io62 A MANUAL OF ANATOMY 



the occipital bone over about its outer half, or more. The posterior 

 border of the muscle forms the anterior boundary of the posterior 

 triangle of the neck, and has the following nerves related to it : 

 (i) the small occipital ascends along it to the head ; (2) the great 

 auricular passes upwards and forwards over it towards the lobule 

 of the auricle ; (3) the superficial cervical crosses it in a forward 

 direction ; (4) the spinal accessory appears from behind it, along 

 with the branches of the third and fourth cervical nerves to the 

 trapezius ; and (5) the descending superficial branches of the 

 cervical plexus emerge from underneath it. 



The glandulsB concatenatae belong to the deep cervical glands, 

 and are situated along the posterior border of the sterno-cleido- 

 mastoid muscle. They will be afterwards described. 



The levator anguli scapulae, rhomboids, serratus posticus superior, 

 splenitis, complexus, transversalis cervicis, trachelo-mastoid, semi- 

 spinalis colli, intertransversales, and interspinals muscles will be 

 found described in connection with the muscles of the back, see 

 p. 287 et seq. 



Second and Third Parts of the Occipital Artery.— At the mastoid 

 process this vessel lies very deeply. Having crossed the rectus 

 capitis lateralis muscle, it enters the occipital groove on the inner 

 aspect of the mastoid process, where it is covered by the following 

 structures, in order from the surface downwards : (i) stemo-cleido- 

 mastoid ; (2) splenius capitis ; (3) trachelo-mastoid ; (4) mastoid 

 process ; and (5) the posterior belly of the digastric. In its back- 

 ward course the vessel rests, in succession, upon the insertions of 

 the obliquus capitis superior and complexus, and it escapes from 

 beneath the muscles covering it in the following order : posterior 

 belly of the digastric, trachelo-mastoid, splenius capitis, and stemo- 

 cleido-mastoid. After emerging from beneath the last-named 

 muscle, it lies for a little in the posterior triangle, close to the apex, 

 and then, piercing the occipital origin of the trapezius, it enters 

 upon the third part of Us, course. This part ascends, along with 

 the great occipital nerve, to the occipital region, where it divides 

 into several long tortuous branches. 



Branches. — ^The branches of the second and third parts are as 

 follows : mastoid, posterior meningeal, arteria princeps cervicis, 

 communicating, muscular, and terminal. The mastoid artery 

 passes through the arterial fissure on the outer surface of the 

 mastoid process, and supplies the diploe and mastoid cells, as well 

 as the adjacent dura mater. The posterior meningeal artery enters 

 the cranial cavity through the jugular foramen, and takes part in 

 the supply of the dura mater of the posterior fossa. The arteria 

 princeps cervicis arises under cover of the splenius capitis, and at 

 the outer border of the complexus it divides into a superficial and 

 deep branch. The superficial branch is distributed to the splenius 

 capitis and trapezius, and anastomoses, in the latter muscle, 

 with the superficial cervical artery. The deep branch passes 

 beneath the complexus, and anastomoses, upon the semispinalis 



