Gross & Neuro-Anatomy

1. Maxilla, Mandible & Hyoid Bone
Dr. Rabia Inam Gandapore
Assistant Professor
Head of Department Anatomy
(Dentistry-BKCD)
B.D.S (SBDC), M.Phil. Anatomy (KMU),
Dip. Implant (Sharjah, Bangkok, ACHERS) , CHPE
(KMU),CHR (KMU), Dip. Arts (Florence, Italy)

2. Teaching Methodology
 LGF (Long Group Format)
 SGF (Short Group Format)
 LGD (Long Group Discussion, Interactive discussion with the use of models or diagrams)
 SGD (Short Group)
 SDL (Self-Directed Learning)
 DSL (Directed-Self Learning)
 PBL (Problem- Based Learning)
 Online Teaching Method
 Role Play
 Demonstrations
 Laboratory
 Museum
 Library (Computed Assisted Learning or E-Learning)
 Assignments
 Video tutorial method

3. Goal/Aim (main objective)
 Norma Frontalis:
a) Identify the skeletal features of norma frontalis (including Zygoma, Maxilla & Mandible).
b) Describe muscle attachments.
c) Enlist structures passing through foramina.
d) Enumerate relevant clinical problems of Norma frontalis.

4. Specific Learning Objectives (cognitive)
 At the end of the lecture the student will able to:
 Identify the skeletal features of norma frontalis , Lateralis, Basalis, Verticalis,
Occipitalis.
 Describe muscle attachments.
 Enlist structures passing through foramina.
 Enumerate relevant clinical problems

5. Psychomotor Objective: (Guided response)
 Ask student to submit assignment of tabulated form of the structures passing through all foramen and fossa

6. Affective domain
 To be able to display a good code of conduct and moral values in the class.
 To cooperate with the teacher and in groups with the colleagues.
 To demonstrate a responsible behavior in the class and be punctual, regular, attentive and on
time in the class.
 To be able to perform well in the class under the guidance and supervision of the teacher.
 Study the topic before entering the class.
 Discuss among colleagues the topic under discussion in SGDs.
 Participate in group activities and museum classes and follow the rules.
 Volunteer to participate in psychomotor activities.
 Listen to the teacher's instructions carefully and follow the guidelines.
 Ask questions in the class by raising hand and avoid creating a disturbance.
 To be able to submit all assignments on time and get your sketch logbooks checked.

7. Lesson contents
Clinical chair side question: Students will be asked if they know what is clinical relevance of Pterion & Asterion
Outline:
 Activity 1 The facilitator will explain the student's about skeletal features of norma frontalis , Lateralis,
Basalis, Verticalis, Occipitalis.
 Describe muscle attachments.
 Enlist structures passing through foramina.
 Enumerate relevant clinical problems
 Activity 2 The facilitator will ask the students to submit assignment of tabulated form of the structures
passing through all foramen and fossa
 Activity 3 The facilitator will ask the students a few Multiple Choice Questions related to it with flashcards.

8. Recommendations
 Students assessment: MCQs, Flashcards, Diagrams labeling.
 Learning resources: Langman’s T.W. Sadler, Laiq Hussain Siddiqui, Snell Clinical Anatomy, Netter’s
Atlas, BD Chaurasia’s Human anatomy, Internet sources links.

14. Maxilla

15. Maxilla
 Maxilla is the 2nd Largest bone of face
 2 maxillae form the whole of the upper jaw
 Maxilla assists in forming 3 cavities:
1. Roof of the mouth
2. Floor & lateral wall of nose
3. Floor of the orbit

17.  2 Fossae
Infratemporal
Pterygopalatine
 2 Fissures
Inferior Orbital
Pterygomaxillary

20. Body of Maxilla
 Body of maxilla is pyramidal in shape, with its
1. Base: directed medially at Nasal surface (lateral
wall of nose)
2. Apex: directed laterally at Zygomatic process of
maxilla
3.Roof: formed by floor of orbit & traversed by
infraorbital canal
4. Floor: formed by alveolar process of maxilla, Lies
about 1.2cm below level of floor of nose

21.  It has four surfaces &
encloses a large cavity:
Maxillary sinus.
1. Anterior or facial
2. Posterior or
infratemporal
3. Superior or orbital
4. Medial or nasal

23. Four Processes of Maxilla
 Zygomatic Process
 Frontal Process
 Alveolar Process
 Palatine Process

25. Functions
 Speech and voice resonance
 Reduce the weight of skull
 Filtration of inspired air
 Immunological barrier
 Regulation of intranasal pressure

26.  Superiorly: it articulates with 3-bones
1. Nasal
2. Frontal
3. Lacrimal
 Medially: 5 bones
1. Ethmoid
2. Inferior nasal concha
3. Vomer
4. Palatine
5. Opposite maxilla
 Laterally: 1 Bone
Zygomatic Bone

27.  At birth:
-Transverse and anteroposterior diameters greater than vertical diameter
-Frontal process is well marked
-Body consists of a little more than the alveolar process
-Tooth sockets close to floor of orbit
-Maxillary sinus is a mere furrow on lateral wall of nose
 In Adults
-Vertical diameter is greater due to developed alveolar process
-Increase in the size of the sinus
 In Old
-Infantile condition
-Its height is reduced as a result of absorption of the alveolar process

31. Mandible

32. Mandible
 Latin word Mandibula “Jawbone or
inferior Maxillary bone)
 Movable bone of skull “Ball & Socket
Joint
 Formed by fusion of left & right
processes & joins to form mandibular
symphysis, (faint ridge in midline)
composed of fibrocartilage
 It fuses together in early childhood.

33. Components:
Mandible consists of:
 Horseshoe-shaped body
 Pair of rami
 Body of mandible & meets
with ramus at angle of
mandible or gonial angle.

34. 1. Body of Mandible

35. 1. Body of Mandible
1). Body : curved somewhat
horse-shoe shaped. It has:
A). 2-surfaces
Internal surface
External surface
B). 2- borders
Upper border
Lower border

36. A).SURFACES

37. a) External Surface
 In midline,a faint ridge indicating line of fusion of 2 halves
during development at symphysis menti.
 This ridge divides below and encloses a triangular eminence,
the mental protuberance,
 Base of which is depressed in center but raised on either side
to form mental tubercle.
 Running backward and upward from each mental tubercle is
a faint ridge, oblique line (attachment to depressor labii
Inferioris, depressor anguli oris,platysma is attached
below it) which is continuous with anterior border of ramus.

43. On either side of symphysis,below incisor
teeth, is a depression, incisive fossa, gives
origin to mentalis muscle (small portion of
orbicularis oris muscle attachement) for
passage of mental vessels & nerve.
Mental foramen below second pre-molar
tooth, it transmits terminal branch of inferior
alveolar nerve and vessels.

46. b) Internal Surface
 On Medial surface of body of mandible in median plane are Mental spines or genial
tubercles.
 Give origin to:
Above: Genioglosses muscle (origin: Superior genial tubercle)
Below: Genio-hyoid muscle (origin: Inferior genial tubercle)*(Posterior surface of symphysis
menti)
 Below mental spines, on either side of middle line, is an oval depression for attachment of
anterior belly of digastric
 Mylo-hyoid line an oblique ridge that runs backward and laterally from area of mental spines
to an area below and behind 3rd molar tooth which gives origin to mylohyoid muscle.
 Posterior part of this line, near alveolar margin, gives attachment to a small part of Superior
Constrictor of pharynx & pterygomandibular raphe (immediately behind 3rd molar).

50.  Sub-mandibular fossa, for superficial part of
submandibular salivary gland, lies below posterior part of
mylohyoid line
 Sublingual fossa ,for sublingual gland lies above anterior
part of mylohyoid line.

53. B).Borders

54. a. Upper Border (The Alveolar Crest)
 In adults contains 16 sockets for
roots of teeth.
 Inter-alveolar septa is one of thin
plates of bone separating alveoli
of teeth in the mandible.
 To outer lip of superior border, on
either side, buccinators
muscle is attached as far forward
as 1st molar tooth.

56. B. Lower Border (The Base)
 Digastric fossa is a
small,roughened depression on
base, on either side of symphysis
menti.
 Anterior bellies of the digastric
muscles are attached in fossae.
 At point where it joins lower border
of ramus a shallow groove;
for facial artery.

61. 2).The Ramus

62.  Ramus has
2-processes
2-surfaces
4- borders
 2 processes are seperated by mandibular notch(* masseteric nerve & vessels pass
through it)
 Pterygoid fovea a concave surface on uppermost medial side of ramus located
behind mandibular notch & below of condyloid process
 Pterygoid fovea is located on anterior surface of neck of mandible & serves for
attachment of lateral pterygoid muscle.
 Condyle & posterior mandibular ramus make up mandibular buttress establishing
posterior facial height.

67. 1. Processes
1). Anteriorly: Coronoid process , it recieves on its
medial surface attachement of temporalis muscle.
2). Posteriorly: Condyloid process, consists of two
portions:
a. Condyle or Head (TMJ joint-Mandibular fossa,
Palpable infront of tragus)
b. Neck (attachment of lateral pterygoid muscle
+auriculotemporal nerve & superficial temporal
artery related to medial side of neck)

69. 2. Surfaces
A). Lateral surface of ramus
is flat & has oblique ridges (buccinator muscle,
depressor anguli oris) at its lower part; it gives
attachment to masseter muscle.
Incisive fossa: Mentalis muscle, orbicularis oris.
Posterio-superior part: Parotid gland
Lower border: Platysma,Investing layer of deep
fascia

71. B). Medial surface of ramus
 Mandibular foramen, for inferior alveolar
nerve & vessels (*maxillary artery).
 In front of foramen is a projection of bone:
lingula, for attachement of sphenomandibular
ligament.
 The foramen leads into mandibular canal,
which opens on lateral surface of body of
mandible at mental foramen.
 The incisive canal is a continuation forward of
mandibular canal beyond mental foramen &
below incisor teeth.
 Mylohyoid groove runs obliquely downward &
forward, and lodges mylohyoid vessels &nerve
(*lingual nerve is related to medial surface of
ramus infront of mylohyoid groove).
 Behind this groove is a rough surface, for
insertion of Medial pterygoid muscle

75. 3. BORDERS
1).Upper border of ramus thin & curved downwards forming
mandibular notch
2).lower border of ramus backward continuation of base of
mandible
3).Posterior border of ramus lower border ends posteriorly &
becomes continuous with posterior border at angle of mandible
4).Anterior border of ramus thin, while posterior border is thick

77. Blood, Nerves & Lymph
Supply

78. Nerves
 Inferior alveolar nerve branch of mandibular
division of trigeminal nerve,
 Enters mandibular foramen & runs forward
in mandibular canal, supplying sensation to
teeth.
 At mental foramen the nerve divides into 2
terminal branches:
a. Incisive nerve: runs forward in mandible &
supply anterior teeth.
b. Mental nerve: exits mental foramen & supply
sensation to lower lip.

81. Arterial Supply
 Inferior alveolar artery which is a branch of the
maxillary artery (branch of external carotid).
 This travels through mandibular canal (which
can be found on the internal aspect of the
mandible).
 From here, this artery branches off into dental
and incisive branches to supply the lower teeth.
 Inferior alveolar artery then exits the canal via
the mental foramen to give rise to the mental
branch, which goes on to supply the chin

84. Venous Supply:
Internal Jugular vein &
external jugular vein
through maxillary vein,
facial vein & pterygoid
plexus
Inferior alveolar vein is the
sole collector of blood from
the mandibular teeth
pumped around mandible &
it drains into pterygoid
venous plexus.

86. Lymph Nodes
 Parotid,
 Submandibular
 Submental

87. Variation
 Gender:
Males: have squarer, stronger & larger mandibles than females.
Mental protuberance: more pronounced in males but can be
visualized & palpated in females.
 AGE:
Infants & Children: mandible is obtuse 140 degree angle
Adults: angle reduces to about 110-120 degree because
ramus become almost verticle
Old Age: angle again becomes obtuse about 140 degree
because ramus is oblique.

89. Muscle Origin Insertion Nerve Supply Action
1 Platysma Deep fascia over
pectoralis major and
deltoid
Body of
mandible and
angle of mouth
Facial nerve
cervical branch
Depresses mandible &
angle of mouth
2 Sternocleidomastoid Manubrium sterni and
medial third of clavicle
Mastoid
process of
temporal bone
& occipital
bone
Spinal part of
accessory nerve &
C2, C3
Two muscles acting
together extend head &
flex neck; one muscle
rotates head to
opposite side
3 Digastric -
Posterior belly
Mastoid process of
temporal bone
Intermediate
tendon is held
to hyoid by
fascial sling
Facial nerve Depresses mandible or
elevates hyoid bone
Digastric-
Anterior belly
Body of mandible Nerve to mylohyoid

90. Clinical Relevance

91. Mandibular Fractures
 Parasymphysis region lateral to the mental
prominence is a naturally weak area susceptible for
parasymphyseal fracture. This is because of the
presence of incisive fossa and mental foramen
 Body of mandible is considerably thicker than ramus &
junction between these two portions constitutes a line
of structural weakness
 Strength of lower jaw varies with presence or absence
of teeth. The presence of impacted lower third molars
or excessive long roots of canines make the area
more vulnerable for fracture

94. HYOID BONE

95. Hyoid bone (lingual bone or tongue-bone
 U shaped & consist of
1).A Body
2).Two pairs of horns
a).Two-Greater Cornua
b).Two-Lesser Cornua
 It is attached to:
a. Skull by stylo-hyoid ligament
b. Thyroid cartilage by thyro-hyoid membrane.

99.  It is mobile & lies in neck just
ABOVE: Larynx
BELOW: Mandible.
 Hyoid bone forms a base for tongue & is suspended in
position by muscles that connect it to:
Mandible
Styloid process of the temporal bone
Thyroid cartilage
Sternum
Scapula.
 Unlike other bones, hyoid is only distantly articulated to other
bones by muscles or ligaments.

101. Functions
 It aids in tongue movement & swallowing.
 Hyoid bone provides attachment to:
Above: Muscles of the floor of mouth & tongue
Below: Larynx
Behind: Epiglottis and Pharynx

102. BODY
 It has
1). Anterior and posterior surfaces (2 surfaces)
2). Upper and lower borders (2 borders)
1. Anterior surface:
- Convex & is directed forward and upward.
- Its divided by a median ridge into 2 lateral halves.
2. Posterior Surface:
- Concave & is directed backward and downward
-each lateral end of body is continuous posteriorly with greater horn or
cornua.
(Till middle life connection between body & greater cornua is fibrous)

105. HORNS or CORNUA:
1). Greater cornua : Flattened from above downwards.
-Each cornua tapers posteriorly,but ends in a tubercle. It has:
a).2-surfaces (upper and lower)
b).2-borders (medial and lateral
c).A tubercle
2). Lesser cornua: Small conical pieces of bone which project
upwards from junction of body & greater cornua.
- They are connected to body by fibrous tissue.
-Occasionally, connected to greater cornua by synovial joints which
usually persist throughout life, but may get ankylosed.

106. Muscles of Hyoid Bone
A). SUPERIOR
1). Hyo-glossus
2). Middle pharyngeal constrictor
3). Genio-glossus
4). Genio-hyoid
5). Stylo-hyoid ligament
6). Intrinsic muscles of the tongue
7). Mylo-hyoid
8). Supra hyoid muscle
8). Digastric & Stylo-hyoid muscles
B). INFERIOR
1). Omo-hyoid
2). Sterno-hyoid
3). Thyro-hyoid

107. Muscle Origin Insertion Nerve Supply Action
4 Stylohyoid Styloid process Body of hyoid bone Facial nerve Elevates hyoid bone
5 Mylohyoid Mylohyoid line of body of
mandible
Body of hyoid bone &
fibrous raphe
Inferior alveolar
nerve
Elevates floor of mouth &
hyoid bone or depresses
mandible
6 Geniohyoid Inferior mental spine of
mandible
Body of hyoid bone 1st cervical
nerve
Elevates hyoid bone or
depresses mandible
7 Sternohyoid Manubrium sterni &
clavicle
Body of hyoid bone Ansa cervicalis;
C1, 2 & 3
Depresses hyoid bone
8 Sternothyroid Manubrium sterni Oblique line on lamina
of thyroid cartilage
Ansa cervicalis;
C1, 2, and 3
Depresses larynx
9 Thyrohyoid Oblique line on lamina of
thyroid cartilage
Lower border of body
of hyoid bone
1st cervical
nerve
Depresses hyoid bone or
elevates larynx
10 Inferior belly
Omohyoid
Upper margin of scapula
and suprascapular
ligament
Intermediate tendon is
held to clavicle and
first rib by fascial sling
Ansa cervicalis;
C1, 2, and 3
Depresses hyoid bone
Superior belly
Omohyoid
Lower border of body of
hyoid bone

109. Blood Supply
 lingual artery which runs down
from tongue to greater horns of bone.
 A branch of this artery, the
suprahyoid branch runs along the
upper border of hyoid bone & supplies
blood to the attached muscles.

111. Clinical Significance

112. Obstructive Sleep Apnea
 Hyoid bone physiological functions, includes: Breathing, swallowing & speech.
 Play a key role in keeping upper airway open during sleep, & development and
treatment of obstructive sleep apnea (characterized by repetitive collapse of upper
airway during sleep).
 Inferiorly positioned hyoid bone is strongly associated with presence & severity of
disorder.
 Movement of hyoid bone is also modify upper airway properties
 Surgical procedure potentially increase & improves airway is called hyoid
suspension.

113. Fracture
 Due to its position, hyoid bone is not easily susceptible to
fracture.
 In a suspected case of murder, a fractured hyoid strongly
indicates throttling or strangulation in an adult.
 Not necessarily the case in children & adolescents, where
hyoid bone is flexible as ossification is yet to be completed.

114. Thank You