The vestibule of the mouth is the space between the lips and the teeth. If you start in the mid line along the bottom, you can feel the inferior frenulum. Move your finger to the side until it moves up along a ridge, this is the anterior border of the ramus of the mandible. While your finger is on this border, bite down and you will feel the masseter muscle contracting. If you move your finger as far up as you can go, you will feel the coronoid process of the ramus and the tendinous insertion of the temporalis muscle. Now move your finger in the upper recess of the vestibule until you come to the mid line again and you will feel the upper frenulum. Look in your own mouth for the opening of the parotid duct that enters the vestibule opposite the 2nd upper molar tooth.
|Structures that you should be able to feel or see in your own mouth.
First, the boundaries of the mouth are:
|Surface of the tongue viewed from above.
Note the tip of tongue, epiglottis and soft palate with the uvula as points of reference!
|Here is a perfect example of how important it is to orient yourself.
In order to show the structures in the floor of the mouth, the tongue must
be reflected posteriorly (notice the vertebral column). I always look for
mandible for anterior orientation.
In opening up the floor of the mouth, the mucous membrane is gently incised just above the sublingual gland and the fascia covering the gland (sg) is pulled posteriorly along with the tongue. This reveals:
|Note where the tip of the tongue is
It has been displaced posteriorly.
Removal of the fascia around the sublingual gland (slg) and the deep part of the submandibular gland (sm) allows you to visualize the remainder of the structures of the mouth.
|styloglossus||styloid process||merges with hyoglossus and genioglossus muscles in the tongue||draws tongue up and back to aid swallowing food||XII|
|hyoglossus||greater horn of hyoid bone||merges with styloglossus and genioglossus muscles||draws side of tongue down||XII|
|genioglossus||genial tubercle of mandible||fans out in the tongue to make up the bulk of the tongue||pulls tongue forward, sticking the tongue out||XII|
|intrinsic muscles||tissues of tongue||tissues of tongue||produce small changes in the contour of the surface of tongue||XII|
|mylohyoid||mylohyoid line of mandible||hyoid bone and raphe||elevates hyoid bone and floor of mouth to aid in swallowing||nerve to mylohyoid (V3)|
|geniohyoid||lower genial tubercle of mandible||body of hyoid bone||elevate hyoid bone or depress mandible||C1|
|You will now identify the structures found in the lateral wall of the
oropharynx. This is where the palatine tonsil is located. Again, orient
yourself: identify the tongue, hard palate, hyoid bone and soft palate.
Identify the palatoglossal arch and the palatopharyngeal arch. Find the palatine tonsil between the two arches, if it is present. Beneath the mucosa of the arches, identify the small palatoglossus (pg) and palatopharyngeus (pp) muscles. You might also see the superior pharyngeal constrictor (SC) and middle pharyngeal constrictor (mc) at this stage.
|When the tonsil is removed, you can see the structures that make up
the tonsillar bed and that could be injured during a tonsilectomy.
|Nasal Cavity & Paranasal Sinuses||Larynx|
|Copyright© 1999 by Wesley Norman, PhD, DSc|