Pedagogical Anthropology - Maria Montessori

Age	Frontal index	Frontal diameter	Amount of increase
11 years	73.05	107.5	—
12 years	74.11	112.0	4.5
13 years	74.14	112.5	0.5
14 years	74.80	114.4	1.9
15 years	75.67	116.8	2.4
16 years	77.24	120.1	3.3
17 years	77.02	120.6	0.5
18 years	77.36	121.5	0.9
19 years	77.60	122.8	1.3
20 years	77.15	122.1	0.7

Accordingly, between the years of fourteen and sixteen there is a puberal acceleration of growth, accompanied by an elevation of the forehead (high frontal index).

Vitali gives, as extreme limits of the frontal index, 68 and 83.

But in order to give a better illustration of the author's figures, his own words may be quoted: "It appears from our observations that the forehead begins to develop in notable proportions during the fourteenth year, and that the development of the frontal region as compared with the parietal region continues to augment up to the sixteenth year; after this it still increases, but only by a few millimetres, until the end of the sixteenth year. The cephalic development is completed between the sixteenth and eighteenth years. This observed fact is of great importance in relation to the development of the intellect."

The most complete figures at the present time on the growth of the brain, are those of Quétélet, which follow its development from birth until the fortieth year. They are summarised in the following table:

INCREASE IN THE CIRCUMFERENCE OF THE BRAIN AND IN ITS THREE MAXIMUM DIAMETERS
(According to Quétélet)

Age	Circumference in millimetres		Maximum diameters
Age	Circumference in millimetres		Antero-post.		Transverse		Vertical
	Men	Women	Men	Women	Men	Women	Men	Women
At birth	335	335	120	120	100	100	80	80
1 year	440	439	158	157	127	126	105	105
2 years	471	469	168	167	135	134	113	113
3 years	486	483	171	170	137	136	117	115
4 years	496	493	174	173	138	137	119	116
5 years	503	500	176	175	139	138	120	117
6 years	508	505	178	177	140	139	121	117
7 years	513	509	179	178	142	140	122	118
8 years	519	512	180	179	143	141	123	118
9 years	523	515	181	180	144	141	124	119
10 years	527	517	182	180	145	142	125	119
11 years	531	518	183	181	146	142	126	120
12 years	535	519	184	181	147	143	127	121
13 years	539	520	185	182	147	143	128	122
14 years	543	521	186	182	148	144	129	123
15 years	547	523	186	183	149	144	130	124
16 years	551	525	187	183	150	145	130	125
17 years	555	528	188	184	151	145	130	125
18 years	561	531	189	184	152	146	131	126
19 years	563	533	190	185	153	146	131	126
20 years	564	535	191	185	153	147	131	126
25 years	564	537	191	186	153	147	131	127
30 years	564	538	191	186	153	147	131	127
40 years	564	538	191	186	153	147	131	127

It appears from the foregoing table that after the twenty-fifth year the growth of the cranium practically ceases in all directions. In regard to the rhythm of growth, the problem is rendered clearer by the following table, which gives the annual increase:

ANNUAL INCREASE IN THE MAXIMUM CRANIAL MEASUREMENTS IN MALES
(From Figures Given by Quétélet)