HEAD AND ANTERIOR CERVICAL STRUCTURES. 



>7 



Muscles of the mouth : 



Labial group of Muscles, 466. (460) 



Levator labii superioris alaque nasi, 466. (460) 



Origin. Insertion. Structure. Nerve-supply. Action. Relations. 

 Levator labii superioris, 466-7. (460-1) 



Origin. Insertion. Structure. Nerve-supply. Action. Relations, 

 /ygomaticus minor, 467. (461) 



Origin. Insertion. Structure. Nerve-supply. Action. Relations. 

 Divide the levator labii superioris transversely, midway between the origin and insertion. Reflect the 

 upper portion to the origin and the lower portion to ihe insertion, and expose the levator anguli oris. 

 Care must be exercised not to injure the vessels and nerves in reflecting the muscle. 



Levator anguli oris, 464-5. (459) 



Origin. Insertion. Structure. Nerve-supply. Action. Relations. 

 Depressor labii inferioris or quadratus menti, 467. (461) 



Origin. Insertion. Structure. Nerve-supply. Action. Relations. 

 Expose the buccinator. In cleaning the muscle avoid injury to the nerve branches on its surface. The 

 alveolar origin will be shown ; the origin from the pterygo-maxillary ligament (2) will be demon- 

 strated at a later period of the dissection. 



Buccinator, 462-3-4; Fig. 311. (45 7-8) 



Origin. Insertion. Structure. Nerve-supply. Action. Relations. 



The orbicularis oris should now be fully exposed and its parts demonstrated. To expose the incisive 

 slips, evert the lip and strip off the mucous membrane, when they can be readily shown. 



Orbicularis oris, 461-2; Fig. 311. (456) 

 Attachments to bone : (i), (2), (3). 

 Structure: 



Fibres: Transverse set, labial portion. 

 Vertical fibres, facial portion. 



Sagittal or antero-posterior fibres, in labial portion. 

 Musculi incisivi. 

 Nerve-supply. Action. Relations. 



Evert the lower lip and draw it downward ; strip off the mucous membrane and expose the levator menti. 



Levator menti, 468. (462) 



Origin. Insertion. Structure. Nerve-supply. Action. Relations. 

 Muscles of the Nose, 459-60-1, 429-30; Fig. 516. (453-4-5t 97~8) 

 Pyramidalis: 



Origin. Insertion. Structure. Nerve-supply. Action. Relations. 



Variation. 

 Compressor narium : 



Origin. Insertion. Structure. Nerve-supply. 

 Depressor alae nasi : 



Origin. Insertion. Structure. Nerve-supply. 

 Dilator naris anterior : 



Origin. Insertion. Structure. Nerve-supply. 

 Dilator naris posterior: 



Origin. Insertion. Structure. Nerve-supply. 

 Vessels of the nose, nerves, 930. (909) 

 Arteries. 

 Veins. 

 Nerves. 

 Facial nerve: (Motor). 



Temporo- facial division, 810. (790-1) 



Temporal branch. 



Malar branch. 



Infraorbital, infraorbital plexus. 

 Cervico-facial division, 8io-n. (792) 



Buccal branch. 



Supramandibular branch. 



Inframandibular branch (distribution shown later). 



Action. Relations. 



Action. Relations. 



Action. Relations. 



Action. Relations. 



