Toe - Toe Anatomy and Physiology

Toe Anatomy and Physiology

The human foot consists of multiple bones and soft tissues which support the weight of the upright human. Specifically, the toes assist the human while walking, providing balance, weight-bearing, and thrust during the gait. Toe bones articulate around the metatarsal bones which make up the central portion of the human foot. The joints between bones of the toe are known as interphalangeal joints. Movements are generally instigated by way of tendons actuated by muscles in the lower leg.

The hallux (large toe) is primarily flexed by the flexor hallucis longus muscle, located in the deep posterior of the lower leg, via the flexor hallucis longus tendon. Additional flexion control is provided by the flexor hallucis brevis. It is extended by the abductor hallucis muscle and the adductor hallucis muscle. The remaining toes are primarily controlled by the flexor digitorum brevis muscle and the extensor digitorum brevis muscle. Finally, the fifth toe (the smallest toe) has a separate set of control muscles and tendon attachments, the flexor and abductor digiti minimi. Numerous other foot muscles contribute to fine motor control of the foot. The connective tendons between the minor toes accounts for the inability to actuate individual toes.

Humans usually have five toes on each foot. Exceptions include polydactyly (more than five toes), and syndactyly or amputation (fewer than five toes). The four smallest toes consist of three phalanx bones, while the largest consists of two phalanx bones and two sesamoid bones. Many of the flexor tendons are shared, making it impossible to move individual toes independently; however, some prehensility, or grasping capability, does exist for most humans.

Forefoot shape, including toe shape, exhibits significant variation among people; these differences can be measured and have been statistically correlated with ethnicity. Such deviations may affect comfort and fit for various shoe types. Research conducted by Freedman for the U.S. Army indicated that larger feet may still have smaller arches, toe length, and toe-breadth. Specifically measurable toe and forefoot metrics for humans include:

• height
• breadth and girth
• ball length
• digital pattern
• heel to toe length
• footprint layout

Each of these metrics has been correlated to particular ethnic groups, but absolute deviations in dimensions are relatively small; such deviations may or may not be practically significant from the ergonomic or comfort standpoint...