osteology of head and neck and its applied aspects

OSTEOLOGY OF HEAD AND NECK

SKULL JOINTS

SERRATE SUTURE (SAGITTAL)Present between two parietal

bones

Between parietal bones and

occipital bone

DENTICULATE SUTURE

PLANE SUTUTRE

Between two palatine bones

ANATOMIC POSITION OF SKULL

METHODS OF STUDY OF SKULL

SUPERIOR VIEW OR NORMA VERTICALISPOSTERIOR VIEW OR NORMA OCCIPITALISANTERIOR VIEW OR NORMA FRONTALISLATERAL VIEW OR NORMA LATERALISINFERIOR VIEW OR NORMA BASALIS

EXTE

RNAL

LYIN

TERNALLY

CRANIAL VAULT

CRANIAL BASE DIVIDED INTO 3 CRANIAL FOSSASANTERIORMIDDLEPOSTERIOR

NORMA VERTICALIS

BRACHYCEPHALY- FLATTENED HEADPREMATURE BILATERAL FUSION OF

CORONALSUTURES

ASSOSIATED WITH SYNDROMES SUCH AS APERT SYNDROME

CARPENTER SYNDROME CLEIDOCRANIAL DYSOSTOSIS.

DOWNS SYNDROME.

PLAGIOCEPHALY- SKEW HEAD.DUE TO UNILATERAL FUSION OF

CORONAL SUTURE

SCAPHOCEPHALY OR DOLICOCEPHALY – ELONGATED HEAD

DUE TO PREMATURE CLOSURE OF SAGGITAL SUTURE.

ASSOCIATED WITH SYNDROMES LIKE CROUZON SYNDROME AND MARFAN

SYDROME

TRIGONOCEPHALY- TRIANGULAR HEADDUE TO PREMATURE FUSION OF METOPIC

SUTURE.

OXYCEPHALY-HIGH HEADDUE TO PREMATURE CLOSURE OF CORONAL

SUTURE, PLUS LAMBDOID SUTURE

NORMA OCCIPITALIS

NORMA FRONTALIS

The metopic suture is always present at birth but usually disappears at 6-7 yrs. ( metopon= forehead)

The metopic suture may persist throughout life and be mistaken for a fracture

The paired frontal sinuses are posterior to the superciliary arches, between the upper and inner tables of the frontal bone.

Each usually underlies a triangular area on the surface of the face, its angles formed by the nasion, a point 3 cm above the nasion and the medial one-third and lateral two-thirds of the supraorbital margins.

They are rarely symmetrical The average dimensions of an adult

frontal sinus are height 3.2 cm, breadth 2.6 cm , depth 1.8 cm.

They open into anterior part of corresponding middle meatus or medial to hiatus semilunaris.

They are rudimentary or absent at birth , generally well developed between the seventh and eigth years, but reach full size after puberty.

Frontal air sinuses

Frontal bossing

Blow out fracture of the orbit

Maxilla ossifies in membrane from three centres One from maxilla proper and Two from premaxilla.

The centre for maxilla proper appears above canine fossa during the sixth week of intrauterine life.

Of the two premaxillary centres, the main centre appears above the incisive fossa during seventh week of intrauterine life.

The second centre appears at the ventral margin of nasal septum during tenth week and soon fuses with the palatal process of maxilla.

Ossification of maxilla

a) Fronto-nasal buttress

b)Malar-zygomatic buttress

c) Pterygoid buttress

Vertical trajectories of force

The largest of the paranasal sinuses and completely fills the bodies of maxillae

Pyramidal in shape Innervated by infra-orbital and

alveolar branches of maxillary nerve

Drains in middle meatus through hiatus semilunaries

The size of the sinus is variable. Average measurements are

Height- 3.5 cm Width-2.5 cm anterioposterior depth- 3.5 cm Clinical note: Extraction of upper

teeth might lead to fistula formation and sinusitis

Maxillary sinus

The mandible is the second bone , next to the clavicle , to ossify in the body.

Its greater part ossifies in membrane.

The parts ossifying in the cartilage include the incisive part below the incisor teeth, the coronoid and the condyloid processes, and the upper half of the ramus above the level of the mandibular foramen.

Each half of the mandible ossifies from only one centre which appears at about 6th week of the intrauterine life in the mesenchymal sheath of Merckel’s cartilage near the future mental foramen.

Ossification of mandible

• From beneath the teeth 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.

Mandibular fractures

Facial bone fractures result from direct trauma and usually follow one of only a small number of

patterns. Some search patterns can aid in the interpretation.The eye follows these lines to check

these common fracture patterns.

McGrigor-Campbell lines

Campbell's and Trapnell's lines

NORMA LATERALIS

keens Transoral approach

Elongation of styloid process in eagles

syndrome

Gilles Temporal approach

NORMA BASALIS

Pharyngeal tubercle

Anterior part of norma basalis

GUERIN’S SIGN

TREATMENT SCHEDULE

Latham appliance

Vanderwoude syndrome

Middle part of norma basalis

posterior part of norma basalis

Foramen magnum

Jugular foramen

INTERNAL SURFACE OF CRANIAL VAULT

INTERNAL SURFACE OF BASE OF THE SKULL

Anterior fossa

Cibriform plate of ethmoid

Racoon eyes Rhinorrhea

ANTERIOR CRANIAL FOSSA

Middle cranial fossa

Sphenoid bone

Foramen LacerumStructures passing whole length:1. Meningeal branch of Ascending pharyngeal artery2. Emissary vein3. Internal carotid artery4. Greater petrosal nerve

Sphenoidal air sinus

The sphenoidal sinuses are two large irregular cavities within the body of the sphenoid and therefore lie posterior to the upper part of nasal cavity.

At birth the sinuses are minute cavities, and their main development occurs after puberty.

The average adult dimensions are vertical height 2cm, Transverse breadth 1.8 cm , anterioposterior depth 2.1 cm.

MIDDLE CRANIAL FOSSAHemotympanum CSF leak ottorhea

Foramen magnum

Jugular foramen

Posterior cranial fossaBattle’s sign

Bruising over sub-occipital region Cranial nerve injuriesDouble ring sign- Fluid from ear or nose placed on filter paper and a halo of double ring may be seen.

HYOID BONE

Attachments to hyoid bone

CERVICAL VERTEBRAE

Typical cervical vertibrae

Atlas

Axis

Seventh cervical vertebra