Dynamic support of the human longitudinal arch. A biomechanical evaluation

Area of Science:

• Biomechanics
• Human Anatomy
• Orthopedics

Background:

• The human longitudinal arch is crucial for load distribution during locomotion.
• Understanding the dynamic support mechanisms of the arch is vital for diagnosing and treating foot pathologies.

Purpose of the Study:

• To evaluate the dynamic support of the human longitudinal arch.
• To determine the contributions of leg muscles and the plantar aponeurosis to arch stability.

Main Methods:

• Utilized ten cadaveric specimens in a materials testing machine.
• Tensioned individual leg tendons (posterior tibialis, flexor digitorum longus, flexor hallucis longus, peroneus longus, peroneus brevis, Achilles) under varying plantar loads (0, 350, 700 N).
• Employed a 3D movement analysis system to record angular relationships and assessed plantar aponeurosis function via toe dorsiflexion.

Main Results:

• The plantar aponeurosis provided the most significant sagittal plane arch support, increasing the angle between the first metatarsal and talus by 3.6 degrees at 350 N and 2.3 degrees at 700 N.
• The posterior tibialis tendon consistently supported the arch under both 350 N and 700 N loads.
• The peroneus longus tendon consistently abducted the forefoot in the transverse plane at tested load levels.

Conclusions:

• The plantar aponeurosis is a primary dynamic stabilizer of the longitudinal arch, particularly through toe dorsiflexion.
• Specific leg muscles, including the posterior tibialis and peroneus longus, play significant roles in maintaining arch integrity and foot alignment under load.