The smallest of the five toes, the pinky toe is found along the lateral side of the foot. It is supplied by its own tendons from the flexor digiti minimi brevis and abductor digiti minimi muscles and therefore functions independently of the other toes. Like the other small toes, though, it is also controlled by the flexor digitorum longus and flexor digitorum brevis. The little toe is involved in the maintenance of balance when standing upright and walking, though its relevance to the function of the foot as a whole is frequently called into question. It has been suggested that its contribution to human movement is so minimal that evolution will cause it to shorten until it eventually disappears.
Alternately known as the fifth toe, little toe, or baby toe, the pinky toe is the most lateral of the toes, meaning that is nearest to the outside of the foot. Beneath the skin and fat that cover the toe is a dense network of nerves, blood vessels, and tendons that allow it to perform its movements of flexion, extension, abduction, and adduction. The nerves attaching to the little toe are the superficial branch of the lateral plantar nerve, the lateral branch of the intermediate dorsal cutaneous nerve, and the sural nerve, all of which transmit signals to the brain in response to stimuli, such as whether the surface the toe pushes off of is hard or soft.
Also contained within the pinky toe are the lateral plantar and dorsal digital arteries, the tendons of the flexor digitorum longus and brevis muscles, the tendons of the flexor digiti minimi brevis and abductor digiti minimi muscles, and three small bones laid end-to-end that are known as phalanges. The arteries supply blood and therefore nutrients and oxygen to the toe, while the tendons attach the muscles that move the toe to the phalanges within. It is the attaching muscles that determine the function of the little toe.
The flexor digitorum longus and brevis muscles attach to all four smaller toes and are responsible for the action of flexing or curling the toes as a unit. Individual movements of the pinky toe are controlled by two muscles of the lateral foot: the flexor digiti minimi brevis and abductor digiti minimi. The flexor digiti minimi brevis flexes and adducts the toe, or draws it inwards toward the fourth toe.
Abduction or the outward flaring of the toe is caused by the abductor digiti minimi muscle, a movement that along with flexion is likely the most significant to the pinky toe’s purpose. During walking and standing movements, the pinky toe not only curls downward to push off or grip the ground but also spreads when planted. This spreading motion is said to be the pinky’s contribution to balance, however minimal.