1584 A MANUAL OF ANATOMY 



should be made to show all its connections, especially its upward con- 

 tinuation into the carotid canal of the pars petrosa. The middle and inferior 

 cervical ganglia will probably have been met with in a previous dissection, 

 the former being associated with the inferior thyroid artery, and the latter with 

 the vertebral artery. From each ganglion, respectively, in order from above 

 do^^iwards, there come the superior, middle, and inferior cervical cardiac 

 branches ; but, though these are actually present, the dissector should not 

 feel disheartened if he cannot verify their existence. 



Carotid Canal and its Contents. — The dissector is now getting into as deep 

 water as it would be safe for him to enter. His knowledge of osteology 

 should come to his aid. His object is to display the intrapetrous part of 

 the internal carotid artery, and for this purpose he will remove whatever 

 bone he deems desirable. In intimate association with this part of the 

 internal carotid he will find the upward continuation of the cervical sympa- 

 thetic cord. He may be able to show how this upward prolongation divides 

 into two branches, external and internal, the former giving rise to the 

 carotid plexus, and the latter going on to form the cavernous plexus. The 

 dissector should carefully read the description given of these plexuses in the 

 text. 



The foramen lacerum posterius, or jugular foramen, is next to be dissected. 

 Its three compartments, already familiar to the dissector, namely (i) antero- 

 intemal, transmitting the inferior petrosal sinus ; (2) middle, transmitting 

 the glosso-pharyngeal, pneumogastric, and spinal accessory nerves ; and 

 (3) postero-extemal, transmitting the lateral sinus, may now be completely 

 verified by opening up the foramen referred to. 



PJiarynx, Solt Palate, and Mouth. — To prepare these important regions for 

 dissection, the skull must be divided into two parts. The leading blood- 

 vessels and nerves, as well as the trachea and oesophagus, are to be divided 

 close to the root of the neck. The pharynx is then to be carefully separated 

 from the prevertebral muscles quite up to the base of the skull, and the 

 basilar region of the skull is to be divided with the chisel and mallet, aided 

 by the saw. The front part of the skull) bearing the pharynx, along with 

 the great bloodvessels and nerves, is to be separated from the back part, 

 which bears the cervical portion of the vertebral column, with the pre- 

 vertebral muscles. The pharynx having been distended with tow, the 

 superior, middle, and inferior constrictor muscles are to be dissected, and 

 whilst doing so the pharyngeal plexus of veins is to be noted. The manner 

 in which the constrictor muscles overlap one another from below upwards 

 is to be noted. The stylo-pharyngeus muscle and glosso-pharyngeal 

 nerve are to be shown in the interval between the lower border of the 

 superior constrictor and the upper border of the middle constrictor. 

 Upon the surface of the middle constrictor muscle the dissector should 

 make an effort to show the pharyngeal plexus of nerves, formed by 

 the pharyngeal branches of the glosso-pharyngeal and pneumogastric, 

 and branches from the superior cervical ganglion of the sympathetic. Be- 

 tween the lower part of the middle constrictor and upper part of the 

 inferior constrictor there will be found the internal laryngeal nerve and the 

 superior laryngeal artery. The relation of the lower border of the inferior 

 constrictor to the oesophagus is to be noted, and passing beneath this border 

 of the hiuscle there are the inferior or recurrent laryngeal nerve and artery. 

 The pharyngeal branch of the external carotid artery and the inferior palatine 

 and tonsillar branches of the cervical part of the facial artery may admit of 

 being dissected at this stage, but the injection often fails to enter these 

 arteries. Above the upper border of the superior constrictor muscle the dis- 

 .sector is to note the sinus of Morgagni and the pterygo-mandibular ligament, 

 the latter separating the superior constrictor from the buccinator muscle. 

 The wall of the pharynx, above the superior constrictor muscle, is then to be 

 carefully opened, when the levator palati and tensor palati muscles will 

 admit of dissection. 



The dissection of the exterior of the pharynx having been completed, the 

 interior is to be shown by opening the pharynx by means of (i) a median 



