02 - skletal system

8/3/2019 02 - Skletal System

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SKLETAL SYSTEM

•It is divided into twoparts :

•Axial.

•Appendicular.



AXIAL SKELETON

•It forms thelongtudinal axis of thebody.

•It is divided into threeparts :

•Skull.

•

Vertebral Column.•Bony thorax.



SKULL

•It is formed of twosets of bones :

•Cranium.

•Facial bones.

•Most of Its bones are flat.



CRANIUM

•it encloses andprotects the brain.

•It is formed of eight

large flat bones.•Two of them are

paired and the othersare single.



CRANIUM

•The bones are :

•Frontal.

•Parietal.

•Temporal.

•Occipital.

•The bones are joined

together by sutures.



FACIAL BONES

•They hold the eyes inan anterior position.

•They are (14) bones.

•Twelve are pairedand only the mandibleand vomer are single.

•They are : maxillae,

palatine,zygomatic,lacrimal, nasal, vomerand mandible.



VERTEBRAL COLUMN

•It is the axial supportof the body.

•It extends from the

skull which it supportsto the pelvis, where ittransmits the weightof the body to the

lower limbs.



VERTEBRAL COLUMN•

It is formed of (24)single bones(Vertebrae) :

•Cervical vertebrae

(7).•Thoracic

vertebrae(12).

•Lumbar vertebrae (5).

•Sacrum (fused 5vertebrae).

•Coccyx (fused 4vertebrae).



VERTEBRAL COLUMN

•The single vertebraeare separated bypads of flexible

fibrocartilage (intervertebral discs).

•The intervertebral discs absorb shocks

and allow the spineflexibility.



TYPICAL VERTEBRA

•It is formed of :

•Body.

•Vertebral arch: laminaeand pedicle.

•Vertebral foramen.

•Transverse process.

•Spinous process.

•Superior and inferior

articular processes.•THEY ARE IRREGULAR

BONES.



DIFFERENT VERTEBRAE

•Cervical :smallest ,the spine is dividedinto two branches.Transverse processcontain foramen.

•Thoracic : body isheart shaped and hastwo costal facets.

•Lumbar : massiveblock like bodies.



BONY THORAX

•It is formed of thesternum,ribs andthoracic vertebrae.

•It protects the organsof the thoracic cavity.

•Sternum

•

Manubrium.•Body.

•Xiphoid process.



RIBS

•They are (12) pairswhich are divided asfollows :

•

True (7) : attachdirectly to thesternum.

•False (5) : either

attach indirectly to thesternum or not at all.

•Floating : last twopairs.



APPENDICULAR SKELETON


•Pectoral girdle.

•Pelvic girdle.

•Bones of the upperand lower limbs.



PECTORAL GIRDLE


•CLAVICLE : it holdsthe arm away from

the thorax.•SCAPULA (WING).



UPPER LIMB

•ARM :Humerus.•FORE ARM: Radius

& Ulna.•Long bones :

•They are formed of :•Epiphysis : on each

end.•Diaphysis : a tubular

shaft. It is coveredexternally by theperiosteum.



HAND

•WRIST : Carpalbones.

•PALM : Metacarpal

bones.•FINGERS :

Phalanges.

•

They are examples ofshort bones.



PELVIC GIRDLE

•Formed of the twoHIP bones.

•Each hip bone isformed of three parts :

•ILium.

•Ischium.

•Pubis.

•The hip bones andthe sacrum form thebony pelvis.



LOWER LIMB

•THIGH : Femur.

•LEG : Tibia & Fibula.



FOOT

•TARSUS : Tarsalbones.

•Metatarsals.

•Phalanges.

02 - skletal system

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