Question

Number of ball and socket joints present in human body is
A. 2 pairs
B. 4 pairs
C. 6 pairs
D. 8 pairs

Answer 1

A ball-and-socket joint consists of a ball-like surface of one bone fitting into a cup-like depression of another bone. These joints are multiaxial (polyaxial) allowing a wide range of movement in almost any direction.

Complete answer:
1.There are various types of joints on the basis of the degree of motion in them. Such as non- movable joints (Synarthroses), Imperfect movable joints (Amphiarthrosis) and Perfect movable joints (Diarthroses).
2.Non- movable joints have no joint cavity, no movement possible. These joints include Sutures, Gomphoses and Shindylases.
3.Imperfect movable joints are with or without the joint cavities, permitting a small amount of movement, also called cartilaginous joints. Example- Between bodies of the vertebrae, united by an intervertebral disc, in Between the manubrium and body of the sternum, etc.
4.Perfect movable joints are called synovial joints Movable joints are called synovial joints which have a synovial or joint cavity, a space between articulating bones. Articular cartilage consisting of hyaline cartilage covers the surface of articulating bones.

5.Types of synovial joints:
a.Ball-and-Socket Joints: A ball-and-socket joint consists of the ball-like surface of one bone fitting into a cup-like depression of another bone. These joints are multiaxial (polyaxial) allowing a wide range of movement in almost any direction. e.g., the shoulder and hip joints i.e 2 pairs.
b.Hinge Joints: Bone has a convex surface which fits into the concave surface of another bone. Hinge joints produce an angular, opening-and-closing motion. e.g., knee, elbow, and interphalangeal joints.
c.Saddle Joints: The articular surface of one bone is saddle-shaped and the articular surface of the other bone fits into it. e.g., carpometacarpal joint between the trapezium of the carpus and metacarpal of the thumb.
d.Pivot Joints: The rounded or pointed surface of one bone articulates with a ring formed partly by another bone and partly by a ligament. e.g., atlanto-axial joint and radio-ulnar joint.
e.Gliding (Planar) Joints: The articulating surfaces of bones are flat or slightly curved Gliding joints primarily permit side-to-side and back-and-forth gliding movements.e.g.,intercarpal joints (between carpal bones at the wrist), intertarsal joints (between tarsal bones at ankle) and articular processes between vertebrae.
f.Ellipsoidal (Condyloid) Joints: These are modified ball-and-socket joints.. e.g., atlanto-occipital joint, radiocarpal and metacarpo phalangeal joints.

Hence, the correct answer is option (A)

Note: There are various disorders of joints. Such as:
1.Arthritis- Arthritis, an inflammation of any joint, is the most common and best known of the joint disorders.
2.Rheumatoid arthritis is an autoimmune disease in which the immune system of the body attacks its own tissues.
3.Osteoarthritis, commonly known as "wear and tear" arthritis or degenerative arthritis, is the most common type of arthritis. It is a progressive, degenerative disorder of synovial joints.
4.Gout is a hereditary disease, most common in men in which monosodium urate crystals accumulate in the joints and irritates the articular cartilage and synovial membrane.