THE SKULL AS A WHOLE 



151 



lacerated foramen. From this it may pass across the body of the sphenoid, through the pituitary 

 fossa to the middle lacerated foramen of the other side, and may indeed travel round the whole 

 cranium, so as completely to separate the anterior from the posterior part. The course of the 

 fracture should be borne in mind, as it explains the symptoms to which fracture in this region may 

 give rise; thus, if the fissure pass across the internal auditory meatus, injury to the facial and 

 auditory nerves may result, with consequent facial paralysis and deafness; or the tubular pro- 

 longation of the arachnoid around these nerves in the meatus may be torn, and thus permit of 

 the escape of the cerebrospinal fluid should there be a communication between the internal ear 

 and the typanum and the membrana tympani be ruptured, as is frequently the case; again, if 

 the fissure passes across the pituitary fossa and the mucoperiosteurn covering the under surface 

 of the body of the sphenoid is torn, blood will find its way into the pharynx and be swallowed, 

 and after a time vomiting of blood will result. Fractures of the Anterior fossa, involving the bones 

 forming the roof of the orbit and nasal fossa, are generally the results of blows on the forehead; 

 but fracture of the cribriform plate of the ethmoid may be a complication of fracture of the nasal 

 bone. When the fracture implicates the roof of the orbit, the blood finds its way into this cavity, 

 and, travelling forward, appears as a subconjunctival ecchymosis. Subconjunctival ecchymosis 

 can also be caused by fracture of the malar bone. If the roof of the nasal fossa be fractured, 

 the blood escapes from the nose. In rare cases there may be also escape of cerebrospinal fluid 

 from the nose where the dura and arachnoid have been torn. In fractures of the posterior fossa 

 extravasation of blood takes place beneath the deepjascja, a^id discoloratinn_qf the skin is sopn^ 

 observed in the course of the posterior auricular artery, the oiscoloration firsT appearing in theT 

 skin over the tip of the tnastoid process of the temporal bone (Battle's sign). Some of the 

 blood which was extravasated beneath the deep fascia approaches the surface through the open- 

 ings in the deep fascia for the passage of vessels and nerves. 



The bones of the skull are frequently the seat of nodes, and not uncommonly necrosis results 

 from this cause, also from injury. Necrosis may involve the entire thickness of the skull, but 

 is usually confined to the external table. Necrosis of the internal table alone is rarely met with. 

 The bones of the skull are also sometimes the seat of sarcomatous tumors. 



The skull in rhachitis is peculiar the forehead is high, square, and projecting, and the antero- 

 posterior diameter of the skull is long in relation to the transverse diameter. The bones of the 

 face are small and ill-developed, and this 

 gives the appearance of a larger head 

 than actually exists. The bones of the 

 head are often thick, especially in the 

 neighborhood of the sutures, and the 

 anterior fontanelle is late in closing, 

 sometimes remaining unclosed until the 

 fourth year. The .condition of cranio tabes 

 has by some been also believed to be the 

 result of rhachitis, by others is believed to 

 be due to inherited syphilis. In all prob- 

 ability it is due to both. In these cases 

 the bone undergoes atrophic changes in 

 patches, so that it becomes greatly thinned 

 in places, generally where there is pres- 

 sure, as from the pillow or nurse's arm. 

 It is, therefore, usually met with in the 

 parietal bone and vertical plate of the 

 occipital bone. 



In congenital syphilis deposits of porous 

 bone are often found at the angles of the 

 parietal bones and two halves of the 

 frontal bone which bound the anterior 

 fontanelle. These deposits are separated 

 by the coronal and sagittal sutures, and 

 give to the skull the appearance of a hot 

 cross bun. They are known as Parrot's 

 nodes, and such a skull has received the 



name of natifonn, from its fancied resemblance to the buttocks. The cells of the mastoid are 

 sometimes the seat of suppuration as the result of infection extending backward from the 

 tympanic cavity. In such cases the antrum of the mastoid must be opened in order that the 

 pus escape. This is done by applying the gouge between the posterior wall of the external audi- 

 tory meatus and the posterior root of the zygoma. This space is called the suprameatal triangle of 

 MacEwan. 



In connection with the bones of the face a common malformation is cleft palate, owing to 

 the nonunion of the palatal processes of the maxillary or preoral arch. This cleft may involve 



FIG. 118. Division of the mastoid process into four equ 

 parts. An opening in the upper anterior quadrant reaches 

 the mastoid antrum; into the upper posterior quadrant 

 reaches the lateral sinus; the lower anterior quadrant into 

 mastoid cells; a superficial opening into the lower posterior 

 quadrant reaches mastoid cells; a deep opening reaches the 

 descending limb of the lateral sinus. (A. E. Schmitt.) 



