"pertaining to the spinal cord," 1835, medical Latin, from nucha "spinal cord" (c.1400), from Medieval Latin nucha, from Arabic nukha "spinal marrow."
Online Etymology Dictionary, © 2010 Douglas Harper
Examples from the Web for nuchal
It has no nuchal spine, and no trace of paired fins is preserved.A Guide to the Study of Fishes, Volume 1 (of 2)
David Starr Jordan
Most animals have a conspicuous Cinnamon patch on the nuchal region.Speciation in the Brazilian Spiny Rats
The lateral parts of the nuchal overlie the second pair of ribs.
The groove between the maxillary and the nuchal crest is very shallow.The Beaked Whales of the Family Ziphidae
The spot where the river takes its rise is called by some Nuchal, and by others Dara.