Head and neck osteology

OSTEOLOGY OF
MAXILLOFACIAL SKELETON
DR ADITYA SAMANTARAY
1ST YR PG
DEPT OF OMFS
2

CONTENTS
• INTRODUCTION
• DEVELOPMENT OF SKULL AND APPLIED ASPECTS
• ANATOMICAL POSITION OF SKULL FIRST PART
• PECULIARITIES OF SKULL BONES
• JOINTS OF SKULL AND CLINICAL ANATOMY
• NORMAS OF SKULL AND CLINICAL ANATOMY
- NORMA VERTICALIS
- NORMA OCCIPITALIS
- NORMA FRONTALIS
- NORMA LATERALIS SECOND PART
- NORMA BASALIS
• INDIVIDUAL BONES OF SKULL AND APPLIED ASPECTS
• CAVITIES OF SKULL AND APPLIED ASPECTS
• REFERRENCES
3

BONES OF SKULL CAN BE
DIVIDED INTO TWO MAIN
PARTS
1- THE CALVARIA
(CRANIUM)
2- THE FACIAL SKELETON
4

CRANIAL BONES
NUMBER OF BONES – 14
PAIRED BONES – 5 PAIRS
- PARIETAL BONES
- TEMPORAL BONES
- MALLEUS
- INCUS
- STAPES
MALLEUS, INCUS AND STAPES ARE EAR OSSICLES
UNPAIRED BONES – 4
- FRONTAL
- OCCIPITAL
- SPHENOID
- ETHMOID
5

FACIAL SKELETON
NUMBER OF BONES – 14
PAIRED BONES – 12 / 6 PAIRS
- MAXILLA
- ZYGOMATIC
- NASAL
- LACRIMAL
- PALATINE
- INFERIOR NASAL CONCHA
UNPAIRED BONES – 2
- MANDIBLE
- VOMER
HYOID BONE IS ALSO INCLUDED
7

DEVELOPMENT OF SKULL
PRIMODIA FOR THE HEAD AND NECK REGION
• MESODERM (PARAXIAL AND LATERAL PLATE MESODERM)
• ECTODERM (NEURAL TUBE, NEURAL CREST, ECTODERMAL PLACODES)
• ENDODERM (PHARYNGEAL POUCHES ORIGINATING FROM THE
PHARYNGEAL GUT – THE CEPHALIC PART OF THE FOREGUT)
8

SKELETAL STRUCTURES OF THE HEAD AND FACE.
MESENCHYME FOR THESE STRUCTURES IS DERIVED FROM NEURAL CREST (BLUE),
PARAXIAL MESODERM (SOMITES AND SOMITOMERES) (RED),
LATERAL PLATE MESODERM (YELLOW).
9

DEVELOPMENT OF SKULL
NEUROCRANIUM
• THE HARD TISSUE SURROUNDING
THE BRAIN AND ORGANS OF
SPECIAL SENSE
VISCEROCRANIUM
• FORMS THE SKELETON OF FACE
10
MEMBRANOUS PART
• CONSISTS OF FLAT BONES WHICH
SURROUND BRAIN AS A VAULT
CARTILAGINOUS PART
• ALSO KNOWN AS
CHONDROCRANIUM, FORMS THE
BONES OF THE BASE OF SKULL
NASOMAXILLARY COMPLEX
MANDIBLE

MEMBRANOUS NEUROCRANIUM
• DERIVED FROM NEURAL CREST
CELLS AND PARAXIAL
MESODERM.
• MESENCHYME OF THOSE TWO
SOURCES UNDERGOES
MEMBRANOUS OSSIFICATION.
• RESULTING IN A NUMBER OF
FLAT, MEMBRANOUS BONES THAT
ARE CHARACTERIZED BY THE
PRESENCE OF NEEDLELIKE BONE
SPICULES.
• SPICULES PROGRESSIVELY
RADIATE FROM PRIMARY
OSSIFICATION CENTERS TOWARD
THE PERIPHERY.
• WITH FURTHER GROWTH DURING
FETAL AND POSTNATAL LIFE,
MEMBRANOUS BONES ENLARGE
BY APPOSITION OF NEW LAYERS
ON THE OUTER SURFACE AND BY
SIMULTANEOUS OSTEOCLASTIC
RESORPTION FROM THE INSIDE.
11

• HUMAN EMBRYO
(80 MM/4TH TO 7TH WEEK IUL)
DEVELOPING FRONTAL BONE
DEVELOPING PARIETAL BONE
DEVELOPING SQUAMA OF OCCIPITAL BONE
DEVELOPING SQUAMA OF TEMPORAL BONE
DEVELOPING MAXILLA
DEVELOPING MANDIBLE
DEVELOPING NASAL BONE
DEVELOPING ZYGOMATIC BONE
DEVELOPING LACRIMAL BONE
DEVELOPING VOMER
DEVELOPING PALATINE BONE
YELLOW – MEMBRANOUS ELEMENTS
DARK BLUE – CHONDRAL ELEMENTS
12

CARTILAGINOUS NEUROCRANIUM
BLUE – CHONDRAL
ELEMENTS NEURAL CREST
RED – CHONDRAL
ELEMENTS PARAXIAL
MESODERM
BASE OF SKULL
SPHENOID, PART OF
OCCIPITAL, STYLOID
CARTILAGE ETC.
THE CARTILAGES FUSE
FORMS THE BASE OF SKULL
OSSIFICATION BY
ENDOCHONDRAL
OSSIFICATION
13

VISCEROCRANIUM
- INVOLVES EPITHELIAL COMPONENTS OF NEURAL FOLDS,SURFACE
ENDODERM AND ECTODERM, NEURAL CREST CELLS OF
DIFFERENT ORIGIN,ECTODERMAL PLACODES.
- THE NASOMAXILLARY COMPLEX AND MANDIBLE DEVELOPMENT IS
ENTIRELY FROM NEURAL CREST CELLS VIA PHARYNGEAL
(BRANCHIAL ) ARCHES.
- PHARYNX AND LARYNX DEVELOP FROM ECTODERM, ENDODERM AND
NEURAL CREST.
- THE SKELETAL ELEMENTS OSSIFY THROUGH BOTH MEMBRANOUS
OSSIFICATION (SQUAMOUS TEMPORAL,MAXILLARY, ZYGOMATIC
BONE,MANDIBLE) AND ENDOCHONDRAL OSSIFICATION
14

PHARYNGEAL ARCHES
15
THE PHARYNGEAL ARCHES ARISES
AS OUTGROWTHS
ON THE VENTRAL SURFACE OF THE
EMBRYO ROSTRAL
TO THE FOREGUT DURING 4TH
WEEK OF
DEVELOPMENT.
IT IS LINED EXTERNALLY BY
ECTODERM AND
INTERNALLY BY ENDODERM.
THE ARCHES ARE LATERALLY
EXTENDING BANDS OF
TISSUE.

EACH ARCH HAS ITS OWN
NEURAL ,VASCULAR SUPPLY &
CARTILAGE.
THE ARCHES ARE GROOVED ON
THE EXTERNAL SURFACE BY
PHARYNGEAL CLEFTS
WHEREAS ON THE INTERNAL
SURFACE BY PHARYNGEAL
POUCHES.
THE ENDODERM WITHIN THE BRANCHIAL
POUCHES BECOMES SPECIALIZED AND
EVENTUALLY TRANSFORMS INTO
IMPORTANT STRUCTURES OF THE NECK AND
FACE.
THE FIRST BRANCHIAL CLEFT, LINED WITH
ECTODERM, WILL FORM THE EXTERNAL EAR
CANAL.
16

DERIVATIVES OF THE PHARYNGEAL ARCHES
17
PHARYNGEAL ARCH NERVE SKELETON MUSCLES
1.MANDIBULAR
(MAXILLARY
AND
MANDIBULAR
PROCESSES)
V.TRIGEMINAL
(MAXILLARY AND
MANDIBULAR DIVISIONS
PREMAXILLA, MAXILLA, ZYGOMATIC
BONE, PART OF THE TEMPORAL
BONE,
MECKEL’S CARTILAGE, MANDIBLE
MALLEUS, INCUS, ANTERIOR
LIGAMENT OF MALLEUS,
SPHENOMANDIBULAR LIGAMENT
MASTIFICATION (TEMPORAL;
MASSETER; MEDIAL,
LATERAL
PTERYGOIDS); MYLOHYOID;
ANTERIOR BELLY OF
DIGASTRICS; TENSOR
PALATINE, TENSOR TYMPANI
2.HYOID VII.FACIAL STAPES; STYLOID PROCESS;
STYLOHYOID LIGAMENT; LESSER
HORN
AND UPPER PORTION OF BODY OF
HYOID BONE
FACIAL EXPRESSION
(BUCCINATOR, AURICULARIS,
FRONTALIS, PLATISMA,
ORBICULARIS ORIS,
ORBICULARIS OCULI);
POSTERIOR BELLY OF
DIGASTRICS; STYLOHYOID;
STAPEDIUS
3. IX.GLOSSOPHARYNGEAL GREATER HORN AND LOWER
PORTION
OF THE BODY OF THE HYOID BONE
STYLOPHARYNGEUS
4 AND 6 X.VAGUS – SUPERIOR
LARYNGEAL BRANCH
(NERVE
TO 4TH ARCH. RECURRENT
LARYNGEAL BRANCH
(NERVE
TO 6TH ARCH)
LARYNGEAL CARTILAGES (THYROID,
CRICOIDS, ARYTENOIDS,
CORNICULATE, CUNEIFORM)
CRICOTHYROID; LEVATOR
PALATINE; CONSTRICTORS
OF
PHARYNX
INTRINSIC MUSCLES OF
LARYNX

DIAGRAMMATIC
REPRESENTATION OF
BONES AND
CARTILAGES OF
RESPECTIVE
PHARYNGEAL
ARCHES.
18

THE FIRST PHARYNGEAL ARCH
• CONSISTS OF DORSAL PORTION- MAXILLARY PROCESS
VENTRAL PORTION- MANDIBULAR PROCESS
• MESENCHYME OF MAXILLARY PROCESS GIVES RISE TO
• PREMAXILLA
• MAXILLA
• ZYGOMATIC BONE
• PART OF TEMPORAL BONE
(THROUGH MEMBRANOUS OSSIFICATION)
• MANDIBLE IS FORMED BY MEMBRANOUS OSSIFICATION OF
MESENCHYME SURROUNDING MECKEL’S CARTILAGE.
• THE FIRST PAIR OF PHARYNGEAL ARCHES PLAYS A MAJOR
ROLE IN FACIAL DEVELOPMENT
19

DERIVATIVES OF PHARYNGEAL
ARCH CARTILAGES
• THE DORSAL END OF FIRST ARCH CARTILAGE (MECKEL CARTILAGE) OSSIFIES TO FORM
MALLEUS AND INCUS
• THE MIDDLE PART OF CARTILAGE FORMS ANTERIOR LIGAMENT OF MALLEUS AND
SPHENOMANDIBULAR LIGAMENT
• VENTRAL PART OF THE FIRST ARCH CARTILAGES FORM PRIMORDIUM OF THE
MANDIBLE
• THE CARTILAGE DISAPPEARS AS MANDIBLE DEVELOPS AROUND IT
• THE DORSAL END OF SECOND ARCH CARTILAGE (REICHERT CARTILAGE) OSSIFIES TO
FORM THE STAPES AND STYLOID PROCESS OF THE TEMPORAL BONE
• THE VENTRAL END OF SECOND ARCH CARTILAGE OSSIFIES TO FORM THE LESSER CORNU
AND SUPERIOR PART OF THE BODY OF THE HYOID BONE. ITS PERICHONDRIUM FORMS
THE STYLOHYOID LIGAMENT
• THE THIRD ARCH CARTILAGE OSSIFIES TO FORM THE GREATER CORNU AND THE
INFERIOR PART OF THE BODY OF THE HYOID BONE
• THE FOURTH AND SIXTH ARCH CARTILAGES FUSE TO FORM THE LARYNGEAL
CARTILAGES EXCEPT EPIGLOTTIS WHICH DEVELOPS FROM HYPOPHARYNGEAL
EMINENCE
• THE FIFTH PHARYNGEAL ARCH IS RUDIMENTARY AND HAS NO DERIVATIVES
20

DEVELOPMENT OF MAXILLA
• THE MANDIBULAR ARCH GIVES OFF A
BUD FROM ITS DORSAL END WHICH
GROWS VENTRO MEDIO- CRANIALLY
CALLED AS MAXILLARY PROCESS.
• THE MAXILLA ALSO DEVELOPS FROM
A CENTER OF OSSIFICATION IN THE
MESENCHYME OF THE MAXILLARY
PROCESS OF THE FIRST ARCH.
• NO ARCH CARTILAGE OR PRIMARY
CARTILAGE EXISTS IN THE MAXILLARY
PROCESS. BUT THE CENTER OF
OSSIFICATION IS ASSOCIATED
CLOSELY WITH THE CARTILAGE OF
THE NASAL CAPSULE.
22

• FROM THIS CENTER, BONE
FORMATION SPREADS
POSTERIORLY BELOW THE ORBIT
TOWARD THE DEVELOPING
ZYGOMA AND ANTERIORLY
TOWARD THE FUTURE INCISOR
REGION .
• OSSIFICATION ALSO SPREADS
SUPERIORLY TO FORM THE
FRONTAL PROCESS.AS A RESULT
OF THIS PATTERN OF BONE
DEPOSITION ,A BONY TROUGH
FORMS FOR THE INFRAORBITAL
NERVE.
• FROM THIS TROUGH A
DOWNWARD EXTENSION OF
BONE FORMS THE LATERAL
ALVEOLAR PLATE FOR MAXILLARY
TOOTH GERM.
• OSSIFICATION ALSO SPREADS
INTO THE PALATINE PROCESS TO
FORM THE HARD PALATE.
23

• A SECONDARY CARTILAGE ALSO
CONTRIBUTES TO THE
DEVELOPMENT OF THE MAXILLA.
• A ZYGOMATIC, OR MALAR
CARTILAGE APPEARS IN THE
DEVELOPING ZYGOMATIC
PROCESS AND FOR A SHORT TIME
ADDS CONSIDERABLY TO THE
DEVELOPMENT OF THE MAXILLA.
• THE BODY OF THE MAXILLA IS
RELATIVELY SMALL BECAUSE THE
MAXILLARY SINUS HAS NOT
DEVELOPED. THIS SINUS FORMS
DURING THE SIXTEENTH WEEK AS
A SHALLOW GROOVE ON THE
NASAL ASPECT OF THE
DEVELOPING MAXILLA.
• AT BIRTH THE SINUS IS STILL A
RUDIMENTARY STRUCTURE
ABOUT THE SIZE OF A SMALL PEA.
24

DEVELOPMENT OF MANDIBLE
• AT THE 6TH WEEK OF DEVELOPMENT A
CARTILAGINOUS ROD FORMS, ALSO
KNOWN AS MECKEL’S CARTILAGE FROM
THE REGION AROUND THE EAR TO THE
MIDLINE MANDIBULAR PROCESSES.
• THE MANDIBULAR NERVE SPLITS AT
THIS TIME INTO THE LINGUAL AND
INFERIOR ALVEOLAR BRANCHES AND
WILL LINE THE CARTILAGE.
• DURING 7TH WEEK THE FIRST
OSSIFICATION CENTER FORMS AT THE
FURCATION POINT OF NERVES AND
FROM THIS POINT BONE DEVELOPS
OUT TO THE MIDLINE.
• OSSIFICATION ALSO TAKES PLACE IN
THE MEMBRANE COVERING THE OUTER
SURFACE OF MECKEL'S CARTILAGE
• ALSO EACH HALF OF THE BONE IS
FORMED FROM A SINGLE CENTER
WHICH APPEARS, IN THE REGION OF
THE BIFURCATION OF THE MENTAL AND
INCISIVE BRANCHES, ABOUT THE 6TH
WEEK OF FETAL LIFE.
25

• A CANAL ALSO FORMS BACKWARD TO CONTAIN
THE ALVEOLAR NERVE. MEDIAL AND LATERAL
ALVEOLAR PLATES FORM SO THAT TOOTH GERMS
CAN FORM IN A TROUGH BETWEEN THEM. THE
BONE OF THE MANDIBLE WILL CONTINUE TO
FORM AFTER THE TEETH HAVE DEVELOPED TO
SUPPORT THEM.
• AROUND 10TH WEEKS MANDIBLE IS
RECOGNIZABLE AND MUCH OF THE BONE HAS
FORMED.
• AFTER THIS POINT THERE WILL BE A STRONG
DEPENDENCE FOR FORMATION OF BONE ON 3
CARTILAGES:
1. THE CONDYLAR CARTILAGE,
2. THE CORONOID CARTILAGE
3. THE SYMPHYSEAL CARTILAGE.
• THE CONDYLAR CARTILAGE WILL BE CONVERTED
ALMOST ENTIRELY TO BONE, BUT THE SMALL
PORTION OF CARTILAGE THAT REMAINS AT THE
ARTICULAR END IS NECESSARY FOR THE
CONTINUOUS GROWTH OF THE MANDIBLE POST
NATALLY.
• THE CORONOID AND MIDLINE SYMPHYSEAL
CARTILAGES ARE ALSO IMPORTANT FOR GROWTH
AND DEVELOPMENT, BUT DISAPPEAR BEFORE
BIRTH AND IN THE YEAR AFTER RESPECTIVELY. 26

FORMATION OF THE PRIMARY AND SECONDARY PALATE
• THE PALATE AS A WHOLE FORMS FROM TWO
PRIMORDIA KNOWN AS THE PRIMARY AND SECONDARY
PALATE.
• AROUND 6TH WEEK OF DEVELOPMENT PRIMARY PALATE
BEGINS TO FORM ARISING FROM THE MEDIAL NASAL
PROCESS.
• IT IS COMPOSED OF MESODERM, THIS EXTENDS TO
FORM THE FLOOR OF NASAL CAVITY .
• AROUND 7 & 8TH WEEK OF DEVELOPMENT SECONDARY
PALATE BEGINS TO DEVELOP FROM TWO LATERAL
PALATINE PROCESSES & COMPLETED AROUND THE 12TH
WEEK
• AS MANDIBLE DEVELOPS, THE TONGUE DROPS AND
PALATINE PROCESSES GROW MEDIALLY AND FUSE IN
MIDLINE. THEY ALSO FUSE WITH NASAL SEPTUM AND
THE PRIMARY PALATE.
27

• OSSIFICATION OCCURS IN AN
ANTEROPOSTERIOR
DIRECTION.
• THE POSTERIOR PORTIONS OF
THE LATERAL PALATINE
PROCESSES DO NOT BECOME
OSSIFIED, BUT EXTEND PAST
THE NASAL SEPTUM AND FUSE
TO FORM THE SOFT PALATE
AND UVULA.
• THIS IS THE LAST PORTION OF
THE PALATE TO FORM.
28

APPLIED ASPECTS
STAGES TIME (POST FERTILIZATION) RELATED SYNDROME
GERM LAYER FORMATION DAY 17 (APPROX.) FETAL ALCOHOL SYNDROME
NEURAL TUBE FORMATION DAY 18-23 ANENCEPHALY
ORIGIN, MIGRATION AND
INTERACTION OF CELL
POPULATION
DAY 19-28 HEMI FACIAL MICROSOMIA,
TREACHER COLINS’ SYNDROME
FORMATION OF ORGAN
SYSTEM
DAY 28-38 CLEFT LIP AND/OR PALATE,
OTHER
FACIAL CLEFTS
SECONDARY PALATE DAY 42-55(6-9WKS) CLEFT PALATE
ORIGIN, MIGRATION AND
INTERACTION OF CELL
POPULATION
DAY 50-BIRTH ACHONDROPLASIA,
CROUZON'S,
APERT’S SYNDROME ETC.
29

APPLIED ASPECTS
30
FETAL ALCOHOL SYNDROME
DUE TO DERANGEMENT OR
OBSTRUCTIONS DUE TO CHEMICAL
FACTORS WHILE THE PRIMARY GERM
LAYERS ARE FORMING. THE
PROLIFERATION, DIFFERENTIATION,
NEURONAL MIGRATION, AXONIC
OUTGROWTH, INTEGRATION AND FINE
TUNING OF THE NEURONAL ELEMENTS
ARE AFFECTED WHICH MAY GIVE RISE TO
THIS SYNDROME.
ABNORMAL APPEARANCE, SHORT
HEIGHT, LOW BODY WEIGHT, SMALL
HEAD SIZE, POOR COORDINATION, LOW
INTELLIGENCE, BEHAVIOR PROBLEMS,
AND PROBLEMS WITH HEARING OR
VISION

ANENCEPHALY
• IT IS A CEPHALIC DISORDER THAT
RESULTS FROM A NEURAL TUBE
DEFECT THAT OCCURS WHEN THE
ROSTRAL END OF THE NEURAL
TUBE FAILS TO CLOSE, USUALLY
BETWEEN THE 23RD AND 26TH
DAY FOLLOWING CONCEPTION
• THE FETUS IS USUALLY STILL
BORN OR DIES WITHIN HOURS OF
BIRTH.
31

HEMI FACIAL MICROSOMIA
DISRUPTION DURING ORIGIN, MIGRATION AND
INTERACTION OF CELL POPULATION
DAY 19-28
TREACHER COLINS’ SYNDROME
32

CLEFT PALATE
A - NORMAL LIP AND PALATE
B - CLEFT UVULA (FISH TAIL APPEARANCE)
C - UNILATERAL CLEFT OF THE SECONDARY PALATE: RESULTS FROM FAILURE
OF MESENCHIMAL MASSES IN THE LATERAL PALATINE PROCESSES TO
MEET WITH EACH OTHER AND NASAL SEPTUM
D - BILATERAL CLEFT OF THE SECONDARY PALATE
33
lip Incisive
papilla
hard
palate
soft
palate
nasal
cavity
nasal
septum
A B
C D

CLEFT LIP AND CLEFT PALATE
A - COMPLETE UNILATERAL CLEFT OF THE LIP AND ALVEOLAR PROCESS OF THE
MAXILLA WITH UNILATERAL CLEFT OF THE ANTERIOR PALATE – RESULTS FROM
FAILURE OF MESENCHYMAL MASSES IN THE PALATINE SHELVES TO MEET
AND FUSE WITH THE MESENCHYME IN THE PRIMARY PALATE
B - COMPLETE BILATERAL CLEFT OF THE LIP AND ALVEOLAR PROCESS OF THE
MAXILLA WITH BILATERAL CLEFT OF THE ANTERIOR PALATE.
34
primary palate
Site of incisive foramen
secondary
palate
A B

DIFFERENT TYPES OF CLEFT LIP AND PALATE
35

TREATMENT SCHEDULE OF CLEFT LIP AND PALATE
36

ACHONDROPLASIA
DISRUPTION IN ORIGIN, MIGRATION AND
INTERACTION OF CELL POPULATION DAY 50 TILL
BIRTH
CROUZON SYNDROME
APERT’S SYNDROME
37

ANATOMICAL POSITION OF SKULL
38
THE SKULL CAN BE PLACED IN PROPER
ORIENTATION BY CONSIDERING ANY OF
THESE TWO PLANES
FRANKFURT’S HORIZONTAL PLANE
A PLANE PASSING THROUGH THE INFERIOR
MARGIN OF THE ORBIT (ALSO CALLED
ORBITALE) AND THE UPPER MARGIN OF
EXTERNAL AUDITORY MEATUS, A POINT
CALLED THE PORION, WAS MOST NEARLY
PARALLEL TO THE SURFACE OF THE EARTH. AT
THE POSITION THE HEAD IS NORMALLY
CARRIED IN THE LIVING SUBJECT
REID’S BASE LINE
HORIZONTAL LINE OBTAINED BY JOINING THE
INFRAORBITAL MARGIN TO THE CENTRE OF
EXTERNAL ACOUSTIC MEATUS ALSO KNOWN
AS THE AURICULAR POINT

PECULIARITIES OF SKULL BONES
AT BIRTH SKULL IS OF ONE
TABLE ONLY. BY 4YRS OF
AGE TWO TABLES ARE
FORMED. BETWEEN THE
TWO TABLES THE SPACE IS
CALLED DIPLOES. THIS
SPACE CONTAINS RED
BONE MARROW
FORMING RBCs, WBCs
AND PLATELETS. FOUR
DIPLOIC VEINS DRAIN THE
FORMED BLOOD CELLS
INTO THE NEIGHBOURING
VEINS.
39
OUTER
INNER

FONTANELLES
AT BIRTH THE 4 ANGLES OF
PARIETAL BONE HAVE
MEMBRANOUS GAPS CALLED
AS FONTANELLES.
1. ANTERIOR FONTANELLE
2. POSTERIOR FONTANELLE
3. SPHENOID FONTANELLE
4. MASTOID FONTANELLE
PURPOSE –
1. HELP DURING VAGINAL
DELIVERY
2. ALLOW SKULL BONES AND
BRAIN TO GROW IN SIZE
AFTER BIRTH
40

ANTERIOR FONTANELLE
FORMED BY JOINING FOUR SUTURES IN
MIDPLANE.
- ANTERIORLY FRONTAL BONE
- POSTERIORLY SAGGITAL SUTURE
- ON EITHER SIDE CORONAL SUTURE
- DIAMOND LIKE SHAPE.
- FLOOR IS MADE BY A MEMBRANE.
- OSSIFIED AT 18MONTHS AFTER BIRTH.
41
ANTERIOR FONTANELLE
POSTERIOR FONTANELLE

CLINICAL SIGNIFICANCE
• PALPATION THROUGH INTERNAL
EXAMINATION DENOTES THE DEGREE OF
FLEXION OF THE HEAD.
• FACILITATES MOULDING OF THE HEAD.
• AS IT REMAINS MEMBRANOUS LONG
AFTER BIRTH, HELPS IN
ACCOMMODATING THE MARKED BRAIN
GROWTH, THE BRAIN BECOMING ALMOST
DOUBLE ITS SIZE DURING FIRST YEAR OF
LIFE.
• PALPATION OF THE FLOOR REFLECTS
INTRACRANIAL STATUS - DEPRESSED IN
DEHYDRATION, ELEVATED IN RAISED
INTRACRANIAL TENSION.
• COLLECTION OF BLOOD AND EXCHANGE
TRANSFUSION, ON RARE OCCASION, CAN
BE PERFORMED THROUGH IT VIA THE
SUPERIOR LONGITUDINAL SINUS.
• CEREBROSPINAL FLUID CAN BE DRAWN,
RARELY, THROUGH THE LATERAL ANGLE
OF THE ANTERIOR FONTANELLE FROM
THE LATERAL VENTRICLE. 42

CAPUT SUCCEDANEUM
• OFTEN CONFUSED WITH
SWELLING OF ANTERIOR
FRONTANELLE
• JUST AN EDEMATOUS SWELLING
OF THE FETAL SCALP, MAY BE
BECAUSE OF TEARING OF A
SUPERFICIAL BLOOD VESSEL OF
SCALP
• DISAPPEARS IN 7-10 DAYS
WITHOUT TREATMENT
• NO PATHOLOGICAL SIGNIFICANCE
43

POSTERIOR FRONTANELLE
FORMED BY JUNCTION OF THREE
SUTURES.
• SAGGITAL SUTURE ANTERIORLY.
• LAMBDOIDAL SUTURE ON EITHER
SIDE
• TRIANGULAR IN SHAPE.
• MEASURE ABOUT 1.2 X1.2CM.
• ITS FLOOR IS MEMBRANOUS BUT
BECOME BONY AT 3MONTHS
SPHENOID FONTANELLE AND
MASTOID FONTANELLE HAS NO
CLINICAL SIGNIFICANCE. SPHENOID
FONTANELLE CLOSES AT ABOUT 6
MONTHS AFTER BIRTH. MASTOID
FRONTANELLE CLOSED AT ABOUT 6
TO 18 MONTHS AFTER BIRTH.
44

SAGITTAL FRONTANELLE AND METOPIC
FONTANELLE
SAGITTAL FRONTANELLE ALSO KNOWN AS THIRD
FRONTANELLE
SITUATED ON THE
SAGGITAL SUTURE AT THE JUNCTION OF ANTERIOR
TWO-THIRD
AND POSTERIOR ONE-THIRD
PRESENT IN ABOUT 50% OF CASES
USUALLY OBLITERATED BY BIRTH
CLINICALLY ASSOCIATED WITH DOWN’S SYNDROME
METOPIC FRONTANELLE SITUATED
FRONTAL BONE IN ABOUT 5% CASES AS
AN EXTENSION OF ANTERIOR
FRONTANELLE
IF PRESENT CLOSES BY 2YRS OF AGE
45
SAGITTAL FRONTANELLE
METOPIC FRONTANELLE
SOURCE – JOURNAL OF ANTHROPOLOGY 2014, MELANIE BEASLEY

CRANIOSYNOSTOSIS
CRANIOSYNOSTOSIS IS A CONDITION IN WHICH ONE OR MORE
CRANIAL SUTURES OR ONE OR MORE FONTANELLES
PREMATURELY FUSE EITHER DURING EMBRYONIC LIFE OR EARLY
CHILDHOOD AND RESULT IN A CHANGE IN THE GROWTH
PATTERN OF THE SKULL.
• FOUR FRONTANELLES
• SIX MAJOR CRANIAL SUTURES ALSO KNOWN AS SKULL JOINTS
THE METOPIC SUTURE
THE SAGITTAL SUTURE
TWO CORONAL SUTURES
TWO LAMBDOID SUTURES
46

SKULL JOINTS
MOSTLY SUTURES BUT ALSO GOMPHOSIS, SYNOVIAL JOINTS, SCHINDYLESIS
47
INTERNASAL SUTURE
CORONAL SUTURE
LAMBDOID SUTURE
PARIETOTEMPORAL SUTURE
VOMER SPHENOID SUTURE

SKULL JOINTS
48
TEMPORO MANDIBULAR JOINT
2 OTHER PAIRS OF SYNOVIAL JOINT
BETWEEN OSSICLES OF MIDDLE EAR
SYNOVIAL JOINT
GOMPHOTIC JOINT
BETWEEN TOOTH AND ALVEOLAR BONE

CORONAL SUTURE
SERRATE SUTURE
50

SERRATE SUTURE (SAGITTAL)
PRESENT BETWEEN TWO PARIETAL BONES
51

DENTICULATE SUTURE
BETWEEN PARIETAL BONES
AND OCCIPITAL BONE
52

PLANE SUTUTRE
BETWEEN TWO PALATINE
BONES
53

CRANIOSYNOSTOSIS
CAUSE
BONY GROWTH OF THE SKULL OCCURS IN OSTEOBLASTIC CENTERS LOCATED
AT THE SUTURE SITES.BONE IS LAID DOWN PARALLEL AND PERPENDICULAR
TO THE DIRECTION OF THE SUTURE
PREMATURE SUTURE CLOSURE PREVENTS PERPENDICULAR GROWTH BUT
ALLOWS PARALLEL GROWTH. THIS PATTERN IS TERMED VIRCHOW'S LAW AND
LEADS TO CLINICALLY RECOGNIZABLE CRANIAL BONE DEFORMATIONS, ALL OF
WHICH CARRY SPECIFIC NOMENCLATURE
55
VIRCHOW'S LAWNORMAL SUTURES

PLAGIOCEPHALY
CONSEQUENCE OF A UNILATERAL CORONAL
SUTURE SYNOSTOSIS/ OBLIQUE HEAD
ACROCEPHALY
ALSO KNOWN AS OXYCEPHALY/ TURRICEPHALY
MEANING TOWER HEAD
56
THE FOREHEAD AND SUPRAORBITAL
RIM ARE RETRUDED (DEPRESSED), THE
INTERPALPEBRAL FISSURE IS
WIDER, AND THE ORBIT IS OFTEN
HIGHER THAN ON THE NON
SYNOSTOTIC SIDE
MULTIPLE
SUTURE CLOSURES, SUCH AS BOTH
CORONALS, THE
SAGITTAL, AND POSSIBLY THE
LAMBDOIDALS

BRACHYCEPHALY
MEANS SHORT HEAD, REFERRS TO
GROWTH IN ANTERO-POSTERIOR AXIS
SCAPHOCEPHALY
MEANS BOAT HEAD, LONG IN ANTERO-
POSTERIOR AXIS, NARROW BI-
TEMPORALLY
57
RESULT OF BILATERAL CLOSURE OF
THE CORONAL
SUTURES
PREMATURE
CLOSURE OF THE SAGITTAL SUTURE

TRIGONOCEPHALY
MEANS TRIANGULAR HEAD
KLEEBLATTSCHIIDEL
MEANS CLOVER LEAF SKULL
58
RESULT OF SYNOSTOSIS OF THE
CORONAL, LAMBDOIDAL, AND
SAGITTAL SUTURESRESULT OF SYNOSTOSIS OF THE
METOPIC SUTURE

SKULL BASE SUTURE SYNOSTOSIS
IN CONTRAST TO CALVARIAL SUTURE FUSION, WHICH CAUSES DIFFERENT
CRANIAL DEFORMATIONS, SKULL BASE SUTURE FUSION CAUSES JUST 1
CONSTELLATION OF ABNORMALITIES, MIDFACIAL HYPOPLASIA
CONSISTS OF
• MAXILLARY HYPOPLASIA
• BEAK-SHAPED NOSE
• HYPERTELORISM
• SHALLOW ORBITS WITH PROPTOSIS
• HIGH-ARCHED PALATE WITH DENTAL
MALOCCLUSION
• RELATIVE MANDIBULAR PROGNATHISM
DUE TO RETRUDED MAXILLA)
SEEN IN CROUZON SYNDROME
59

EXTERIOR OF SKULL
SKULL CAN BE STUDIED FROM OUTSIDE OR
EXTERNALLY IN DIFFERENT VIEWS
1. NORMA VERTICALIS (VIEWED FROM ABOVE)
2. NORMA OCCIPITALIS (VIEWED FROM BACK)
3. NORMA FRONTALIS (VIEWED FROM FRONT)
4. NORMA LATERALIS (VIEWED FROM SIDE)
5. NORMA BASALIS (VIEWED FROM BELOW)
62

NORMA VERTICALIS
• GENERALLY ELLIPSOID
SHAPE ( MODIFIED OVOID
SHAPE)
• WIDER POSTERIORLY THAN
ANTERIORLY
• BONES SEEN
- UPPER PART OF FRONTAL
BONE ANTERIORLY
- UPPERMOST PART OF
OCCIPITAL BONE POSTERIORLY
- PARIETAL BONE ON EACH SIDE
63

SUTURES –
• CORONAL SUTURE –
BETWEEN FRONTAL BONE AND TWO
PARIETAL BONES
• SAGITTAL SUTURE –
BETWEEN TWO PARIETAL BONES
• LAMBOID SUTURE –
POSTERIORLY BETWEEN OCCIPITAL AND
TWO PARIETAL BONES
• METOPIC SUTURE –
PRESENT IN ABOUT 3 TO 8% INDIVIDUALS
IN MEDIAN PLANE
BETWEEN TWO HALFS OF FRONTAL BONE
NORMALLY FUSES AT 6 YRS OF AGE
64
CORONAL SUTURE
SAGITTAL SUTURE
LAMBOID SUTURE
METOPIC SUTURE

LANDMARKS
VERTEX – HIGHEST POINT OF
SAGITTAL SUTURE
BREGMA – MEETING POINT OF
CORONAL AND SAGITTAL SUTURE
(POSITION ANTERIOR FRONTANELLE)
LAMBDA – MEETING POINT OF
SAGITTAL AND LAMBOID SUTURE
(POSITION POSTERIOR FRONTANELLE)
OBELION – POINT ON SAGITTAL
SUTURE BETWEEN PARIETAL
FORAMEN
PARIETAL TUBER – AREA OF
MAXIMUM CONCAVITY OF PARIETAL
BONE
PARIETAL FORAMEN – ONE ON EACH
SIDE, PIERCE PARIETAL BONE AT
UPPER BORDER, 2.5 TO 4 CM IN
FRONT OF LAMBDA, TRANSMIT
EMISSARY VEIN FROM VEINS OF
SCALP TO SUPERIOR SAGITTAL SINUS
65
VERTEX
BREGMA
LAMBDA
PARIETAL TUBER
OBELION
PARIETAL FORAMEN

CLINICAL ASPECTS
• FRONTANELLES ARE SITE OF GROWTH OF SKULL
• ANTERIOR AND POSTERIOR FRONTANELLES EARLY CLOSURE IS
MAJOR REASON FOR DEVELOPMENT OF CRANIOSYNOSTOTIC
SYNDROMES
• PARIETAL TUBER/ PARIETAL EMINENCE IS A VERY COMMON
SITE OF FRACTURE OF SKULL
66

SHAPE
THE OUTLINE IS CONVEX UPWARDS AND
ON BOTHSIDES. FLAT ON LOWER SIDE.
BONES
ABOVE – POSTERIOR PARTS OF PARIETAL
BELOW – UPPER PART OF SQUAMOUS PART
OF OCCIPTAL BONE
SIDE – MASTOID PART TEMPORAL BONE
SUTURES
LAMBOID SUTURE
OCCIPITOMASTOID SUTURE
PARIETOMASTOID SUTURE
SAGITTAL SUTURE
68

LANDMARKS
LAMBDA - MEETING POINT OF SAGITTAL AND
LAMBOID SUTURE
OBELION - POINT ON SAGITTAL SUTURE BETWEEN
PARIETAL FORAMEN
EXTERNAL OCCIPITAL PROTUBERANCE – A
MEDIAN PROMINENCE IN LOWER PART OF OCCIPTAL
BONE
INION – THE MOST PROMINENT POINT OF EXTERNAL
OCCIPITAL PROMINENCE
OCCIPITAL POINT – A MEDIAN POINT LITTLE ABOVE
THE INION. IT IS THE POINT FARTHEST FROM
GLABELLA.
HIGHEST NUCHAL LINES – NOT ALWAYS PRESENT.
CURVED BONY RIDGE 1 CM ABOVE SUPERIOR NUCHAL
LINE. BEGIN FROM UPPER PART OF EXTERNAL
OCCIPITAL PROMINENCE
SUPERIOR NUCHAL LINES – CURVED BONY RIDGES
STARTING FROM OCCIPITAL PROTRUBERANCE. PASS
LATERALLY
INFERIOR NUCHAL LINES – CURVED BONY RIDGES
STARTING FROM MIDDLE OF EXTERNAL OCCIPITAL
CREST
EXTERNAL OCCIPITAL CREST - A RIDGE ALONG
THE MIDLINE, BEGINNING AT THE EXTERNAL
OCCIPITAL PROTUBERANCE AND DESCENDING TO
THE FORAMEN MAGNUM 69
LAMBDA
OBELION
INION
EXTERNAL
OCCIPITAL
CREST

FORAMINA
TWO PARIETAL FORAMINA
( CONTENTS – PARIETAL EMISSARY
VEINS )
TWO MASTOID FORAMINA
( CONTENTS - MASTOID EMISSARY
VEINS, MENINGEAL
BRANCH OF OCCIPITAL
ARTERY)
70
PARIETAL FORAMINA
MASTOID FORAMEN

EXTERNAL OCCIPITAL PROTUBERANCE
UPPER PART GIVES ORIGIN TO TRAPEZIUS, LOWER PART GIVES ATTACHMENT TO UPPER END OF
LIGAMENTUM NUCHAE
SUPERIOR NUCHAL LINE
MEDIAL 1/3 GIVES ORIGIN TO TRAPEZIUS, LATERAL 1/3 PROVIDES INSERTION TO
STERNOCLEIDOMASTOID ABOVE AND SPLENUS CAPITIS BELOW.
HIGHEST NUCHAL LINE
IF PRESENT, IT PROVIDES ATTACHMENT TO EPICRANIAL APONEUROSIS MEDIALLY. GIVES ORIGIN
TO OCCIPITALIS OR OCCIPITAL BELLY OF OCCIPITOFRONTALIS MUSCLE LATERALLY.
IF ABSENT, THESE STRUCTURES ATTACHED TO SUPERIOR NUCHAL LINE.
AREA BETWEEN SUPERIOR AND INFERIOR NUCHAL LINE
THIS AREA PROVIDES INSERTION TO SEMISPINALIS CAPITIS IN THE MEDIAL SURFACE AND
SUPERIOR OBLIQUE MUSCLE IN THE LATERAL SURFACE.
THE AREA BELOW INFERIOR NUCHAL LINE PROVIDES INSERTION TO RECTUS CAPITIS POSTERIOR
MINOR IN THE MEDIAL SURFACE AND RECTUS CAPITIS POSTERIOR MAJOR IN THE LATERAL
SURFACE.
72

CLINICAL ASPECTS
INCA BONE
LARGE, MOSTLY TRIANGULAR BONE LOCATED
AT THE APEX OF SQUAMOUS OCCIPITAL. NOT
A SUTURAL OR ACCESSORY BONE. THE
SUTURES ARE CONFUSED WITH FRACTURE
LINES RADIOLOGICALLY
73
INCA BONE
3,4-SUTURAL BONES
INION
IT MARKS THE TERMINATION OF STRAIGHT
AND SUPERIOR SAGITTAL SINUS AND
COMMENCEMENT OF TRANSVERSE SINUS.
THEREFORE OF A VITAL LANDMARK FOR
NEUROSURGERY
REF.- DOI:10.4103/2152-7806.161241

CLINICAL ASPECTS
OCCIPITAL NEURALGIA
INION IS USED AS THE REFERRENCE
POINT TO BLOCK NERVES OR TO
ADMINISTER STEROIDS TO TREAT
SEVERE, OTHERWISE UNRESPONSIVE
CASES OF OCCIPITAL NEURALGIA.
74

SHAPE
ROUGHLY OVAL IN SHAPE. WIDER ABOVE
THAN BELOW
BONES
FRONTAL BONE – FORMS FOREHEAD
MAXILLA – FORMS THE UPPER JAW
NASAL BONES – FORMS BRIDGE OF NOSE
ZYGOMATIC BONES – PROMINENCE OF
CHEEK
MANDIBLE – FORMS THE LOWER JAW
SUTURES
• INTERNASAL SUTURE
• FRONTONASAL SAUTURE
• NASOMAXILLRY SUTURE
• LACRIMOMAXILLARY SUTURE
• FRONTOMAXILLARY SUTURE
• INTERMAXILLARY SUTURE
• ZYGOMATICOMAXILLARY SUTURE
• ZYGOMATICOFRONTAL SURURE
76

NORMA FRONTALIS
CAN BE DIVIDED INTO FOUR PARTS
• FRONTAL REGION
• ORBITAL OPENING
• ANTERIOR BONY APERTURE OF
NOSE
• LOWER FACE
77
FRONTAL REGION
ORBITAL OPENING
NASAL OPENING
LOWER FACIAL REGION

LANDMARKS OF FRONTAL
REGION
• SUPERCILIARY ARCH
(ROUNDED CURVED ELEVATION JUST
ABOVE THE MEDIAL ASPECT OF EACH
ORBIT, OVERLIES THE FRONTAL SINUS,
MORE MARKED IN MALES)
• GLABELLA
( MEDIAN ELEVATION CONNECTING THE
SUPERCILIARY ARCHES)
• NASION
( MEDIAN POINT OF ROOT OF NOSE,
INTERNASAL SUTURE MEETS THE
FRONTONASAL SUTURE)
• FRONTAL TUBER/EMINENCE
( LOW ROUNDED ELEVATION ABOVE
SUPERCILIARY ARCHES, MORE
PROMINENT IN FEMALES AND CHILDREN)
78
SUPERCILIARY ARCHGLABELLA
NASION
FRONTAL TUBER

ORBITAL OPENINGS
QUADRANGULAR IN SHAPE
FOUR MARGINS
- SUPRA-ORBITAL MARGIN – FORMED BY
FRONTAL BONE, AT JUNCTION OF
LATERAL 2/3 AND MEDIAL 1/3, THE
SUPRAORBITAL NOTCH OR FORAMEN IS
PRESENT
- INFRAORBITAL MARGIN – FORMED BY
ZYGOMATIC BONE LATERALLY AND
MAXILLA MEDIALLY
- MEDIAL ORBITAL MARGIN – FRONTAL
BONE ABOVE, LACRIMAL CREST OF
FRONTAL PROCESS OF MAXILLA BELOW
- LATERAL ORBITAL MARGIN – MOSTLY BY
FRONTAL PROCESS OF ZYGOMATIC BONE
BUT COMPLETED ABOVE BY THE
ZYGOMATIC PROCESS OF FRONTAL BONE.
FRONTOZYGOMATIC SUTURE IS PRESENT
AT THE UNION OF THE BONES.
79

ANTERIOR BONY APERTURE OF
NOSE ( PIRIFORM APERTURE)
- SHAPE – PEAR SHAPED, WIDE BELOW,
NARROW ABOVE
- BOUNDARIES – ABOVE – LOWER BORDER
OF NASAL BONES, BELOW- NASAL NOTCH
OF BODY OF MAXILLA ON EACH SIDE
- ARTICULATIONS – NASAL BONE
ATRICULATES ANTERIORLY BY OPPOSITE
BONES AT INTERNASAL SUTURE;
POSTERIORLY, WITH FRONTAL PROCESS
OF MAXILLA: SUPERIORLY, WITH FRONTAL
BONE AT FRONTONASAL SUTURE:
INFERIORLY, UPPER NASAL CARTILAGE
- ANTERIOR NASAL SPINE – A SHARP BONY
PROJECTION AT THE LOWER BOUNDARY
OF NASAL APERTURE
- RHINION – LOWERMOST POINT OF
INTERNASAL SUTURE
80
RHINION

FACE
MAXILLA – THREE OUT OF THE FOUR
PROCESSES OF MAXILLA ARE SEEN IN
NORMA FRONTALIS, FRONTAL PROCESS,
ZYGOMATIC PROCESS AND ALVEOLAR
PROCESS
ZYGOMATIC BONE – FORMS THE
PROMINENCE OF CHEEK
MANDIBLE - LOWER JAW, THE UPPER
BORDER OR ALVEOLAR ARCH CONTAINING
TEETH, LOWER BORDER IS ROUNDED. THE
OBLIQUE LINE, WHICH STARTS FROM THE
MENTAL TUBERCLE IS SEEN IN NORMA
FRONTALIS.
81
MAXILLA
ZYGOMATIC BONE
MANDIBLE

LANDMARKS
- SUPERCILIARY ARCH
- GLABELLA
- NASION
- FRONTAL TUBER / EMINENCE
- SUPRAORBITAL NOTCH/ FORAMEN
- ANTERIOR NASAL SPINE
- RHINION
- NASAL NOTCH OF MAXILLA
- INCISIVE FOSSA OF MAXILLA
- CANINE FOSSA OF MAXILLA
- MENTAL POINT OR GNATHION
- SYMPHYSIS MENTI
- MENTAL PROTRUBERANCE
- MENTAL TUBERCLES
- THE OBLIQUE LINE ( ANTERIOR PART)
82

FORAMINA NORMA FRONTALIS
1 - SUPRAORBITAL FORAMEN –
CONTAINS SUPRAORBITAL NERVES AND
VESSELS
2 – INFRAORBITAL FORAMEN –
CONTAINS INFRAORBITAL NERVES AND
VESSELS
3 – ZYGOMATICOFACIAL FORAMEN –
CONTAINS ZYGOMATICOFACIAL NERVE, A
BRANCH OF MAXILLARY NERVE
4 – MENTAL FORAMEN – CONATINS
MENTAL NERVE AND BLOOD VESSELS
83
ZYGOMATICOFACIAL FORAMEN
ZYGOMATICOTEMPORAL FORAMEN

MUSCLE ATTACHMENTS
1. CORRUGATOR SUPERCILII – ORIGINATES
FROM MEDIAL PART OF SUPERCILIARY ARCH
2. PROCERUS – ORIGINATES FROM NASAL BONE
NEAR THE MEDIAN PLANE
3. ORBICULARIS OCULI - ORBITAL PART
ORIGINATES FROM FRONTAL PROCESS OF
MAXILLA AND NASAL PART OF FRONTAL BONE
4. LEVATOR LABII SUPERIORIS ALAEQUE NASI –
FRONTAL PROCESS OF MAXILLA
5. LEVATOR LABII SUPERIORIS – FROM MAXILLA
BETWEEN INFRAORBITAL MARGIN AND
INFRAORBITAL FORAMEN
6. LEVATOR ANGULI ORIS – FROM CANINE FOSSA
7. NASALIS – SURFACE OF MAXILLA NEAR NASAL
NOTCH
8. DEPRESSOR SEPTI – SURFACE OF MAXILLA
NEAR NASAL NOTCH
9. INCISIVUS – JUST BELOW DEPRESSOR SEPTI,
PART OF IT
10. ZYGOMATICUS MAJOR AND MINOR –
SURFACE OF ZYGOMATIC BONE
84

MUSCLE ATTACHMENTS
11. COMPRESSOR NARIS – MAXILLA JUST LATERAL TO
NOSE
12. DILATOR NARIS - MAXILLA OVER LATERAL
INCISOR
13. BUCCINATOR – UPPER FIBRES FROM MAXILLA
OPPOSITE MOLAR TEETH, LOWER FIBRES FROM
MANDIBLE OPPOSITE MOLAR TEETH
14. DEPRESSOR ANGULI ORIS – OBLIQUE LINE OF
MANDIBLE
15. DEPRESSOR LABI INFERIORIS – ANTERIOR PART
OF OBLIQUE LINE
16. MENTALIS – MANDIBLE INFERIOR TO INCISORS
85

CLINICAL ASPECTS
METOPIC SUTURE MAY
PERSIST THROUGHOUT
LIFE AND MISTAKEN AS A
FRACTURE
86
METOPIC SUTURE

BLOW OUT FRACTURE OF
THE ORBIT
HERNIATION OF ORBITAL
SOFT TISSUE INTO
MAXILLARY ANTRUM
87

SADDLE NOSE
FRACTURE OF NASAL BONE
CREATES THIS DEFORMITY
NASAL BONE FRACTURE IS
ONE OF THE MOST
COMMON FACIAL BONE
FRACTURE
88

FRACTURE OF MID-
FACIAL BONES
LeFORTE I FRACTURE
HORIZONTAL FRACTURE- INVOLVING
THE LATERAL BONY MARGIN OF THE
NASAL OPENING, MEDIAL AND
LATERAL BUTTRESSES OF MAXILLARY
SINUS, TRAVELING THROUGH THE
FACE JUST ABOVE THE ALVEOLAR
RIDGE OF THE UPPER DENTAL ARCH.
AT THE MIDLINE, THE INFERIOR NASAL
SEPTUM IS INVOLVED. IT HAS ALSO
BEEN REFERRED TO AS A GUÉRIN
FRACTURE,
89

LeFORTE II FRACTURE
PYRAMIDAL FRACTURE - IT EXTENDS
FROM THE NASAL BRIDGE AT OR
BELOW THE NASOFRONTAL SUTURE
THROUGH THE SUPERIOR MEDIAL WALL
OF THE MAXILLA, INFEROLATERALLY
THROUGH THE LACRIMAL BONES
WHICH CONTAIN THE LACRIMAL DUCTS,
AND INFERIOR ORBITAL FLOOR
THROUGH OR NEAR THE INFRAORBITAL
FORAMEN.
90

LeFORTE III FRACTURE
TRANSVERSE FRACTURE/CRANIOFACIAL
DISSOCIATION - INVARIABLY INVOLVE
THE ZYGOMATIC ARCH. THESE
FRACTURES BEGIN AT THE
NASOFRONTAL AND FRONTOMAXILLARY
SUTURES AND EXTEND POSTERIORLY
ALONG THE MEDIAL WALL OF THE
ORBIT, THROUGH THE NASOLACRIMAL
GROOVE AND ETHMOID AIR CELLS. THE
SPHENOID IS THICKENED POSTERIORLY,
LIMITING FRACTURE EXTENSION INTO
THE OPTIC CANAL. THE FRACTURE
CONTINUES ALONG THE ORBITAL FLOOR
AND INFRAORBITAL FISSURE,
CONTINUING THROUGH THE LATERAL
ORBITAL WALL TO THE
ZYGOMATICOFRONTAL JUNCTION AND
ZYGOMATIC ARCH
91

SHAPE –
Roughly triangular in shape. The base of triangle is convex. The apex of
the triangle is formed by mental protuberance of mandible.
BONES – SUTURES -
• Frontal - Coronal suture
• Parietal - Temporo-parietal suture
• Occipital - Lamboid suture
• Temporal - Zygomatico temporal
• Sphenoid - Zygomatico frontal
• Zygomatic - Occipito mastoid
• Mandible - Naso maxillary
• Maxilla - Fronto maxillary
• Nasal - Temporo sphenoidal
• Lacrimal - Frontosphenoidal
94

LAMDMARKS, FORAMINA, FOSSA ON NORMA LATERALIS
 Temporal Lines Zygomatico-temporal foramen
 Supramastoid Crest Spheno-palatine foramen
 Zygomatic arch Mastoid foramen
 Pterion
 Asterion
 Gonion
 Mastoid process
 External acoustic meatus
 Suprameatal triangle
 Articular tubercle
FOSSA
• Temporal fossa
• Infra temporal fossa
• Pterygopalatine Fossa
95

TEMPORAL LINES
Begin at zygomatic process of frontal bone.
Over parietal bone there are two lines-
Superior and Inferior. Traced anteriorly, they
fuse to form a single line. Traced posteriorly,
the superior line fades but the inferior
temporal line continues downwards and
forwards with zygomatic arch.
Supramastoid Crest –inferior temporal line
merges with it. This bony prominence of
temporal bone forms the posterior root of
zygomatic arch.
97
Supramastoid Crest

ZYGOMATIC ARCH
Formed by temporal process of zygomatic
bone in anterior one third and the zygomatic
process of temporal bone in posterior two
third. Zygomaticotemporal suture cross the
arch obliquely.
Lateral surface of zygomatic arch is
subcutaneous. The anterior end of upper
border is called Jugal Point.
Posterior end of Zygomatic Arch –
Attached to Squamous Temporal by two roots
Anterior Root & Posterior Root
98
Jugal Point.

EXTERNAL ACOUSTIC MEATUS
Opens just below the posterior part of
posterior root of zygomatic arch. The
anterior and inferior margins and the
lower part of posterior margin is formed
by tympanic plate . The posterosuperior
margin is formed by squamous temporal
bone. The margins are rough for
attachment of auricular cartilage.
99

SUPRAMEATAL TRIANGLE
Also known as McEwen triangle. It is
a small depression posterosuperior
to external auditory meatus.
Bounded above by supramastoid
crest, front by posterosuperior
margin of meatus, behind by a
vertical tangent to the posterior
margin of meatus . This triangle is
the lateral wall of tympanic or
mastoid antrum.
100

PTERION
The pterion is the region where the frontal,
parietal, squamous part of temporal, and
greater wing of sphenoid bone join together
by five cranial sutures : sphenoparietal suture
joins the sphenoid and parietal
bones,coronal suture joins the frontal bone
to the sphenoid and parietal
bones,squamous suture joins the temporal
bone to the sphenoid and parietal bones ,
spheno frontal suture joins the sphenoid and
frontal bones, sphenosquamosal suture joins
the sphenoid and temporal bones
GONION
The gonion is the lowest, posterior, and
lateral point on the angle of mandible.This is
at the apex of the maximum curvature of the
mandible, where ascending ramus becomes
body of the mandible.
ASTERION
It is the point where three cranial bones
meet Parietal bone , Occipital bone and
Mastoid portion of the Temporal bone.
101
GONION

MASTOID PROCESS
The mastoid process is a pyramidal bony
projection from the posterior section of
the temporal bone. The superior border
of the mastoid portion of the temporal
bone articulates with the parietal bone.
The posterior border articulates with the
occipital bone, and the anterior border is
merged with the descending portion of
the squamous section of the temporal
bone. The petrosquamous suture runs
vertically from the superior border of the
mastoid process. The tympanomastoid
fissure is placed on the anterior aspect of
base of the mastoid process. Mastoid
foramen lies near the occipitomastoid
suture. Appears at about 2 yrs of age.
102

STYLOID PROCESS
The styloid process is a slender pointed
bone projecting down and forward from
the inferior surface of the temporal bone,
serves as an anchor point for several
muscles associated with the tongue and
larynx.
Proximal part (Tympanohyal) is ensheathed
by the tympanic part of the temporal bone
Distal part (Stylohyal) gives attachment to
the following:
• stylohyoid ligament
• stylomandibular ligament
• styloglossus muscle
• stylohyoid muscle
• stylopharyngeus muscle
• The stylohyoid ligament extends from
the apex of the process to the lesser
cornu of the hyoid bone, and can
sometimes be partially or completely
ossified.
103

FORAMINA
1. Mastoid Foramen
- Emissary vein from sigmoid
sinus to posterior auricular vein
- meningeal branch of occipital
artery
2. ZygomaticoTempopral Foramen
Nerve of same name
3. Sphenopalatine Foramen
connects the nasal cavity with
pterygopalatine fossa
104

TEMPORAL FOSSA
Boundaries –
-Above by superior temporal line
-Below by lateral border of zygomatic
arch, medially by infratemporal crest of
sphenoid
-Anteriorly by zygomatic bone and part of
frontal and sphenoid.
-Medially by frontal bone, parietal bone,
temporal bone, and sphenoid bone
-Laterally by Temporal fascia
Contents –
- Temporalis muscle
- Deep temporal arteries
- Deep temporal nerves
- Superficial temporal artery (from
external carotid)
- Zygomaticotemporal nerve
105

INFRATEMPORAL FOSSA
Boundaries-
• anteriorly – posterior surface of body of
maxilla
• roof – infratemporal surface of greater
wing of sphenoid
• medial – lateral pterygoid plate and
pterygoid process of palatine bone
• lateral – ramus of mandible
Contents –
- Lateral pterygoid muscle
- Medial pterygoid muscle
- Mandibular nerve with branches, otic
ganglion
- Maxillary nerve with posterior superior
alveolar nerve
- Chorda tympani, branch of VII nerve
- 1st and 2nd part of maxillary artery and
branches
- Posterior superior alveolar artery,
branch of 3rd part of maxillary artery
- Pterygoid venus plexus
106

PTERYGOPALATINE FOSSA
Small pyramidal space situated deeply
below the apex of orbit
Boundaries –
- Anterior – superomedial part of
posterior surface of maxilla
- Posterior – root of pterygoid process
and anterior surface of greater wing of
sphenoid
- Medial – perpendicular plate of
palatine bone
- Lateral – opens into infratemporal
fossa through pterygomaxillary fissure
- Superior – undersurface of body of
sphenoid
- Inferior – closed by pyramidal process
of palatine bone
107

Communications –
- Anteriorly – orbit through inferior
orbital fissure
- Posteriorly – middle cranial fossa
through foramen rotundum
- Medially – nose through
sphenopalatine foramen
- Laterally – infratemporal fossa
through pterygomaxillary fissure
- Inferiorly – oral cavity through greater
and lesser palatine canal
Contents –
- Third part of maxillary artery and its
branches
- Maxillary nerve and zygomatic and
posterior superior alveolar branches
of maxillary nerve
- Pterygopalatine ganglion and its
branches
108

ATTACHMENT
Temporal fascia- from superior temporal
line to upper border of zygomatic arch
Temporalis Muscle – from whole of
temporal fossa. It passes medial to the
zygomatic arch and forms a tendon which
inserts onto the coronoid process of the
mandible
Masseter – arises from medial surface
and lower border of zygomatic arch
Sternocleidomastoid, Splenius capitis
and longissimus capitis are inserted on
the posterior part of lateral surface of
mastoid process.
Posterior belly of digastric arises from
mastoid notch
Lateral ligament of TMJ is attached to the
tubercle of root of zygoma
109

APPLIED ASPECTS
Zygomatic Arch fracture is a common
occurrence . To reduce the fracture,
Rowe zygomatic elevator is inserted
deep to the temporalis fascia and
superficial to the temporalis muscle
and outward force is applied to
reduce the fracture (Gillies
Approach).
110

ASTERION
Neurosurgeons use this
point to orient
themselves, in order to
plan safe entry into the
skull for some operations,
such as retro-sigmoid
approach.
111

PTERION
The pterion is known as the
weakest part of the skull. The
anterior division of the middle
meningeal artery runs
underneath the pterion.
Consequently, a traumatic blow
to the pterion may rupture the
middle meningeal artery causing
an extradural haematoma
compressing motor area of brain
leading to contralateral side
paralysis . The pterion may also
be fractured indirectly by blows
to the top or back of the head
that place sufficient force on the
skull to fracture the pterion.
112

GONION
Cephalometric landmark
Used as a forenesic tool to
determine gender.
113

EAGLE SYNDROME
Caused by an elongated or
misshapen styloid process and/or
calcification of the stylohyoid
ligament, which interferes with the
functioning of neighboring regions in
the body, giving rise to pain in the
jaw bone and joint, back of the
throat, and base of the tongue,
triggered by swallowing, moving the
jaw, or turning the neck.
114

SUPRAMEATAL TRIANGLE
In the adult, the mastoid antrum
lies approximately 1.5 to 2 cm
deep to the suprameatal triangle.
This is an important landmark
when performing a cortical
mastoidectomy or to place
chochlear implants. Through this
triangle an instrument may be
pushed into the mastoid antrum
to clean it.
115

TEMPORAL AND INFRATEMPORAL
FOSSA
Temporalis muscle is very often used as a
flap to reconstruct oropharynx defects.
Pterygoid venous plexus located in
infratemporal fossa. Veins in the head,
including those of the pterygoid venous
plexus, do not have valves.Infections may
therefore reverse the flow of blood into
the cavernous sinus, resulting ultimately
in meningeal infections. Frey’s syndrome
can occur after parotid surgery due to
injury of the auriculotemporal nerve.
- For nerve blocks it is a referrence
point
- Bleeding due to injury to pterygoid
venous plexus while giving posterior
superior alveolar nerve block
116

PTERYGOPALATINE FOSSA
• Maxillary Nerve Block
Extensive dental surgery may require
total nerve block of the maxillary
nerve. The maxillary nerve in the
pterygopalatine fossa is most often
approached intraorally via the greater
palatine canal.
• Chronic Epistaxis
The sphenopalatine artery is often
referred to as the artery of epistaxis.
In cases of chronic epistaxis, the
pterygopalatine fossa can be
surgically approached via the
maxillary sinus, and the artery ligated
to control bleeding.
117

SHAPE –
Roughly Oval In shape.
BONES –
• Hard palate formed by Palatine processes of the
maxilla and palatine bones
• The vomer
• Sphnoid bone with
I. The pterygoid processes
II. The under surfaces of the great wings
III. Spinous processes
• Temporal bone mastoid and petrous portions
• Occipital bone
119

SUTURES
Frontoethmoidal suture
Sphenofrontal suture
Sphenopetrosal suture
Sphenoethmoidal suture
Petrosquamous suture
Sphenosquamosal suture
120

ANTERIOR PART OF NORMA BASALIS
STRUCTURES-
- Alveolar Arch – bears the sockets for
roots of upper teeth
- Hard Palate –
Formed by in anterior 2/3rd by
palatine process of maxilla and posterior
1/3rd by horizontal plates of palatine
bone.
A cruciform suture present, formed by
intermaxillary, interpalatine and
palatomaxillary sutures.
Arched in all directions.
Posterior Border of hard palate is free.
Presents Posterior Nasal Spine in median
plane.
Foramina Present –
- Incisive Foramen
- Greater Palatine Foramen
- Lesser Palatine Foramen
122

MIDDLE PART NORMA BASALIS
From posterior border of hard palate to
anterior border of foramen magnum. It can
be subdivided into a median area and a
lateral area.
MEDIAN AREA –
Shows posterior border of Vomer which
separates two posterior nasal apertures.
Inferior border of vomer articulates with
palate.
Palatinovaginal canal – opens anteriorly into
posterior wall of pterygopalatine fossa.
Vomerovaginal canal – formed by lateral
border of ala of vomer and vaginal process
of medial pterygoid plate.
123

Lateral Area –
Shows Pterygoid process and greater wing of Sphenoid Bone. Three
parts of temporal bone is also seen – petrous temporal, tympanic plate
and squamous temporal.The medial and lateral pterygoid plates form
Pterygoid fossa.Pterygomaxillary fissure separates fused pterygoid
plates anteriorly from maxilla.
Infratemporal Surface of Greater wing of Sphenoid is seen. It is
pentagonal in shape. The posteriormost point between the
posterolateral and posteromedial margins project downwards to form
the spine of sphenoid.
Foramina Present –
- Foramen ovale- lateral pterygoid plate
- Foramen spinosum- sphenoid bone
- Emissary sphenoidal foramen or foramen of Vesalius - sphenoid
- Canaliculus innominatus – sphenoid bone
- Foramen lacerum – between occipital and sphenoid bone
124

POSERIOR PART NORMA BASALIS
From anterior border of foramen magnum upto
external occipital protruberance. Can be
divided into a median area and lateral area.
Median Area –
Shows Foramen Magnum, external occipital
crest, external occipital protuberance, Nuchal
lines.
Foramen Magnum is the largest foramen of the
skull. Opens upwards to posterior cranial fossa,
downwards into vertebral canal. Oval in shape.
external occipital crest begins at posterior
margin of foramen magnum upto above
external occipital protuberance.
external occipital protuberance is a projection
at the posterior end of the crest. This is the
point when back of neck becomes scalp.
Nuchal lines are usually two, superior and
inferior. Sometimes a third , the highest nuchal
line may be present.
125

Lateral Area –
Shows – condylar part of occipital bone
- squamous part of occipital bone
- jugular foramen between occipital and squamous temporal
- styloid process of temporal bone
- mastoid part of temporal bone
Condylar part of Occipital bone – articulate with atlas superior articular facet
forming atlanto-occipital joint. Hypoglossal Canal pierce it anterosuperior to
the condyle. Posterior condylar canal is present sometimes in the floor, opens
into sigmoid sulcus.
Squamous part of occipital bone is marked by the nuchal lines.
Jugular foramen between occipital and squamous temporal bones with the
long axis directed forwards and medially. At its posterior end it presents
Jugular fossa. Jugular fossa is larger on right side than on left.
Stylomastoid foramen is present at the root of styloid process.
126

1. Tensor veli palatini – palatine crest
2. Superior constrictor muscles of pharynx – pharyngeal tubercle
3. Longus capitis – lateral to pharyngeal tubercle
4. Rectus capitis anterior – posterior and medial to hypoglossal canal
5. Pterygomandibular raphe – tip of pterygoid humulus to mandible behind 3rd
molar
6. Pterygospinous ligament- middle of medial pterygoid plate
7. Lateral pterygoid – lateral surface of lateral pterygoid plate
8. Medial pterygoid – medial surface of lateral pterygoid plate
9. Sphenomandibular ligament, anterior ligament of malleus and
pterygospinous ligament – tip of sphenoid
10. Levator veli palatini – inferior surface of petrous temporal
11. Anterior atlanto-occipital membrane, posterior atlanto-occipital membrane,
alar ligament- margins of foramen magnum
12. Ligamentum nuchae – external occipital protuberance and crest
13. Rectus capitis lateralis – inferior surface of jugular process of occipital
14. Semispinalis capitis, superior oblique- area between superior and inferior
nuchal lines
15. Rectus capitis posterior major and minor – area below inferior nuchal line
16. Posterior belly of digastric – mastoid notch
128

CONTENTS OF FORAMINA
• Incisive foramen – greater palatine vessels, nasopalatine nerve
• Greater palatine foramen – greater palatine vessels, anterior palatine
nerve
• Lesser palatine foramen – middle and posterior palatine nerve
• Palatinovaginal canal – pharyngeal branch of pterygopalatine ganglion,
pharyngeal branch of maxillary artery
• Vomerovaginal canal – branches of pharyngeal branch of pterygopalatine
ganglion and vessels
• Foramen ovale – MALE – mandibular nerve, accessory meningeal artery,
lessor petrosal nerve, emissary vein
• Foramen spinosum – middle meningeal artery, meningeal branch of
mandibular nerve and posterior trunk of middle meningeal vein
• Foramen of vesalius – emissary vein cavernous sinus with pterygoid plexus
• Carotid canal – internal carotid artery and the venous and sympathetic
plexus aroud it
129

• Foramen Lacerum – lower part - meningeal branch of ascending pharyngeal
artery and emissary vein from cavernous sinus
• Foramen lacerum – upper part – greater petrosal nerve unites with deep
petrosal nerve to form nerve of pterygoid canal ( Vidian’s Nerve)
• Foramen magnum – Anterior Part –
Apical ligament of Dens
vertical band of cruciate ligament
Membrana tectoria
Posterior Part –
lowest part of medulla oblongata
three meninges
Subarachnoid Space –
Spinal accessory nerves
vertebral arteries
posterior spinal arteries
anterior spinal artery
•
130

• Jugular Foramen - Anterior Part –
inferior petrosal sinus
meningeal branch of ascending
pharyngeal artery
Middle Part –
9th, 10th and 11th cranial nerves
Posterior Part –
internal jugular vein
meningeal branch of occipital Artery
• Stylomastoid Foramen - facial and stylomastoid branch of posterior auricular
artery
• Mastoid Canaliculus – Arnold’s Canal – transmits auricular branch of vagus
nerve ( Arnold’s Nerve )
• Tympanic Canaliculus – Transmits tympanic branch of glossopharyngeal nerve
(Jacobson’s nerve) to middle ear cavity
131

• Largest and strongest bone of the face
• Developed from first pharyngeal arch.
• Horseshoe shaped bone
• Second bone in the body to ossify after clavicle.
• Ossification - partly membranous & partly
cartilaginous in ossification
133
Cartilaginous Ossification
• Incisive part below symphysis menti
• Coronoid process
• Condylar process
Membranous ossification
• Whole of body except lower incisive part
• Lower half of ramus upto mandibular foramen

OSSIFICATION
• Its greater part ossifies in membrane . Each half of mandible ossifies from
one centre which appears in the 6thweek of intrauterine life in
mesenchymal sheath of Meckle’s cartilage in the region of bifurcation of
inferior alveolar nerve into mental and incisive branches. As the
ossification continues, the meckel’s cartilage become surrounded and
invaded by bone.
• Ossification stops at the site that will later become the mandibular lingula
from where the meckel’s cartilage continues into the middle ear and
develops into the auditory ossicles i.e. malleus and incus.
134

Endochondral ossification is seen in 3 areas of mandible:
• The condylar process:-Ossification starts by14th week.
• The coronoid process:-Ossification starts by about the 10-
14 week of IU life.
• The mental region:-Ossification starts by the 7thmonth of
I.U. life.
• The two halves of the mandibular body are united by
fibrous joint at the symphysis menti which is replaced by
the bone within 2nd year.
135

PARTS OF MANDIBLE
The mandible can be divided into
several sub-units like
• Body
• Ramus
• Chin
• Alveolar process
• Coronoid process
• Condylar process
• Angular process
• Lingual tuberosity
136

Body
Each half of body has outer and inner
surface and upper and lower border.
Outer Surface Features –
Symphysis Menti
Mental Protuberance
Median triangular projecting area
Its inferolateral angles form mental
tubercles
Mental Foramen
Between the premolar teeth
Oblique Line
Continuation of the sharp anterior
border of ramus of mandible. Runs
downwards and forwards towards the
mental tubercles.
Incisive Fossa
depression just below incisor teeth 137

Inner surface features
Mylohyoid line
a prominent ridge running obliquely
downwards and forwards from below third
molar to the median area below genial
tubecles
Genial Tubercles
posterior surface of symphysis menti.
Four small elevations- superior and inferior
genial tubercles
Submandibular Fossa
below mylohyoid line
Sublingual fossa
Above mylohyoid line
Mylohyoid Groove
Extends from ramus below the posterior
end of mylohyoid line
Digastric Fossa
near midline the base shows a oval
depression called digastric fossa
138

RAMUS
Quadrilateral in shape. Has two surfaces – lateral and
medial, four borders – upper, lower, anterior and
posterior, two processes – coronoid and condylar
processes.
Lateral Surface –
Flat, bears a number of oblique ridges
Medial Surface –
- Mandibular foramen – little above centre, at the
occlusal level of teeth, leads to mandibular canal,
opens at mental foramen
- Lingula – anterior margin of mandibular foramen,
sharp tongue shaped projection, directed towards
head of condylar process
- Mylohyoid Groove – begins just below mandibular
foramen, runs downwards and forwards, gradually
lost over submandibular fossa
Upper Border –
Thin, curved downwards forming mandibular notch.
Lower Border –
Continuation of base of mandible
Anterior Border is thin, posterior border is thick
139

Coronoid Process
Flattened triangular upward projection
from the anterosuperior part of ramus.
Its anterior border is continuous with
anterior border of ramus and posterior
border bounds the mandibular notch.
Condyloid Process
Upward projection from posterosuperior
part of ramus. Upper end forms head.
Constriction below head is the neck. Its
anterior surface presents a depression
called pterygoid fovea. Head is covered
with fibrocartilage and articulates with
temporal bone to form the
temporomandibular joint.
140

ATTACHMENTS AND RELATIONS
THE LATERAL SURFACE
1. From The Oblique line :
Origin to Buccinator and In front of this origin:
depressor labii inferioris and depressor anguli
oris below the mental foramen
2. Incisive fossa:
Gives origin to mentalis and mental slips of
orbicularis oris.
3. Whole of lateral surface of ramus except
posterosuperior part provides insertion to
masseter.
4.Posterosuperior part: covered by parotid
gland.
5. Lateral surface of the neck provides insertion
to the lateral ligament of TMJ.
6. Parts of both the inner and outer surfaces just
below the alveolar margins are covered by
mucous membrane of the mouth.
7. Platysma is inserted into the lower border.
8. The deep cervical fascia ( investing layer) is
attached to the whole length of the lower
border.
141

THE MEDIAL SURFACE
1.Digastric fossa: arises Anterior belly of
digastric
2.Genial tubercles: arises Genioglossus and
Geniohyoid.
3.Mylohyoid line : arises Mylohyoid
4.From an area above the posterior end of
mylohyoid line: arises Superior constrictor
of pharynx.
5.Pterygomandibular Raphe: Attached
immediately behind the third molar tooth
in continuation with the origin of superior
constrictor .
7.Below and behind the mylohyoid groove:
insertion of Medial pterygoid muscle .
8.At the apex of coronoid process:
Temporalis is inserted ;extend downwards
on ant. Border of ramus.
9.Into the pterygoid fovea: insertion of
Lateral pterygoid.
10.Sphenomandibular Ligament: is
attached to the lingula.
142

FORAMINA
• Mental foramen
mental nerve and vessels
• Mandibular foramen
inferior alveolar nerve and
vessels
143

RELATION TO NERVES AND VESSELS
• Mylohyoid nerve and vessels lie in the mylohyoid groove.
• The lingual nerve is related to the medial surface of the ramus in front of
the mylohyoid groove.
• The area above and behind the mandibular foramen is related to the
INFERIOR ALVEOLAR NERVE and VESSELS ; and MAXILLARY ARTERY
respectively.
• The masseteric nerve and vessels pass through the mandibular notch.
• The auricotemporal nerve is related to the medial side of the neck of the
mandible.
144

BLOOD SUPPLY OF THE MANDIBLE
• Central blood supply via THE INFERIOR ALVEOLAR
ARTERY except the coronoid process , which is
supplied by temporalis muscle vessels.
• Peripheral blood supply via the PERIOSTEUM..
• Periosteal supply ,which generally runs parallel to
cortical surfaces of bone, giving off nutrient vessels.
Those penetrate cortical bone and anastomose with
the branches of inferior alveolar artery.
145

NERVE SUPPLY OF MANDIBLE
It is basically derived from mandibular branch of trigeminal
nerve.
• The long buccal nerve: The anterior division of the
mandibular nerve. It supplies mucosa opposite the last three
mandibular molars on their buccal aspect.
• The inferior alveolar nerve: The posterior division of the
mandibular nerve. It supplies all lower jaw teeth, lower lip,
buccal mucosa from the incisors to the premolar & the skin
over the chin.
• The lingual nerve: The posterior division of the mandibular
nerve. It gives sensory supply to the anterior 2/3rd of tongue,
the mucosa on the lingual aspect of the lower teeth & the
floor of mouth.
146

LYMPHATIC DRAINAGE
• Most of the mandible & lower teeth drain into the
submandibular group of lymph nodes .
• A small wedge in the symphysis region & the lower incisors
drain into the submental group of lymph nodes.
• From the submental group the lymph drains to the
submandibular group of nodes.
• Most of the submandibular nodes ultimately drain to the
jugulo-omohyoid group of deep cervical lymph nodes.
• Few extremely posterior submandibular nodes drain to
jugulo-digastric group of deep cervical lymph nodes.
147

AGE CHANGES IN THE MANDIBLE
148

CLINICAL ASPECTS
149
From beneath the teeth the occlusal force trajectories join
together in common pillar- ends at condyle.Mandibular nerve
and canal are protected. Trajectories from sympysis, gonial angle
and coronoid process join this main pillar. These force
trajectories play vital role in 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.
• The body of the mandible is
considerably thicker than the ramus
and the junction between these two
portions constitutes a line of structural
weakness.
• Strength of the lower jaw varies with
the 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.
150

• The slender neck of the
mandibular condyles renders it
particularly liable to fracture as
a result of direct violence
applied to the chin.
• This acts as a safety
mechanism , as a fracture of
neck of the condyle prevents
injury to the middle cranial
fossa.
• Direct blow to the chin region
can lead towards fracture of
one or both condyles.
• Sideways blow can bring about
fracture of the opposite
condylar neck along with the
parasymphysis fracture at the
same side of the blow.
151

External oblique ridge
• Resective surgery difficult because
of the amount of bone to be
removed.
• Apical positioning of the flap is
difficult in these areas.
• A high buccinator attachment
results in a shallow vestibule,
making grafting procedures
difficult.
Lingual nerve Injury
Because of the superficial presence of
lingual nerve Injury to the lingual nerve
during flap reflection, releasing
incisions, anesthestic injections may
happen.
152

MAXILLA
Maxilla is the second largest bone of the face, the first being the
mandible. Each maxilla forms a part in formation of nose, mouth,
orbit, infratemporal and pterygopalatine fossa.
Parts of Maxilla –
1. Body - a) 4 Surfaces
•Anterior or Facial
•Posterior or Infratemporal
•Superior or Orbital
•Medial or Nasal
b)Maxillary Sinus OR Antrum Of Highmore
2. 4 Processes
•Frontal
•Zygomatic
•Alveolar
•Palatine
155

Anterior Surface
157
Canine Fossa
Depressor septi
Incisivus
Nasalis
Levator anguli oris
Nasalis
Levator labi superioris

Posterior / Infratemporal Surface
158
Maxillary tuberosity
Superficial Head Of Medial
Pterygoid
Alveolar Canals For
Posterior Superior
Alveolar Nerve

Medial/Nasal Surface
160
Forms part of lateral wall of nose. Postero superiorly – Large irregular opening
of maxillary sinus - Maxillary Hiatus. Above the Hiatus- Parts of air sinuses.
Below the Hiatus- Inferior meatus. Behind the Hiatus- surface articulates with
the perpendicular plate of palatine bone. Infront of the Hiatus- Nasolacrimal
groove converts to Nasolacrimal canal- transmits Nasolacrimal ducts to the
inferior meatus of nose

Maxillary Sinus
Large cavity in the body of Maxilla. Pyramidal shape- Base directed medially
and apex laterally. Sinus opens into Middle meatus. Height approx. 3.5cm ,
width 2.5 cm, anteroposterior depth 3.5cm. Roof – floor of Orbit, Floor-
Alveolar process of Maxillae.Reaches full size after the eruption of permanent
Teeth.
161

Processes of Maxilla
• Frontal Process - Articulates with Frontal,Nasal and Lacrimal bones.
• Palatine Process - Thick horizontal plate projecting medially. Inferior
surface is concave. Two palatine processes form anterior three fourths of
bony palate. Superior surface is concave side to side. Medial border is
thicker in front than behind. Posterior border articulates with horizontal
plate of palatine bone. Lateral border is continuous with the alveolar
process.
• Zygomatic Process - Pyramidal lateral projection on which the anterior ,
posterior and superior surfaces of maxilla converge. Superiorly it is rough
for the articulation with the zygomatic bone.
• Alveolar Process - It bears sockets for roots of the upper teeth. Buccinator
arises from the posterior part of its outer surface up to the first molar.
162

PARIETAL BONE
• Paired Bone of Cranium
• Two Surfaces – Outer Convex Surface
Inner Concave Surface
• Four Borders - Superior or Sagittal Border
Inferior or Squamosal Border
Anterior or Frontal Border
Posterior or Occipital Border
• Four Angles – Anterosuperior or Frontal Angle
Anteroinferior or Sphenoidal Angle
Posterosuperior or Occipital Angle
Posteroinferior or Mastoid Angle
164

Occipital Bone
Three Parts – Squamous Part
Basilar Part
Condylar or Lateral Part
167

Consists of Five Parts
1. Squamous Part
2. Petromastoid Part
3. Tympanic Part
4. Styloid Process
5. Zygomatic Process of Temporal Bone
170

Squamous Part - Outer Surface
171
Groove for middle
temporal artery
Supramastoid crest
Suprameatal triangle
Articular tubercle

Squamous Part - Inner Surface
172
Groove for Middle meningeal artery

Petrous Part
Roughly Triangular In Shape. Base is fused with squamous and mastoid parts, apex forms the
posterolateral boundary of Foramen Lacerum. Has Three Surfaces – Anterior, Posterior and
Inferior
Anterior Surface
175
Trigeminal Impression
Tegmen Tympani

Posterior surface
176
Internal Acoustic Meatus

Zygomatic Process
• Starts from the outer surface of squamous part . Has superior and inferior surface.
• Inferior surface has two roots – Anterior Root , Posterior Root; Converge at Articular Tubercle
• Mandibular Fossa lies behind Articular Tubercle, consists of anterior articular part –
squamous temporal and posterior non articular part – tympanic plate of temporal bone.
177

Tympanic Part
Contains External Acoustic Meatus
Its bony part - 16 mm long
Inner end is closed by tympanic
membrane
Styloid Process
Directed downwards, forwards and
medially.
Base is related to Facial Nerve.
Apex is crossed by External Carotid
178
Styloid Process

Clinical Aspects
The mastoid process in children is not fully developed till 6yrs of age, thus cannot be palpated
easily. Hence the postauricular incision in children should be given more horizontally to prevent
injury to the facial nerve.
The tympanosquamous and tympanomastoid sutures are landmarks for the “vascular strip”
incisions used in tympanomastoid surgery.
Meckel’s cave or Trigeminal Impression - For relief of pain in trigeminal neuralgia glycerol
injection is given in the gasserian ganglion in this region.
181

Griesinger’s sign - Tenderness and edema over the mastoid region are
pathognomonic for suppurative thrombophlebitis of the sigmoid sinus and
reflect thrombosis of the mastoid emissary veins.
Arcuate eminence - Present in about 85% of temporal bones, approximates
the position of the superior semicircular canal (SSCC) and is a key landmark in
middle cranial fossa surgery.
Digastric groove - Medial to the mastoid tip is the digastric groove for the
posterior belly of the digastric muscle. This is an important landmark for the
identification of facial nerve during parotid surgery.
182

FRONTAL BONE
183
• Unpaired Bone
• Forms the forehead, most of the roof of orbit and
floor of anterior cranial fossa
• Three parts – 1. Squamous Part
2. Orbital Plates
3. Nasal Part

184
Glabella
Frontal air sinus

SPHENOID BONE
• Resembles a bat with out stretched wings
• Comprises of - Body
- Two lesser wings from anterior part of body
- Two greater wings from lateral part of body
- Two Pterygoid Processes
187
Lesser wings
Greater
wing
Pterygoid
process
Body

Superior view Landmarks
188
Jugum sphenoidale
Sulcus chiasmaticus
Tuberculum sellae
Sella turcica
Dorsum sellae

Greater wing - Foramen
189
Contents - 1. Foramen Rotundum - The maxillary branch of the trigeminal nerve
2. Foramen Ovale - Mandibular nerve, Accessory meningeal artery , Lesser petrosal nerve, An
Emissary vein
3. Foramen spinosum - Middle meningeal vessels, meningeal branch of the mandibular nerve
Lesser Wing – Optic Canal - transmits the optic nerve and ophthalmic artery

Superior Orbital Fissure
Triangular gap between the Lesser wing and Greater wing of sphenoid
through which the middle cranial fossa communicates with orbit.
Contents -
190

Ethmoid Bone
Cuboid shaped bone located between the orbits. Comprises of Cribiform
Plate, Perpendicular Plate and a Pair of Labyrinths. Cribirorm plate contains
foramina for Olfactory Nerve Rootlets. Perpendicular plate forms upper part
of nasal septum. Labyrinth contains anterior, middle and posterior ethmoidal
air sinus.
191

Clinical Aspects
Naso orbito ethmoidal fracture – A complex of fractures due to facial
trauma – most commonly due to RTA, fall from height etc.
Fracture of cribriform plate – branches of the olfactory bulb may be sheared.
This may cause anosmia
Fracture of the labyrinth – may allow communication between the nasal
cavity and the orbit. Possible for air to enter the orbit and cause orbital
emphysema.
CSF Rhinorrhoea - Fracture of cribriform plate may allow communication
between the nasal cavity and the central nervous system. Consequently,
cerebrospinal fluid (CSF) can enter the nasal cavity and drain out from the
nose. This manifests clinically as a clear watery discharge from one side of the
nose – known as CSF rhinorrhoea.
The leaks normally stop spontaneously and can be managed conservatively,
however surgery is sometimes required. Spontaneous CSF rhinorrhoea can
also occur due to congenital or acquired defects in the ethmoid bone.
192

Vomer
Single thin flat bone forming the posteroinferior part of nasal septum.
193
Free border
Palatine bone
Maxilla
Septal cartilage

Nasal Bone
Oblong shaped pair of bones forming bridge of nose.
194
Posterior view Anterior view
Frontal Process
of Maxilla
Nasal Part of Frontal
Nasal Cartilage
Vascular Foramen

Lacrimal Bones
Smallest of skull bones. Form the anterior part of medial part of orbit.
195
Orbital surface Groove for lacrimal sac
Descending Process For Inferior Nasal Concha

Inferior Nasal Conchae
Two curved bony laminae, horizontally placed in the lower part of lateral walls
of nose. Between this concha, the inferior meatus of nose is present.
196

Zygomatic Bone
Quadrilateral shaped bones present on the upper and lateral part of face
forming prominence of cheek.
197

Palatine Bones
L- Shaped bones present in the posterior part of nasal cavity forming lateral
wall and floor of nasal cavity, roof of oral cavity, part of floor of orbit and part
of pterygopalatine fossa. Has 2 plates ( Horizontal and Perpendicular) and 3
processes ( Pyramidal, Orbital and Sphenoidal)
199

Processes of Palatine Bone
200

Referrences
• Gray’s Anatomy – 38th Edition
• Ten cate's oral histology - 8th edition
• Cunningham's Manual of Practical Anatomy VOL 3
Head, Neck and Brain – 16th edition
• Inderbir Singh’s Human Embryology – 2017
• BD Chaurasia's Handbook of General Anatomy – 7th
edition
202

CLINICAL ASPECTS OF
MAXILLOFACIAL OSTEOLOGY
205

ANTILINGULA
The antilingula is a bony tubercle or prominence on the lateral surface of the
ramus of the mandible. Antilingula is an important landmark in mandibular
ramus surgery in which the medial surface of the ramus is not visualized such
as sagittal split ramus osteotomy, inverted L osteotomy etc.
208

Retromolar Region
209
• The retromolar fossa is a landmark for IAN block.
• Serves as a landmark for posterior extension of Dentures

Retromolar Triangle
Neoplasms of retromolar trigone have important peculiarities due to their spatial
relationships with the surrounding structures. Tumours that involve this area can
extend to nearby muscles; adipose spaces; and other anatomic structures, such as
the soft palate, the tonsillar fossa, the parapharyngeal space, and the floor of the
mouth.
210

• The mandible is basically tubular long bone which is bent
into a blunt “v” –shape, therefore presenting a prominent
surface
• The cortical bone is thicker anteriorly and at the lower
border of mandible , while posteriorly the lower border is
relatively thin.Average thickness of Cortex in symphysis &
parasymphisis region is 3.5 mm. Average thickness of
Cortex in premolar & Body region is 2.5 mm
• Thus the mandible is strongest anteriorly in the midline
with progressively less strength towards the condyle
• Mandible fracture at sites of tensile strain, produced by
pulling of different muscles, since the resistance to
compressive forces is greater
• Energy of 44.6-74.4 kg/m required to fracture the
mandible
211

Muscle attachments
212
Mentalis
Orbicularis oris

Weak areas of mandible
• Junction between alveolar bone & basal mandibular bone.
• Symphysis region - junction of two individual bones.
• Parasymphyseal region - lateral to the mental prominence, incisive fossa
and mental foramen.
• Junction of the ramus and the body are fractured commonly.
• Presence of impacted tooth, canine with long roots.
216

The different muscle pull can produce favourable and unfavourable types of
fractures.
218

Force Trajectories of Beninghoff
• Force trajectories are orientation of bony trabeculae in a bone. These are pathways of
maximal pressure and tension. Bone trabeculae is thicker in regions of greater stress.
In mandible, From beneath the teeth, the occlusal force trajectories join together in
common pillar- ends at condyle. Trajectories from sympysis, gonial angle and coronoid
process join this main pillar. These force trajectories form the basis of Champy’s
Principle of Osteosynthesis in mandibular fracture.
219

Champy’s principles
• Forces of mastication produce tensional forces on upper border & forces of
compression on lower border. Champy put forward the lines where plates &
screws have to be placed - “ideal osteosynthesis lines”. It corresponds to course of
a line of tension at base of the alveolar process. Only in symphysis region, 2 plates
are placed to neutralize torsional forces generated by genioglossus and
geniohyoid. In body of mandible, Champy’s line is the same as the External
Oblique Ridge.
220

External oblique ridge
• Resective surgery difficult because of the amount of bone to
be removed.
• Apical positioning of the flap is difficult in these areas.
• A high buccinator attachment results in a shallow vestibule,
making grafting procedures difficult.
Lingual nerve Injury
• Because of the superficial presence of lingual nerve, Injury to
the lingual nerve during flap reflection, releasing incisions,
anesthestic injections may happen.
222

Mandible As A source of Autogenous Bone Harvesting Site
Donor sites include the chin bone, the ramal bone, the mandibular body
window bone, the mandibular torus bone. The other intraoral donor sites are
the maxillary torus bone, the sinus anterior wall and the maxillary tuberosity
bone. The chin bone is the most abundant source. Used for reconstruction of
alveolar cleft, lateral crest augmentation before dental implantation and sinus
floor augmentation
223

224
Ramus harvesting
Retromolar harvesting

Blood supply of Mandible and its Effects
Vascular supply of mandible is mainly from Inferior Alveolar Artery. Therefore the
occurrence of osteomylitis in mandible is more than other facial skeleton. Blood
supply from the surrounding periosteum plays very important role in healing of
fractures specially in elderly and in injuries involving the inferior alveolar canal.
Therefore in severely atrophic mandible, minimum stripping of periosteum is done
in open reduction.
Condylar Vascular Supply –
226
It is mainly from terminal branches of
transverse facial artery, superficial temporal
artery, posterior tympanic artery and deep
temporal artery ( along lateral pterygoid
muscle). The vascular supply at lateral dorsal
edge is relatively less, therefore it is the most
suitable place to start surgical repositioning in
case of fracture of condylar neck.

Applied Anatomy of Midfacial Skeleton
It is the area bounded superiorly by a line drawn from the
zygomaticofrontal suture across the frontonasal &frontomaxillary suture
to the zygomaticofrontal suture at the opposite side. Inferiorly by the
occlusal plane or the alveolar ridge, and posteriorly as far as the frontal
bone above and body of sphenoid below.
It is composed of the following:
1- Two maxillae
2- Two zygomatic bones.
3- Two palatine bones.
4- Two zygomatic process of temporal bone.
5- Two nasal bones.
6- Two lacrimal bones.
7- Vomer
8- Ethmoid and its attached conchae.
9- Two inferior conchae.
10- Pterygoid plates of sphenoid.
227

Maxillary Buttress Concept
• Although it is considered as the crumple zone of neurocranium, there are
pillars of stronger bone as described by Sicher and Tandler. They are called
Buttresses of Face. They are used for maxillary re-costruction.
228
pterygomaxillary
nasomaxillary
zygomatic

In response to apllication of blunt force to midfacial skeleton, the anatomical
construction of midface causes it to fracture in three levels of bone weakness
as described by Rene Le Fort (1901) in order to absorb as much energy as
possible before it hits neurocranium. The fracture lines usually follow the
suture lines.
230

Le Fort 1
• Low level or Guerin Fracture or Floating Maxilla
• Laterally – lateral margin of anterior nasal aperture- lateral wall of
maxillary sinus- below zygomatic buttress- lower 1/3rd of pterygoid
lamina- associated palatine bone
• Medially – lower 1/3rd of nasal septum – lateral margin of anterior nasal
aperture – proceeding posteriorly to join the lateral fracture behind
tuberosity
231

Le Fort 2
• Pyramidal Fracture
• Anteriorly - Frontonasal suture, crossing the frontal process of maxilla, into
the medial wall of orbit, lacrimal bone behind lacrimal sac, turning
forward to cross the infraorbital margin, extending downwards across
lateral wall of maxillary sinus, at the zygomaticmaxillary suture, middle
1/3rd of pterygoid lamina horizontally
• Posteromedially – separation of the block from base of skull via nasal
septum. May involve anterior cranial fossa.
233

Subconjuctival Hemorrhage
Restricted to the medial half of eyeball
Depressed bridge of nose
235

Le Fort 3
• Suprazygomatic Fracture or Craniofacial Dysjunction
• The fracture runs from near the frontonasal sutures transversely
backwards, parallel with the base of the Skull and involves the full depth
of the ethmoid bone, including the cribriform plate. Within the orbit, the
fracture passes below the optic foramen into the posterior limit of the
inferior orbital fissure. From the base of the inferior orbital fissure the
fracture line extends in two directions; backwards across the
pterygomaxillary fissure to fracture the roots of the pterygoid laminae and
laterally across the lateral wall of the orbit at frontozygomatic suture.
• Fracture of zygomatic arch is an integral part of Le Fort 3 fracture. In this
way the entire middle third of the facial skeleton becomes detached from
the cranial base.
236

Signs and Symptoms – All the signs and symptoms present in Le Fort 2 Fracture. In
addition, the following may be present.
csf rhinorrhoea
csf rhinorrhoea
237
csf rhinorrhoea
Panda face
Bi-lateral sub-conjuctival Hemorrhage
Posterior limitation not seen

Zygoma
238
Zygomatic bone articulates with temporal, sphenoid, frontal
and maxillary bones. By virtue of its attachments, it forms the
lateral wall and floor of orbit, roof and lateral wall of maxillary
sinus.

239
The lateral orbital tubercle, or Whitnall's tubercle, is found on the zygomatic bone. it is typically
around 11 mm inferior to the frontozygomatic suture and sits 4-5 mm posterior to the lateral
orbital rim around the midline (2).
Attachments
"4 L's":
Lateral rectus check ligament
Lockwood suspensory ligament
Lateral palpebral ligament
Levator aponeurosis

Zygomatic fractures result from direct impact to bone. This causes
fracture at either one or more of its processes. Any zygomatic
fracture involves discontinuity along the floor of orbit. By virtue of
its muscle attachments, the displacement is usually posteriorly,
inferiorly and medially.
240

Signs and Symptoms
• Subconjuctival and periorbital hemorrhage. In many cases it is confined to the
distribution of orbital septum producing spectacle hematoma.
• Hypoesthesia or anesthesia of infraorbital nerve distribution.
241

• Because Lateral Canthal Ligament and Lockwood’s Suspensory Ligament are
attached to Whitnall’s Tubercle, in case of inferior and posterior displacement of
zygoma, it causes the globe to migrate medially, inferiorly, causing enophtalmous.
• Medial displacement of zygoma may compress the volume of orbit and produce
exophtalmous rather than enophtalmous.
242

Naso-Orbito-Ethmoid Region
• Central region at the junction of upper and middle third of facial skeleton.
• Bones present – Nasal
- Frontal Process of Maxilla
- Frontal
- Ethmoid
• Forces transmitted directly to the nasal bridge dissipate into the ethmoid
air cells, which act as a crumple zone minimising injury to the cerebral
structures.
243

Nasal bone
Nasal bones articulate superiorly to nasal part of frontal bone through a
serrated joint. Laterally they articulate with frontal process of maxilla. The
two nasal bones articulate with each other on their posterior surface to form
a vertical crest which articulates with the nasal spine of frontal bone to form a
pyramid. This protects the ethmoid and lacrimal bone and lacrimal apparatus.
244
key stone area
Perpendicular plate of ethmoid bone

Lacrimal Apparatus
It consists of Puncta, Canaliculi and Ampulla, Nasolacrimal Sac and Duct and Medial
Canthal Ligament Complex of eyelids. The Medial Canthal Ligament of eyelids are
attached anteriorly to the frontal process of maxilla near suture with nasal bone
extending laterally upto anterior lacrimal crest of lacrimal bone, posteriorly it
continues as lacrimal fascia. As this ligament supports the eyelid which is of great
esthetic importance, the various layers are precisely arranged during surgical repair
of this area.
245

Saddle Nose Deformity CSF Rhinorrhoea
246

Telecanthus
Due to displacement or disruption of
medial canthal ligament
Epicanthal fold Obliteration
247

Orbital Blow Out Fracture –
The roof - orbital plate frontal bone, lesser wing of sphenoid near the apex of the
orbit. The floor - orbital surface of maxilla, the orbital surface of zygomatic bone
orbital process of palatine bone. The medial wall-orbital plate of ethmoid, frontal
process of maxilla, the lacrimal bone. The lateral wall - frontal process of zygomatic,
posteriorly by the orbital plate of the greater wing of sphenoid. The bones meet at
the zygomaticosphenoid suture. The lateral wall is the thickest wall of the orbit.
Therefore most fractures happen either on medial wall or floor.
248
Tear drop appearance

Pterion - The pterion is the region where the frontal, parietal, squamous part
of temporal, and greater wing of sphenoid bone join together. The weakest
part of the skull. The anterior division of the middle meningeal artery runs
underneath the pterion. Consequently, a traumatic blow to the pterion may
rupture the middle meningeal artery causing an extradural haematoma
compressing motor area of brain leading to contralateral side paralysis . The
pterion may also be fractured indirectly by blows to the top or back of the
head that place sufficient force on the skull to fracture the pterion.
250

EAGLE SYNDROME
• Caused by an elongated or misshapen styloid process and/or calcification
of the stylohyoid ligament, which interferes with the functioning of
neighboring regions in the body, giving rise to pain in the jaw bone and
joint, back of the throat, and base of the tongue, triggered by swallowing,
moving the jaw, or turning the neck
251

Battle's sign
• Mastoid ecchymosis, is an indication of fracture of middle cranial fossa of
the skull, and may suggest underlying brain trauma. Battle's sign consists
of bruising over the mastoid process, as a result of extravasation of blood
along the path of the posterior auricular artery.
252

• The mastoid process in children is not fully developed till 6yrs of
age, thus cannot be palpated easily. Hence the postauricular
incision in children should be given more horizontally to prevent
injury to the facial nerve.
• The tympanosquamous and tympanomastoid sutures are
landmarks for the “vascular strip” incisions used in tympanomastoid
surgery.
• Meckel’s cave or Trigeminal Impression - For relief of pain in
trigeminal neuralgia glycerol injection is given in the gasserian
ganglion in this region.
253

• Digastric groove - Medial to the mastoid tip is the digastric groove for the
posterior belly of the digastric muscle. This is an important landmark for
the identification of facial nerve during parotid surgery.
254

Anterior portion of squamous part of frontal bone contains frontal air sinus.
This sinus usually has a septum dividing it into right and left parts. The
posterior wall of the sinus is the only barrier between the sinus and anterior
cranial cavity. Thus the sinus acts as a safeguard. The sinus drains into middle
meatus via frontonasal duct. The anterior sinus wall can withstand a force of
350-1000 kg per square inch.
• The fracture of outer and
inner table may lead to
CSF Rhinorrhoea.
• Space occupying lesions in
the sinus may erode bone &
compress the cranial cavity.
• Frontal sinus infection may
spread to adjacent eyes and
brain.
256

• Parietal tuber/ parietal eminence is a very common site of fracture of
skull
• The parietal bone is diploeic in structure. It contains an outer and an inner
cortical plate with spongy bone in between.
258

• Thus the parietal bone is the most appropriate source for cranial bone
grafts harvesting site. The inner and the outer cortex is thick with a wide
diploë in between. The harvesting area should stay away 2.0 cm from the
cranial suture lines, in particular from the midline, in order to prevent
injury to the sagittal sinus.
• There are several types of bone grafts that may be taken:
Shaved corticocancellous outer table graft with attached pericranium
Bone paste or bone dust
Split thickness outer table grafts
Full thickness parietal bone graft
Inner table grafts taken from a full thickness bone flap
• Uses –
Used for reconstruction of the zygoma, orbit, and nasal bone.
Bony reconstruction of midfacial defects caused by ablative tumor
surgery
Correction of craniofacial deformities in patients with Treacher
Collins, Crouzon, and Apert syndromes
Split thickness graft for the reconstruction of the skull defect.
259

260
Split thickness graft
Ideal site for harvest

261
Multiple harvesting can be done

262
Bone dust or bone paste harvesting

References
• Fractures of the Facial Skeleton, Peter Banks
• Oral and Maxillofacial Trauma, 4th Edition,Raymond Fonseca, H. Dexter
Barber, Michael Powers,David E. Frost
• Peter Ward Booth - 1
• Rowe And William - 2
• Killey‟s Fractures Of The Middle Third Of The Facial Skeleton
• Vadim P. Nikolaenko,Yury S. Astakhov; Orbital fractures, A Surgeon’s
Manual
• Gray’s Anatomy, 40th Edition
• Diagnostic Approach to Retromolar Trigone Cancer by Multiplanar
Computed Tomography Reconstructions; Silvio Mazziotti MD AIgnazio
Pandolfo MD Tommaso D'Angelo MD Achille Mileto MD Carmela Visalli
MD Santi Racchiusa MD Alfredo Blandino MD Giorgio Ascenti MD
263

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