AXIAL SKELETON

The skeleton is a supportive framework of the body.The human skeleton is divide into two parts mainly exoskeleton and endoskeleton.

EXOSKELETON

The exoskeleton is made up of hard parts which are present on the surface of the body.It is found in vertebrates and invertebrates .eg shells on snails.

ENDOSKELETON

Bones and cartilage are the hard parts which are present inside the body.Bones and cartilage are the supportive  connective tissue .

The complete bifurcation of the human skeleton is given below-

AXIAL SKELETON                                                                                                             

The axial skeleton consists of all the bones which are present on the axis of the body.The axial skeleton which has 80 bones it includes the bones present in the skull,vertebral column,thoracic cage and the hyoid bone.

a)SKULL-

The cranium bone includes the bones present on the surface of the head.They protect us from injury.Actually these bones have a gap when a baby is born,these gaps helps in parturation.These gaps get ossified after two years and they are know as the fontanles .The ethmoid is a bone that separates the nasal cavity from the brain.

The ear ossicles are the bones which are present in the ear which are mainly malleus,incus and stapes.They help in conduction of sound.

To remember the facial bone it is important to remember their position.

The nasal bone is present in each nostrils.The two inferior nasal conchae is present on the sides of the nostrils.The vomer is present exactly in centre of the nasal cavity.The two maxillary bone are form the upper jaw while the manidble forms the lower jaw.The palatine bone form the hard palate and soft palate present in buccal cavity.While the zygomatic bone are present near each eye orbit

(b)VERTEBRAL COLUMN                                                            The vertebral column is made up of 26 bones.They are present in the dorsal side and they protect the spinal chord.         

     

There are five types of vertebrate:

• cervical(7 vertebrate)
• thoracic(12 vertebrate)
• lumbar(5 vertebrate)
• sacrum(1 vertebrate)
• coccyx(1 vertebrate)

The sacrum vertebrate is made up of five bones which fuse up to form the asacrum bone or the sacrum vertebrate.While the coccyx vertebrate is made up of 4 bones which fuses up to form the coccyx bone.

(c)THORACIC CAGE:

The thoracic cage is made up of 25 bones.The thoracic cage is made up of sternum and has 24 ribs.

The sternum looks like a sword and it is made up of three parts

• manibrium
• body
• xiphoid process

Each of the ribs articulates or joins in the front to the sternum and to the thoracic vertebrate on the back.As it articulates on the dorsal side it is known as bicephalic.Out of the 24 ribs it means 12 on each side 7 ribs articulate directly it to sternum with the help of hylaine cartilage,hence they are known as true ribs.While the 8,9,10th rib joins the 7th rib with the help of hylaine cartilage hence it is known as floating ribs.The 11,12th do not articulate at all hence they are known as false ribs.

(d)HYOID BONE: