NTRODUCTION

Skeletal system means the study of bones and their structure in the body. In this system. we will study all the small and big bones in the body and their structure. Bones provide the frame work to the body. It works to provide structural support to our body. Due to which our body structure is maintained. Bone forms the framework of the body and also protects the organs in the cavity.

The scientific study of bone and its structure and disorder is known as osteology. The skeletal system provides attachment, security and a fixed shape to our body and body parts.

The skeletal system is found inside and outside the body. It has two types.

Exo-skeleton

Endo-skeleton

Exo-skeleton:
The outer side of this body is seen, which gives the body a certain shape and provides protection to the body. Which includes skin and skin derivatives.

Endo-skeleton:
It is found inside the human body, which gives a fixed shape to the body.
It is made up of skeleton bone and cartilage.

SKELETON TISSUE:

Skeleton tissue is a type of connective tissue.
There are two types of skeleton tissue:

1: Cartilage
2: Bone

1. Cartilage:

Cartilage is a rigid form of connective tissue.
It has 3 types.

1: Hyaline cartilage
2: Fibrocartilage
3: Elastic cartilage

Hyaline cartilage:

Hyaline cartilage is flexible and smooth.
Hyaline cartilage is made up of transparent blue tissue and cells and is embedded in a protein matrix called chondrin.
Cartilage is found in chondrocyte cells and forms chondrin.
Hyaline cartilage is found on the surface area of ​​the bone and forms the cartilage joint.
Hyaline cartilage is the costal cartilage that connects the ribs and the sternum.
It is found in the lower part of the body.

• Anterior part of the nose
  -larynx
• trachea

• Fibrocartilage:

White collagen fibers are found between fibro cartilage, so it is also known as white cartilage.
This cartilage is somewhat flexible and firm (soft).
This cartilage is found in the intervertebral disc.
It is also found in the symphysis pubic.

Elastic cartilage:

Yellow elastic fibers are found in elastic cartilage so it is known as yellow cartilage.
This is a flexible type of cartilage that exhibits elasticity.
In human body it is found in the following parts: ear pinnae
In epiglottis (part of larynx)

2. BONE:

Bone is a hard connective tissue, in which the endo-skeleton is connected to the joint in the human body.
Bone is made up of the following substances:
-Inorganic substance (50%)
-organic matter (30%)
-water(20%)

According to the structure of the bone, there are 2 types of bone:

1. Compact bone 2. Cancellous bone or spongy bone

Compact bone

Compact type of bone is strong.
These bones are made up of tube-like units called osteons or Haversian system.
An osteon is made up of a central canal which can also be called Haversian canal which is surrounded by a circular ring like structure.
Blood vessels, nerves and lymphatic channels are located in this central or Haversian canal.
This bone is found on flat bone and long bone.

2. CANCELLOUS BONE OR SPONGY BONE:

This bone is flexible (able to bend) which is found at the edge (upper part) of long bone and small bone.
A cross section of spongy bone shows many small ducts called trabeculae, which are made up of lamellae and osteocytes that are interconnected by interstitial fluid called canaliculi.
Red bone marrow fills the space between trabeculae.
Red bone marrow produces red blood cells and white blood cells and provides nutrition to bone cells.

BONE CELLS:

Bone cells are responsible for the formation of new bone.
A protein called Matrix is ​​found around the Haversian system in Bone.
Bone cells are found in the matrix that helps in bone formation.

There are 3 types of bone cells.

Osteoblast

Osteoclast

Osteocyte

Osteoblast:
Osteoblast cells are found in new bone cells. This cell is found in the deeper layer of the periosteum which is found at the fracture site and in the bone marrow of the long bone.
Osteoblast cells release collagen and have only one nucleus.
This cell is helpful in the deposit of inorganic salt. e.g. Calcium, Phosphate NOTE:
Periosteum: membrane of fibrous tissue overlying bone
Collagen: It is an insoluble protein found in white fibers that are found in bone.

Osteoclasts:

This is a large cell that has more than one nucleus (more than 50).
This cell absorbs the bone tissue due to which the bone breaks down and calcium and phosphate are released from it.
This cell is located on the upper surface of the bone.
It continuously remolding bone tissue.

Osteocyte:

These cells are located on the inner side of the bone.
Osteocyte cell is a type of osteoblast cell in which the matured osteoblast cell is known as osteocyte cell.

BONE TYPES:

Long bone
Short bone

Irregular bone
Flat bone
Sesamoid bone

1. Long bone:

Bones of this type are long in size with epiphysis at the edges and shaft in the middle.
In this type of bone, its length is greater than its width.
Bones of this type are found in the hand and leg, such as humoral, radius, ulna in hand, femur, tibia, fibula in leg, long bone is found.

2. Short bone:

Bones of this type are small in size.
The part of the shaft is absent in this bone.
This type of bone is found in the wrist of the hand as a carpal bone.

3. Irregular bone:

This type of bone does not have a fixed size, so it is called Irregular bone.
This type of bone is found on the face and in vertebrates.
The shaft is absent in this type of bone.

4. Flat bone:

The bone of this type is flat in shape.
Such bone is found where organs are located inside the cavity. This bone is there for the protection of such an organ, there are such bones.
Such bones are skull, chest bone-sternum and ribs.

5. Sesamoid bone:

The bone of this type is seen in the shape of sesame.
This bone is found around some joints.
Example.. knee cap

• DEVELOPMENT OF BONE:

The development of bone in the human body starts already at birth and it continues till the age of 21 years.
The process of bone development is known as ossification.

Bone development takes place in 2 ways:

1.membranous ossification

2. cartilaginous ossification

• Structure of Long Bone.

There are bones of different shapes in the body. In which long bone, short bone, irregular bone, flat bone and sesamoid bone are found.
Long bone means cylindrical shaped bones in the body like humerus bone, femur bone etc.
The length of this type of bone is more than the thickness. In which the following characteristics are found.

Epiphysis.

These are parts of both ends of the long bone. The distal and proximal portions of long bones are known as epiphyses. It has compact bone tissue on the outside and spongy bone on the inside. Red bone marrow is found at this end of the bone.

Diaphysis.

This is the middle part of the long bone. It is also known as part of bone marrow. This is the main part of the bone where the compact tissue is mainly found and the yellow bone marrow is found in this middle part of the bone. Between these parts is a canal-like structure, known as the medullary canal or medullary cavity. In which we will look in detail at the time of microscopic structure of bone.

3. Metaphysis.

The portion of a long bone where the epiphyseal plate joins with the diaphysis is known as the metaphysis.

Articular Cartilage.

The covering lining the epiphyses is called articular cartilage. With the help of this cartilage, shock, jerk is absorbed at the bone joint and movement becomes painless.

• Periosteum.

The outermost layer of the long bone, except the ends covered by articular cartilage, is called the periosteum. The periosteum is made up of fibrous connective tissue. Which has the structure of blood vessels, lymph vessels and nerves. As this layer is strong, it also acts to protect the bone from the outside. Its outer surface being rough can give better attachment to muscles.

Besides this, the medullary cavity is located on the surface of the bone. The outer lining of the medullary cavity, which contains the yellow bone marrow, is called the endosteum. In which there are basic cells of bone and osteoclast cells.

• Ossification.

The process of bone formation and maturation of bone is called ossification. Bone growth starts from the time the baby is in the mother’s uterus and it continues to grow throughout childhood and adolescence. Bones in children are soft and weak, as they age, they become hard, strong and mature.

• FUNCTIONS OF BONE:

The function of bone is as follows:
Bone provides stability and support to our body.
Bone provides protection to our body. Example. Thoracic rib cage gives protection to lung and heart, Skull gives protection to brain.
Bone helps in many movements of muscles and joints.
Bone acts as a reservoir in our body, which stores minerals like calcium and phosphorus.
Bone cells form from bone.
Red bone marrow is found in the epiphysis of the long bone, from which red blood cells are made. The process of making these blood cells is known as hematopoiesis.

• TENDONS:

Tendon is a structure made of fibrous connective tissue that connects muscle to bone.
Tendon secures the muscle attached to the bone which helps in the movement of the muscle.
Tendon keeps parts and surrounding organs in fixed position.

• LIGAMENTS:

LIGAMENTS are made of connective tissue that keeps one bone attached to another bone.
Ligament holds the organ and gives support.
Ligament holds the joint together.

• Human Skeleton

Human skeleton is made up of many bones. There are total 206 bones in the adult human body. Skeletal in human body is divided into 2 parts:

1. Axial skeleton
2. Appendicular skeleton

• Axial skeleton

Axial skeleton is found in the center part of the human body.
Axial skeleton has the following bones.. skull, vertebral column, ribs, sternum, etc.

There are a total of 80 bones in the axial skeleton.

There are total 22 bones in Skull.
Cranium in KV 8
14 of Face
Total number of Vertebrae 26
Total number of Ribs 24
The total number of ear bones is 6.

Apart from this, sternum bone and hyoid bone are included in the axial skeleton. Both of them are in the number of 1’s.

1. SKULL:

Skull is found in the upper part of the body above the vertebral column.
In which there are 2 parts as follows.

1. cranium
2. face
3. Cranium:

The upper part of the skull bone is known as cranium.
8 irregular cranial bones together form the cranial cavity.
The human brain is located in the cranial cavity.
The lower part of the cranium is known as the base and the upper part as the vault. Its shape is like a dome shape.
Cranial bones join together to form immovable joints known as sutures.

Sutures of the cranium bone.

The cranium is made up of irregular bones. These flat bones join to form an immovable joint. This joint is known as suture. Indications for cranium cavity are as follows.

Coronal suture

Suture between frontal bone and 2 parietal bones is called coronal suture.

Sagittal suture.

Suture between 2 parietal bones is called sagittal suture.

Lambdoidal suture.

2 The suture between the parietal bone and the occipital bone is called the lambdoidal suture.

Squamous suture.

The suture between the parietal bone and the temporal bone is called the squamous suture.

The above suture forms a depression like structure between the joints called fontanelles. These fontanelles are in the number of 2 in the infant skull.

The Anterior Fontanelle is located near the junction where the coronal and sagittal sutures join at the front of the skull. It can also be known as bregma. It is big in size. By the time the child is 1.5 years old, it closes due to skeletal maturity (Growth). It is of diamond shape.

The Posterior Fontanelle is located near the junction where the sagittal and lambdoidal sutures join at the back of the skull. It can also be known as lemda. It is small in size. By the time the child is 6 to 8 weeks old, it closes due to skeletal maturity (Growth). It is of tri-angular shape.

The cranium in the skull is made up of many different flat and irregular bones. Cranium consists of 8 bones in total, which are as follows:

1. Frontal bone 1
2. Parietal bone 2
3. Temporal bone 2
4. Occipital bone 1
5. Sphenoid bone 1
6. Ethmoid bone 1

Frontal bone.

These bones are numbered 1 in the most anterior part of the cranium KV. It is also called fore head bone. It lies above the orbital cavity and nasal cavity. Above the orbital cvt there is a raised margin on both sides of the frontal bone, which is called the supra-orbital margin. A foramen is also located near this margin. It is called supra orbital foramen. The part between the two orbital margins is known as the glabella.

Parietal bone.

There are 2 of these bones in the cranial cavity and they form the roof of the cranial cavity. It is the bone attached to all the sutures of the cranium cavity.

Temporal bone.

It is in the number of 2. On either side of the cranium cvt is a bone near the ear. The temporal bone is connected to the zygomatic bone by the zygomatic process. Also it joins with the mandible bone to form the only movable joint of the skull, the temporomandibular joint. The mastoid portion of the temporal bone is connected to the middle ear by an air cell.

Occipital bone.

It is the number 1 bone in the cranium cavity. It forms the back of the skull and part of the base. At the bottom of this bone is a large foramen, known as the foramen magnum. Through which the spinal cord emerging from the brain passes.

On either side of this foramen there are raised parts. Which is called condyle. The first vertebra of the vertebral column joins the atlas forming a hinge joint. The most prominent part of the back of the occipital bone is called the occipital protuberance.

Ethmoid bone.

It is a bone located anteriorly at the base of the cranium cvt. It is in the number of 1. It is a cubical shaped bone. The olfactory nerve passes through its path from the nose to the brain.

Sphenoid bone.

It is in the number of 1. It lies anterior to the occipital bone at the base of the cranium cvt. It is a butterfly shaped bone. There is a depression in the middle of it. It is known as hypophysial fossa or sella tarsica. Pituitary gland is located in this part. This bone is connected to all the bones of the cranium cavity.

• Facial bones.

The bones of the face are called facial bones. It is 14 in total. These bones are found as follows.

Maxilla bone.

It is also known as upper jo bone and is numbered 2. Upper teeth come in its margin. This bone forms the roof of the mouth and the floor of the nasal cavity and orbital cavity. A portion of this bone also forms the hard palate.

Zygomatic bone.

It is known as cheek bone. They are in number of 2. It forms the upper part of the cheek. This bone articulates anteriorly with the maxilla bone and with the temporal bone.

Mandible bone.

It is the bone at the bottom of the face. It is the only movable and strong bone of the skull. Which plays a very important role in chewing. It is in the number of 1.

The upper edge of this bone is known as the alveolar ridge. Teeth are arranged along this ridge.

The front part of this bone is called the body. A curved part is called an angle. From there the flattened part on the upper side is called the ramus. The next part is divided into two processes. In which coronoid process and condylar process are seen.
Muscles attach to the coronoid process while the temporal bone attaches to the condylar process to form the temporomandibular joint.

Nasal bone.

They are flat bones numbering 2. It forms the bridge of the nose. It forms the superior and lateral walls of the nasal cavity.

Lacrimal bones.

They are bones in number of 2. It forms the medial wall of the orbital cavity and carries eye secretions to the nose through the nasolacrimal duct. This bone is shaped like a finger nail.

Vomer bone.

It is the number 1 bone. The bone in the middle of the nasal cavity is attached to the septum of cartilage anteriorly. It separates the nasal cavity into 2 parts. On the upper side it is attached to the ethmoid bone.

Palatine bones.

They are bones in number of 2. It creates a hard palette. It has 2 L shape bones joined together to form part of the palette.

Inferior conchae.

They are in number of 2. It is a bar-shaped bone located in the lateral wall of the nasal cavity. It works by filtering and warming the incoming air.

• Vertebrae and Vertebral Column.

Below the foramen magnum of the occipital bone, the irregularly shaped vertebrae join together to form a column called the vertebral column.

Vertebrae are bones of strong and irregular shape. A canal-like structure is formed between each of these vertebrae to form the vertebral column. From this canal, the structure of the spinal cord passes continuously downwards from the brain. The vertebrae provide protection to the spinal cord.

The approximate length of the vertebral column is found to be 70 cm in males and 60 cm in females.

In the vertebral column, different types of vertebrae join according to region to form different vertebral regions. Its number is as follows.

Cervical Vertebrae. 7
Thoracic Vertebrae. 12
Lumbar Vertebrae. 5

Sacral Vertebrae Five vertebrae fuse to form 1 Sacral Vertebrae.

Coccygeal Vertebrae Four vertebrae fuse to form 1 Coccygeal Vertebrae.

Thus, a total of 26 typical vertebrae are found in the vertebral column according to all the above regions. Between the bodies of each of these vertebrae is a disc made of fibrous cartilage called the intervertebral disc.

• Common Characteristics of Vertebrae.

All the vertebrae of the vertebral column have the following common K

Body

At the front of the vertebra is a flattened body part. Its size varies according to the vertebra of each region. As such, the body segment is found to be smallest in the cervical vertebrae and increases in size towards the thoracic and lumbar vertebrae. The body is the largest and thickest in the lumbar vertebrae

Process of Vertebrae

The two processes extending posteriorly from the body of the vertebra are called pedicles. This pedicle extends posteriorly and forms a portion of a V septum, the portion known as the lamina. From the junction of these laminae, a straight process called the spinous process emerges posteriorly.

At the junction of the vertebra pedicle and the lamina, a horizontal process called the transverse process arises on either side.

Between all these processes a foramen is formed, called the vertebral arch or neural arch. The spinal cord passes through this arch. This arch is the largest found in the cervical vertebra. The opening of this arch becomes smaller as it moves towards the thoracic and lumbar vertebrae.

In addition, the superior surface and inferior surface of each vertebra have articulating processes to join the vertebrae.

• Specific Characteristics of Vertebrae.

Each vertebra of the vertebral column has a specific characteristic according to its region. The characteristic sticks according to this region are seen below.

Cervical Vertebrae

There are 7 cervical vertebrae in number. These vertebrae are ring shaped. The body is the smallest and the neural arch is the largest. The processes of the cervical vertebrae are short and smooth.

The first vertebra of the cervical vertebrae is known as the atlas. This atlas vertebra articulates with the condyle across the foramen magnum of the occipital bone to form a hinge joint. This vertebra supports the skull, hence it is called the atlas vertebra.

The second vertebra of the cervical vertebrae is known as the axis. On the superior surface of this vertebra is a serrated process, called the odontoid process. This process joins the atlas vertebra to form a pivot joint. Due to this joint of the atlas and axis vertebra, all types of rotational movements of the head are possible.

In addition, there is a foramen on both sides of the cervical vertebra on the lateral side, which is called the transverse foramen. Nerves and vessels pass through this foramen.

Thoracic Vertebrae

There are 12 thoracic vertebrae. The bodies of these thoracic vertebrae are larger than those of the cervical vertebrae and smaller than those of the lumbar vertebrae.

The neural arch of this vertebra is smaller than the cervical vertebrae and larger than the lumbar vertebrae.

The processes on the thoracic vertebrae are very long and slender.

The lateral inferior side of the body of this vertebra has one facet on each side. At this facet, the heads of the ribs are joined on both sides. Thus the thoracic vertebrae play an important role in forming the thoracic cage.

These vertebrae are stronger than the cervical vertebrae.

Lumbar vertebrae

There are 5 lumbar vertebrae. These vertebrae are the strongest and largest of all vertebrae.

The body of the lumbar vertebra is the largest of all vertebrae and its neural arch is the smallest.

The processes of the lumbar vertebrae are short and fairly thick.

Lumbar Vertebra The fifth lumbar vertebra forms the lumbosacral joint with the sacrum vertebra below it.

Sacrum Vertebrae

The sacrum is a bone below the fifth lumbar vertebra and made up of 5 vertebrae. This bone is of triangular shape. The following characteristics are found in this bone.

Base
Apex
Anterior Surface
Posterior Surface
Lateral Mass

The broad part above the sacrum bone is part of the base. which joins with the fifth lumbar vertebra to form the lumbosacral joint. Part of this bay has a wing-like structure on either side known as the sacral ala.

The apex of the sacrum bone is the triangular shaped portion on the underside. which articulates with the coccyx vertebrae and forms the sacrococcygeal joint.

The anterior surface of the sacrum bone is called the anterior surface. It is smooth and concave. On the medial side of this surface is a raised portion, which is important in midwifery as an obstetrical landmark. It is called the sacral promontory. This surface joins the five vertebrae to form a horizontal line in the middle known as the transverse line and the foramen found on this surface is called the anterior sacral foramen.

The posterior surface of the sacrum bone is called the posterior surface. It has an irregular and rough surface. The raised and rough part in it is called sacral tuberosity. The transverse line is not clearly visible on the posterior surface but the posterior transverse foramen can be seen.

The transverse processes of each attached vertebra in the sacrum bone join together to form the lateral side of the sacrum bone, known as the lateral mass. Both sides of the ilium of the innominate bone join to form the sacroiliac joint.

In females the sacrum bone is short, broad and curved.

Coccyx Vertebrae

The coccyx vertebra is the triangular bone at the outermost end of the vertebral column. It is made up of 4 coccygeal vertebrae.

This bone joins the apex of the sacrum bone on the upper side to form the sacrococcygeal joint.

Thus, 26 separate vertebrae are found in the vertebral column and each of these vertebrae joins together to form the vertebral column. In this vertebral column there is no movement between separate 2 vertebrae but some movement of the entire vertebral column. Which is as follows.

Flexion – A forward bending movement of the vertebral column.
Extension – A backward bending movement of the vertebral column.
Lateral Flexion – Side bending movement on either side of the vertebral column.
Rotation – The movement of rotation in a half circle is seen in the vertebrae of the cervical and lumbar regions.

Functions of Vertebral column.

The vertebral column at the top of the skull supports the skull.

Between the bodies of two vertebrae is the intervertebral disc which absorbs shock during movement and protects the brain from jerks.

A small canal-like strong structure is formed in the middle of the vertebral column through which the spinal cord passes. This works to provide protection to the spinal cord.

The transverse processes or pedicles of the vertebrae form the foramen on either side. Nerves, blood vessels and lymph vessels pass through this foramen.

Provides attachment for joining other bones. Gives a framework to the body. So many moments are possible.

It gives the ribs room to join. Thus thoracic cage is formed and also provides attachment to form solder joint and pelvic joint.

It connects the axial skeleton to the appendicular skeleton.

Due to this, the posture of the body is maintained in different movements, sitting and walking.

• Hyoid Bone.

This is the axial skeletal bone. It is located in the soft tissue of the neck above the layers. It is a U-shaped bone that attaches to the base of the tongue and provides support to the tongue.

• Thoracic Cavity.

The chest portion is known as the thoracic cavity. This part is a KV of the concept. In which the superior side is chained and the inferior side is wide. The thoracic cavity is a cavity made of bone. In which organs like lungs and heart are protected. The following bones are attached to form this KVT.

Sternum Bone 1
Thoracic Vertebrae 12
Ribs. 12 pairs

Apart from this, the sternum bone and clavicle bone of the thoracic cvt connect with the solder joint and the upper extremity i.e. the appendicular skeleton.

Sternum Bone Sternum Bone.

The sternum bone is the bone of the axial skeleton. It is the anterior medial bone in the thoracic cavity.

It is the bone immediately below the skin. Sternum bone is also known as breast bone. The sternum is a flat bone.

The ribs are attached to the sternum bone with the help of costal cartilage. Hence it is a very important bone for building the thoracic cage.

Three parts below the sternum bone

1. Manubrium.

The uppermost part of the sternum bone is called the manubrium. It forms the upper broad part of the sternum. It has a rough triangular shape.

The notch in the middle of the uppermost part of the manubrium is called the suprasternal notch. The suprasternal notch is also known as the second jugular notch.

On the lower side of the suprasternal notch of the manubrium, there is a small notch called the clavicular notch. At this notch, the clavicular bone joins and forms the sternoclavicular joint.

The first pair of ribs are attached to the menorium by the costal cartilage.

The second pair of ribs are joined by costal cartilages near the angle between the manubrium and the body.

2. Body…

The body forms the longest part between the sternum bone no. On its upper side is the manubrium and on its lower side is the xiphoid process. The part between these two is known as the sternum body.

There are many small grooves on both sides of the body. On either side of this groove, the third, fourth, fifth, sixth and seventh pairs of ribs are connected with the help of costal cartilage.

3. Xiphoid process..

The lowest part of the sternum bone is called the xiphoid process. This part is attached to the muscles of the abdominal wall as well as the diaphragm.

• Ribs.

Ribs are important for building the thoracic cage. It is found in pairs of 12 i.e. total number of 24. Anteriorly, each pair of ribs is attached to the sternum bone by means of costal cartilage, and posteriorly, these ribs are attached to a thoracic vertebra. Thus each of these ribs join together to form the thoracic cavity.

There are total 12 pairs of ribs. The first pair of 7 ribs are called true ribs, because each of these ribs is attached directly to the sternum bone anteriorly by costal cartilage and posteriorly to the thoracic vertebra.

8, 9 and 10 These three pairs of ribs are called false ribs, because they attach to the thoracic vertebrae posteriorly but not directly to the sternum anteriorly but to the 10th rib to the 9th rib, the 9th rib to the 8th rib And the 8th rib is connected to the 7th rib hence it is called false ribs.

Pairs of both the 11th and 12th ribs are known as floating ribs. This pair of ribs articulates with the thoracic vertebrae on the posterior side, but does not articulate anywhere on the anterior side, hence it is known as a pair of floating ribs.

• Characteristics of Rib.

A rib is a flat bone. This bone has two extremities and a smooth part.

At the posterior end of the rib towards the vertebral end is a flattened part, called the head of the rib. This head part is attached to the body of the thoracic vertebrae.

The narrow part after the head is called the neck. Then there is a raised part called tubercle. Part of this tubercle is attached to the facet of the transverse process of the thoracic vertebra.

The bend of the rib after the tubercle is known as angle of rib.

The middle part of the rib is called the clean part. The superior border of this part is smooth. Also its inferior border is bordered. It has a groove called costal groove. The costal nerve and blood vessels pass through this groove.

The front part of the surface of the rib is called the anterior surface. Intercostal muscles are attached to it. When the posterior surface of the rib is in contact with the pleura of the lung.

Towards the end of the anterior side of the rib i.e. this end is also called the sternum end. Where the anterior side of the rib is attached to the sternum bone with the help of costal cartilage.

The space between two ribs is called intercostal space. Intercostal muscles are attached to this part. Due to the contraction and relaxation of these intercostal muscles, respiration occurs and the diameter of the thoracic cavity fluctuates.

• Appendicular Skeleton.

Appendicular skeleton includes solder joint, upper limb and pelvic joint and lower limb.

There are total 126 bones in the appendicular skeleton.

Upper extremity has 60 bones.
Lower extremity has 60 bones.

• Shoulder Joint.

Solder joint is also called solder girdle. The bones that make up the solder joint are as follows.

Scapula Bone. 1
Clavicle Bone. 1
Humorous Bone. 1

A solder joint is formed where the head of the humerus bone joins the glenoid cavity of the scapula bone. The clavicle bone does not form a direct solder joint.

Clavicle Bone.

This bone is also called collarbone. It is an S-shaped long bone. It has two ends or two extremities. In which the medial end of the clavicle bone joins with the clavicular notch of the manubrium of the sternum bone to form the sternoclavicular joint.

The clavicle bone joins with the acromion process of the lateral and a scapular bone to form the acromioclavicular joint.

Scapula Bone
Humorous Bone

• Ulna Bone.

It is a long bone in the forearm in the upper limb. This bone is also attached to the accompanying radius bone. In the forearm, the ulna bone is on the medial side and the radius bone is on the lateral side.

The ulna bone has two extremities and a socket.

The fang-like process at the upper extremity of the ulna bone is called the olecranon process and the smaller process at its lower end is called the coronoid process. Between these two processes lies a notch called the trochlear notch. Part of the trochlea of ​​the humerus bone joins this groove to form the elbow joint. This joint is of Hige joint type.

From the upper extremity of the ulna bone to the distal side, its diameter decreases. The muscles of the forearm are located in the part of the thigh.

The lower extremity of the ulna bone has an incisor process at the tip. It is known as styloid process of ulna. This part articulates with the proximal carpal bone to form the wrist joint.

The ulna bone joins the radius at the upper extremity to form the proximal radioulnar joint. Also the ulna and radius bone join at the lower extremity to form the distal radioulnar joint.

• Radius Bone.

It is a long bone in the upper limb. It is a bone on the lateral side of the forearm.
The radius bone has two extremities and a socket.

At the upper extremity of the radius bone there is a rounded part called the head. The next narrow part is called the neck and the next raised part is called the radial tuberosity.

Radius bone increases in diameter from the upper extremity downwards.

The soft part is found cylindrically round.

At the lower extremity there is a spiny process called styloid process of radius. This part joins with the proximal carpal bones to form the wrist joint.

• Carpal Bones.

It is also called wrist bone. They are arranged four by four in two rows of 8 in such a way that,

Proximal Row

Four carpal bones are arranged in the upper row. It contains the scaphoid, lunate, triquentral and pisiform bones. The carpal bones of this proximal row join the ulna and radius on the upper side to form the wrist joint.

Distal Row

The carpal bones in the distal row include the trapezium, trapezoid, capitate and hamate.

The carpal bones of the distal row attach to the proximal carpals superiorly and to the metacarpal bones inferiorly forming the carpometacarpo joint.

Metacarpal Bones.

Palm part is prepared with these bones. The number of metacarpals is found to be 5. In which the metacarpal of the thumb side is considered as the first metacarpal.

The metacarpal articulates superiorly with the carpal of the distal row. Also joins the proximal phalanges on the lower side.

• Phalanges.

The small bones in the fingers are called phalanges. It is found in number 14. There are two phalanges in the thumb. The remaining fingers have three phalanges.

Upper phalanges are called proximal phalanges, middle phalanges are called middle phalanges and end phalanges are called distal phalanges.

• Pelvic Joint.

Pelvic joint is also called pelvic girdle. The following are the bones that make up the pelvic joint.

Innominate Bone. 2
Sacrum Bone. 1
Femur Bone. 1

The acetabulum of the innominate bone joins the head of the femur bone to form the hip joint.

• Pelvis.

A pelvis is a basin-shaped cavity. Which is formed by two innominate bones, a sacrum and coccyx bone.

This creates a rounded area in the middle of the pelvis, called the pelvic brim. The part below the pelvis is called the true pelvis because of its importance in obstetrical terms. The upper part of the pelvic brim is called the false pelvis.

Innominate bone..

The innominate bone is the bone of the pelvic girdle. It is also known as hip bone.
They are two in number in the body. It is located one on both the right side and left side of the pelvic cavity. Both the innominate bones articulate with the sacrum bone behind and form the pelvic cavity.

The innominate bone is the larger bone. It is a flat and irregular type of bone.
Each innominate bone consists of three bones.

Ilium

Two ischiums

pubis.
Ilium
Innominate Bone The ma ilium bone is a flat bone on the upper side. At its uppermost point there is a ridge called the iliac crest. It falls below the iliac crest.
Anterior superior iliac spine (top of front)
Anterior inferior iliac spine (at the bottom of the front)
Posterior superior iliac spine (upper back)
Posterior inferior iliac spine (lower back)
The ilium bone forms the sacroiliac joint where it joins the sacrum bone at the back.
There is a big groove at the bottom of this joint. The notch is called the greater sciatic notch. From where the sciatic nerve and blood vessels pass to the lower extremities.
The gluteal muscles attach to the posterior surface of the ilium bone. And that makes up the gluteal region.
The anterior surface of the ilium bone is known as the iliac fossa. In this part there is a depressed part where the muscles are attached.
ischium
Below and behind the ilium bone lies the ischium bone.
Between the ilium bone and the ischium bone, the posterior side is an inferior pointed part. This part is called ischial spine.
Below it lies a small notch called the laser sciatic notch.
This laser has a strong thick process below the sciatic notch. Which is called ischial tuberosity. Body no weight comes on this part while sitting in sitting position. This has a stronger structure than a weight beer.
pubis
The pubis bone forms the most anterior part of the innominate bone. Both the innominate bones of the pubis bone join anteriorly to form the symphysis pubis joint.

There is a large foramen at the bottom of this pubis bone. It is called obturator foramen. Through which nerves and blood vessels pass downwards towards the extremity.
The three bones ilium, ischium and pubis located in the hip bone form a cavity-like structure called the acetabulum cavity. The head of the femur bone joins this KVT and the hip joint is formed there.

Femur Bone (Femur Bone).

The femur bone is the bone in the lower extremity. It is the longest and strongest bone among all the bones in the body.

This bone has two extremities and a smooth part. Which are as follows.

Upper extremity.

The uppermost one-third of the femur bone is called the upper extremity. It has the following structure.

head..

The frontmost part of the femur bone is the round bone part.The part which is called head of femur.

This round part joins with the acetabulum cavity of the innominate bone to form the hip joint.

The hip joint is a synovial joint so all the characteristics of a synovial joint can be seen here.

Neck..

The narrow part after the head is called the neck. Which is found in four to five centimeters long and round shape.

Greater trochanter and lesser trochanter..

Where the neck ends, two large rough and raised portions of bone are seen. Which is called trochanter.

The larger portion that protrudes outward is called the greater trochanter.While the smaller part that is raised on the inside is called the lesser trochanter. The line connecting these parts of the trochanter is called the intertrochanteric line. This part is where the muscles are attached.

After the upper extremity is completed, the middle part of the bone i.e. the middle part of the bone is known as the saft. Its structure is as follows.

Linea Aspera..

A bony ridge is raised on the posterior side of the face.It is called linea aspera. This part is where the muscles are attached. The smooth part of the femur bone is cylindrical and round in shape.

Lower Extremity..

The lower one-third of the femur bone is called the lower activity. In which the lower side is seen as two rounded bony parts. Which is called condyle. The condyle on the medial side is the medial condyle and the lateral side is the lateral condyle. The part separating these two condyles is called the intercondylar notch.

The anterior surface of this condyle is a smooth surface called the patellar surface where the patella bone articulates.

A triangular surface is formed at the back of the lower extremity of the femur bone. It is called the popliteal surface. Popliteal vessels and nerves are seen in this part.

Patella Bone.

It is also known as the knee cap bone. It is a sesamoid bone of triangular shape. This bone is located on the anterior side of the knee joint. This bone maintains its position with the help of ligaments and is the bone of movement.

• Tibia Bone.

It is also known as shin bone. The tibia is a long bone in the lower extremity. It has two extremity and saft. This bone is a strong and weighty beer bone.

The upper extremity of the tibia bone has two condylar surfaces on the superior surface. The lateral and medial condyles of the femur bone join this surface to form the knee joint.

On the anterior surface of the tibia bone there is a rough raised area called tuberosity of tibia.

The fibula bone joins on the lateral side of the tibia bone to form the proximal tibiofibular joint.

The smooth part of the tibia bone is irregularly triangular. There is a sharp crest on its anterior surface, known as crest of tibia. The part of this crest that lies immediately under the skin can be felt by touching with the hand.

A smooth elongated process is present on the medial side of the lower extremity of the tibia bone. It is called medial malleolus. This part joins with the tarsal bone to form the ankle joint.

The lower extremity joins the tibia and fibula to form the distal tibiofibular joint.

• Fibula.

The fibula bone is a long bone in the leg. It is located on the lateral side of the tibia bone. It has two extremities and a clean.

There is a quadrangular head at the upper extremity of the fibula bone. The narrow part below it is called the neck.

The fibula bone has an irregular margin on the soft side and a process on the lateral side of the lower extremity called the lateral malleolus.

The fibula bone is deep in the muscle.

• Tarsal Bones.

The tarsal bone is also known as the second ankle bone. It consists of 7 different irregular shaped bones which are as follows.

Talus. 1
Calcaneus. 1
Navicular. 1
Cuneiform. 3
Cuboid. 1

All the above tarsal bones join together and form the foot arch.
The talus bone joins the tibia and fibula bones to form the ankle joint.
The calcaneus bone forms part of the heel of the foot.

• Metatarsal Bones.

Metatarsal bones are located distal to the tarsal bones. They are in number of 5. Below it are the phalanges. It is 14 in number. There are 2 phalanges in the toe and 3 phalanges in the remaining fingers. All these phalanges form the interphalangeal joints.