550 



THE BLOOD-VASCULAR SYSTEM 



in the lateral fissure (fissure of Sylvius), into the anterior and middle cerebral 

 arteries. 



In its course up the neck it often forms one or more curves, especially in old 

 people. Between the internal and the external carotids, at their angle of diver- 

 gence, is situated the carotid body or gland [glomus caroticum]. 



The internal carotid is the continuation upward of the primitive dorsal aorta, 

 and supplies the greater part of the brain, the contents of the orbit, and parts of 

 the internal ear, forehead, and nose. It is divided into three portions: — (1) a 

 cervical; (2) a petrosal; and (3) an intracranial. 



1. The Cervical Portion 



Relations. — In the neck (fig. 453) the artery is at first comparatively superficial, having 

 in front of it, as it Mes in the superior carotid triangle, the skin, superficial fascia, platysma and 



Fig. 453. — The Caeotid Arteries. (After Toldt, "Atlas of Human Anatomy," Rebman Lon- 

 don and New York.) 



Posterior deep temporal artery 

 Temporal muscle \ 



Anterior deep temporal artery 

 Lacrimal gland 



Lateral palpebral arteries 



v Supraorbital artery 

 ^\ X / Frontal artery 



) 



Masseteric i .^r . 

 artery v(i-\-'. 

 External ^»^v \ 

 pterygoid "^Av^* 

 muscle 

 Middle tern- v 

 poral artery ^' 

 Middle men- 

 ingeal artery "~^. 



Superficial tem- 

 poral artery ^ 

 Internal maxil- 

 lary artery 

 Inferior alveolar 



artery — 



Spheno-mandibular 



ligament 

 Stylomastoid artery - 

 Inferior alveolar — 

 nerve 

 Posterior auricular 

 artery 

 Mylohyoid branch 



Posterior belly of 

 digastric muscle 



Internal pterygoid muscle 

 Lingual nerve 

 Buccinator artery 

 Occipital artery 

 External carotid artery '' 

 External maxillary artery ■ 

 Sternocleidomastoid artery /' / 

 Lingual artery '' /' 

 Hyoglossus muscle '' , 

 Hyothyreoid membrane -' 

 Superior thyreoid artery 

 Internal carotid artery 

 Posterior branch 



Anterior branch -'' 

 Common carotid artery 



Thyreohyoid muscle 



^,' ^ Dorsal nasal artery 



Superior anterior 

 alveolar artery 



Infraorbital artery 



Superior pos- 

 terior alve- 

 olar artery 



^ Superior la- 

 bial artery 



.Inferior labial 

 artery 



"Mental artery 



Mylohyoid muscle 



^-^^ External maxillary 



artery 

 Submental artery 



^ Thyreohyoid muscle 



Hyoid branch of the lingual artery 



Superior laryngeal artery 



\ Crico-thyreoid branch 

 Middle crico-thyreoid ligament 



deep fascia, and the overlapping edge of the stcrno-mastoid muscle. Higher up, as it sinks be- 

 neath the parotid gland, it becomes deeply placed, and is crossed by the posterior belly of the 

 digastric and stylo-hyoid muscles, the hypoglossal nerve, and the occipital and posterior auricu- 

 lar arteries; whilst still higher it is separated from the external carotid artery, which here gets 



