A very warm welcome to you . this is the second topic in 'THE SKELETAL SYSTEM' i.e. " THE AXIAL SKELETON". I am running an YouTube channel in the name "NURSING ABSTRACT". Where you can get the topic in both Tamil & English. I'm giving the link below if you need kindly click the link below.
English video:https://youtu.be/F8s-oDqtBOI
Tamil video: https://youtu.be/cpRLf_RjyIQ
THE AXIAL SKELETON
BODY PLANES:
There are three body planes and they lie at right angles to each other.
These planes divide the body into sections and they are used to visualise or describe its internal arrangement from different angles.
Median plane: It divides the body longitudinally through the midline into right and left halves .
Frontal Plane: It divides the body longitudinally into its anterior (front) and posterior (back) sections..
Transverse Plane: It provides a cross section dividing the body or body part into upper and lower parts.
THE AXIAL SKELETON:
The bony framework of the body is called as the skeleton. It forms the cavities (depressions or hollows) that protect some structures and fossae i.e it forms the joints and gives attachment to muscles
The skeleton is described in two parts: The Axial skeleton and The Appendicular skeleton(the appendages attached to the axial skeleton).
The axial skeleton consists of the
- Skull
- Vertebral column
- Sternum (breast bone)
- The ribs.
SKULL:
The skull is divided in 2 parts, the cranium, which consists of the brain, and the face.
It consists of several bones, which develop separately .And they fuse together as they mature.
The only movable bone is the mandible also called as lower jaw.
FUNCTIONS OF SKULL:
The various parts of the skull have specific as well as different functions .
It protects delicate structures which includes the brain, eyes and inner ears
Maintaining patency of the nasal passages enabling breathing.
The teeth are embedded in the mandible and maxilla which allows in eating.
Movement of the mandible allows chewing.
VERTEBRAL COLUMN:
The vertebral column consists of 24 movable bones (vertebrae) , the sacrum and the coccyx.
These bones are separated from each other by intervertebral discs, consisting of fibrocartilage.
The vertebral column consists of five parts :
• 7 cervical
• 12 thoracic
• 5 lumbar
• 1 sacrum (5 fused bones)
• 1 coccyx (4 fused bones).
The first cervical vertebra, called the atlas which forms a joint which articulates with the skull.
After that each vertebra forms a joint with the vertebrae immediately above and below.
More movement is possible in the cervical and lumbar regions compared to the thoracic region.
The sacrum consists of five vertebrae which is fused into one bone. The sacrum articulates with the fifth lumbar vertebra above and the coccyx below and on each side with innominate (pelvic or hip) bone .
The coccyx consists of four last vertebrae which are fused together and forms a small triangular bone and it articulates with the sacrum above.
FUNCTIONS OF VERTEBRAL COLUMN:
The vertebral column has several important functions:
• It protects the spinal cord. In each vertebra is a hole called the vertebral foramen, and it is collectively called the foramina which form a canal in which the spinal cord lies.
• Adjacent vertebrae form openings called as intervertebral foramina which protect the spinal nerves which passes from the spinal cord .
• In the thoracic region the ribs articulate with the vertebrae which forms the joints and that allows the movement of the ribcage during respiration.
THE THORACIC CAGE:
The thoracic cage is formed by:
• 12 thoracic vertebrae
• 12 pairs of ribs
• 1 sternum or breast bone
Functions of thoracic cage:
The thoracic cage or the rib cage protects the contents of the thorax including the heart, lungs and large blood vessels.
.The rib cage forms joints between the upper limbs and the axial skeleton.
. The upper part of the sternum i.e the manubrium, articulates with the clavicles forming the only joints between the upper limbs and the axial skeleton.
. The Thoracic cage gives attachment to the muscles of respiration: – intercostal muscles occupy the spaces between the ribs and when they contract the ribs move upwards and outwards, it increases the capacity of the thoracic cage, and inspiration occurs – the diaphragm is a dome-shaped muscle which separates the thoracic and abdominal cavities; when the diaphragm contracts it assists with inspiration
.It Enables breathing to take place.
These are the slides which I'm using in my videos.
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