666 
investing the artery in the cranium. 
THE NERVOUS SYSTEM. 
The outer division forms the lower carotid 
plexus (pl. caroticus internus); the inner division gives rise to the upper cavernous 
plexus (pl. cavernosus). 
Both plexuses supply offsets to the artery and its branches, 
and form communications with certain cranial nerves. 
The carotid plexus communicates by fine branches with (a) the abducent nerve, 
and (6) the Gasserian ganglion, and gives off (¢) the great deep petrosal and (d) 
Sy. || 
Be | 
ae 
Cant 
FIG. 
478.—THE CONSTITUTION OF 
THE CARDIAC PLEXUSES. 
Sy, Cervical sympathetic cord ; C.1, 
Superior, C.2, Middle, and C.3, In- 
ferior cervical ganglia; Car.1, 
Superior, Car.2, Middle, and Car.3, 
Inferior cervical cardiac sympa- 
thetic branches ; Va, Pneumogastric 
nerve; R.L, Recurrent laryngeal 
nerve ; s, Superior, and i, Inferior 
cervical cardiac branches of vagus 2 
D.C.P, Deep cardiac plexus ; S 3.C alls 
Superficial cardiac plexus ; A.P. p, 
Anterior pulmonary plexus ; P.P.P, 
Posterior pulmonary plexus ; 
R.Car.P, Right, and L.Car.P, Left 
coronary plexuses; Art.Pul, Pul- 
monary artery. 
the small dee 2p petrosal nerves. The great deep 
petrosal nerve joins the great superficial petrosal 
nerve from the geniculate ganglion of the facial, 
upon the foramen lacerum medium. By their union 
the Vidian nerve is formed, which, after traversing 
the Vidian canal, ends in Meckel’s ganglion. The 
small deep petrosal nerve passes to the tympanic 
plexus. ‘This plexus, formed by the small deep petrosal 
nerve, the tympanic branch of the glosso- pharyngeal, 
and a twig from the geniculate ganglion of the facial 
nerve, 18 placed on the inner wall of the tympanum. 
It supplies the mucous lining of the tympanum 
and Eustachian tube; and the small superficial 
petrosal nerve passes from it to the otic ganglion. 
The cavernous plexus communicates ‘with (a) the 
oculo-motor, and (6) the trochlear nerves, and (c) the 
ophthalmic division of the trigeminal nerve; it also 
(d@) supplies twigs to the pituitary body, and (@) 
forms the sympathetic root of the cilary ae 
This may pass to the ganglion independently, 0 
imay be incorporated in the long root of the oat 
from the nasal branch of the ophthalmic nerve. 
MIDDLE CERVICAL GANGLION. 
Central Communicating Branches.— 1. Gray 
rami communicantes arise from the ganglion for the 
anterior prunary divisions of the fifth and sixth 
cervical nerves. The subclavian loop (ansa Vieus- 
senii) is a loop of communication from this ganglion, 
which, after passing over and supplying offsets to 
the subclavian artery and its branches, joins the 
inferior cervical ganglion. 
Peripheral Branches of Distribution.—1. Heart. 
—A slender middle cervical cardiac branch descends, 
either separately or in company with other cardiac 
nerves, behind the large vessels into the thorax, 
where it ends in the deep part of the cardiae plexus 
on each side. 
2. Thyroid. Body.— Branches extend inwards 
along the inferior thyroid artery to supply the thyroid 
body. 
When the middle ganglion is absent, the branches 
deseribed arise from the commissural cord. 
INFERIOR CERVICAL GANGLION. 
Central Communicating Branches.—1. Gray 
rami communicantes arise from this ganglion for the 
anterior primary divisions of the seventh and eighth 
cervical nerves. 2. The subclavian loop already 
mentioned connects the middle and inferior ganglia over the front of the subclavian 
artery. 
A communication frequently occurs with the inferior laryngeal nerve. 
