What’s up guys ! Swapnil Patil here and today I’m going to talk about the Human skeletal system.The body is supported within or around by a hard framework called skeleton. In the vertebrates, the skeletal system is mainly divided into exoskeleton and endoskeleton.
Bones and cartilages are the hard, supporting parts present inside the body forming endoskeleton. The study of bones is called osteology. Human endoskeleton is mainly bony with some supporting cartilages. The human endoskeleton consists of 206 bones in an adult.
The skeleton performs many functions. It gives definite shape to the body and protects the internal vital organs like heart, brain, lungs, etc. The bones and cartilages provide surface for the attachment of muscles and also act as a system of lever and help in movement of body parts and locomotion.The bones and cartilages provide surface for the attachment of muscles.Blood act as store house of Ca,P,Mg,salts.
HUMAN SKELETON :-
Human endoskeleton is divided into two parts namely Axial skeleton and Appendicular skeleton.
A) Axial skeleton :-
Axial skeleton consists of 80 bones. It consists of Skull,Vertebral column and Thoracic cage.
a) skull : –
The skeleton of head is called skull. It Consists of “29 bones” and encloses brain inside it. skull includes
Following parts :-
i) Cranial Bones (8) :–
– forms hard protective Covering for the brain.
frontal (1), parietal (2), occipital (1), temporal (2),sphenoid (1), Ethmoid (1)
ii) Ear Ossicles 2x(3) : –
There are six ear ossicles (2 malleus, 2 incus and 2 stapes) found in the skull.
iii) Hyoid bone (1) :-
This is a U-shaped bone.
iv) Facial bones (14) :-
Forms the front part of the skull.
b) Vertebral Column (Backbone) :-
It Consists of “26 bones”. Protects spinal Cord. Supports the head.
The human vertebral Column Contain following five groups of vertebrae :-
i) Cervical (7)
iii) lumbar (5)
iv) sacral (1- fused)
v) Coccygeal (1-fused)
c) Thoracic Cage :-
It Consists of “25 bones”. Protects Lungs and heart.
i) Ribs (24) :-
First 7 pairs of ribs are Called True ribs.
- 8th, 9th and 10th pairs of the ribs are false ribs/vertebrochondral .
-The last two pairs of ribs i.e. (11th and 12th) called floating ribs.
ii) sternum(1) :-
Also called as breast bone.
It is flat bone,located in the middle line of thorax ventrally.
B) Appendicular skeleton :-
The appendicular skeleton consists of 126 bones. It includes forelimbs, hindlimbs , pectoral girdle and pelvic girdle.
a) Bones of limbs :-
It consists of “120 bones”.
i) Fore limbs (Each 30) :–
Humerus (1), Radius (1), ulna(1), carpals (8), Metacarpals (5), phalanges (14).
ii) Hind limbs (Each 30) :–
Femur (1), Patella (1), Tibia (1), Fibula(1), Tarsals(7), Metatarsals (5), Phalanges (14).
b) Girdles :-
It consists of “6 bones”.
i) Pectoral (4) :-
It is simply called shoulder girdle.It contains two separate right and left halves. Each half is composed of two bones,
Scapula (2) and clavicle (2).
ii) Pelvic (2) :-
In humans, each half of pelvic girdle is known as Coxal or innominate bone.
Ilium (2) :- on upper side
Ischium (2) :- on inner Side
Pubis (2) :- below pubis
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