GREAT VESSELS AND NERVES OF NECK 225 



proceed from it, have been displayed. The inferior ganglion, 

 which lies deeply, in the hollow between the transverse process 

 of the seventh cervical vertebra and the neck of the first rib, is 

 still to a certain extent concealed, and must now be displayed. 

 Dislodge the subclavian artery from its place on the first rib 

 behind the scalenus anterior muscle, and turn it medially. To 

 do that efficiently, it will be necessary to cut the costo-cervical 

 artery at its origin. Great care must be taken to preserve un- 

 injured the fine nerves which proceed downwards anterior to 

 the first part of the subclavian artery. If more space for the 

 dissection is required, the anterior part of the first rib may be 

 removed by the bone-forceps, but, as a general rule, that will 

 not be necessary. 



Truncus Sympathicus in the Neck. The cervical part of 

 the sympathetic trunk takes a vertical course through the neck, 

 anterior to the roots of the transverse processes of the vertebrae. 

 It lies between the internal and common carotid arteries 

 anteriorly and the longus capitis (O.T. rectus capitis anticus 

 major) and longus colli muscles posteriorly. Above, it is pro- 

 longed upwards in the form of a stout, ascending nerve-trunk, 

 the nervus caroticus internus, which accompanies the internal 

 carotid artery into the carotid canal ; below, it becomes con- 

 tinuous, over the neck of the first rib and posterior to the 

 apex of the pleura, with the thoracic portion of the sympa- 

 thetic trunk. Only three ganglia are developed upon the 

 cervical part of the trunk and no white rami communicantes 

 from the cervical nerves enter either the trunk or the ganglia. 



Ganglion Cervicale Superius. The superior cervical gang- 

 lion, the largest of the three ganglia, is an elongated fusiform 

 body which varies somewhat in size. It is placed upon the 

 upper part of the longus capitis, opposite the second and 

 third cervical vertebras, and posterior to the carotid sheath. 

 From its upper end the stout nervus caroticus internus passes 

 into the carotid canal^ whilst its lower end tapers downwards 

 into the trunk. Numerous branches issue from it ; some of 

 them connect it with neighbouring nerves, whilst others are 

 distributed in various ways. 



The connecting branches are: (i) slender grey rami 

 communicantes which connect it with the upper four cervical 

 nerves ; (2) twigs to both ganglia of the vagus ; (3) to the 

 petrous ganglion of the glosso-pharyngeal ; and (4) to the 

 hypoglossal. It is not connected with the accessory. 



The branches of distribution are: (i) nervus caroticus 

 internus; (2) nervi carotici externi ; (3) rami laryngo- 

 pharyngei ; (4) nervus cardiacus superior. 



VOL. in 15 



