654 THE NERVOUS SYSTEM. 
surrounding the gullet. This part of the cesophagus also receives fibres from the 
great splanchnic nerve and ganglion. From the cesophageal plexus branches 
supply the muscular wall and mucous membrane of the cesophagus. 
Pericardiac branches are also supplied from the plexus to the posterior surface of 
the pericardium. 
THE ELEVENTH oR SPINAL ACCESSORY NERVE. 
The spinal accessory nerve (n. accessorius) consists of two essentially separate 
parts, different both in origin and in distribution. One portion is accessory to 
the vagus nerve, and arises, in series with the 
fibres of that nerve, from the side of the medulla 
oblongata. The other, spinal portion, arises from 
the lateral aspect of the spinal cord, between 
the ventral and dorsal roots of the spinal 
nerves, its origin extending from the level of 
the accessory portion as low as the origin of the 
sixth cervical nerve (for the deep origin, see 
p- 477). Successively joining together, the root- 
lets form a trunk which ascends in the subdural 
space of the spinal cord, behind the hgamentum 
denticulatum, to the foramen magnum. There 
the accessory and spinal portions unite into a 
single trunk, which leaves the cranial cavity 
through the jugular foramen in the same com- 
partment of dura mater as the pneumogastric 
nerve (Fig. 457, p. 636). 
In the jugular foramen the accessory portion 
of the nerve (after furnishing a small branch to 
the ganglion of the root of the pneumogastric 
nerve) apples itself to the ganglion of the trunk, 
and in part joms the ganglion, in part the trunk 
of the nerve beyond the ganghon. By means of 
these connexions the pneumogastric receives 
viscero-motor and cardio-inhibitory fibres. 
Fic. 470.—ScCHEME OF THE ORIGIN, CON- The spinal portion of the DLS extends into 
NEXIONS, AND Distrigution or tHe the neck, where at first it lies along with other 
SPINAL AccEssorY NERVE. nerves, in the interval between the internal 
Sp.Ace, Spinal accessory nerve ; C.1-4, First carotid artery and the internal jugular vein. 
ad cervical nerves (dorsal roots); Passing obliquely downwards and outwards over 
a, Pheumogastric nerve ; R, Ganglion Soe: ‘ ; : : 
of the root ; T, Ganglion of the trunk; the vein, it descends beneath the sterno-mastoid 
G.Ph, Glosso-pharyngeal nerve ; S.M, muscle, which it supples as it pierces it on its 
AE See to sterno-cleido-mastoid ; Tr, deep surface. After crossing the posterior triangle, 
erves to trapezius; F.M, Foramen ; ce : 
magnum ; J.F, Jugular foramen. the nerve ends by supplying the trapezius muscle 
on its under surface. The spinal portion of the 
nerve communicates in three situations with nerves from the cervical plexus— 
(1) in or beneath the sterno-mastoid, with the branch for the muscle derived from 
the second cervical nerve; (2) in the posterior triangle, with branches from the 
third and fourth cervical nerves; (3) beneath the trapezius, with the branches for 
the muscle derived from the third and fourth cervical nerves. 
THE TWELFTH OR HYPOGLOSSAL NERVE. 
The hypoglossal nerve (n. hypoglossus) arises by numerous radicles from the 
front of the medulla oblongata between the pyramid and the olive (Fig. 452, p. 633 
(for deep origin, see p. 476). The root fibres arrange themselves in two bundles 
which separately pierce the dura mater, and unite in the anterior condyloid foramen, 
or after emerging from the skull. In the neck the nerve arches downwards 
and forwards towards the hyoid bone, and then turns inwards among the supra- 
hyoid muscles to the tongue. At first it is placed deeply, along with other cranial 
