Oral cavity, pharynx radio-anatomy

1. Anatomy of Oral cavity and Pharynx
Dr Mohit Goel
JR1
22 aug. 2012

2. Oral Cavity
2 parts:
1] Oral vestibule
2]Oral cavity proper
Oral vestibule = slit space between teeth- buccal gingiva
and lips-cheek .
>Vestibule communicates with exterior through mouth.
>Size of opening is controlled circumoral muscles such as
orbicularis oris, buccinator,depressors and elevators of
lips.

3. ORAL CAVITY PROPER
 It is the cavity within the
alveolar margins of the
maxillae and the
mandible
 Its Roof is formed by the
hard palate anteriorly
and the soft palate
posteriorly
 Its Floor is formed by the
mylohyoid muscle. The
anterior 2/3rd of the
tongue lies on the floor.
hard
soft palate
mylohyoid

4. FLOOR OF THE MOUTH
Covered with mucous
membrane
In the midline, a mucosal
fold, the frenulum,
connects the tongue to
the floor of the mouth
On each side of frenulum
a small papilla has the
opening of the duct of
the submandibular gland
A rounded ridge
extending backward &
laterally from the papilla
is produced by the
sublingual gland

5. NERVE SUPPLY
oSensory
 Roof: by greater palatine and nasopalatine nerves
(branches of maxillary nerve)
 Floor: by lingual nerve (branch of mandibular
nerve)
 Cheek: by buccal nerve (branch of mandibular
nerve)
oMotor
 Muscle in the cheek (buccinator) and the lip
(orbicularis oris) are supplied by the branches of
the facial nerve

6. MUSCLES
 The tongue is
composed of two
types of muscles:
• Intrinsic
• Extrinsic

7. Mylohyoid
The main muscle forming the floor of the mouth is mylohyoid.

8. GENIOHYOID
Geniohyoid is a narrow muscle which lies above the medial part of . It
arises from the inferior mental spine (genial tubercle) on the back of the
symphysis menti, and runs backwards and slightly downwards to attach to
the anterior surface of the body of the hyoid bone.
Genioglossus
It arises from a short tendon attached to the superior genial tubercle behind
the mandibular symphysis, above the origin of geniohyoid. From this point it
fans out backwards and upwards.

9. Hyoglossus
Hyoglossus is thin and quadrilateral, and arises from the whole length of the
greater cornu and the front of the body of the hyoid bone. It passes vertically
up to enter the side of the tongue between styloglossus laterally and the
inferior longitudinal muscle
medially.
Styloglossus
It arises from the anterolateral
aspect of the styloid process near
its apex
Passing downwards and forwards,
it divides at the side of the tongue
into a longitudinal part, which
enters the tongue dorsolaterally to
blend with the inferior longitudinal
muscle in front of hyoglossus, and
an oblique part, overlapping
hyoglossus and decussating with
it.

10. Tip:
Submental nodes
bilaterally & then deep
cervical nodes
Anterior two third:
Submandibular
unilaterally & then
deep cervical nodes
Posterior third:
Deep cervical nodes
(jugulodigastric
mainly)
Lymphatic Drainage

11. Classification of Neck Nodes According to Levels
Level I
Level II
Level III
Level IV
Level V
Level VI
Level VII
Submental (IA)
Submandibular (IB)
Upper jugular
middle jugular
Lower jugular
Posterior triangle group
(Spinal accessory and
transverse cervical
chains)
Prelaryngeal
Pretracheal
Paratrachal
Nodes of upper mediastinum

12. PHARYNX
Extends from the base of the skull to the lower border of
the cricoid cartilage (at which point it border of the
cricoid cartilage (at which point it becomes the
oesophagus).
Portions of the pharynx lie
posterior :
• nasal cavity (nasopharynx)
• oral cavity (oropharynx)
• larynx (laryngopharynx)

13. Nasopharynx
Roof : body of sphenoid,
basilar part of occipital,
bone pharyngeal tonsil
Floor: soft palate,
pharyngeal isthmus
Anterior wall : post. nasal
apertures
Posterior wall: ant. arch of atlas
Lateral wall : auditory tube , tubal elevation , salpingo
pharyngeal fold and tubal tonsil

14. Oropharynx
Roof : soft palate,
pharyngeal isthmus
Floor : post. 1/3 tongue,
epiglottis, lingual tonsil,
median glossoepiglottic fold,
2 lateral glosso epiglottic
Fold and vallecula.
Anterior wall : mouth, tongue
Posterior wall : C2,C3
Lateral wall : palatoglossal , palatopharyngeal
arches/folds and palatine tonsils

15. Laryngo pharynx
• Walls:
Ant. – inlet of pharynx
Post. – C3 – C6
Lat. – thyroid cartilage

16. The pharyngeal muscles are a group of muscles that act upon the pharynx.
They include:
Inferior constrictor muscle
Middle constrictor muscle
Superior constrictor muscle
Stylopharyngeus muscle
Salpingopharyngeus muscle
Palatopharyngeus muscle

19. MRI
BUCCINATOR
MASSETER
INTRINSIC MUSCLE OF
TONGUE
GENIOGLOSSUS
MYLOHOID
LINGUAL SEPTUM
GENIOHYOID
DIGASTRIC
PLATYSMA

20. HARD PALATE
TONGUE
HYOGLOSSUS M.
LINGUAL TONSIL
SUBMANDIBULAR GLAND
GLOSSOEPIGLOTIC FOLD
DIGASTRIC M.
PLATYSMA

21. NASOPHARYNX
PAROTID GLAND
UVULA
PALATINE TONSIL
DIGASTRIC MUSCLE
SUBMANDIBULAR GLAND
PLATYSMA
LATERALPTERYGOID
MEDIAL PTERYGOID

22. HARD PALATE
NASOPHARYNX
SUPERIOR CONSTRIC. M
SOFT PALATE
INTRINSIC MUSCLE OF TONGUE
MIDDLE CONSTRIC. M.
GENIOGLOSSUS
MYLOHOID
OROPHARYNX
EPIGLOTIS
HYPOPHARYNX
INFERIOR CONSTRICTOR M.

23. Buccinator m.
Hard palate
Masseter muscle
Lateral & medial pterygoid
m.
Nasopharynx
Longus capitis muscle

24. Buccinator m.
Tongue(genioglossus m.)
Masseter muscle
Medial pterygoid m.
Palatine tonsil
Oropharynx
Longus capitis muscle

25. Orbicularis oris
Hyoglossus
Genioglossus
Mylohoid
Oropharynx
Submandibular gland
Palatopharyngeus m.
Superior constrictor m.

26. Orbicularis oris
Hyoglossus
Genioglossus
Mylohoid
Epiglotis
Hypopharynx
Submandibular gland
Palatopharyngeus m.
Middle constrictor m.

27. Mandible
Digastric m.
Mylohyoid
Geniohyoid
Hyoid bone
Submandibular gland
Epiglotis
Hypopharynx
Piriform recess
Inferior constrictor m.

28. SUBLINGUAL SPACE
Paired non-fascial lined spaces of oral cavity in deep oral tongue above floor of
mouth superomedial to mylohyoid muscle
Communication between sublingual spaces occurs in midline anteriorly as a
narrow isthmus beneath frenulum
o SLS communicates with SMS(submandibular space) and inferior para
pharyngeal space (PPS) at posterior margin of mylohyoid muscle
• There is no fascia dividing posterior
SLS from adjacent SMS.Therefore there is direct
communication with SMS and PPS in this location.
Posterior aspect of SLS is divided into medial
and lateral compartments by hyoglossal
muscle.
Clinical Importance
• Since neurovascular bundle to tongue travels
in SLS,oral cavity SCCa involving posterior SLS is
challenging to treat.
• If SCCa crosses lingual septum to contralateral
SLS, lesion becomes unresectable for cure.

33. SUBMANDIBULAR SPACE
Fascial-lined space inferolateral to mylohyoid muscle containing
submandibular gland, nodes and anterior belly of digastric muscles.
SMS is defined as a superficial space above hyoid bone deep to platysma and
superficial to mylohyoid sling . Continues inferiorly into infrahyoid neck as
anterior cervical space.
Inferolateral to mylohyoid muscle of floor of mouth
• Deep to platysma muscle
• Cephalad to hyoid bone
• "Vertical horseshoe-shaped" space between hyoid bone below and
mylohyoid
sling above.
• SMS communicates posteriorly
with sublingual space and inferior
para pharyngeal space at
posterior margin of mylohyoid
muscle.
• Continues inferiorly into infrahyoid
neck as anterior cervical space.

38. RETROMOLAR TRIGONE
Triangle-shaped area of mucosa posterior to last mandibular molar that covers
anterior surface of lower ascending ramus of mandible.
Pterygomandibular raphe (PMR)-
Thick fascial band that extends between posterior border of mandibular
mylohyoid ridge and hamulus of medial
pterygoid plate.
It represents thickening of middle layer of
deep cervical fascia condensed between
posterior margin of buccinator muscle and
anterior margin of superior constrictor
muscle.

42. Clinical Importance
• SCCa (squamous cell ca.) of RMT may spread along PMR
(Pterygomandibular raphe ).
o Cephalad spread along PMR takes tumor up to inferolateral pterygoid
plate- Anteromedial masticator space.
• Tumor is seen at level of inferior pterygoid Plate involving posterior
buccinator muscle and anterior superior constrictor muscle.
• Enlarging tumor involves maxillary sinus, Buccal and masticator spaces.
o Caudal spread along PMR takes tumor inferiorly to posterior margin of
mylohyoid m.
• Enlarging tumor in this location involves floor of mouth of oral cavity.

43. THANK U