THE INTERNAL MAXILLARY ARTERY. 



739 



between the posterior belly of the digastric above and the hypoglossal nerve below. 

 (^b) The facial portion is easily exposed where it crosses the mandible at the ante- 

 rior border of the masseter, either by a vertical cut parallel with that muscle and the 

 artery or by a horizontal cut crossing the vessel and placed under the inferior margin 

 of the jaw so as to leave the scar in an inconspicuous position. Beneath the skin 

 and the superficial fascia the platysma and deep fascia are the only structures that 

 require division. The vein lies in the groove between the artery and the edge of the 

 masseter. 



4. The Internal Maxillary Artery. — The internal maxillary ("a. maxillaris 

 interna) (Fig. 692) is a large branch which arises from the anterior surface of the 



Fig. 6q2. 



Small meningeal branch 



Middle meningeal 



Tympanic bianch 



Superficial temporal 



Stylo-mastoid 

 Meningeal branch 



Posterior auricular 



Trachelo-mastoideus 

 Occipital artery 

 Sterno-mastoid branch — — 

 Trapezius — — 



Splenius 



Levator anguli scapulje 



Internal carotid artery 



Externa! carotid artery 

 Superior thyroid artery 



Scalenus medius 

 Common carotid artery 



Scalenus anticus 



Longus colli 



Superficial cervical 



Posterior scapula! 



Scalenus medius>^^ 

 Tendinous origin of scalenus medius 



Deep temporal branches 



Branches of internal maxillary 

 artery to superior maxilla 



Posterior superior dental 



Internal maxillary artery 

 Inferior dental artery 

 Buccal branch 

 Internal pterygoid muscle 



Buccinator 

 Ranine artery 

 .Tonsilar artery 

 Ascending palatine 

 Facial artery, cut 

 'Sublingual artery 

 Dorsalis linguae 



Hyoglossus muscle, cut 



Suprahyoid branch 

 Lingual artery 



Laryngeal branch 



Sterno-mastoid branch 

 Ascending cervical artery 



Transverse cervical artery 

 Inferior thyroid artery 

 Thyroid axis 

 Vertebral artery 

 Subclavian artery 



Internal mammary artery 



First rib 



Sterno-mastoid brancn Suprascapular artery 



Deeper dissection, showing carotid and subclavian arteries. 



external carotid, opposite the neck of the mandible. It passes forward with a flexuous 

 course, lying at first between the neck of the mandible and the spleno-mandibular 

 ligament, and then passing either between the two pterygoid muscles, in which case it 

 crosses the inferior dental and lingual nerves, or else over the external surface of the 

 external pterygoid, between that muscle and the temporal. It then passes between 

 the two heads of the external pterygoid, in the one case passing from below upward 

 and in the other from without inward, and enters the spheno-maxillary fossa, in 

 which it is directed upward and inward towards the sphenc -palatine foramen, which 

 it traverses under the name of the spheno-palatine artery. 



Branches. — For convenience in description it is customary to regard the internal maxillary 

 artery as consisting of three portions. Its first, or mandibular portion, is that which lies inter- 



