BY: ABDUL AKBAR

1ST YEAR PG OMR

CONTENTS

INTRODUCTION

SKULL INDIVIDUAL BONES

FRONTAL

PAREITAL

OCCIPITAL

TEMPORAL

SPHENOID

ETHMOID

MAXILLAE

ZYGOMATIC

NASAL

PALATINE

LACRIMAL

INFERIOR NASAL CONCHAE

VOMER

MANDIBLE

CERVICAL VERTEBRAES

ATLAS

AXIS

TYPICAL CERVICAL VERTEBRAE

SEVENTH CERVICAL VERTEBRAE

INTRODUCTION

THE SKULL :- Consist of 28 bones

CRANIAL BONES -14

FACIAL BONES -14

CRANIAL BONES :-

1. Frontal

2. Occipital

3. Sphenoid

4. Ethmoid

5. Parietal (2)

6. Temporal (2)

7. Malleus (2)

8. Incus (2) ear ossicles

9. Stapes (2)

FACIAL BONES :-

1. Nasal (2)

2. Maxillae (2)

3. Zygomatic (2)

4. Palatine (2)

5. Lacrimal (2)

6. Inferior nasal conchae

(2)

7. Mandible

8. vomer

SKULL INDIVIDUAL BONES

FRONTAL BONE:-

The large bone that makes up the forehead and supplies the upper edge and roof of the orbit (eye socket).

The frontal bone articulates (comes together) with a number of other bones including the parietal, nasal, ethmoid, maxillary, and zygomatic bones.

Landmarks:

Squama: flat portion that forms the forehead

Supraorbital margin: ridge under the eyebrow, forming the upper part of the orbit (eye socket)

Supraorbital foramen: small hole within supraorbitalmargin for blood vessels and nerves

Frontal sinuses: hollow spaces behind the squama, act as sound chambers to give the voice resonance.

PARIETAL BONES

The main bone on the side of the skull.

The word "parietal" comes from the Latin "parietalis" meaning "belonging to the wall."

It articulates (joins) with the other parietal bone in the midline (top of the head), with the frontal bone in front of it, with the occipital bone behind it, and with the sphenoid and temporal bones lower down on the side of the skull.

OCCIPITAL BONE

From the Latin, meaning the part of the head opposite the front.

The bone that forms the rear and the rear bottom of the skull.

The occipital bone articulates (joins) with the parietal and temporal bones of the skull, the sphenoid bone in front of it, and the first cervical vertebra (the atlas) beneath it

Landmarks:

Foramen magnum: large hole, allowing passage of the spinal cord

External occipital protuberance (EOP): prominent projection on back of occiput

Nuchal lines: a superior and inferior line running laterally from the midline, serve as a point of muscle attachment

SPHENOID BONE

A prominent, irregular, wedge-shaped bone at the base of the skull. The sphenoid bone has been called the "keystone" of the cranial floor since it is in contact with all of the other cranial bones.

The Greek physician Galan wrote that the sphenoid bone was "like a wedge thrust between the skull and the superior maxilla."

Landmarks

Greater wings: large lateral projections of bone that help to form the lateral border of the skull

Lesser wings: smaller lateral projections of bone above the greater wings

Pterygoid processes: two long downward projections from the greater wings that act as a point of muscle attachment.

Sella turcica: known as the Turkish Saddle which cradles the pituitary gland.

TEMPORAL BONE

A large irregular bone situated at the base and side of the skull. The temporal bone is connected with the mandible (the jaw bone) via the temporomandibular (TM) joint.

The temporal bone is formed of three parts (squamous, tympanic and petrous) that are distinct at birth but then fuse. The petrousportion of the temporal bone contains the structures of the inner ear.

Landmarks:

Squama: flat portion of the temporal bone forming the anterior and superior part of the temple

Zygomatic process: process forming part of the cheek

Petrous portion: internal, forming part of the floor of the cranium. Contains the ear canal and internal ear structures.

Mandibular fossa: socket between squama and petrousportion, articulates with the condyle of the mandible (TMJ)

External auditory meatus: opening to the ear canal

Mastoid process: bony prominence behind the external auditory meatus

Styloid process: looks like an elephant’s tusk located between the mastoid process and the jaw. Acts as a point of attachment for muscles and ligaments.

ETHMOID BONE :-

An irregularly shaped, spongy bone that provides the floor of the

front part of the skull and the roof of the nasal cavity.

The ethmoid consists of two masses of thin plates enclosing air

cells and looks like a sieve.

Landmarks:

Lateral masses: form most of the wall between the nasal

cavity and the orbits

Perpendicular plate: forms the superior portion of the nasal

septum

Cribiform plate: forms the roof of the nasal cavity

Olfactory foramina: small holes within the cribiform plate for

passage of the first cranial nerve (for smell)

Crista galli: upward extension of bone above the cribiform

plate, acts as an anchoring point for one of the coverings of

the brain.

Nasal concha (turbinates): two scroll-shaped projections

with a mucus membrane on either side of the nasal septum.

Function to cause air turbulence and trap inhaled particles.

MAXILLARY BONES

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The largest bones of the face, except for the mandible and form, by their union, the whole of the upper jaw.

They hold the upper teeth, and connect on the left and right to the zygomatic bones (cheek bones).

Each assists in forming the boundaries of three cavities, namely, the roof of the mouth, the floor and lateral wall of the nose, and the floor of the orbit.

Landmarks:

Infra Orbital foramen: hole below the orbit, for blood vessels and nerves

Alveolar process: arch of the maxilla containing the upper teeth

Palatine process: horizontal projection of the maxilla forming the anterior ¾ of the hard palate.

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Maxilla (Anterior View) (Yellow Colored Bones)

NASAL BONES

Varying in size and

form in different

individuals

They are placed side by

side at the middle and

upper part of the face

and form, by their

junction, "the bridge" of

the nose

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Nasal Bones (Anterior View) (Bridge of the nose, below frontal bone)

ZYGOMATIC BONES

Commonly referred to as

the cheekbone.

It is situated at the upper

and lateral part of the

face: it forms the

prominence of the cheek

and part of the lateral wall

and floor of the orbit.

It articulates with the

zygomatic arch of the

temporal bone.34

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Zygomatic Bones (Anterior View) (Pink Colored Bones)

MANDIBLE

Largest and strongest bone of the face.

Forms the lower jaw and holds the lower teeth in place.

The mandible consists of a curved, horizontal portion, the body, and two perpendicular portions, the rami, which unite with the ends of the body

nearly at right angles.

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Largest and strongest bone of the face.

Forms the lower jaw and holds the lower teeth in place.

Landmarks:

Body: curved horizontal portion of the mandible

Rami: two upward projections of bone that are perpendicular to the body of the mandible.

Angle of the mandible: angle formed where the body meets the ramus

Condylar process: a condyle on the posterior portion of the ramus that articulates with the mandibular fossa of the temporal bone.

Coronoid process: a sharp projection of bone on the anterior portion of the ramus that acts as a point of muscle attachment.

Alveolar process: arch of bone containing the lower teeth

Mental foramen: small hole on the side of the body for blood vessels and nerves.

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Mandible (Anterior View) (Lower Jaw)

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Mandible (Lateral View) (Lower Jaw)

PALATINE BONE :-

It contributes to the walls of three cavities: the floor and lateral wall of the nasal cavity, the roof of the mouth, and the floor of the orbit

LACRIMAL BONE

Smallest and most

fragile bone of the

face, is situated at

the front part of the

Medial of the

orbit.

Contains the lacrimal

sac and the naso-

lacrimal duct.

INFERIOR NASAL CONCHAE :-

Extends horizontally

along the lateral wall

of the nasal cavity

and consists of a

lamina of spongy

bone, curled upon

itself like a scroll

VOMER :-

One of the unpaired

facial bones of the

skull.

Located in

the midsagittal line,

and touches the

sphenoid, the

ethmoid, the left and

right palatine bones,

and the left and right

maxillary bones.

THE VERTEBRAL COLUMN

Below the skull, the

central axis of body is

formed by the backbone

or vertebral column

7 - cervical vertibrae

12 - thoracic vertibrae

5 - lumbar vertibrae

5 - sacral vertebrae

4 - coccyx

CERVICAL VERTIBRAES

INTRODUCTION

Thaere are 7 cervical

vertebraes

three atypical and

four typical

ATYPICAL CERVICAL VERTEBRAES :-

1. ATLAS :-

Atlas is the first cervical vertibrae,it look very defferent

from a typical vertebre ,it has no body and no spine.

It has two lateral masses ,joined togother anteriorly by

anterior arch and posteriorly by posterior arch.

Two large transverse process seen on lateral sides ,and

pierced by a foramen called foramen transversarium.

Superior aspect of each lateral masses show elongated

concave facets which articulate with the corresponding

condyle of occipital bone and form a atlanto-occipital

joint.

The inferior aspect each lateral masses large oval facet

for articulation with corresponding superior articular

aspect of axis to form atlanto-axis joint.

2. AXIS :-

Second cervical vertebrae, it has most conspicous

feature of the axis ,which didtinguishes it from all

other vertebrae, is the presence of a thick finger like

projection arising from the upper part of the body.

This projection is called dens or odontoid process.

This dens fits in to the space between the ant. Arch

of the atlas and its transverse ligament to form the

median atlanto occipital joint.

3. SEVENTH CERVICAL VERTEBRAE:-

Seventh cervical vertebrae deffers from typical

vertebrae in having a long thick spinous process

which ends in a single tubercle.

The tip of the process forms a prominent surface

land marks and becase of this it reffered to as

vertibrae prominence.

The transverse process are also large and have

prominent posterior tubercles.

TYPICAL CERVICAL VERTEBRAES:-

STRUCTURE OF A TYPICAL VERTEBRAE:-

PARTS :-

1. body:- lies anteriorly,having flat upper and lower

surfaces. That attached to adjoining vertebrae

through intervertebral discs.

2. Pedicles:- (right and left) are short rounded bars

projects backwards from posterior part of body.

3. Lamina:- each pedicle is continous posterio

medially and form a vertical plate of bone called

the lamina.

4. The pedicle and lamina togother constitute the vertebral arch.

5. Spine:-passing backwards from the junction of teolaminae , there is spinous process.

6. Vertebral foramen:-bounded anteriorly by posterior aspect of body . On sides of pedicles and behind the lamina.

7. Transverse process:-passing laterally from the junction of each pedicle and the corresponding lamina there is a transverse process

8. Superior articular process:-projecting upwords from the juntion of the pedicle and the laminae and it directed posteriorly and some what laterally.

9. Inferior articular process:- projecting down words from junction of the pedicle and laminae and it is directed forwards and some what medially.