CHAPTER XVI. 



DISEASES OF THE ALIMENTAKY TKACT, PEEITONEUM, 

 AND DIGESTIVE GLANDS. 



THE LIPS. 



THE lips are well supplied with blood from the coronary arteries 

 of the facial, and this, together with their mode of development, 

 may account for the frequency with which they are the site of 

 angeiomata or naevi. Their exposed position renders them liable 

 to injury and subsequent inflammation, and should a fissure be 

 produced, the contraction of the circular fibres of the orbicularis 

 oris frequently interferes with healing because of the want of 

 rest thereby induced, in a manner similar to that caused by the 

 action of the external sphincter in cases of anal fissure. 



The presence of many and large mucous glands explains the 

 incidence of mucoceles or retention cysts. 



A carbuncle occurring on the upper lip is always a serious 

 affection, because of the possibility of thrombosis spreading from 

 the facial to the ophthalmic vein through the communication at 

 the internal canthus of the eye, and so backwards to involve 

 the cranial sinuses, particularly the cavernous, whereby severe 

 cerebral symptoms may be produced. 



A primary syphilitic infection may occur on either lip from 

 contact. 



Carcinoma, in the form of epithelioma, occurs almost exclusively 

 in the lower lip, a reason for this fact being that the lower lip is 

 the one which is irritated in the use of a pipe. 



The lymphatic glands w r hich are affected in inflammation and 

 epithelioma of the lips are first the submental and submandi- 

 bular, and afterwards the deep glands along the carotid sheath, 



