THE BONES. 65 



67. Appendage. Os Hyoichum, s. linguale, tongue bone. 



Position: free in the neck, above and before, between the 

 tongue and the larynx, horizontal. 



Shape ; a Parabola like the Greek letter upsilon v. 



Conjunctions ; by ligaments with the temporal bones and the 

 thyroid cartilage. Parts : 1 body, 4 cornua. 



1. Body, basis, the horizontal, anteriorly convex, central portion, is upon the 



a. Anterior surface, divided by a cruciform projection, a trace of the tongue 

 bones of animals, into a superior and inferior half. 



b. Posterior surface, excavated, concave, separated by fibrous tissue from the 

 epiglottis. 



c. Inferior border, for muse. Hyo-thyreoideus. 



d. Superior border, for ligam. suspensor. lingua and lig. flavum s. hyo-thy- 

 reoideum. 



Terminations, covered with cartilage, for the reception of the great Cornua. 



Attachment of muscles; to the Transverse lines, Myb-hyoideus, above that 

 genio-hyaideus ; to the Superior half: digastricus, hyoghssus, stylo-hyoideus / to the 

 inferior half; sterno-hyaideus, omo-hyoideus, and the thyreo-kyoideus. 



2. Great Cornua, longer than the body, ascend from before backwards and 

 upwards, for Kerato- (Hyo-) glossus, Kerato-pharyngeus (part of middle con- 

 strictor) ; capitulum, for ligam. hyothyreoideum laterale, at the apex. 



3. Lesser Cornua, or corpuscula triticea, like a grain of wheat, situated ob- 

 liquely upwards and outwards at the point of junction of the great Cornua 

 with the Body, for the muse. Chondro-glossus (part of Hyo-glossus) and Chondro- 

 pharyngeus (a portion of Constric. Med.); unites with the Proc. Stylmdeus by 

 the ligam. suspensorium, sometimes ossified; it is connected with the great 

 cornua and the body. 



Development: proceeds slowly from five ossific points, from 

 the termination of foetal life ; it commences in the great cornua. 



The Cavities of the facial region. 



68. 1. Orbitse. Orbital cavities, 2. ; for the organs of sight 



and lacrymation. 



Figure : an obtuse, quadrilateral pyramid, the base directed 

 forwards and outwards, the apex backwards and inwards ; the 

 axes of both would cross behind the sella turcica. 



1. Base, formed by four borders, with four angles, Frontal, Nasal, Temporal, 

 Malar. 



a. Margo supraorbilalis, with foram. sometimes Sulcus supraorb., formed 

 by Frontal bone; 



b. M. orbitalis externus, with/cram, zygomatic., by malar bone, and malar 

 or external angular process of frontal ; 



c. M. infraorbitalis, with for. infraorbitale and anterior dental foramen, by 

 the malar and sup. Maxillary bones ; 



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