The skeletal structure of the foot is similar to that of the
hand, but because the foot bears more weight, it is stronger but less movable.
The bones of the foot are organized into the tarsal bones,
metatarsal bones, and phalanges.
The foot begins at the end of the tibia and fibula, the two
bones of the lower leg. At the base of those, a grouping of bones form the
tarsals, which make up the ankle and upper portion of the foot.
The seven tarsal bones are:
- Calcaneus:
The largest bone of the foot, it is commonly referred to as the heel of the
foot. It points upward, while the remaining bones of the feet point downward.
- Talus:
This irregularly shaped bone creates the lower portion of the ankle joint. It
is the second largest bone in the foot.
- Cuboid:
This multisurface bone sits on the outside of the foot near the fifth phalange
(little toe).
- Cuneiforms:
These three small bones are closest to the five metatarsal bones. They sit in a
row that begins at the inside of the foot and moves toward the cuboid on the
outside of the foot.
- Navicular:
This curved bone sits between the talus and cuneiforms.
There are five metatarsal
bones in each foot. Similar to the bones of the hand, these nearly parallel
bones create the body of the foot. Numbered one through five, the bone that
sits behind the big toe is No. 1, and the one behind the little toe is No. 5.
The phalanges create the toes. Each toe consists of three
separate bones and two joints, except for the big toe, which has only two bones—distal
and proximal phalanges—and one joint like the thumb in the hand. The phalanges
are made up of the distal phalanges at the tip, middle phalanges, and proximal
phalanges closest to the metatarsals.
Bones are connected via fibrous ligaments. The ankle and
other parts of the foot are surrounded by a web of ligaments, and the
metatarsal bones are strung together by ligaments to keep them from stretching
too far apart. Each individual toe joint is wrapped in ligaments.
Because of its number of
bones, the foot also contains numerous pieces of cartilage, a connective tissue that pads bones, and joints. This
cartilage can be damaged with excessive use or injury. Cartilage damage can
cause joint pain.