OF THE NECK. 539 



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Branches. This vein receives the occipital occasionally, the posterior exter- 

 nal jugular, arid, near its termination, the suprascapular and transverse cervical 

 veins. It communicates with the anterior jugular, and, in the substance of the 

 parotid, receives a large branch of communication from the internal jugular. 



The Posterior External Jugular Vein returns the blood from the integument 

 and superficial muscles in the upper and back part of the neck, lying between 

 the Splenius and Trapezius muscles. It runs down the back part of the neck, 

 and opens into the external jugular just below the middle of its course. 



The Anterior Jugular Vein collects the blood from the integument and mus- 

 cles in the middle of the anterior region of the neck. It passes down between 

 the median line and the anterior border of the Sterno-mastoid, and, at the lower 

 part of the neck, passes beneath that muscle to open into the subclavian vein, 

 near the termination of the external jugular. This vein varies considerably in 

 size, bearing almost always an inverse proportion to the external jugular. Most 

 frequently there are two anterior jugulars, a right and left; but occasionally 

 only one. This vein receives some laryngeal branches, and occasionally an 

 inferior thyroid vein. Just above the sternum, the two anterior jugular veins 

 communicate by a transverse trunk, which receives branches from, the inferior 

 thyroid veins. It also communicates with the external and with the internal 

 jugular. There are no valves in this vein. 



The Internal Jugular Vein collects the blood from the interior of the cranium, 

 from the superficial parts of the face, and from the neck. It commences at the 

 jugular foramen, in the base of the skull, being formed by the coalescence of 

 the lateral and inferior petrosal sinuses. At its origin it is somewhat dilated, 

 and this dilatation is called the sinus, or gulf of the internal jugular vein. It 

 runs down the side of the neck in a vertical direction, lying at first on the 

 outer side of the internal carotid, and then on the outer side of the common 

 carotid, and at the root of the neck unites with the subclavian vein, to form 

 the vena innominata. The internal jugular vein, at its commencement, lies 

 upon the Rectus Lateralis, behind, and at the outer side of the internal carotid, 

 and the eighth and ninth pairs of nerves ; lower down, the vein and artery lie 

 upon the same plane, the glosso-pharyngeal and hypoglossal nerves passing 

 forwards between them ; the pneumogastric descends between and behind them, 

 in the same sheath ; and the spinal accessory passes obliquely outwards, behind 

 the vein. At the root of the neck the vein of the right side is placed at a 

 little distance from the artery ; on the left side, it usually crosses it at its lower 

 part. The right internal jugular vein crosses the first part of the subclavian 

 artery. This vein is of considerable size, but varies in different individuals, 

 the left one being usually the smaller. It is provided with a pair of valves, 

 which are placed at its point of termination, or from half to three-quarters of 

 an inch above it. 



Branches. This vein receives in its course the facial, lingual, pharyngeal, 

 superior and middle thyroid veins, and sometimes the occipital. At its point 

 of junction with the branch common to the temporal and facial veins it becomes 

 greatly increased in size. 



The lingual veins commence on the dorsum, sides, and under surface of the 

 tongue, and passing backwards, following the course of the lingual artery and 

 its branches, terminate in the internal jugular. 



The pharyngeal vein commences in a minute plexus, the pharyngeal, at the 

 back part and sides of the pharynx, and after receiving meningeal branches, 

 and the Vidian and spheno-palatine veins, terminates in the internal jugular. 

 It occasionally opens into the facial, lingual, or superior thyroid vein. 



The superior thyroid vein commences in the substance and on the surface of 

 the thyroid gland, by branches corresponding with those of the superior thyroid 

 artery, and terminates in the upper part of the internal jugular vein. 



The middle thyroid vein collects the blood from the lower part of the lateral 



