198 THE HEAD AND NECK 



If the roof of the sinus is pushed upwards, the eye becomes 

 more prominent, and neuralgia may occur from pressure on the 

 infra-orbital nerve. The pain in this case may be referred over 

 the whole distribution of the trigeminal. If the pressure is 

 mainly exerted on the medial wall, the naso-lacrimal duct 

 is obstructed, causing epiphora. As the tumour grows, it 

 pushes its way into the nasal fossa and blocks that side of the 

 nose. Forward growth obliterates the canine fossa, and down- 

 ward growth invades the palate and gives rise to a swelling in 

 the roof of the mouth. Owing to the depth of the infra-temporal 

 fossa, backward growth may go on for some time before the 

 presence of a tumour is suspected. 



Eradication of malignant disease in this region necessitates 

 the removal of the whole maxilla. The reader should follow 

 on the skull the description given below, as it is important 

 that the method of approach should be clearly understood, 

 since it may also be employed for removal of naso-pharyngeal 

 fibro -sarcomata. 



Preliminary laryngotomy and temporary occlusion of the 

 external carotid artery materially assist the surgeon in perform- 

 ing this operation. 



The incision begins just below the medial palpebral (internal 

 tarsal) ligament, which can be felt quite distinctly at the medial 

 angle of the eye, when the lateral palpebral commissure (external 

 canthus) is drawn laterally. It passes down the side of the nose, 

 round the ala nasi, and down through the upper lip into the 

 mouth in the median line. The horizontal part of the incision 

 runs along the lower margin of the orbit to the zygomatic bone, 

 and is kept parallel to the branches of the facial nerve (p. 178). 

 If the external .carotid has not been occluded, the cut branches 

 of the external maxillary artery bleed profusely, as the incision 

 is at once carried right down to the periosteum. The flap is 

 rapidly elevated from the maxilla, and the reflection of the 

 mucous membrane from the gum to the cheek is divided, so that 

 the flap may be turned down, kinking the external maxillary 

 artery, and thus arresting the haemorrhage. In elevating the 

 flap, the orbicularis oculi, the zygomaticus, and several other 

 facial muscles are cut through, and the infra-orbital nerve and 

 its artery are divided as they leave the foramen. 



In the next step, the periosteum is elevated from the orbital 

 surface of the maxilla. It must be preserved, because it sub- 

 sequently forms a support for .the eye, and because it will prevent 



