DISSECTION OF THE HEAD AND NECK. 197 



maxillo-muscular, and posterior auricular arteries. The last two spring 

 from the second portion of the artery, and have already been dissected. 

 The Submaxillary or Facial Artbey is detached from the external 

 carotid beneath the digastric muscle. It is a vessel of large calibre, 

 being nearly equal to the parent vessel beyond its point of detachment. 

 It descends over the pharyn.^, being nearly parallel to the posterior 

 edge of the great cornu, and about an inch behind it. At first under 

 cover of the digastric and stylo-hyoid muscles, it then turns round the 

 anterior edge and outer surface of the stylo-hyoid where the intermediate 

 tendon of the digastric plays through it. Continuing its course, it 

 crosses Wharton's duct and the lower extremity of the submaxillary 

 gland to the outer side, and appears in the intermaxillary space 

 between the internal pterygoid and subscapulo-hyoid muscles. Its 

 further course in the intermaxillary space and on the face has already 

 been followed. Behind the great cornu the artery is in company with 

 the 12th nerve. From its origin to the extremity of the submaxillary 

 gland, it detaches three collateral branches, viz., the pharyngeal, lingual, 

 and submental arteries. 



1. The Pharyngeal Artery is a small branch given off at the anterior 

 edge of the stylo-hyoid or under cover of that muscle. It reaches the 

 pharynx by passing beneath the great cornu, crossing either outwardly 

 or inwardly the 9th nerve. It is distributed to the pharynx, giving also 

 a forward branch to the soft palate. 



2. The Lingual Artery, whose volume is about equal to that of the 

 distal part of the parent trunk, has its point of origin over the tip of 

 the thyroid cornu. It descends on the cerato-hyoid muscle, and reaches 

 the tongue by passing beneath the great hyo-glossus muscle. It is the 

 main vessel of supply to the tongue, and will be followed in the dissec- 

 tion of that organ. 



3. The Submental Artery is detached at the extremity of the sub- 

 maxillary gland, as the parent artery appears in the intermaxillary 

 space. It has already been seen in the dissection of that space. 



The Occipital Vein. This vein descends from beneath the wing o 

 the atlas, in company with the artery of the same name ; and joins the 

 jugular at the posterior edge of the parotid gland, a little above the 

 termination of the submaxillary vein. It is formed by the union of 

 branches corresponding to those of the artery ; and, besides these, it 

 receives a branch which comes from the spinal canal by traversing the 

 ring of the atlas, beneath the wing, and another from the subsphenoidal 

 sinus. This \a^t will be exposed at a later stage. 



The 9th Cranial Nerve, also called the Glosso-Pharyngeal (Plate 

 32), issues from the cranium by the posterior part of the foramen lacerum 

 basis cranii. It descends on the guttural pouch, behind the great cornu 

 of the hyoid bone, and under cover of the digastric and stylo hyoid 



