Leg

From Encyclopedia Jr, free information reference for Kids

For other senses of this word, see leg (disambiguation).

Diagram of an insect leg

In general, a leg is the part of an animal's body that support the rest of the body above the ground and is used for locomotion. In higher land animals, such as the tetrapod vertebrates, anatomists usually use the term 'leg' to refer to the portion of the limb distal to the hip joint (hind limb) or shoulder joint (fore limb).

In bipedal vertebrate animals, the lower limb is usually referred to as the 'leg' and the upper limb as the 'arm'.

Legs mostly come in even-numbered quantities that are characteristic of some taxonomic groups:

• in vertebrates, 2 (the bipeds) or 4 (the quadrupeds);
• in many familiar arthropods, 6, 8, or 12;
• in some arthropods, more than a dozen and sometimes over 100 -- but despite what their names might suggest,
  • centipedes seldom have exactly a hundred, and
  • millipedes apparently never even approach a thousand.

[edit] The human leg

Main article: Human leg

The bones of the human leg are:

• the femur (or thighbone), which attaches to the pelvis
• the patella (kneecap)
• the tibia (shinbone)
• the fibula (calf bone)

The front edge of the tibia is not covered by a thick layer of muscle or fat: this is why being kicked in the shins is so painful.

[edit] See also

• Body plan
• Arthropod leg