OTIC GANGLION AND TENSOR PALATI 293 



and when he was examining the infratemporal region refer- 

 ence was made to the otic ganglion, which is associated 

 with the' trunk of the mandibular nerve and the branch which 

 it supplies to the internal pterygoid muscle. This ganglion 

 and its connections should now be displayed, and afterwards 

 the tensor palati muscle should be cleaned and followed from 

 its origin to the hamulus of the medial pterygoid lamina. 



Dissection. Cut the lingual and inferior alveolar nerves immediately 

 below their origins ; evert the upper part of the mandibular nerve and 

 examine the otic ganglion ; then divide the internal pterygoid, along the 

 posterior border of the lateral pterygoid lamina, depress the lower part of 

 the muscle and clean the tensor palati, which forms the medial relation 

 of the middle meningeal artery, the otic ganglion and the mandibular nerve, 

 separating them from the lateral surface of the auditory tube (Eustachian). 



Ganglion Oticum. This is a minute oval body about 

 4 mm. in length. It lies immediately below the foramen 

 ovale, between the mandibular nerve laterally, the tensor veli 

 palatini medially, and the middle meningeal artery posteriorly ; 

 and it is intimately associated with the origin of the nerve to 

 the internal pterygoid. 



The otic ganglion is usually described as receiving motor, sensory, and 

 sympathetic roots. The motor root is supplied by the nerve to the internal 

 pterygoid muscle ; the sympathetic root comes from the plexus around the 

 middle meningeal artery. In addition to these, the small siiperficial petrosal 

 nerve enters the posterior border of the ganglion, and conveys to it sensory 

 fibres. 



The following are the branches which proceed from the otic ganglion : 



( A twig which passes downwards and anteriorly to the 

 Branches of I tensor veli palatini. (Tensor palati.) 

 distribution, j A twig which proceeds upwards and posteriorly to 



V. supply the tensor tympani. 



C One or more fine filaments to one or both of the roots 

 Connecting of the auriculo-temporal nerve, 



branches. j A minute communicating filament to the chorda 



V. tympani. 



Musculus Tensor Veli Palatini. This flat and band-like 

 muscle is closely applied to the deep surface of the internal 

 pterygoid muscle. It arises from the scaphoid fossa at the 

 root of the medial pterygoid lamina, from the posterior 

 border of the lower surface of the great wing of the sphenoid, 

 from the spine of the sphenoid, and from the lateral aspect of 

 the auditory tube (O.T. Eustachian). It descends to the 

 lower end of the medial pterygoid lamina and ends in a 

 tendon which turns horizontally under the hamulus into 

 the soft palate, where its attachments will be seen later. 



n19 b 



