HUMAN BIOLOGY

the SKeLetaL SyStem 97

Figure 5.10 Animated! A–e Body parts can move in various ways at synovial joints. The synovial joint at the shoulder permits the
greatest range of movement. (© Cengage Learning)

extension

at shoulder

flexion at knee

flexion at

shoulder

extension at knee

abduction

abduction

abduction

adduction

adduction

adduction

Flexion reduces the angle between two bones, while

extension increases it. Hyperextension, as when you tip

your head back, increases the angle beyond 180.

circumduction

rotation

B circumduction and rotation

In circumduction a limb traces

an imaginary cone. Rotation

moves a body part around

its axis.

C abduction and adduction

Abduction moves a limb away from the body’s

midline; adduction moves a limb toward the

midline or beyond it.

pronation

supination

E

gliding movement

between carpals

D supination and pronation

In supination forearm bones rotate so that

the palms face outward; in pronation the

rotation turns the palms to the rear.

A flexion and extension

hyperextension

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