| OCR Text |
Show 414 MR. A. SANDERS ON THE [June 9, superficial fibres also join those of the opposite side in a raphe covering the glosso-hyal. Submentalis arises from the inferior surface of the dentary piece immediately outside and a short distance behind the symphysis, and is inserted into mucous membrane lining the floor of the anterior part of the mouth, and into the side of the tongue outside the genio-hyo-glossus. Thyro hyoid arises from the basihyal, and is inserted into the outer circumference of the thyroid cartilage. Cerato-hyoid arises from near the distal extremity of the thyro-hyal, and, passing downwards internal to the mandible, it is inserted into the segment of the cerato-hyal. Omo-hyoid arises from the anterior border of the clavicle for about half its length, extending upwards to the claviculo-scapular articulation, and, passing forwards and downwards, it is inserted, broad and thin, into the posterior edge of the basihyal and thyrohyal. Sterno-hyoid arises from the interclavicle thick and fleshy, and, passing forwards, spreads out into a thin plane of muscular fibres, which is inserted entirely into the thyro-hyal dorsad of the last. Sterno-cleido-mastoid arises from the posterior edge of the transverse apophysis of the interclavicle, and is connected with the anterior edge of the sternum by means of a tough membrane; passing upwards and forwards across the clavicle, it receives a small muscular slip from that bone, and is inserted into the extremity of the exoccipital behind its articulation with the os quadratum. Temporal is a very thick and powerful muscular mass, arising, behind, from the anterior surface of the os quadratum, above from the squamosal and parietal, and in front from the frontal; the anterior fibres run directly downwards, the posterior downwards and forwards; and all are inserted into the articular, supraangular, and coronoid pieces of the mandible. Neuro-mandibular.-This muscle appears to correspond with one of that name in serpents. It arises broad from the aponeurosis of the back of the head and edge of the complexus, and is inserted narrow into the posterior extremity of the articular piece of the mandible. External pterygoid arises fleshy from the lower surface of the posterior part of the pterygoid bone, and tendinous from the posterior border of the anterior part of the same bone ; it forms a rounded muscular mass enclosing the posterior part of the mandible, and is inserted into the external surface of the supraangular, and upper surface of the posterior part of the articular piece ; this last part also arises from the lower end of the posterior side of the os quadratum. Internal pterygoid.-A triangular muscle with its apex directed upwards arises from the anterior point of the prootic, and from the columella, and is inserted into the inner border of the articular piece of the mandible behind the coronary process ; this muscle has no connexion with the pterygoid bone. Within this are two remarkable muscles ; the more external arises from a point at the lower surface of the parietal, just above tbe articulation of the prootic with the |
