8z 1'XACTJCAL ANATOMY. 



small part of the posterior part of the muscle is inserted into the body of the 

 hyoid bone ; the greater part of the muscle is inserted into the median line with 

 its fellow of the opposite side. (Fig. 35.) 



Relations of the Mylo-hyoid Muscle. Cut through the mucous mem- 

 brane, between the border of the tongue and the alveolar process of the 

 mandible, and you will see the superior surface of the mylo-hyoid muscle. On 

 this surface find : 



1. The gustatory nerve, the sensory (a branch of the fifth cranial), anasto- 

 mosing, in the substance of the tongue, with the hypoglossal, the motor nerve 

 of the tongue. (Fig. 45.) 



2. Find the sublingual salivary gland, communicating, around the posterior 

 margin of the mylo-hyoid, with the submaxillary salivary gland. (Fig. 45.) 



3. Find the anterior belly of the digastric muscle (Fig. 35) under resting 

 upon the under surface of the mylo-hyoid muscle. Note a branch of the mylo- 

 hyoid nerve to this muscle. This muscle arises from the digastric fossa of 

 mandible. (Fig. 9.) 



4. The hyo-glossus muscle arises from the body and both horns of the 



Transverse muscular nbr 



Superior lingual 

 muscle 



Septum 



SubmuoouB 



tissue 



Inferior lingual 

 muscle, mixed 

 with extrinsic 

 fibres 



- YT'rEM'VW 



Vertical muscular fibres 



FIG. 46. TRANSVERSK SECTION THROUGH THE LEFT HALF OF THE TONGUE. 



(Magnified.) 

 (From a preparation by Mr. J. Pollard, Middlesex Hospital Museum.) 



hyoid bone. (Fig. 48.) It is inserted into the tongue. On its outer surface find 

 the hypoglossal nerve. (Fig. 34.) On its inner surface see the lingual artery 

 (Fig. 47) dividing in (i) the dorsalis linguae; (2) the ran in e artery. (Fig. 36.) 



The Stylo-glossus and Stylo-hyoid. Trace the former to the side of the 

 tongue, the latter to the side of the body of the hyoid bone. Their origins will 

 be seen at a later stage of the dissection. (Fig. 48.) 



The musculi linguales, or proper intrinsic muscles of the tongue, may be 

 studied in the longitudinal section (Fig. 46) to a limited extent on your work. 



Deep Dissection of the Pterygo-styloid Region. In this region you will find 

 the following : 



1. The stylo-maxillary or stylo-mandibular ligament, a derivative of the 

 first layer of cervical fascia, extending from the styloid process of the temporal 

 bone to the ramus and angle of the mandible. It is between the masseter muscle 

 and the internal pterygoid muscle. 



2. The temporo-mandibular articulation, with its interarticular fibro-car- 

 tilage dividing the glenoid cavity into an anterior and a posterior synovial cavity. 



