SURGICAL ANATOMY OF THE BONES OF THE FACE. 225 



vault, as in falls on the head, where the fissure starts from the part of the vault which first 

 struck the ground. Sometimes, however, they are caused by direct violence, when foreign 

 bodies have been forced through the thin roof of the orbit, through the cribriform plate of the 

 ethmoid from being thrust up the nose, or through the roof of the pharynx. Other cases of 

 fracture of the base occur from indirect violence, as in fracture of the occipital bone from impac- 

 tion of the spinal column airainst its condyles in falls on the buttocks, knees, or feet, or in cases 

 win-re the glenoid cavity has been fractured by the violent impact of the condyle of the lower jaw 

 against it from blows on the chin. 



The most common place for fracture of the base to occur is through the middle fossa, and 

 here the fissure usually takes a fairly definite course. Starting from the point struck, which is 

 generally somewhere in the neighborhood of the parietal eminence, it runs downward through 

 the parietal and squamous poition of the temporal bone and across the petrous portion of this 

 bone, frequently traversing and implicating the internal auditory meatus. to the middle 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 to completely 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 eerebro-spinal fluid should there be a communication between the internal ear 

 and the tympanum and the niembrana tympani be ruptured, as is frequently the case ; again, if 

 the fissure passes across the pituitary fossa and the muco- periosteum 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 fore- 

 head : 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. If the roof 

 of the nasal fossa be fractured, the blood escapes from the nose. In rare cases there may 

 be also escape of eerebro-spinal fluid from the nose where the dura mater and arachnoid have 

 been torn. . In fractures of the posterior fossa extravasation of blood may appear at the nape of 

 the neck. 



The bones of the skull, being subcutaneous, are frequently the seat of nodes, and not un- 

 coinmonly necrosis results from this cause, as well as from injury. Necrosis may involve the en- 

 tire 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 frequently the seat of sarcoma- 

 tous tumor. 



The skull in rickets 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 till the fourth 

 year. The condition of cram'otabes has by some been also believed to be the result of rickets, by 

 others is believed to be due to inherited syphilis. In these cases the bone undergoes atrophic 

 changes in patches, so that it becomes greatly thinned in places, generally where there is 

 pressure, 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 an appearance like a "hot 

 cro>s bun." They are known as Parrot's nodes, and such a skull has received the name of nati- 

 /'/////. from its fancied resemblaooe to the buttocks. 



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

 the non-union of the palatal processes of the maxillary or pre-oral arch (see page 118). This 

 cleft may involve the whole or only a portion of the hard palate, and usually involves the soft 

 palate also. The cleft is in the middle line, except it involves the alveolus in front, when it fol- 

 low* the suture between the main portion of the Done and the pre-rn axillary bone. Sometimes 

 the cleft runs on either side of the pre-maxillary bone, so that this bone is quite isolated from 

 the maxillary bones and hangs from the end of the vomer. The malformation is usually asso- 

 ciated with hare-lip, which, when single, is almost always on one side, corresponding to the posi- 

 tion of the suture between the lateral incisor and canine tooth. Some few cases of median hare- 

 lip have been described. In double hare-lip there is a cleft on each side of the middle line. 



The bones of the face are sometimes fractured as the result of direct violence. The two 

 most commonly broken are the nasal bone and the inferior maxilla, and of these the latter is by 

 far the most frequently fractured of all the bones of the face. Fracture of the nasal bone is 

 for the most part transverse, and takes place about half an inch from the free margin. The 

 broken portion may be displaced backward or more generally to one side by the force which 

 produced the lesion, as there are no muscles here which can cause displacement. The malar 

 bone is probably never broken alone ; that is to say, unconnected with a fracture of the other 

 bones of the face. The zygomatic arch is occasionally fractured, and when this occurs from 



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