488 THE ARTERIES 



from the junction of the mucous meml)rane and the skin. It is usually larger 

 than the inferior coronary. The superior coronary anastomoses Avith its fellow 

 of the opposite side, and gives off a small artery to the septum — arteria 

 septi nasi. Compression of this vessel will sometimes control luemorrhage from 

 the nose. 



In the operation for hare lip, the pin or suture should l^e passed sufficiently deep 

 to transfix the divided coronary artery, or haemorrhage may continue into the mouth. 

 Bleeding from either coronary vessel can be readily controlled by the thumb and 

 forefinger grasping tlie lip. 



(4) The lateral nasal artery (fig. 334) is a small twig or twigs given oft' from 

 the facial opposite the ala of the nose. It passes forwards over the ala and lower 

 \>axi of the nose, supplying the integuments, muscles, and cartilages, and anasto- 

 moses with the artery of the septum, the vessel of the opposite side, and the nasal 

 branches of the ophthalmic. 



(5) The angular artery (fig. 334) is the name given to the termination of the 

 facial arter}'. It anastomoses at the inner canthus of the eve Avith the nasal 

 branch of the ophthalmic. It is accompanied by the anterior descending vein 

 from the scalp. It lies to the inner side of the lachrymal sac, and supplies that 

 structure and the lower part of the orbicularis oculi, beneath which a l^ranch anas- 

 tomoses with the infraorbital artery. The situation of the artery to the inner side 

 of the lachrymal sac should be borne in mind in opening a lachrymal abscess. 



5. THE OCCIPITAL ARTERY 



The occipital artery (fig. 335) is usually a vessel of considerable size. It 

 comes off from the posterior part of the external carotid opposite the facial, or else 

 a little higher than that vessel. It then winds upwards and l)ackwards to the 

 interval between the mastoid process of the temporal lione and transverse process 

 of the atlas, and, after running horizontally liackwards in the occipital groove 

 on the mastoid j^ortion of the temporal bone, again turns upwards, and ends liy 

 ramifying in the scalj) over the Ixick of the skull, extending as far forwards as the 

 vertex. 



The vessel may be divided into three parts — viz. that internal to the sterno- 

 mastoid muscle; that beneath the sterno-mastoicl; and that external to the sterno- 

 mastoid. 



In the first part of its course the occipital artery is covered l)y the integu- 

 ments and fascia, and is more or less overlapped by the posterior Ijelly of the 

 digastric muscle, the parotid gland, and temporo-maxillary vein. It is crossed by 

 the hj'po-glossal nerve as the latter winds forwards over the carotid vessels to reach 

 the tongue. It successively crosses in front of the internal carotid arter}-, the hypo- 

 glossal nerve, the pneumogastric nerve, the internal jugular vein, and the spinal 

 accessory nerve. 



In the second part of its course it sinks deeply beneath the digastric muscle 

 into the interval between the mastoid process of the temporal l)one and the trans- 

 verse process of tlie atlas. It is here covered by the sterno-mastoid, si)lenius capitis, 

 and trachelo-mastoid muscles and by the origin of the digastricus; and lies, first 

 on the rectus capitis lateralis, which separates it from the vertebral artery, then in 

 the occipital groove on the mastoid portion of the temporal lione, and then on the 

 insertion of the supcricn- oblicpie muscle. 



In the third part of its course it enters the triangular interval formed by the 

 diverging borders of the s})lenii capitis and the sujierior curved line of the occipital 

 bone. Here it lies beneath the integuments and the aponeurosis uniting the occi- 

 pital attachments of the sterno-mastoid and trapezius, and rests upon thecomplexus 

 just before the insertion of that muscle into the occipital l)one. In company with 

 the great occipital nerve, it perforates either this aponeurosis, or less often the 

 posterior belly of the occipito-frontalis, and folhjws roughly, l>ut in a tortuous 

 course, the line of the lambdoid suture lying between the integument and the 

 cranial aponeurosis. In the scal]> it divides into several large l)ranches, Avhich 

 ramify over the ])ack of the skull and reach as far forwards as the vertex. They 



