Mouth Cavity

Mouth Cavity

4 years ago 1331

Mouth Cavity

The oral cavity is divided into
  • Outer vestibule
  • Inner large oral cavity proper
The vestibule of the mouth is a narrow space bounded
  • Externally by lips & cheeks
  • Internally by teeth & gums
The parotid gland opens on the inner surface of the cheek in the vestibule opposite the crown of the upper 2nd molar tooth.

Oral Cavity Proper Boundary
  • Anterolaterally by teeth
  • Posteriorly by oropharynx
  • Roof by hard & soft palate
  • Floor by tongue
Content of the oral cavity:
1) Tongue with papillae
2) Teeth
3) Lingual tonsil
4) Palatine mucus gland
5) Opening of the ducts of sublingual, submandibular & parotid gland
 
Oropharyngeal isthmus:
The junction between the oral cavity proper and the oropharynx
Bounded
  • Superiorly by the soft palate
  • Inferior by the posterior part of the tongue
  • On each side palatoglossal arches
Nasopharyngeal/ Pharyngeal isthmus:
The junction between the nasopharynx and oropharynx

Notes: The tonsillar fossa is bounded by anteriorly by the palatoglossal arch & posteriorly by the palatopharyngeal arch

Opening of 3 Pairs of Salivary Glands:
  • On each side of the frenulum of the tongue, there is a sublingual fold.
    On the medial end of the sublingual fold, it shows an elevation called sublingual papillae, where the duct of the submandibular gland open
  • Similarly, the edge of the sublingual fold has an opening for the sublingual gland
  • The parotid gland opens in the vestibule opposite the crown of the upper 2nd molar tooth.

Teeth:

Parts of teeth-
  • Root
  • Neck
  • Crown, projecting above the gum
Deciduous teeth- 20 in number
Permanent teeth- 32 in number

Teeth in each half of the jaw:
  • 2 incisors
  • 1 canine
  • 2 premolars
  • 3 molars
Nerve supply of teeth
  • Upper teeth and upper jaw
    By branches of superior alveolar nerves, the branch of the maxillary nerve, which is the branch of the trigeminal nerve
    That’s why correlation with its nerve supply, pain from the upper jaw and teeth is referred to the skin over the maxilla and lower eyelid.

  • Lower teeth and lower jaw
    By the inferior alveolar nerve, the branch of the mandibular division of the trigeminal nerve
Clinical correlation:
1) Stomatitis is inflammation/ ulceration around the mouth
     It can be subdivided into
  • Cheilitis - inflammation around the lip
  • Glossitis means inflammation of the tongue
  • Gingivitis means inflammation of the gum
  • Pharyngitis means inflammation around the back of the mouth
    (esp. oropharynx)
2) In scurvy (caused by the deficiency of vitamin C), the gums are swollen and spongy and bleed on the touch.

3) In gingivitis, the edges of the gums are red and bleed easily.

4) Due to its correlation with its nerve supply (maxillary nerve), pain from the upper jaw and teeth is referred to as the skin over maxilla, lower eyelid.