VEjys OF THE HEAD A.\I> XECK (317 



Some anatomists describe the external jugular vein as being formed by the 

 junction of the ]>osterior auricular and occipital veins. The vein here regarded as 

 the upper part of the trunk of the external jugular is looked upon by them merely 

 as a brancli of communication between the external jugular and tem])oro-maxillary 

 vein. 



The chief variations of the external jugular vein are: — (1) It maj' be very small, or much 

 smaller or much larger tliau tlic opposite veiu ; (2) it may be wantiii.tr on one or both sides, the 

 veins whie-li nurmallj' form it tlieii opening into the internal jugular ; (3) it may be turnied merely 

 \)y the posterior auricular vein ; (4) it may be perforated by the supei-ficialis colli neiTe ; (5) it 

 may receive the facial, the lingual, and the cephalic veins ; (0) it may pass over the clavicle and 

 open into the cephalic or subehivian vein. 



Tributaries and communications. — From al)Ove downwards, the external 

 jugular receives a branch from the internal jugular vein; the posterior external 

 jugular, which in the ffjetus was part of the primitive jugular vein; a large 

 Itranch connecting it with the facial vein; one or two small branches of communi- 

 cation from the anterior jugular vein; near its termination, the transverse cervi- 

 cal and suprascapular veins ; and sometimes the anterior jugular vein at the 

 po.sterior l)order and hinder surface of the sterno-mastoid. At times the occipital 

 vein opens into the external jugular, and is by some anatomists regarded as the 

 normal termination of the former vein. 



The posterior external jugular vein descends from the upper and back part 

 of the neck, receiving small tributaries from the superficial structures and muscles. 

 At times it communicates with the oi/cipital, or may appear as a continuation of 

 tliat vein. It opens into the external jugular as the latter vein is leaving the 

 sterno-mastoid muscle. In the foetus this vein returns the blood from the interior 

 of the cranium through the post-glenoid foramen. Vestiges of the foetal trunk are 

 said to remain in the mastoid vein. 



The suprascapular veins, two in number, correspond to the suprascapular 

 artery. They usually form one trunk before they "open into the external jugular 

 vein. They contain well-marked valves. 



The transverse cervical veins — or venae comites of the transverse cervical 

 artery — accompany that vessel and open Avith the suprascapular vein into the 

 external jugular close to the spot where the latter vein joins the sul)clavian. 



The anterior jugular vein begins below the chin by communicating with the 

 mental, submental, inferior labial, and inferior hyoid veins. It descends a little 

 external to the middle line, receiving branches from the superficial structures at 

 the frcjut and side of the neck, and occasionally a branch from the larynx and thyroid 

 l)ody. .Just above the clavicle it turns outwards, and, piercing the fascia, passes 

 beneath the sterno-mastoid muscle and opens into the external jugular vein just 

 before the latter joins the subclavian; at times it opens into the subclavian vein 

 it.self. In its course down the neck it communicates with the external jugular; and, 

 as it turns outwards beneath the sterno-mastoid, sends a branch across the trachea, 

 between the layers of cervical fascia, to join the anterior jugular of the ojtijosite 

 side. This communicating vein may be divided in the operation of tracheotomy, and 

 is then often found greatly engorged with blood. Another branch, often of consider- 

 able size, courses along the anterior margin of the sterno-mastoid and joins the 

 facial vein. When the anterior jugular vein is large, the external jugular is small, 

 and rice rersd. It is usually also of large size when the corresponding vein on the 

 opposite side is absent, as is fre(iuently the case. It contains no valves. 



The p(jsition of the anterior jugular vein beneath the t<'ndon of the sterno-mastoid 

 should be borne in mind in tenotomy of that muscle for wry-neck. 



THE DEEP VETXS OF THE HE AD AXD XEOR' 



The deep veins of the head and neck may be divided into — 1. the veins rjf 

 the diploi'; L'. the venous sinuses of the cranium; o. the veins of the brain; 4. the 

 veins of the nasal cavities; 5. the veins of the ear; 6. the veins of the orbit; 7. the 

 veins of the pharynx and larynx; and 8. the deep veins <»f the neck. The veins of 



