| OCR Text |
Show 20 MR. E. J. SIDEBOTHAM ON THE [Jan. 20, part. These fibres chiefly converge to the anterior inferior angle of the muscle and form a large fleshy mass, which is inserted into anterior border and outer surface of coronoid process, whilst the posterior few fibres are inserted into outer surface of coronoid. Lhe much larger deep part is separated from it by tendinous fibres. It arises from the whole of the temporal fossa and posterior part ot inner surface of zygoma. It is inserted into inner surface and upper border of coronoid. Internal pterygoid.-Arises from outer surface of pterygoid. Its fibres passing outwards, backwards, and slightly downwards, are inserted into border of incurved portion of lower jaw, its posterior fibres meeting those of masseter as described above. External pterygoid.-A small roundish muscle, arising from pterygoid at upper and posterior part of internal pterygoid. Its fibres pass downwards and backwards, and are inserted into base of condyle of jaw. Sterno-hyoid.-Long, ribbon-shaped, arising from inner surface of second piece of sternum ; inserted into front of hyoid. Sterno-thyroid.-Smaller than preceding and overlain by it. Arises with sterno-hyoid, and is united with it for a short distance. United above with its fellow, and inserted with it into front of thyroid. Thyroid hyoid.-Passes from side of thyroid to great comu of hyoid. Omo-hyoid.-A long narrow hand arising from vertebral border of scapula. Inserted into hyoid, just external to sterno-hyoid. No tendinous intersection could be seen. Mylo-hyoid.-Flat and thin, arising from posterior half of mylohyoid ridge of lower jaw. Inserted into median raphe, and its posterior fibres into tendinous expansion of posterior belly of digastric. Genio-hyoid.-Narrow origin by tendinous fibres from inner border of lower jaw close to symphysis. It lies close to its fellow, and is inserted into front of hyoid. It sends a small muscular fasciculus to genio-hyoglossus. Hyoylossus.-A large muscle extending from side of hyoid under cover of genio-hyoid. Its fibres pass forwards and inwards to be inserted into side of tongue for its posterior two thirds. Genio-hyoylossus.-Arises from inner side of lower jaw close to middle line. Its fibres arch back to be inserted into posterior half of under surface of tongue and lower border of internal surface of hyoid, to which it is connected by tendinous fibres. Diyastric.-Posterior belly arises by a rounded tendon from par-occipital process. It forms a rounded belly which flattens out, forming a tendinous expansion which meets its fellow in middle line. Anterior belly arises from superficial aspect of this expansion, and forming a flat muscle, is inserted into lower border of lower jaw at its middle. Paroccipito-hyoid.-A narrow band of fibres passing from parocci-pital process, just internal to origin of posterior belly of digastric to great comu of hyoid. |
