492 THE ARTERIES 



called — at times a branch of the deep temporal — passes forwards along the upper 

 border of the zygoma in the fat lietween tlie superficial and deep layers of the tem- 

 poral aponeurosis, and, after giving branches to the orbicularis oculi, sends one or 

 more twigs into the orbit through the orljital foramina in the malar bone to anas- 

 tomose with the lachrymal and })al})el_>ral branches of the ophthalmic. 



(8) The anterior terminal branch ramifies tortuously in an upward and 

 forward direction over the front part of the skull. It lies, first between the skin 

 and temporal fascia, and then between the skin and occij^ito-frontalis aponeurosis. 

 It supplies the anterior belly of the occipito-frontalis and the orl)icularis oculi 

 nuiscles, and anastomoses with the supraorljital, supratrochlear, and frontal 

 branches of the ophthalmic, and with the corresponding artery of the opposite 

 side. The secondary branches given off' from this vessel to the scalp run from 

 before backwards. 



(9) The posterior terminal branch ramifies on the side of the head between 

 the skin and temporal fascia. Its branches anastomose, in front with the anterior 

 terminal branch; behind, with the posterior auricular and occipital arteries; and 

 al)ove, across the vertex of the skull, with the corresponding artery of the opposite 

 side. 



8. THE INTERNAL MAXILLARY ARTERY 



The internal maxillary artery (fig. 336) is the larger of the tAvo terminal 

 divisions of the external carotid. It arises opposite the neck of the jaw in the 

 substance of the parotid gland, and, passing first between the neck of the jaw and 

 the spheno-mandibular ligament — the so-called internal lateral ligament of the lower 

 jaw — and then between the external and internal pterygoid muscles, sinks deeply 

 into the spheno-maxillary fossa, and there breaks up into its terminal branches. 

 It is divided into three portions: a maxillary, a pterygoid, and a spheno- 

 maxillar3\ 



(1) In the first part of its course (the maxillary portion) the artery lies 

 between the neck of the jaw and the spheno-mandibular ligament, taking a hori- 

 zontal course forwards and inwards parallel to and a little below the auriculo- 

 temporal nerve and the external pterygoid muscle. It is here embedded in the 

 deep portion of the parotid gland, and usuall}^ crosses in front of the mandibular 

 (inferior dental) nerve. 



(2) In the second part of its course (the pterygoid portion) the artery lies 

 either between the two pterygoid muscles and the ramus of the jaw, and then turns 

 upwards over the outer surface of the external pterygoid, beneath tlie temporal 

 muscle to gain the two heads of the external pterygoid, between which it sinks into 

 the spheno-maxillary fossa; or it passes behind and internal to the external ptery- 

 goid, and is covered l)y that muscle till it reaches the interval between its two 

 heads, where it then often forms a projecting loop as it turns into the spheno- 

 maxillary fossa. 



(3) In the third part of its course (the spheno-maxillary portion) the 

 artery lies in the spheno-maxillary fossa beneath tlie maxillary division of the fifth 

 nerve, and in close relationship with Meckel's ganglion, and there breaks uj) into its 

 terminal branches. 



Branches of the Internal Maxillary Artery 



The branches of the internal maxillary artery are: — 



(A) From the first part : — (1) The deep auricular; (2) the tympanic; (3) the 

 large middle meningeal; (4) the mandibular (inferior dental); (5) the small 

 middle meningeal (sometimes). All these vessels pass through bony or cartilagi- 

 nous canals. 



(B) From the second part: — (1) The masseteric; (2j the ])osterior deep 

 temporal; (3) the internal pterygoid; (4) the external ]iterygoid; (o) the l)uccal; 

 and (6) the anterior dee)) tem])<)ral. All these branches supply muscles. 



(C) From the third part: — (1) The posterior dental, or alveolar; (2) the 

 infra-orbital; (3) the posterior, or descending i)alatinc; (4) the Vidian; (5) the 



