178 MYOLOGY. 



SCUTO-AURICULARIS EXTERNUS. 

 (Fie. 70. b. c. d.) 



Origin. From the external surface of the scutiform cartilage. 



Insertion. To the inner side of the conchal cartilage. It is 

 composed of three bundles, covered by the attollens maximus, 

 and it assists that muscle to turn the opening of the ear forwards. 



SCUTO-AURICULARIS INTERNUS. 

 (FiG. 72. a. b.) 



It consists of two pale bundles which cross each other. 



Origin. The under surface of the scutiform cartilage, the 

 fibres being directed backwards. 



Insertion. The posterior portion of the base of the concha. 



Action. It turns the opening of the ear outwards and back- 

 wards, thus antagonising the externus. 



MUSCLES OF THE TRUNK. 



This large division includes the rest of the muscles, excepting 

 those which more especially belong to the limbs. We shall 

 divide the trunk into the following regions, thus indicating the 

 groups into which the muscles most naturally fall : 



Cervical. 

 Pectoral. 

 Costal. 

 Abdominal. 



Diaphragmatic. 

 Dorso-lumbar. 

 Sublumbar. 

 Coccygeal. 



CERVICAL REGION. 



The muscles of the neck may be said to consist of an inferior 

 and two lateral groups, the latter lying on each side of the central 

 division formed by the vertebrae and the ligamentum nuchae, and 

 the former being situated underneath the vertebras. 



INFERIOR CERVICAL GROUP. 



The following muscles, eight in number, may be placed in this 

 group : 



