneal nerve.

CONCLUSIONS: A comparison with cutaneous innervation patterns found in other population groups revealed three new variants which have not been reported in the other populations.