i6o8 HUMAN ANATOMY. 



through the neck from a point midway between the symphysis and the angle of the 

 jaw to the cricoid cartilage, dividing the platysma and the omo-hyoid and sepa- 

 rating the posterior belly of the digastric and the stylo-hyoid from the hyoid bone ; 

 or a subhyoid pharyngotomy will give access to the lower walls of the pharynx by 

 division of the superficial fascia, the sterno-hyoid and thyroid muscles, the thyro- 

 hyoid ligament and membrane, and the mucous membrane of the pharynx at the 

 level of the lower margin of the hyoid bone. These operations are more interest- 

 ing anatomically than surgically. 



The tonsils, as seen from the mouth, are situated between the arches of the 

 palate and the base of the tongue. They may be almost concealed in these re- 

 cesses or may project into the pharynx, and when hypertrophied may actually meet 

 in the middle line. They rest on the superior constrictor muscles and move with 

 those muscles during the act of deglutition. They are somewhat elevated and with- 

 drawn from the pharynx by the coincident contraction of the stylo-pharyngei. 

 Swallowing is therefore apt to be painful in all forms of tonsillitis. If not enlarged, 

 they are often almost hidden in persons who have large palato-glossi muscles, and 

 therefore prominent anterior palatal arches. Externally they are separated by the 

 pharyngeal aponeurosis and the superior constrictor muscle from the pharyngo- 

 maxillary space. This space is bounded by these fibro-muscular structures 

 internally, the internal pterygoid muscle externally, and the antero-lateral aspects of 

 the bodies of the second and third cervical vertebrae. It is occupied by some con- 

 nective tissue and fat. According to Zuckerkandl, the stylo-pharyngeus and stylo- 

 glossus muscles divide the space into an anterior portion in relation to the tonsil 

 and a posterior in relation to the internal carotid artery and internal jugular vein. 



Tonsillitis in the lacunar or follicular form does not usually involve the stroma 

 of the gland, the infection and the exudate being limited to the tonsillar crypts and 

 to the surface. In the suppurative form the infection is deeper, the stroma is 

 affected, and the resulting abscess may in rare cases become peritonsillar, extend to 

 the cellular tissue of the pharyngo-maxillary space, and open the internal carotid 

 artery. Usually, as the infection progresses, even if this space is invaded, the out- 

 ward extension is limited by the internal pterygoid muscle, and the swelling and the 

 ulceration or necrosis take the line of least resistance, i.e. , towards the pharynx, 

 where tonsillar abscesses often open spontaneously. 



During an acute tonsillitis the palato-glossus and its covering of mucous mem- 

 brane, with the soft palate on the affected side, are tense, thinned, and spread out 

 over the surface of the tonsil. Abscesses may be evacuated by incision directly 

 through these structures and from above downward in a direction parallel with the 

 anterior pillar, that is, with the fibres of the palato-glossus. 



The vascular relations of the tonsil should be remembered in this operation or 

 in tonsillotomy for hypertrophy. The internal carotid is nearly 2.5 cm. (i in.) 

 behind and to the outer side of the tonsil. The external carotid is still farther re- 

 moved, as it lies outside of the stylo-glossus and stylo-pharyngeus muscles. Its 

 ascending pharyngeal branch is nearer the tonsil than either of the main trunks, and 

 in a case of accidental wounding by a foreign body has been the source of fatal 

 hemorrhage. Wounding of the tonsillar branch of the facial artery has likewise 

 proved f.it.il ;ift-r tonsillotomy, and either this vessel or the facial itself, especially if 

 it is tortuous where it passes between the stylo-glossus and digastric muscles, is prob- 

 al.lv involved in cases of grave hemorrhage after this operation. The plexus of 

 lymphatics surrounding the follicles of the tonsils communicates directly with the 

 deep cervical lymph-glands behind and beneath the angle of the jaw. These glands 

 are then-fore commonly enlarged in affections of the tonsils, and when tender and 

 palpable are sometimes mistaken for the tonsils themselves. The latter cannot, 

 '''' '" p.'lpat.d externally, except in cases of new growth, as the resistance 

 ed by the Constrictor, the internal ptcrvgoid, and oilier structures intervening 

 en the tonsils and the skin causes them to project towards the pharynx. This 

 >tion maybe a cause of various forms of ill health associated with deficient 



oxygenation, of chronic pharyngitis from mouth-breathing, of thickened articula- 

 tion, and even of alter.itions in the facies or in the skeleton, r.;'., "pigeon- 

 breast " (page 167). 



