1) The document discusses the anatomy and embryology of structures in the oral cavity including the tongue, palate, taste buds, nerves, and muscles. 2) It describes the lymphatic drainage of the oral cavity and discusses how infections can spread rapidly through facial spaces. 3) Ludwig's angina is described as a severe cellulitis of the floor of the mouth that can cause breathing difficulties and requires surgical drainage and antibiotics.

1. Surgical and functional
anatomy of the oral cavity

2. Outline
Orofacial spaces and spread of infection
Ludwig's angina
Lymphatic drainage of the oral cavity
• Tumors-squamous cell carcinoma
Gross anatomy oral cavity
Floor:
• Tongue
• Muscles of the tongue
• Embryology of the tongue
• Taste buds
• Taste pathways
Roof: Palate
• Anatomy of the palate
• Embryology of the palate
• Cleft palate/lip

3. Oral cavity
• Function
Special sense of taste
Physical and chemical digestion
Articulation
Alternative route for air flow into the lungs
• Oral vestibule: Space between teeth and lips/cheeks.
• Contents: Lips, gingivae, upper and lower labial frenula
• Oral cavity proper: Space enclosed by the dental arches
Roof: Hard and soft palates
Floor: Geniohyoid muscles and muscular diaphragm (mylohyoid
muscles); tongue
Lateral walls: Dental arches
Posterior limit: Isthmus of fauces (contains palatine tonsils
between palatoglossal and palatopharyngeal arches, marks the
transition to oropharynx)

4. Dorsum of tongue

5. Tongue
Parts Body, apex, root
Surfaces Dorsal (superior) and ventral (inferior)
Papillae Filiform, fungiform, foliate, vallate
Innervation • Hypoglossal nerve (CN XII): provides motor innervation to all muscles of the
tongue, except palatoglossus muscle (vagus nerve (CN X))
•
Lingual nerve: conveys general somatic afferent impulses from anterior two-
thirds of tongue
•
Glossopharyngeal nerve (CN IX): carries general afferent impulses from
vallate papillae along posterior third of tongue, as well as taste sensation from
postsulcal tongue, vallate papillae, palatoglossal arche and oropharynx
•
Facial nerve (CN VII): taste sensation of anterior two-thirds of tongue and
inferior part of soft palate
• Vagus nerve (CN X): provides taste buds in extreme areas of pharyngeal
tongue
Mucosa Stratified squamous keratinized (dorsal surface) and non-keratinized (ventral
surface) epithelium

6. Taste buds

7. Taste bud
• Taste buds are chemoreceptors located in the papillae of the human
tongue
• Taste buds are composed of basal cells and 3 types of taste cells(
dark, light and intermediate)
• Taste cells extend from the base of the taste bud to the taste pore
where microvilli contact testants dissolved in saliva and mucus.
• Each taste bud contains 50-100 taste receptor cells, numerous basal
cells and support cells.
• Basal cells differentiate into new taste cells (taste cells survive about
10 days only)

8. Taste buds
• The form of transduction used for bitter and sweet tastes is G-protein
coupled receptors
• acidic and salty foods lead to direct activation of ion channels that
cause nerve signal propagation.
• Umami taste sensation appears to involve both G-protein coupled
receptors as well as ion channels.
• Taste may be affected in many clinical conditions due to inflammation
and damage of specific neural pathways involved in taste sensation;
this may be due to infection, drugs, radiation, etc.

9. Taste pathways

10. Bells Palsy
• Disordered movement of the
muscles that control facial
expressions, such as smiling,
squinting, blinking, or closing
the eyelid.
• Loss of feeling in the face.
• Headache.
• Tearing.
• Drooling.
• Loss of the sense of taste on
the front two-thirds of the
tongue.

11. Facial nerve pathway

12. Glossopharyngeal nerve damage
• difficulty swallowing;
• impairment of taste over the posterior one-third of the tongue
• impaired sensation over the posterior one-third of the tongue,
palate and pharynx
• an absent gag reflex
• dysfunction of the parotid gland.

13. Glossopharyngeal nerve injury
• Iatrogenic glossopharyngeal nerve injuries are commonly
associated with procedures such as a tonsillectomy, carotid
endarterectomy, and endotracheal intubation.

14. Glossopharyngeal nerve damage

15. Glossopharyngeal nerve taste pathway

16. Vagus nerve in taste pathway

17. Intrinsic muscles of the tongue
Superior longitudinal muscle Origin: Submucosa of posterior tongue, lingual septum
Insertion: Apex/anterolateral margins of tongue
Action: Retracts and broadens tongue, elevates apex of tongue
Inferior longitudinal muscle Origin: Root of tongue, body of hyoid bone
Insertion: Apex of tongue
Action: Retracts and broadens tongue, lowers apex of tongue
Vertical muscle Origin: Root of tongue, genioglossus muscle
Insertion: Lingual aponeurosis
Action: Broadens and elongates tongue
Transverse muscle Origin: Lingual septum
Insertion: Lateral margin of tongue
Action: Narrows and elongates tongue
Neurovascular supply All supplied by lingual artery, hypoglossal nerve (CN XII)

18. Genioglossus muscle Origin: Superior mental spine of mandible
Insertion: Entire length of dorsum of tongue, lingual aponeurosis, body of hyoid bone
Function: Depresses and protrudes tongue (bilateral contraction); deviates tongue
contralaterally (unilateral contraction)
Neurovascular supply: Lingual and facial arteries, hypoglossal nerve (CN XII)
Hyoglossus muscle Origin: Body and greater horn of hyoid bone
Insertion: Inferior/ventral parts of lateral tongue
Action: Depresses and retracts tongue
Neurovascular supply: Lingual and facial arteries, hypoglossal nerve (CN XII)
Styloglossus muscle Origin: Anterolateral aspect of styloid process (of temporal bone), stylomandibular
ligament
Insertion: Blends with inferior longitudinal muscle (longitudinal part); blends with
hyoglossus muscle (oblique part)
Action: Retracts and elevates lateral aspects of tongue
Neurovascular supply: Lingual artery, hypoglossal nerve (CN XII)
Palatoglossus muscle Origin: Palatine aponeurosis of soft palate
Insertion: Lateral margins of tongue, blends with intrinsic muscles of tongue
Action: Elevates root of tongue, constricts isthmus of throat
Neurovascular supply: Ascending pharyngeal arteries and facial arteries, vagus
nerve (CN X) (via branches of pharyngeal plexus)

20. Hypoglossal nerve injury

21. Tongue innervation summary

22. Tongue embryology 4th week

23. Thyroglossal duct cyst

24. Thyroglossal duct cyst
• Signs and symptoms
• A noticeable lump in the front
of your throat that appears to
be getting larger.
• A noticeable lump in the front
of your throat that feels hard.
• Swollen lymph nodes.
• Difficulty swallowing food or
liquids.
• Clinical examination
Congenital cysts
Benign (1% cancerous)
Can become infected
Younger than ten diagnosis
Surgical excision they do not self
resorb
Low recurrence
Lump moves up with swallowing

26. Ventral surface of the tongue

28. Whartons duct sialothiasis
• Sialothiasis of salivary gland most
common 80-90% in Wharton's duct
Submandibular duct
• It follows a convoluted course crossed
by lingual nerve twice
• Precipitation and accumulation of
calcium phosphate and
hydroxyapatite salts.
• Fever chills ,unilateral pain, palpable
along duct course in floor of the
mouth.
• antiumulation of calcium
phosphate and hydroxyl-apatite (the main
components of submandibular salivary stones) which
leads to stone formation, salivary stasis and eventually
duct obstruction.
• precipitation and accumulation of calcium phosphate and hydroxyl-apatite (the main components of submandibular
salivary stones) which leads to stone formation, salivary stasis and eventually duct obstruction.
• precipitation and accumulation of calcium phosphate and hydroxyl-apatite (the main components of submandibular

29. Facial spaces and oral infections
• Potential spaces along which maxillofacial and oral infections of from
the oral cavity spread
• Rapid spread along facial planes in hours leading to life threating
complications eg pericarditis, respiratory obstruction, cavernous sinus
thrombosis

32. Ludwig's angina

33. Ludwig's angina
• Severe cellulitis involving floor of the mouth
• Usually bacterial
• 80-90% dental origin
• Swelling raises floor of the mouth resulting in difficulty swallowing,
speaking and breathing over a few hours.
• Surgical emergency: tracheostomy, decompressing submental,
submandibular and sublingual spaces by external incision and
drainage; IV antibiotics

34. Palate

35. Soft palate
• Sensory Innervation
• Maxillary nerve through pterygopalatine ganglia via greater palatine,
nasopalatine and lesser palatine nerve
• Motor innervation
• All muscles of the soft palate are supplied by the pharyngeal plexus
except Tensor veli palatini supplied by medial pterygoid nerve branch
of Mandibular nerve
• Lesions of the vagus nerve deviate the uvula to the opposite side

37. Vagus nerve X
• Motor fibers of the vagus nerve
supply levator veli palatini,
salpingopharyngeus,
palatopharyngeus and uvula
• tongue deviation when patient
says “ah” to the unaffected side
due to the unopposed action of
the muscularis uvula
• Soft palate dropped on affected
side

38. Cleft lip and palate

39. Cleft lip and palate

40. Cleft lip and palate
• Most common congenital craniofacial complex
• Female >males (female palate closes 1 week later-hormonal)
• Lowest risk Africans
• Prevalence worldwide 1/700 live births
• Pierre Robin sequence; Treacher Collins syndrome; trisomy 18 and
other various syndromes
• Genetics ; tobacco, drugs and alcohol use during pregnancy; folic acid
deficiency; antineoplastic drugs
• Complications: feeding difficulties infant unable to suckle; speech and
language delays

41. •January 2020
•Journal of Cleft Lip Palate and Craniofacial
Anomalies 7(1):8
DOI:10.4103/jclpca.jclpca_23_19

43. Lymphatic
drainage
• squamous cell carcinoma is
the most common cancer o
(90% of oral cavity cancers
squamous origin)
• HPV associated with 70%
oropharyngeal cancers
• Lateral border of tongue
most frequent site
• Lips, gingivae, cheeks,
palate

45. Lymph drainage of palate and nasopharynx

46. Palate lymph drainage

48. References:
• Clinically oriented anatomy; Keith Moore 6th edition
• Human anatomy color atlas;Gosling, Harris et al 5th edition
• https://www.kenhub.com/en/library/anatomy/tongue
• January 2020
• Journal of Cleft Lip Palate and Craniofacial Anomalies 7(1):8
• DOI:10.4103/jclpca.jclpca_23_19