Thalamic Frontal Lobe Distance

Goldstein I, Reece EA, Pilu G et.al.

Sonographic assessment of the frontal bone:

A potential tool for prenatal diagnosis of microcephaly

Am J Obstet Gynecol 1988;158:1057-1062

GA (wks)	-2SD	Mean	+2SD
15	24	32	40
16	24	32	40
17	24	36	48
18	25	37	49
19	30	38	46
20	33	41	49
21	33	41	49
22	38	46	54
23	38	46	54
24	39	47	55
25	39	51	63
26	40	52	64
27	40	56	72
28	49	57	65
29	53	61	69
30	38	62	86
31	46	62	78
32	48	64	80
33	53	65	77
34	55	67	79
35	57	69	81
36	62	70	78
37	60	72	84
38	57	73	89
39	59	75	91
40	61	77	93