axial skeletal

8/3/2019 Axial Skeletal

http://slidepdf.com/reader/full/axial-skeletal 1/56



The adult human skeleton consists of 206 named

bones.

The skeleton of infant & children have more than206 bones because some of their bones fuse later in

life.

For examples : * Hip bone*Some bones of vertebral

columns (back bone)



ORGANIZATION OF SKELETON

The bones of the body are categorized into two

groups

The axial skeleton -The bones of the axial skeleton revolve

around the longitudinal axis of the human body, an imaginaryvertical line that runs through the body center of gravity from

the head to the space between the feet. (80 bones)

The appendicular skeleton - while the bones of the

appendicular skeleton make up the bones of upper & lower

limbs , plus bone forming the gridles that contact the limbs to

the axial skeleton. (126 bones)



MAJOR BONES

OF AXIAL &APPENDICULAR

SKELETON



AXIAL SKELETON

Structure Number of bones

Skull

•Cranium

•Face

8

14

Hyoid 1

Auditory ossicles 6

Vertebral columns 26

Thorax

•Sternum

•

Ribs

1

24



APPENDICULAR

SKELETON



Structure No. of bones

Pectoral girdles (shoulder)ClavicleScapula

22

Upper LimbsHumerusUlnaRadiusCarpalsMetacarpals

Phalanges

2221610

28

Pelvic girdle (hip)Hip, pelvic, or coxal bone , 2

Lower LimbsFemurPatellaFebulaTibiaTarsalsMetatarsals

Phalanges

22221410

28Subtotal 126 Total 206



Long Bones

Have greater length than width Consist of shaft

Variable no. of extremities

Slightly curved for strength......

Long bone consist mostly of compact bone tissue intheir diaphyses & considerable amount of spongy bonein their epiphyses.

For examples : Femur



Long Bone

For examples :

Femur (Thigh bone)

Tibia & fibula (leg bone)

Humerus (arm bone)

Ulna & radius (Forearm bones)

Phalanges ( finger & toe bones)



Short Bones

Cube shaped

Nearly equal in length & width

Consist of a spongy bone except at the surface

For examples:

Carpal bones (wrist)

Tarsal (ankle)



Flat bones

Flat bones are thin. Composed of two nearly parallel plates of compact

bone tissue enclosing a layer of spongy bone tissue.

Flat bone includes the cranial bones, which protectthe brain

Sternum & ribs ,which protect organs in the thorax

scapula



Irregular bones

Having complex shapes.

Bones includes vertebrae (backbone)

Hip bone

Certain facial bone



Sesamoid bones

Develop in certain tendons where there is considerablefriction ,tension& physical stress

Like palms & soles

Two patellae (knee caps)

Large Sesamoid bone located in the quadriceps

femoris tendon



Skull The skull with its 22 bones , rests on the upper end of

the vertebrae column.

Its bony structure is divided in to two parts

Cranial bones

Facial bones



Cranial bones

8 cranial bones One Frontal bone

Two Parietal bone

Two Temporal bone

One Occipital bone

One Sphenoid bone

One Ethmoid bone



Facial bones

14 Facial bones

Two nasal bones

Two maxillae

Two zygomatic bones One mandible

Two lacrimal bones

Two palatine bones

Two inferior nasal conchae One vomer



The Skull



Frontal bone

This is the bone of the forehead.

It forms the part of orbital cavity & prominent ridges above theeyes, the supra-orbital margins.

Just above the supra-orbital margin ,with in the bone, aretwo air filled cavities (sinuses)

Lined with ciliated mucous membrane , which open intothe nasal cavity



Contd…..

The coronal suture that join the frontal and the parietalbones

The bone originates in two parts joined in the midline

by the Frontal Suture



Parietal bones

These bone forms the sides and roof of the skull.

The internal surface of the parietal bones contain many

protrusions & depressions that accommodate the bloodvessels supplying the dura matter

And the superficial connective tissue covering the brain .



Temporal bones

These bone lie one on each side of the head .

Each temporal bone has several important features.

Squamous part ; is the thin fan shaped area that

articulates with the parietal bone .The zygomatic

process articulates with the zygomatic bone to form the

zygomatic arch (cheek bone)



The Mastoid part

The mastoid part contains the mastoid process athickened region behind the ear.

It contains a large no. of very small air sinuses that

communicate with the middle ear

And lined with the Squamous epithelium.



The Petrous portion

This triangular part located the base of the skull andcontains the organs of hearing & balance.

The temporal bone articulates with the mandible at the

temporomandibular joint, the only movable joint of

the skull.



Occipital bone

This bone forms the back of the head (posterior) & part of the baseof the skull.

The foramen magnum, is the inferior part of the bone.(large hole)

The occipital condyles , oval processes with convexsurfaces on either side of the foramen magnum.

The External occipital protuberance is the mostprominent midline projection on the posterior surface of the bone just above the foramen magnum.



Sphenoid bone

This bone occupies the middle portion of the base of the skull.

It articulates with the occipital , temporal, parietal &

frontal bones.

On the superior surface in the middle of the bone is alittle saddle shaped depression , the hypophyseal fossa

in which the pituitary gland rests.



Ethmoid bone

The Ethmoid bone occupies the anterior part of thebase of the skull & helps to form the orbital cavity ,

nasal septum & the lateral walls of the nasal cavity.

It is anterior to the sphenoid & posterior to the nasal

bones.



Nasal bones

The paired nasal bones meet at the midline & formsthe bridge of the nose

Consist of cartilage



Maxilla

The paried maxilla unite to form the upper jaw bone.

Each maxilla contains a large maxillary sinus that

empty in to the nasal cavity.

The maxilla forms the part of the floors of the orbits,

parts of lateral walls, floor of nasal cavity & most of

the hard palate .



Zygomatic bones

Also known as cheek bones

Forms the prominences of the cheeks & part of lateral

wall & floor of each orbit

The temporal process of the zygomatic bone forms the

zygomatic arch.



Lacrimal bones

The paired lacrimal bones are thin, resemble a finger nail insize & shape.

Smallest bone of face.

Lacrimal bones are posterior & lateral to the nasal bones,forms a part of medial wall of each orbit.

( houses of lacrimal sac, gather tears, & passes them intonasal cavity)



Palatine bones

Two L shaped palatine bones forms the posteriorportion of the hard palate, is formed by the horizontal

plates.



Inferior nasal concha

Forms the inferior lateral wall of nasal cavity

Three pairs of nasal concha ( superior, middle,

inferior) increase the surface area of the nasal cavity.

It helps in swirl & filter air before it passes in to lungs.



vomer

Roughly triangular bone

Forms the inferior portion of the nasal septum



Mandible

Largest & strongest facial bone.

Only movable skull bone.

ADD ON



Nasal septum The inside of nose called nasal cavity.

Divided into right & left sides by a vertical portion knownas nasal septum.

Consist of bone & cartilage

Three components:

Vomer

Septum cartilage

Perpendicular plate



orbits

7 bones of skull join to form each orbit.

Which contain eye ball & associated structure.

3 cranial bone : Frontal

SphenoidEthmoid

4 facial bone : Palatine

Zygomatic

Lacrimal

Maxilla



• Warm and moisten air

• Lighten the skull• Enhance voice resonance

Frontal Sinus

Ethmoid Sinus

Sphenoid Sinus

Maxillary Sinus

http://www.lindgrensmith.com/geras/index8.html



Allows forgrowth

axial skeletal

Documents