Page 28 - Viva ICSE Science 5 : E-book

Ball and socket joint

In ball and socket joint, the ball-like end of one bone
fi ts into a cup-like cavity (socket) of the other bone. It

allows movement in all directions. Shoulder and hip
joints are of this type.
Ball and socket joint

Pivot joint

Pivot joint allows rotation only. In this joint, the

rounded surface of one bone fi ts into a ring formed
by the other bone. Joint between the neck and the
head is a pivot joint.

Pivot joint
Pi j i

Gliding joint

Gliding joint allows the bones to glide over each other. Bones of
the wrist and the ankle have gliding joints.

Gliding joint

Importance of joints

Bones are rigid structures that cannot bend. Joints provide fl exibility to our body

by allowing bones to move in diff erent directions. Diff erent types of joints provide
movement in certain directions only. Fluid present within the joints moisturises the
surface of bones to allow smooth movement. Thus, we can say that joints are the points
of movement within the skeletal system, and hence, are an important component of the
body.

Muscles

Muscles are bundles of elastic fi bres. They are fl exible, and thus, bring about movement
of all body parts.

Types of muscles

There are three types of muscles present in our body—skeletal, smooth and cardiac
muscles.

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