Join the dots between joints and disorders

Today, let's focus on the topic of joints and the disorders of the muscular and skeletal system.

Hyderabad: This article is in continuation to the previous articles focusing on Locomotion and Movement. Today, let’s focus on the topic of joints and the disorders of the muscular and skeletal system.

JOINTS

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• Joints are essential for all types of movements involving the bony parts of the body.

• Locomotory movements are no exception to this.

• Joints are points of contact between bones, or between bones and cartilages.

• Force generated by the muscles is used to carry out movement through joints, where the joint acts as a fulcrum.
• The movability at these joints varies depending on different factors.
• Joints have been classified into three major structural forms, namely, fibrous, cartilaginous and synovial.
Fibrous Joints
• Fibrous joints do not allow any movement.
• This type of joint is shown by the flat skull bones which fuse end-to-end with the help of dense fibrous connective tissues in the form of sutures, to form the cranium.
Cartilaginous Joints
• In cartilaginous joints, the bones involved are joined together with the help of cartilages.
• The joint between the adjacent vertebrae in the vertebral column is of this pattern and it permits limited movements.

Synovial joints

• Synovial joints are characterised by the presence of a fluid filled synovial cavity between the articulating surfaces of the two bones.

• Such an arrangement allows considerable movement.

• These joints help in locomotion and many other movements.

• Ball and socket joint (between humerus and pectoral girdle),

Hinge joint (knee joint),

Pivot joint (between atlas and axis),

Gliding joint (between the carpals) and

Saddle joint (between carpal and metacarpal of thumb) are some examples.

DISORDERS OF MUSCULAR AND SKELETAL SYSTEM

Myasthenia gravis
• Auto immune disorder affecting neuromuscular junction leading to fatigue, weakening and paralysis of skeletal muscle.

Muscular dystrophy

• Progressive degeneration of skeletal muscle mostly due to genetic disorder.
Tetany
• Rapid spasms (wild contractions) in muscle due to low Ca in body fluid.

Arthritis

• Inflammation of joints.

Osteoporosis

• Age-related disorder characterised by decreased bone mass and increased chances of fractures. The decreased levels of estrogen is a common cause.

Gout

• Inflammation of joints due to accumulation of uric acid crystals.