Vertebral level of the termination of the spinal cord in human fetuses.

1. The vertebral level of termination of the spinal cord, the length of the vertebral column and the length of the spinal cord were determined in 78 South Indian fetuses (42 male and 36 female) which varied from 40 to 330 mm CRL. Vertebral level of termination was also determined in 9 (2 male and 7 female) full-term South Indian neonates. The recession of the spinal cord and the ascent of the conus medullaris were calculated. Vertebral level of termination ranged from the 5th sacral to the 1st lumbar vertebrae, recession from 3 to 90 mm and ascent from 4 to 13 vertebrae. 2. There was a rapid ascent of the conus medullaris up to the 120 mm CRL stage, when it reached the 4th or even the 3rd lumbar vertebra. Beyond that, the ascent was fairly uniformly gradual and the spinal cord terminated mostly opposite the 1st or 2nd lumbar vertebrae in the full-term neonates. 3. The South Indian female fetuses had cords terminating at the same or often a higher level than male fetuses. The spinal cords of South Indian neonates terminated at a higher level than North Indian neonates and a vertebra or more higher than the level quoted by Western textbooks. 4. South Indian and Saudi Arabian levels of termination were in general higher than others. Only South Indian and South African neonates reached the adult level of L1 which is one or more vertebrae higher than North Indian and Western levels. 5. The correlation between crown-rump length, length of vertebral column, length of spinal cord, vertebral level of termination and recession of spinal cord among all male, female and both was statistically highly significant.