Bones
The skeletal system is the framework of the body.
It also protects our internal organs like heart, stomach, liver...
It is also the place of production of red blood cells and the storage area of lipids and minerals as the calcium responsible for the hardness of the bones!
In the adult the skeletal system consists of 206 bones, here is how they divide:
Skull
It consists of 29 bones, called symmetrical bones, which are found on either side of the median line of the body, such as the parietal bones of the skull, or unitary bones like the frontal bone.
The twenty-two bones of the skeleton of the head form a protective carapace around the brain, the eyes, the nose and the mouth.
The part that protects the brain from shocks
is called the skull.
It looks like it contains only one bone, but it has eight nested in each other.
The lines between the bones of the skull are the sutures.
Fourteen bones constitute the framework of the face.
Finally, a bone connects the thorax to the head, the hyoid bone, located at the level of the neck.
These 29 bones include the bones of the face as well as the three smallest bones of the body: the hammer, the stirrup and the anvil located in the inner ear!
Spine
It consists of 26 bones, called vertebraeand allowing a great mobility of the body and the "standing up" position!
The vertebral column is divided into three distinct parts in appearance and function.
Thus the cervical part is constituted of 7vertebrae of which the atlas and the axis are the first two.
The thoracic part is made up of 12vertebrae.
Finally the lumbar part is made up of 5 vertebrae wider and more massive to support the upper body.
Rib and sternum
The "Cote-Sternum" set forming the ribcage is made up of 25 bones protecting the lungs and the heart.
This extremely well thought-out structure is solid and very mobile due to the arrangement of the ribs and the cartilages.
Scapular Belt, Arms and Hand
The set consisting of the shoulder, arm and hand is made up of 64 bones.
The scapula in the upper back, the clavicle on each side of the sternum, the humerus, the bone of the arm, forming a hinged joint with the elbow bones: the radius and the ulna.
The articulation of the wrist or "carp" consists of eight bones: the scaphoid, the trapezium, the trapezoid, the capitatum, the hamatum, the lunatum,
the triquetrum and the pisiforme between the bones of the forearm and the bones of The hand: the bones of the metacarpus.
Finally, the bones of the fingers are made up of three phalanges, except for the thumb, consisting of two phalanges in opposition!
The pelvis, the leg and the foot
The " pelvis-leg-foot" set consists of 62 bones.
The pelvis consists of the sacrum, followed by the bones of the coccyx, arranged in an inverted pyramid, with the tip pointing downwards.
The sacrum, in the continuity of the lumbar vertebrae, is connected to the two characteristic structures forming the pelvis: the iliac bones!
This set is connected to the front at the level of the pubic symphysis by a ligament, giving the whole the appearance of a butterfly!
The femur is the bone of the leg, it is inserted in the level of the iliac bone forming a very mobile joint!
After the fémur, are connected the bones of the forefoot: the tibia and the fibula.
To this "set" is added the kneecap at the front of the knee.
Finally, the bones of the foot allow standing and the perfect distribution of loads!
The foot consists of talus, calcaneum, navicular, medial, lateral and middle cuneiform, cuboid, and the five metatarsal bones,
And finally the phalanges made up of three bones for each toe except the big toe that has two bones!
Joints
The joints is where the bones connect.
Without joints, one would be stiff as pickets
Some bones come together to form a hinge like a door.
Thus, the elbow forms a hinged joint, just like the first and second articulations of the fingers or the joint of the knee!
In an enarthrose or spheroidal joint, a head is opposed to a spherical cavity, the joint then has three degrees of freedom as for the articulation of the hip or the shoulder.
Say "No" from the head and you just have used a pivot joint!
This type of articulation is formed when one bone pivots on another separated by a disk to absorb shocks and allow semi-mobility,
such as at the joints of the vertebrae which pivot on each other separated from intervertebral discs.
Finally, some joints are immobile and sutured as for the bones of the skull, where as in a puzzle each bone structure will fit perfectly into the neighboring structure!
Bone Structure
There are two tissues mixed in a bone.
The compact bone tissue is hard as stone, as it contains mineral substances like calcium, phosphorus.
The spongy bone contains collagen, a resistant but supple substance.
Thus, a bone is not completely rigid; It can bend a little bit.
A network of blood vessels provides the bones with minerals and nutrients.
Bone marrow
The bone marrow is a tissue located at the center of the bones.
It is the place of production of blood cells.
Spongy bone
Structure in spongy bone lattice making it both solid and very light.
Inside the spongy bone are nerves and blood vessels bringing important nutriments and oxygen into the bone.
Compact bone
The compact bone is made of tiny tubes rich in calcium, which gives it its hardness.
Somewhat like straws compacted against each other.
These straws are called Haversian channels or tubes.
The Perioste
It's the outermost part of the bone, it's his "very skin"!
The periosteum also contains nerves and blood vessels!
