420 ANGIOLOGY. 



which furnishes usually from the second to the fourth anterior 

 intercostal arteries. 



The Superior cervical artery arises anterior to the dorsal, 

 sometimes along with it, having the same relations until it passes 

 through the first intercostal space. It then runs upwards along 

 the ligamentum nuchse, covered by the complexus major, as far 

 as the vertebra dentata, distributing branches to the muscles of 

 the neck, and anastomosing with the dorsal and vertebral 

 arteries. Within the thorax, it gives otf the first intercostal 

 artery, and a twig to the mediastinum. 



The Vertebral artery arises opposite the first rib, gains the 

 outer side of the trachea and oesophagus, and leaves the thorax, 

 passing under the transverse process of the seventh, and through 

 the foramina in the transverse processes of the sixth to the 

 second cervical vertebrae, covered by the intertransversalis colli. 

 On reaching the atlas it anastomoses with the retrograde branch 

 of the occipital artery, or ramus anastomoticus, which comes 

 through the posterior foramen on the wing of the atlas. Here 

 it is covered by the obliquus capitis posticus muscle. It supplies 

 branches to the muscles of the neck, also to the spinal cord and 

 its membranes, through the intervertebral foramina. 



The Internal thoracic. Pectoral, or Mammary artery, ori- 

 ginates at the first rib, opposite the vertebral. It descends to the 

 second bone of the sternum, passing over the costal cartilages to 

 the ensiform, where it splits into anterior abdominal, and asternal 

 branches, after giving twigs to the pericardium and mediastinum ; 

 and intercostal branches, which are distributed to the pectoral 

 muscles, anastomosing with the external thoracic and first seven 

 intercostal arteries. In the young it supplies the thymus gland. 

 The anterior abdominal leaves the thorax at the ensiform 

 cartilage, penetrates the rectus abdominis, and anastomoses with 

 the epigastric artery. The asternal artery winds round the 

 cartilages of the false ribs, crossing the digitations of the trans- 

 versalis abdominis, and terminating in the thirteenth intercostal 

 space, by anastomosing Avith the intercostal artery ; it supplies 

 the diaphragm and transversalis muscles. 



The Inferior cervical artery is given off as the brachial 

 leaves the thorax, passing between the jugular confluent and the 

 pectoralis parvus, and dividing into ascending and descending 

 branches. The former runs between the levator humeri and sub- 

 scapulo-hyoideus, supplying the lymphatic glands and adjacent 



