Plantar Arch Anatomy and Foot Support Functions

Common Features of Plantar Arches

• Alojar soft tissue found in the plantar foot.
• Provide stability during gait, regularizing loads.
• Distribute pressure harmonically.
• Serve to spring muscles and ligaments in order to increase passive tension.
• Adaptation to ground irregularities.
• Contribute to propulsion or internal movements.

Elements of the Medial Plantar Arch

Bony Elements:

• First Metatarsal: Only touches the floor with its head.
• Wedges (Cuneiforms): These are the only bones that transmit pressure directly, but through the muscles and ligaments covering them. Since the first wedge is strongly attached by ligaments to the second and third wedges, these pressures are transmitted to the second and third metatarsals.
• Scaphoid: It is the highest point of the arch, approximately 15–18 mm from the ground, which explains why the footprint does not mark this area. It receives pressure from the head of the Talus and transmits it to the cuneiforms, and from there to the Sustentaculum Calcanei.
• Talus (Astragalus): Receives and distributes the body weight.
• Calcaneus: Receives pressure via the Sustentaculum Tali.

Sustaining Elements (Ligaments):

• The most important is the glenoid ligament, followed by the calcaneal-talus ligament.

Supporting Muscles:

• Tibialis Posterior: Acts as a partial rope grasping the middle of the medial plantar arch. Its expansions attach to the three metatarsals.
• Peroneus Longus: Acts as a partial rope crossing the midfoot up to the scaphoid, first cuneiform, and first metatarsal.
• Flexor Hallucis Brevis (Short Flexor of the First Toe): Acts almost as a total rope. It stabilizes almost the entire arch and is aided by the common flexor of the toes. As it passes behind the medial malleolus, it prevents the Talus from slipping forward. The long flexor muscle passes below the sustentaculum tali, preventing it from dropping.
• Abductor Hallucis (Separator of the First Toe): Acts as a total rope.

Stabilizing Elements:

• Anterior Tibialis and Extensor Hallucis Longus.

Elements of the Lateral Plantar Arch

Bony Elements:

• Fifth Metatarsal: Only rests on the ground by its head.
• Cuboid: It is the highest point of the arch, approximately 3–5 mm from the ground.
• Calcaneus: Contacts the soil via its posterior tubercles. It receives pressure from the Talus and the interosseous ligaments.

Sustaining Elements:

• The most important element is the calcaneocuboid plantar ligament.
• Peroneus Brevis (Short Fibularis): Acts as a partial cornerstone.
• Peroneus Longus: Acts as a slightly wider rope that stabilizes the middle metatarsals, but by catching the cuboid, it creates an active tension in this arch, leading to the elevation of the cuboid, which confers elastic resistance.
• Abductor Digiti Minimi (Separator of the Fifth Toe): Acts as a total rope that favors the approach of the fifth metatarsal to the cuboid.

Turbulence Elements:

• Triceps, Peroneus Anterior, and Peroneus Longus throughout the medial arch.

Elements of the Toe Arch

Supporters:

• Intermetatarsal ligaments, although without great efficacy.
• Transverse fascicle of the Adductor Longus of the first toe.
• Peroneus: Subjects all subsequent metatarsals.
• Tibialis: Stabilizes the first and second axes.