OPENING THE GUTTURAL POUCHES. 369 



backs. Although the pouch has been opened in the standing 

 position, most operators prefer to have the horse chloroformed and 

 placed on the side, with the head and neck slightly raised. Where 

 excessive dyspnoea exists, it may, however, be aggravated by casting, 

 and Leblanc and others recommend that tracheotomy should first 

 be performed ; but this seems undesirable, and it suffices if the 

 instruments for tracheotomy are at hand. 



Chabert, in 1779, propounded the oldest method, viz., Hyover- 

 tebrotomy, by which the pouch is penetrated through the occipito- 

 hyoideus muscle. The hair in front of the wing of the atlas for 

 an area of 2 to 4 inches is shaved ; an incision is made through 

 the skin about f of an inch in front of the anterior border of 

 the wing, and parallel with it. Just in front of the wing lies the 

 auricular nerve, arising from the second cervical nerve, which must 

 be avoided. 



Separating the subcutis by a few light strokes, the parotid 

 gland appears, and is laid forward. The fascia of one of the 

 muscles of the neck, now in view, is divided in the direction 

 and to the extent of the skin incision. The occipito-hyoideus 

 muscle thus exposed is pierced with the finger, or a pointed 

 bistoury, the back of the knife being turned towards the wing of 

 the atlas, and the handle a little inclined towards it. In this way 

 the point of the knife enters the angle made by the 9th and 10th 

 cerebral nerves with the internal carotid, and without injuring these. 

 Through this opening the finger can be inserted into the guttural 

 pouch. This operation has the disadvantage of endangering the 

 / nerves and vessels mentioned, nor is the opening into the sac sufficient 

 for the removal of such solid contents as chondroids. 



Viborg recommended opening the sac below from the triangle 

 which is formed by the tendon of the sterno-maxillaris muscle and 

 the submaxillary vein, with the vertical border of the lower jaw. 

 In the middle of this triangle, and parallel with the muscle named, 

 an incision is made in the skin, about 2 to 4 inches in length, and 

 reaching to the border of the lower jaw. After separating the 

 panniculus of the neck, and dividing the connective tissue, the 

 guttural pouch is perforated with a trocar, and the opening can 

 then be enlarged with the fingers. This method has the advantage 

 of opening the pouch at its deepest point, thus more easily removing 

 both fluids and solids. The pouch, when distended, is easily reached 

 by this method, which, however, is not always free from difficulty. 

 As has been shown by Hering, some cases of supposed hyoverte- 

 brotomy have only been the evacuation of a parotid abscess. 



