NORMAL MRI ANATOMY OF ORAL CAVITY by rux99038

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									      NORMAL
    MRI ANATOMY
   OF ORAL CAVITY

R.SAOUAB, K.EL HASNAOUI, F.RIAHI, A.SATTE, H. BENCHAABOUN
              MY R. EL HASSANI, N.CHAKIR, M.JIDDANE
 Specialities Hospital, Department of Neuro Radiology, RABAT, MOROCCO
              PLAN

INTRODUCTION

ANATOMY OF THE ORAL CAVITY

MRI EXPLORATION
   INDICATIONS

   TECHNICS

MRI CROSS-SECTIONAL ANATOMY

CONCLUSION
               INTRODUCTION
Oral cavity constitute with oropharynx the upper portion of the
aerodigestive tract.
The anatomy of this cavity is particularly challenging because
there are many different types of tissue located in this relatively
small area.
30 % of cancers of the head and neck region occur in the oral
cavity. Thus, a good knowledge of the anatomy is indispensable.
MRI has become the imaging method of choice.
Our purpose is to spell out imaging techniques in the exploration
of the oral cavity and to describe normal magnetic resonance
imaging (MRI) anatomy.
ANATOMY
               THE ORAL CAVITY



                        +
 the oral vestibule          the oral cavity proper



                      DEEP SPACES
The oral vestibule • is the slit-like space bounded internally by teeth and buccal
                     gingiva; externally by the lips and cheeks.
                     • The vestibule communicates with the exterior through
                     the mouth.
                     • It receives the secretion from the parotid salivary glands
The oral cavity proper
• is the space between the upper and the lower dental arcades
• It is limited :
         • Laterally and anteriorly : by the maxillary and mandibular arches
           housing the teeth and the cheeks which form the movable walls
         • Superiorly : by the soft and hard palates
         • Inferiorly : by the tongue (the anterior 2/3) which partially separated from
           the floor of the mouth by the sublingual sulcus laterally and anteriorly
         • Posteriorly : the oral cavity is divided from the oropharynx by a line
           connecting the anterior tonsillar pillars, the circumvallate papillae, and
           the junction of the hard and soft palate.
 The tonsils are areas of lymphoid tissue on either side of the throat.


        Name                   Location                  Epithelium

Adenoids (also     roof of pharynx                 ciliated pseudostratified
termed "pharyngeal                                 (respiratory epithelium)
tonsils")

Palatine tonsils        sides of pharynx between   non-keratinized stratified
                        glossopalatine             squamous
                        and pharyngopalatine
                        arches
Lingual tonsils         behind terminal sulcus     non-keratinized stratified
                        (tongue)                   squamous
  LATERAL                LIMITS                       CONTENTS                COMMUNICATION
   SPACES

MASTICATOR By the superficial layer of            Masseter.m                   Skull base
  SPACE    the deep cervical fascia               Lateral    and     medial
                 Interiorly    :  Medial          pterygoid. m
               pterygoid muscle                   Temporal. m
                 Exteriorly   :  masseter         Mandibular ramus
               muscle, zygomatic arch,            Masticator and alveolar
               temporal muscle                    nerves (V3)
                                                  Alveolar artery and vein



                  Medially      :   buccinator    Adipose tissue               Posteriorly with the
BUCCAL         muscle                            => “buccal fat pad”          masticator space
 SPACE            Laterally and anteriorly :
                - Superficial layer of the deep
               cervical fascia and
                 -    Muscles      of     facial
               expression
                  Posteriorly the masseter
               muscle, mandible, lateral and
               medial pterygoid muscles and
               the parotid gland
   SPACES /            LIMITS                       CONTENTS                   COMMUNICATION
 FLOOR OF THE
   MOUTH

 SUBLINGUAL        Medial : genioglossus     The sublingual gland and            The submandibular and
                 and geniohyoid muscles     ducts (ducts of Rivinus)           the parapharyngeal space.
  SPACE (SLS)      Lateral / inferior :      The      submandibular gland
                 mylohyoid muscle           duct (Wharton's duct)
                                             The hypoglossal and lingual
                                            nerves
                                             The lingual artery and vein




      THE         Supero-medial         :     The superficial portion of the     Posteriorly with the
                 mylohyoid muscle           submandibular gland                sublingual     and     the
SUBMANDIBULA      Inferior : hyoid bone       The facial vein and artery       parapharyngeal      spaces
 R SPACE (SMS)                                The      submandibular and       (prestyloid compartment).
                                            submental lymph nodes.
    MRI
EXPLORATION
                   TECHNICS
Indications : are essentially the tumoral pathology
(tongue, oropharynx and palate)
Superconducting MRI with 1.5 T.
Circular polarized head coils
Matrix : 256-256 pixels
Slice thickness : 4–5 mm _ interslice gap : 0.4 mm
Sequences [2]:
  T1 SE : axial and sagittal section
  T2 FSE : axial and coronal section with fat suppression,
  T1 SE with fat suppression and GADO injection : axial and
  coronal section.
MRI CROSS-SECTIONAL ANATOMY :
          AXIAL PLAN
                                                  REF [1]
                                         1                                                           10
                  1
          10              13   12                                                                    11
                                    11
                                         2                                                           12
     3                                                                                               13
         14                              3
              5                          4                                                           14
                      4                  5                                                           15
                          6              6                                                           16
15                                       7                                                           17
                                         8                                                           18
                                         9

                                                     FIG 1. Axial MRI : T1 WI + GADO
                                             1.   Alveolaris process of     9.    Jugular vein
                                                  maxilla                   10.   orbicularis oris muscle
                                             2.   Triangularis muscle       11.   Parotid duct
                                             3.   Masseter muscle           12.   Retromolar fossa
                                             4.   Palatoglossus muscle,     13.   Tongue
                                                  palatine tonsil           14.   Mandibular ramus
                                             5.   Medial pterygoid muscle   15.   Parotid gland
                                             6.   Oropharynx                16.   Styloid process
                                             7.   Spinal nerve (XI)         17.   Internal carotid artery
                                             8.   Glossopharyngeus and      18.   Longus capitis muscle
                                                  vagus nerves (IX / X)
                                                                                   BUCCAL SPACE
                                                                                   MASTICATOR SPACE
                                   REF [1]
    1                         1                                                          8


        9             8
                                                                                         9
                 10                                                                      10
            11                2
                                                                                         11
3
                              3
                              4
                  6           5
                          7   6
                              7


                                             FIG 2. Axial MRI : T2 WI

                              1.   Triangularis muscle       7.    Jugular vein
                              2.   Masseter muscle           8.    Mandible
                              3.   Submandibular gland       9.    Genioglossus muscle
                              4.   Posterior belly of the    10.   Mylohyoid muscle
                                   digastric muscle          11.   Hyoglossus muscle
                              5.   Oriculo-temporalis
                                                                    SUBLINGUAL SPACE
                                   nerve                            SUBMANDIBULAR SPACE
                              6.   Internal carotid artery
                           1
                                                       1                                        REF [1]
                  11
                                    12                                                                       11
                       3       2                                                                             12
                                                       2
                                                       3
                                                                                                             13
                                                       4                                                     14
                               15        5             5                                                     15
14                                                     6                                                     16
          7            6                               7
                                                                                                             17
              8                                     8
     10                                      17     9
                                                   10
                                                                FIG 3. Axial MRI : T2 WI
                                                  1.   Mentalis muscle           10. Jugular vein
                                                  2.   Mylohyoid muscle          11.   Mandible
                                                  3.   Geniohyoid muscle         12.   Triangularis muscle
                                                                                 13.   Sublingual gland
                                                  4.   Hyoid bone
                                                                                 14.   Platysma muscle
                                                  5.   Submandibular gland
                                                                                 15.   Infra-hyoid muscles
                                                  6.   Larynx                    16.   Aryepiglottic fold
                                                  7.   External carotid artery   17.   Sterno-cleido-mastoideus
                                                  8.   Internal carotid artery         muscle
                                                                                        SUBMANDIBULAR SPACE
                                                  9.   Vagus nerve
MRI CROSS-SECTIONAL ANATOMY :
        SAGITTAL PLAN
                                                                   1                                 [1]
                                                                   2
                                                                   3
                                                                   4
                               2                                   5

          4   3            6                                       6
              5                                                    7
                                    8                              8
                                                                   9
                  7                     12                         10
                      10                                           11
                                   13                              12
              9       11
                               14
                                                                   13
                                                                   14
                                    16                             15
                                                                   16


                                             FIG 4. Sagittal MRI : T1 WI

1.   Tonsils palate                  7.      Genioglossus muscle           13. Vallecula
2.   Nasopharynx                     8.      Oropharynx                    14. Hyoid bone
3.   Hard palate                     9.      Mandible                      15. Sternohyoid and
4.   Canal incisive                 10.      Geniohyoid muscle               Sternothyroid muscles
5.   Soft palate                    11.      Mylohyoid muscle              16. Vestibular fold
6.   Uvula                          12.      Epiglottis
                                              1                                           [1]
    1             2                           2
                                              3
                            17                4                                                 16
        5                                     5
                                              6                                                 17
             7
                                              7
         8                 15                 8
    9                 13
                                              9                                              18
                                              10
                                                                                             19
                                              11
                                              12                                     ________20
                                              13
                                              14
                                              15


                                                   FIG 5. Sagittal MRI : T1 / T2 WI
                                      1.  Maxillary sinus           11. Mylohyoid muscle
                                      2.  Medial pterygoid muscle   12. Anterior belly of digastric
                           16
                                      3.  Levator veli palatini         muscle
4                     6                   muscle                    13. Hyoid bone
                                 20   4. Maxilla                    14. Epiglottis
                           18
                                      5. Soft palate                15. Hypopharynx
             11                       6. superior pharyngeal        16. Longus capitis muscle
             12
    10                          19        constrictor muscle        17. Atlas
                                      7. Genioglossus muscle        18. Middle pharyngeal
                                      8. Sublingual gland               constrictor muscle
                                      9. Mandible                   19. Longus colli muscle
                                      10. Mental foramen            20. Vertebral artery
                     1                               1
                                                     2
                                                     3                             12
         2                                           4
                                                     5
                                                     6
    3        4
                                                     7
5                    6                               8

    7            8
                                                     9
                                                     10
                                                                            _______ 13
                                                     11
                         10




                              FIG 6. Sagittal MRI : T2 WI

    1.   Internal carotid artery           7.    Mandible
    2.   Lateral pterygoid muscle          8.    Submandibular gland
    3.   Maxilla                           9.    musculus platysma
    4.   Medial pterygoid muscle           10.   Primitive carotid artery
    5.   Buccinator muscle                 11.   longus cervicis muscle
    6.   stylopharyngeus muscle            12.   Internal jugular vein
                                           13.   Thyroid gland
MRI CROSS-SECTIONAL ANATOMY :
        CORONAL PLAN
11                                                                                            [1]
         13                                 1                                                        11
              12                                                                                     12
     2                                     2                                                         13
                                 16        3
 4   3         5                           4                                                          14
                                      15   5
                    6                                                                                 15
                                           6                                                          16
                                                                                                      17
                   18        9             7
                                                                                                      18
                        17                 8                                                          19
                                            9                                                         20
              10                           10
     20                 19
                                                          FIG 7. Coronal MRI : T1 /T2 WI
                                           1.    Pterygopalatine fossa      12.   Nasal fossa
                                           2.    Lateral pterygoid muscle   13.   Pterygoid process
                                           3.    Medial pterygoid muscle    14.   Parotid duct
                                           4.    Parotid gland              15.   Masseter muscle
                                           5.    Soft palate                16.   Mandibular ramus
                                           6.    Tongue                     17.   Hyoglossus muscle
                                           7.    Lingual nerve              18.   Genioglossus muscle
                                           8.    Mandibular canal           19.   Intermediate tendon of
                                           9.    Mylo-hyoid muscle                the digastric muscle
                                           10.   Geniohyoid muscle          20.   Submandibular gland
                                           11.   Zygomatic arch                 SUBLINGUAL SPACE
                                                                                SUBMANDIBULAR SPACE
1                                                                                            9
                                9   1
                                    2                                                        10
                                                                                             11
             2        10            3
                                    4                                                        12
                           11
                 12                 5
         3                                                                                   13
     4                              6                                                        14
                 13                                                                          15
                                    7
         7                                                                                   16
    15                              8                                                        17
             8
                 17
                                                FIG 8. Coronal MRI :T2 WI

                                        1.   Temporalis muscle     10. Lateral pterygoid
                                        2.   Nasal fossa               muscle
                                        3.   Medial pterygoid      11. Masseter muscle
                                             muscle                12. Soft palate
                                        4.   Mandibular ramus      13. Tongue
                                        5.   Mandibular canal      14. Hyoglosse muscle
                                        6.   Mylohyoid muscle      15. Platysma muscle
                                        7.   Submandibular gland   16. Hyoid bone
                                        8.   Omohyoid muscle       17. Vestibulum laryngis
                                        9.   Zygomatic arch
                                                          Submandibular space
                                                          Masticator space
                                                                                            [1]
                                                    1                                             7
                                                                                                  8
    1                     2                         2
                                8                                                                 9
        3                 10                        3
                11                         9        4                                             10
4                         5
                                                    5
                                                    6                            ________________ 11
            6




                                        FIG 9. Coronal MRI :T2 WI

                     1.       Lateral pterygoid muscle   7.    Mandibular condyle
                     2.       Nasopharynx                8.    Lateral pharyngeal wall
                     3.       Medial pterygoid muscle    9.    Masseter muscle
                     4.       Mandibular ramus           10.   Soft palate
                     5.       Uvula                      11.   Palatopharyngeus muscle
                     6.       Submandibular gland
     CONCLUSION
MRI has become the imaging method
 of choice in oral cavity permitting
    excellent tissue contrast and
      multiplanar exploration.
                     REFERENCES
1.   Torsten B.Möller and coll. Atlas de poche d’anatomie en coupes sériées
     TDM-IRM; Tome 1
2.   Mahmood F.Mafee and coll. Imaging of the Head and Neck. Thieme ; 2nd
     Edition
3.   Keith L Moore. Clinically oriented anatomy.
4.   M. Lenz and coll. Methods: MRT. European Journal of Radiology 33 (2000)
     178–184 Methods: MRT
5.   M. Lenz and coll. Oropharynx, oral cavity, floor of the mouth: CT and MRI
     European Journal of Radiology 33 (2000) 203–215
6.   Minerva Becker and coll. Oral Cavity, Oropharynx, and Hypopharynx.
     Seminars in Roentgenology, Vol XXXV, No 1 (January), 2000: pp 21-30
7.   Hyo-Cheol Kim, MDCT and MR Imaging of the Buccal Space: Normal
     Anatomy and Abnormalities. Korean J Radiol 6(1), March 2005

								
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