56 SPECIAL ANATOMY. 



54. 1. Sutures, Suturse Cranii. 



In a newly born infant a suture passes in the central line of the skull from 

 the superior angle of the occipital, to the root of the nose on the frontal bone. 

 This is 



1. The Sagittal, s. sagittalis, between the Parietal bones, with which in the 

 adult, 



2. The frontal, s. frontalis, unites. This long suture is anteriorly, upon the 

 crown of the head, crossed by a transverse suture, the 



3. Coronal, s. coronaks, which unites the parietal with the frontal bones, 

 and is behind bounded by the 



4. Occipital, s. lambdoidea, which joins the parietal and occipital bones 

 together. To this last is added the almost rectangular 



5. Mastoid suture [additamentum suturce lambdoidalis], uniting the Occipital 

 and Parietal bone, a portion of it, with the mastoid portion of the temporal. 

 From this (from the Inrisura parietalis), anteriorly, proceeds the arched 



6. Squamous, s. squamosa, between the parietal and squamous portion of the 

 temporal bone. Lastly, below the frontal bone an irregular transverse suture 

 passes, the 



7. Transverse, s. transversa, connecting together the cranial and facial 

 bones. 



These sutures, which unite the edges of those portions of the bones which 

 become ossified at a later period, continue incomplete even for some time 

 after birth, and therefore present at the angles, where most of the borders meet 

 together, unossified intervals, which are not completely closed until the fourth 

 year, the 



55. 2. Fontanelles,/on/icw/z. 



In the middle line of the skull : 



1. Fonticulus Major, the large quadrangular fontanelle between the superior 

 angles of the Frontal and Parietal bones. 



2. Fonticul. Minor, the smaller fontanelle, triangular, with the base directed 

 towards the occipital; the apex towards the parietal bones, where the Lamb- 

 doidal impinges upon the Sagittal suture. 



On either side of the skull lies a fontanelle, fontic. lateral, above and behind 

 the mastoid process of the temporal bone, in that place where at a later period 

 the parietal meets with the temporal and occipital bones. In this place we 

 frequently meet with the so-called Wormian bones, ossa triquetra; the number, 

 size, and position of which are never constant; they must be regarded as iso- 

 lated, unessential points of ossification. Sometimes a triangular bone is found 

 at the superior angle of the lambdoidal suture, representing even the apex of 

 the occipital bone itself. 



56. 3. Form and Measurement. 



The shape varies with the Diameter of the skull, both according to age, 

 sex, and varieties in the Race. 



1. Longitudinal Diameter; from the for. ccecum to the occipital protuberance = 5 

 inches. 



2. Transverse Diamete)- between the bases of the two petrous bones = 4 

 inches. 



