Classification of bones
Bones may be classified by different ways which are
1. Classification of bone by shape
2. Developmental classification of bones
3. Regional classification of bone
4. Structural classification of bones
1. Classification of bones by Shape
Long bones have an elongated shaft and two epiphyses which are smooth and articular.
Long bones have 3 types
Examples Radius, ulna, femur, tibia, fibula, humerus, metacarpals, and phalanges
The shape of short bones is usually cuboid or scaphoid.
They resemble a shallow plate and form boundaries of the cavities.
These bones are irregular in shape.
first and 2nd cervical vertebrae.
They contain large air spaces and these air spaces are lined by epithelium.
They are found embedded in the tendon or joints capsules. They have no periosteum and their ossification occurs after birth.
They are not always present but may be developed from the extra centers of ossification.
Sutural bones of the skull
2. Developmental Classification of Bones
They ossify in the membrane and thus derived from mesenchymal condensations.
These ossify in cartilages and thus derived from cartilaginous models.
These ossify partly in membranes and partly in cartilages.
These bones developed from pharyngeal arches. These are few.
part of mandible
3. Regional Classification
Regionally bones may be classified into two classes which are
a. Axial Skeleton
The axial skeleton includes bone of
b. Appendicular Skeleton
The appendicular skeleton includes bone of
4. Structural Classification of Bones
Structurally bones may be classified into two classes which are
These are dense and extremely porous bones.
These are open in texture and is made up of a meshwork of rods and plates.
Both spongy and compact bones consist of lamellae and hence they are lamellar bones.
d. Woven Bones
The collagen fibers and crystals are randomly arranged in this type of bones.
These are found in young fetal bones.
Present in teeth.
present in teeth.
It is the framework of the bod. An adult human consists of two hundred and six bones. The bone mass reaches its maximum level at the age of twenty-one. The human skeleton can be divided into two subdivisions that are 1.axial and 2. Appendicular skeleton. The axial skeleton consists of a vertebral column, ribs, skull, and associated bones. The Appendicular skeleton is formed by the shoulder girdle, pelvic girdle, upper limb, and lower limb. The human skeleton performs various functions such as support, movement, protection, etc.
The human skeleton performs six major functions that are
4. Production of blood cells
5. Storage of mineral
6. Endocrine regulation
The skeleton makes the internal framework of the body that supports the body and also maintains the shape of the body. Skeleton provides a floor for the structures of the body. For example pelvis, associated ligaments provide floor to the pelvic structure. Another example is ribcage because without it the intercostal muscles and lungs will collapse.
There are joints that are present between the bones. These joints allow the movement. Some joints allow a wider range of movement while some have restricted movement. For example, a ball and socket joint allows a greater range of movement while the pivot joint of the neck allows less movement. The movement of the bones is lowered by the skeletal muscles that are attached to the skeleton. Muscles, bones, and joints produce movement and are coordinated by the nervous system of the body.
Another important function of the human skeleton is the protection of vital internal organs from being damaged.
1. Skull protects the brain
2. Vertebrae protect the spinal cord
3. Ribcage, sternum protects the lungs, heart, and major blood vessels
Blood cell production
Bone marrow is present in the bones in which the development of blood cells takes place. In children, the development of blood cells occurs in the long bones such as the femur while in adults it occurs mainly in the pelvis and sternum.
The bone matrix is capable to store calcium ions and marrow has the ability to store iron.
Osteocalcin is a hormone released by the bone that regulates blood sugar and fat deposition. This hormone increase insulin secretion and sensitivity.
There are many disorders related to the human skeleton but here we will discuss only two of them that are arthritis and osteoporosis.
Arthritis is a disorder of joints on which inflammation occurs in one or more joints. Joints that are affected by arthritis may be painful to move or may move in the wrong direction, or become immobile. The symptoms of arthritis are different in person because of the type of arthritis the person has. The most common type of arthritis is osteoarthritis. There are over 100 types of arthritis.
1. Inability to walk
5. Weight loss
6. Poor sleep
7. Muscle aches
9. Difficult to move joint
10. Muscle weakness
11. Loss of flexibility
12. Decreased aerobic fitness
The cure for rheumatoid arthritis and osteoarthritis is not known. Treatment can be done according to the type of arthritis that also includes physical therapy, lifestyle changes, orthopedic bracing, and medications. Medication can help to reduce inflammation in the joints that decrease the pain and it also slowed the process of inflammation.
Osteoporosis is a condition in which bone mineral density is reduced that increases the chances of fracture. Osteoporosis is more commonly found in females after menopause. Osteoporosis that occurs after the menopause is known as postmenopausal osteoporosis.
Treatment of osteoporosis includes
1. Stop smoking
2. Decrease alcohol consumption
3. Exercise regularly
4. Healthy diet.
Bone mineral density and conventional radiography are used to diagnose osteoporosis. The popular method of measuring the bone mental density is dual energy X-rays absorptiometry.