DISSECTION OF DEEP VESSELS AND NERVES OF NECK. 



SECTION IX. 



DEEP VESSELS AND NERVES OF THE NECK. 



Parts in this 

 section. 



Position of 

 head. 



Dissection 



In this SECTION are included the deepest styloid muscle, the 

 internal carotid and ascending pharyngeal arteries, and some cranial 

 and sympathetic nerves. 



Position. The position of the part is to remain as before, viz., the 

 neck is to be fixed over a small block. 



Dissection. To see the stylo-pharyngeus muscle, the posterior 

 pharyngeus, belly of the digastric and the stylo-hyoid muscle should be detached 

 from their origin and thrown down. The trunk of the external 

 carotid artery is to be removed by cutting it through where the 

 hypoglossal nerve crosses it, and by dividing those branches that 

 have been already examined : any veins accompanying the arteries 

 are to be taken away. While cleaning the surface of the stylo- 

 pharyngeus muscle, the glosso-pharyngeal nerve and its branches, 

 and the stylo-hyoid ligament are also to be prepared. The side of the 

 jaw is to be drawn forwards on the face. 



The STYLO-PHARYNGEUS MUSCLE (fig. 622, 5 , p. 622), resembles the 

 other styloid muscles in its elongated form. The fibres arise from 

 the root of the styloid process on the inner side, and descend between 

 the superior and middle constrictors to be inserted partly into the wall 

 of the pharynx, and partly into the upper and hinder borders of the 

 thyroid cartilage. 



The muscle lies below the stylo-glossus, and between the two carotid 

 arteries ; and the glosso-pharyngeal nerve turns over the lower end 

 of its fleshy belly. 



Action. It raises the pharynx, and tends to dilate the part of the 

 cavity above the hyoid bone. From its attachment to the thyroid 

 cartilage it will assist in elevating and drawing backwards the 

 larynx. 



The stylo-hyoid ligament is a slender fibrous band, which extends 

 from the tip of the styloid process to the small cornu of the hyoid 

 bone. Its position is between the stylo-glossus and stylo-pharyngeus 

 muscles, and over the internal carotid artery ; while the lower end 

 is placed beneath the hyo-glossus muscle. To its posterior border, 

 the middle constrictor muscle is attached below. It is frequently 

 cartilaginous or osseous in part of, or occasionally in all its extent. 

 Sometimes a slip of fleshy fibres is continued along it. 



The INTERNAL CAROTID ARTERY supplies the deep parts of the 

 head, viz., the brain, the contents of the orbit, and the nose ; and 

 takes a circuitous course through and along the base of the skull 

 before it ends in branches to the cerebrum. 



Part already The arterial trunk in the cranium has been already learnt, and its 

 ophthalmic offset will be seen in the dissection of the orbit ; but the 



and glosso- 

 pharyngeal 

 nerve. 



Stylo- 

 pharyngeus 



origin ; 



insertion 



is between 

 carotid 

 arteries : 



Stylo-hyoid 

 ligament 



lies by side 

 of preced- 

 ing. 



Internal 



carotid 



artery. 



