MUSCLES OF THE HEAD AND NECK. 



165 



composed of ultimate fibres having the transverse striae of the muscle 

 of animal life. 



The muscles may be arranged in conformity with the general divi- 

 sion of the body into, 1. Those of the head and neck. 2. Those of 

 the trunk. 3. Those of the upper extremity. 4. Those of the lower 

 extremity. 



MUSCLES OF THE HEAD AND NECK. 



The muscles of the head and neck admit of a subdivision into those 

 of the head and face, and those of the neck. 



Muscles of the Head and Face. These muscles may be divided 

 into groups corresponding with the natural regions of the head and 

 face ; the groups are eight in number, viz. 



1. Cranial group. 5. Superior labial group. 



2. Orbital group. 6. Inferior labial group. 



3. Ocular group. 7. Maxillary group. 



4. Nasal group. 8. Auricular group. 



The muscles of each of these groups may be thus arranged 



1. Cranial group. 

 Occipito-frontalis. 



2. Orbital group. 

 Orbicularis palpebrarum, 

 Corrugator supercilii, 

 Tensor tarsi. 



3. Ocular group. 

 Levator palpebrae, 

 Rectus superior, 

 Rectus inferior, 

 Rectus internus, 

 Rectus externus, 

 Obliquus superior, 

 Obliquus inferior. 



4. Nasal group. 

 Pyramidalis nasi, 

 Compressor nasi, 

 Dilatator naris. 



, 5. Superior labial group, 

 (Orbicularis oris), 

 Levator labii superioris alaeque 

 nasi, 



Levator labii superioris proprius, 

 Levator anguli oris, 

 Zygomaticus major, 

 Zygomaticus minor, 

 Depressor labii superioris alseque 

 nasi. 



6. Inferior labial group. 



(Orbicularis oris),* 

 Depressor labii inferioris, 

 Depressor anguli oris, 

 Levator labii inferioris. 



7. Maxillary group. 



Masseter, 

 Temporalis, 

 Buccinator, 



Pterygoideus externus, 

 Pterygoideus internus. 



8. Auricular group. 



Attollens aurem, 

 Attrahens aurem, 

 Retrahens aurem. 



* The Orbicularis oris, from encircling the mouth, belongs necessarily to 

 both the superior and inferior labial regions ; it is therefore enclosed within 

 parentheses in both. 



