Anatomy
The human foot and ankle is a strong and complex mechanical
structure containing 26 bones, 33 joints (20 of which are
actively articulated), and more than a hundred muscles, tendons,
and ligaments.
An anthropometric study of 1197 North American adult
Caucasian males (men age 35.5 years) found that a man's foot
length was 26.3 cm with a standard deviation of 1.2 cm.
The foot can be subdivided into the hindfoot, the midfoot,
and the forefoot:
The hindfoot is composed of the talus or ankle bone
and the calcaneus or heel bone. The two long bones of the lower
leg, the tibia and fibula, are connected to the top of the talus
to form the ankle. Connected to the talus at the subtalar joint,
the calcaneus, the largest bone of the foot, is cushioned
inferiorly by a layer of fat.
The five irregular bones of the midfoot, the cuboid,
navicular, and three cuneiform bones, form the arches of the
foot which serves as a shock absorber. The midfoot is connected
to the hind- and fore-foot by muscles and the plantar fascia.
The forefoot is composed of five toes and the
corresponding five proximal long bones forming the metatarsus.
Similar to the fingers of the hand, the bones of the toes are
called phalanges and the big toe has two phalanges while the
other four toes have three phalanges. The joints between the
phalanges are called interphalangeal and those between the
metatarsus and phalanges are called metatarsophalangeal (MTP).
Toes are the
digits of the
foot of a
tetrapod.
Animal species such as
cats that walk on their toes are described as
being
digitigrade.
Humans, and other animals that walk on the soles
of their feet, are described as being
plantigrade;
unguligrade animals are those that walk on
hooves at the tips of their toes. The toes are,
from
medial to lateral:
-
Hallux ("big toe" or "great toe"), the
innermost (most
proximal) toe and the closest to the toes of
the other foot
-
Second toe or "long toe" (although commonly
shorter than the big toe and often the third or
fourth toes)
-
Third toe, occasionally described as the
"ring toe"
-
Fourth toe, sometimes described as the "ring
toe"
-
Fifth toe ("little toe", "pinky toe", or
"baby toe"), the outermost (most distal) toe
