646 THE BLOOD-VASCULAR SYSTEM 



(a) The superficial temporal vein [v. temporalis superficialis] returns the blood from the 

 parietal region of the scalp. It is formed by the union of an anterior and a posterior branch: 

 the former communicates with the supraorbital and frontal veins; the latter with the posterior 

 auricular and occipital veins and the temporal vein of the opposite side. These branches lie 

 superficial to the corresponding branches of the superficial temporal artery, which they roughly 

 though not accurately follow. Like the artery, they he between the skin and the cranial 

 aponeurosis, and descend over the temporal fascia to unite a little above the zygoma, and just 

 in front of the auricle of the ear, to form the superficial temporal trunk. The vein thus formed 

 continues its course downward with the trunk of the temporal artery, and opposite the zygoma 

 is joined by the middle temporal vein to form the common temporal vein. 



(b) The middle temporal vein [v. temporalis media] corresponds with the orbital branch 

 of the temporal artery, and communicates in front with the ophthalmic vein, the external 

 palpebral veins, and the infraorbital veins, and then runs backward between the layers of the 

 temporal fascia to join the superficial temporal vein. The middle temporal vein communicates 

 with the deep temporal veins, and through them with the pterygoid venous plexus. 



(c) The transverse facial vein [v. transversa faciei] corresponds to the transverse facial 

 artery, (d) Articular veins [vv. articulares mandibulae] form the plexus around the temporo- 

 mandibular joint; this plexus receives the tympanic veins [vv. tympanicse), which, together 

 with its corresponding artery, passes through the petrotympanic fissure, (e) Posterior parotid 

 veins [w. parotidese posteriores] emerge from the substance of the parotid gland, (f) Anterior 

 aiuicular veins [w. auriculares anteriores], from the auricle of the ear. (g) Stylo-mastoid vein 

 [v. stylomastoidea] from the facial canal, (h) The internal maxallary vein accompanies the 

 first part of the internal maxillary artery. It begins at the posterior confluence of the veins 

 forming the pterygoid plexus, and passes backward between the stylo-mandibular ligament and 

 the neck of the mandible. It ends by joining the posterior facial vein. 



The pterygoid plexus [plexus pterygoideus] is formed by the veins which correspond to the 

 branches of the internal maxillary artery. It is situated, partly on the medial surface of the 

 internal pterygoid muscle, and partly around the external pterygoid muscle. The veins 

 entering into this plexus are: — the two middle meningeal veins [vv. meningese mediae], which 

 accompany the artery of that name; the posterior superior alveolar (dental); the inferior alveolar 

 (dental); the masseteric; the buccal; the pterygoid veins from the pterygoid muscles; the deep 

 temporal veins [vv. temporales profunda?], by which the plexus communicates with the temporal 

 plexus; the spheno -palatine vein; the infraorbital; the superior palatine; a branch of commu- 

 nication with the lower branch of the ophthalmic vein, which courses through the inferior 

 orbital (spheno-maxillary) fissure; and the rete foraminis ovalis and Vesalian vein, through 

 which the plexus communicates with the cavernous sinus. The plexus ends posteriorly in 

 the internal maxillary vein, which joins the posterior facial vein, and anteriorly in a com- 

 municating vessel (the deep facial vein), which passes forward and downward between the 

 buccinator and masseter muscles to join the anterior facial vein. 



The above-mentioned veins, forming by their confluence the pterygoid plexus, correspond 

 in their course so nearly with that of their companion arteries that a detailed description is 

 not necessary. Although for convenience described with the superficial veins, they are all 

 deeply placed. 



Near the angle of the mandible there is almost always a communicating branch between the 

 posterior facial and the external jugular veins. When large, this branch may drain the greater 

 part of the blood from the posterior facial. 



C. The Common Facial Vein 



The common facial vein [v. facialis communis] is a short thick stem contained 

 within the carotid triangle. It is formed, just below the angle of the mandible, 

 by the union of the anterior and posterior facial veins. It ends opposite the hyoid 

 bone, by opening into the internal jugular vein. In addition to the vessels which 

 form it, sometimes it receives the superior thyreoid, the pharyngeal, and the lin- 

 gual or the sublingual veins. 



D. The External Jugular Vein 



The external jugular vein [v. jugularis externa] (fig. 510) is formed by the con- 

 fluence of the posterior auricular and a short communicating trunk from the 

 posterior facial near the angle of the mandible. It runs obliquely downward and 

 backward across the sterno-mastoid muscle to a point opposite the middle of the 

 clavicle, where it terminates as a rule in the subclavian vein. A line drawn from 

 a point midway between the mastoid process and angle of the jaw to the middle of 

 the clavicle will indicate its course. It is covered by the skin, superficial fascia, 

 and platysma, and is crossed by a few branches of the cervical plexus, the great 

 auricular nerve running parallel to it at the upper part of the neck. It is separated 

 from the sterno-mastoid by the anterior layer of the deep cervical fascia. 



Just above the clavicle it j)erf orates the cervical fascia, by which it is prevented from readily 

 collapsing, the fascia being attached to its walls. It then opens into the subclavian vein, oc- 

 casionally into the internal jugular, or into the confluence of the subclavian and internal jugular 



