THE MUSCLES OF THE HEAD. 



21 



outwards, to insert themselves upon the inner aspect of 

 the mandibular ram us, filling the fossa found in front 

 of the articular enlargement, and in which we find the 

 ramal vacuity. This latter foramen is closed in by the 

 pterygoideus externus in this situation, while outwardly 

 the masseter covers it up, the two muscles at this point 

 being practically in contact. 



20. The digastric arises on either side from an ellip- 

 tical, longitudinal space, of no great size, situated at the 

 base of the cranium, on the externo-lateral angle of the 



FIG. 5. Left lateral aspect of mandible of Corvus corax sinuatus, slightly tipped 

 forwards to show muscular attachment on inner sido. Life-size, m', the 

 point of insertion of the zygornatic division of the masseter. 



basitemporal (see Figs. 7 and 11). From this origin 

 the muscle passes down the side of the neck as a thin, 

 narrow band of fibres. Opposite the angle of the jaw 

 these begin to diverge, and spread out in a fan-like 

 form, to meet a corresponding expansion of the opposite 

 muscle in a median raphe, which extends longitudinally 

 over the superior larynx. They are still more definitely 

 inserted into the cartilaginous continuation of the second 

 basitemporal about its sides. The middle portion of 

 this extremely attenuated muscular stratum is very 



