140 ANATOMY. 



Mention some other Plexuses of the Sympathetic system. They 

 are very numerous ; besides those already mentioned, the most important are 

 the following : 



Tympanic Plexus, described under Nerves of the Tympanum. 

 Meningeal Plexus, on the middle meningeal artery. 

 facial Plexus, surrounding the facial artery. 



Cardiac Plexuses, the deep in front of the bifurcation of the trachea, the 

 superficial in front of the right pulmonary artery ; the first named lies 

 behind the arch of the aorta, the latter beneath it. 

 Coronary Plexuses, anterior and posterior, accompanying respectively the 



left and right coronary arteries. 

 Aortic Plexus, on the sides and front of the aorta between the superior and 



inferior mesenteric arteries. 

 Hypogastric Plexus, on and between the common iliac arteries ; supplying 



the viscera of the pelvic cavity. 



Inferior Hypogastric or Pelvic Plexuses, two in number, one on each side 

 of the rectum and bladder. Their branches are the 



Inferior Hemorrhoidal Plexus. Small Cavernous Nerve. 



Vesical and Prostatic Plexuses. Large Cavernous Nerve. 



Vaginal Plexus. Uterine Nerve. 



What is the Vidian Nerve ? It has generally been described as a branch 

 of the spheno-palatine (Meckel's) ganglion (see p. 137), running backwards 

 through the Vidian canal, and dividing into a Petrosal Branch to the Facial 

 nerve, and a Carotid Branch to the carotid plexus of the Sympathetic. It is 

 now, however, more correctly described as a short nerve of communication, 

 between the Facial and the Sympathetic on the one hand, and the Spheno- 

 palatine Ganglion on the other, supplying that ganglion with its motor and 

 vaso-motor roots. It is formed by the junction of the 



Large Superficial Petrosal, Br. of the Facial (p. 138), with the 

 Large Deep Petrosal, Br. of the Carotid Plexus (p. 140), which occurs in 

 the cartilage filling in the foramen lacerum medium (p. 35). It then enters 

 the Vidian Canal (p. 20), in the pterygoid process of the sphenoid bone, pass- 

 ing through which to finally join the posterior part of the spheno-palatine gan- 

 glion (p. 137). Some filaments, the 



Upper Posterior Nasal Branches, are apparently given off from the Vidian 

 in the canal, to the septum and roof of the nose ; but they are really 

 branches from the ganglion-, bound up in the same sheath with the Vidian 

 nerve. 



