THE VEINK OF THE NECK. 597 



the skull. The trunk of the vein then passes backward behind the neck of the 

 lower jaw, and unites with the temporal vein, forming the temporo-maxillavy vein. 



The Temporo-maxillary Vein, formed by the union of the temporal and 

 internal maxillary veins, descends in the substance of the parotid gland on the 

 outer surface of the external carotid artery, between the ram us of the jaw and 

 the Sterno-mastoid muscle, and divides into two branches, an anterior, which 

 passes inward to join the facial vein, and a posterior, which is joined by the poste- 

 rior auricular vein and becomes the external jugular. 



The Posterior Auricular Vein commences upon the side of the head by a plexus 

 which communicates with the tributaries of the temporal and occipital veins. 

 The vein descends behind the external ear and joins the posterior division of the 

 temporo-maxillary vein, forming the external jugular. This vessel receives the 

 stylo-mastoid vein and some tributaries from the back part of the external ear. 



The Occipital Veins commence at the back part of the vertex of the skull by 

 a plexus in a similar manner to the other veins. These unite and form one or 

 two veins, which follow the course of the occipital artery, passing deeply beneath 

 the muscles of 'the back part of the neck, and terminate in the internal jugular, 

 occasionally in the external jugular vein. As these veins pass across the mastoid 

 portion of the temporal bone, one of them receives the mastoid vein, which thus 

 establishes a communication with the lateral sinus. 



The Veins 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 formed by the junction of 

 the posterior division 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 perpendicularly 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 or in front of the Scalenus 

 anticus muscle. In the neck it is separated from the Sterno-mastoid by the invest- 

 ing layer of the deep cervical fascia, and is covered by the Platysma, the superficial 

 fascia, and the integument. This vein is crossed about its middle by the super- 

 ficialis colli 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 loAver 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. 

 The portion of vein between the two sets of valves is often dilated, and is termed 

 the sinus. These valves do not prevent the regurgitation of the blood or the 

 passage of injection from below upward. 1 



Surgical Anatomy. Venesection used formerly to be performed on the external jugular 

 vein, but is now probably never resorted to. The anatomical point to be remembered in per- 

 forming this operation is to cut across the fibres of the Platysma myoides in opening the vein, 

 so that by their contraction they will expose the orifice in the vein and so allow the flow of 

 blood. 



Tributaries. This vein receives the occipital occasionally, the posterior external 

 jugular, and near its termination, the suprascapular and transverse cervical veins. 



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

 Asphyxia, anatomically and experimentally considered, including the Demonstration of Valves in 

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



