cephalic, a. [L. cephalicus, Gr. , fr. kefalh` head: cf. F. céphalique.].
Cephalic index (Anat.), the ratio of the breadth of the cranium to the length, which is taken as the standard, and equal to 100; the breadth index. -- Cephalic vein, a large vein running from the back of the head alond the arm; -- so named because the ancients used to open it for disorders of the head. Dunglison.