4GO VEINS. 



this vein passes opposite the mastoid process, it receives the mastoid vein, which 

 establishes a communication with the lateral sinus. 



2. YEINS OF THE NECK. 



The Veins of the Neck, which return the blood from the head and face, are 

 the 



External jugular. Anterior jugular. 



Posterior external jugular. Internal jugular. 



Vertebral. 



The External Jugular Vein receives the greater part of the blood from the 

 exterior of the cranium and deep parts of the face, being a continuation of the 

 temporo-maxillary and posterior auricular veins. It commences in the substance 

 of the parotid gland, on a level with the angle of the lower jaw, and runs perpen- 

 dicularly down the neck, in the direction of a line drawn from the angle of the 

 jaw to the middle of the clavicle. In its course, it crosses the Sterno-mastoid 

 muscle, and runs parallel with its posterior border as far as its attachment to the 

 clavicle, where it perforates the deep fascia, and terminates in the subclavian 

 vein, on the outer side of the internal jugular. As it descends the neck, it is 

 separated from the Sterno-mastoid by the anterior layer of the deep cervical 

 fascia, and is covered by the Platysma, the superficial fascia, and the integument. 

 This vein is crossed about its centre by the superficial cervical nerve, and its 

 upper half is accompanied by the auricularis magnus nerve. The external jugular 

 vein varies in size, bearing an inverse proportion to that of the other veins of the 

 neck ; it is occasionally double. It is provided with two pairs of valves, the 

 lower pair being placed at its entrance into the subclavian vein, the upper pair in 

 most cases about an inch and a half above the clavicle. These valves do not prevent 

 the regurgitation of the blood, or the passage of injection from below upwards. 1 



Branches. This vein receives the occipital, the posterior external jugular, and, 

 near its termination, the supra-scapular and transverse cervical veins. It com- 

 municates 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 descends 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 muscles 

 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, bear- 

 ing 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 trans- 

 verse 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 cra- 

 nium, 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 

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



1 The student may refer to an interesting paper by Dr. Struthers, "On Jugular Venesection 

 ;'n Asphyxia, Anatomically and Experimentally Considered, including the Demonstration of 

 Valves iu the Veins of the Neck," in the Edinburgh Medical Journal, for November, 1856. 



