946 



PHARYNX. 



membrane is of great width at its origin, the 

 external carotid foramina marking off the la- 

 teral limits, but it quickly narrows as it de- 

 scends : the sharp angle which it forms is 

 brought into relation with the internal carotid 

 artery and superior cervical ganglia of the sym- 

 pathetic nerve: in the interior of the pharynx 

 a longitudinal sulcus, sometimes crossed by a 

 transverse slip, will be found behind the open- 

 ing of the Eustachan tube, leading to a cul-de- 

 sac which occupies this angle. 



The pharynx is surrounded by muscular 

 fibres which have been collected into three 

 distinct muscles on either side, and named, 

 from their action, constrictors ; these may be 

 considered as intrinsic: two other muscles on 

 either side are inserted into its walls, and are 

 extrinsic as not belonging so exclusively to it. 

 The constrictor muscles are membraniform, 

 spreading as thin muscular laminae around the 

 sides and back part of the pharynx, and have 

 a common insertion into a posterior median 

 raphe : they partly overlap each other from 

 below upwards, so that the inferior constrictors 

 alone can be wholly examined without inter- 

 fering with the rest, and are invested on their 

 outer surface with a dense fascia: they arise by 

 numerous and distinct points of attachment, 

 which gave occasion to their being divided 

 originally into several muscles, each with its 

 appropriate name given according to its par- 

 ticular origin : these are now reduced to three 

 on each side, and arranged into superior, middle, 

 and inferior. 



Constrictor pharyngis inferior* This 

 muscle is the thickest and strongest of the set, 

 has an irregular quadrilateral outline, and is 

 situated at the lower part of the pharynx : it 

 derives its origin from the cricoid and thyroid 

 cartilages by two slips : the one, triangular and 

 fleshy, arises from the side of the cricoid car- 

 tilage between the origins of the crico-arytenoi- 

 deus posticus and crico-thyroideus muscles : 

 from the latter it occasionally receives a few 

 fibres : the other, broader and more extensive, 

 lies on the ala of the thyroid cartilage, and 

 arises from the two tubercles, which the ala 

 presents on its external surface, and from a 

 tendinous structure that stretches obliquely 

 from one tubercle to the other : it is here 

 blended with the attachments of the sterno- 

 thyroid and thy ro-h void muscles : it also em- 

 braces the inferior cornu of the thyroid carti- 

 lage : from these points it spreads round the 

 side and back of the pharynx to the posterior 

 median raphe, into which it is inserted con- 

 jointly with the muscle from the opposite side : 

 the fibres pass in different directions : the su- 

 perior are longer and pursue a more oblique 

 course upwards, while the nearer they are ex- 

 amined to the lower margin of the muscle, the 

 shorter and less oblique they become, and at 

 length assume nearly a transverse direction. 

 The origins of the inferior constrictor muscle 

 are concealed by the thyroid gland and sterno- 

 thyroid muscle : it is in relation laterally to the 



* Thyro-pharyngeus, crico-pharyngeus. 



sheath of the carotid vessels, and posteriorly to 

 the cervical vertebrae and deep muscles of the 

 neck : its internal surface is applied partly 

 upon the mucous membrane and the terminal 

 fibres of the stylo-pharyngeus and palato-pha- 

 ryngeus muscles, but to a greater extent upon 

 the middle constrictor muscle: the oblique 

 upper margin extends as high as the middle of 

 the pharynx and close by its thyroid attach- 

 ment allows the superior laryngeal nerve to 

 pass beneath it: the circular fibres of the ceso- 

 phagus are continued from its lower margin, 

 but distinguished by their greater delicacy and 

 paler colour: close to the cricoid cartilage the 

 inferior or recurrent laryngeal nerve slips be- 

 neath its lower margin. Some of the lower 

 fibres have occasionally been noticed to arise 

 from the first ring of the trachea. 



Constrictor pharyngis medius* is of a trian- 

 gular form, fixed by its apex to the hyoid bone 

 and by an extensive base to the median raphe 

 behind : its origin is received into the angle 

 formed by the greater and smaller cornua of the 

 os hyoides, to which processes the muscular 

 fibres are attached as well as to the lower part 

 of the stylo-hyoid ligament: the origin extends 

 along the greater cornu quite to its posterior 

 extremity, arid is concealed by the hyo-glossus 

 muscle, the lingual artery intervening : from 

 this contracted commencement the middle con- 

 strictor spreads widely over the back of the 

 pharynx, the superior fibres obliquely ascend- 

 ing towards the basilar process of the occipital 

 bone, to the spine of which they are connected 

 through the medium of the raphe, the muscle 

 itself rarely reaching so high; the middle fibres 

 take a more or less transverse direction, while 

 the inferior descend under cover of the inferior 

 constrictor : the whole muscle is inserted, with 

 its fellow from the opposite side, into the 

 raphe. After emerging from beneath the hyo- 

 glossus it is related to the external carotid ar- 

 tery and superior laryngeal nerve laterally, and 

 to the vertebral column behind : by its internal 

 surface it overlaps the superior constrictor, and 

 is applied upon the stylo- and palato-pharyngei 

 muscles and the mucous membrane. Near the 

 great cornu of the hyoid bone the stylo-pha- 

 ryngeus muscle insinuates itself beneath its 

 upper border, separating it from the superior 

 constrictor. 



Constrictor pharyngis superior,^ quadrila- 

 teral in shape and complicated from its very 

 numerous attachments. The fibres of this 

 muscle are paler and it is altogether thinner than 

 the two former: it arises, firstly, by short tendi- 

 nous fibres from the lower half of the posterior 

 edge of the internal pterygoid plate and its ha- 

 mular process; secondly, from an aponeurosis 

 described as the inter- or pterygo-maxillary liga- 

 ment common to it and the buccinator muscle, 

 and which stretches from the inner pterygoid 

 plate to the posterior extremity of the alveolar 

 border of the inferior maxillary bone; thirdly, 

 from the back part of the mylo-hyoid ridge ; 



* Hyo-pharyngeus. 



t Cephalo - pharyngeus, pterygo - pharyngcus, 

 mylo -pharyngeus, glosso-pharyngeus. 



