The arch serves to cushion the force of the impact of the foot when moving.

There are three plantar arches:

• The medial longitudinal arch.
• The lateral longitudinal arch.
• The transverse arch.

Medial longitudinal arch

• Five bones form the prominent medial longitudinal arc:
  1. Calcaneum
  2. Talus
  3. Navicular
  4. First cuneiform
  5. First MT

• The bone, ligament and muscular arrangement of the medial arch allows a greater amount of movement than the other arches of the foot.
• The navicular is the key structure for the fore and aft stabilization of the medial longitudinal arch.
• So it is important that the navicular has good mobility, because any dysfunction of this bone will lead to a bad support of the medial arch.
• Ligament support for the medial arch is obtained from:
  • Calcaneonavicular plantar ligament (“spring”)
  • Long and short plantar ligaments
  • Deltoid ligament
  • Plantar fascia.
• The primary support of the medial longitudinal arc is obtained from the three bands of the plantar fascia.
• The central band, originating from the medium calcaneal tuber and inserting into the distal plantar surfaces of each of the five toes, is the longest and thickest.
• As the central band progresses along the length of the foot, it gives rise to the medial and lateral bands.
• The plantar fascia supports the medial and lateral longitudinal arches in the same way an arc string works to give a curve to the arc.
• Supporting longitudinally the calcaneus at the MT heads, the plantar fascia curves the long arcades of the foot.
• Due to the attachment of the fascia to the phalanges, the extension of the toes attracts the calcaneus to the heads of the MT.
• So the bows are further accentuated because of the windy effect.
• During the walk, the anterior tibial and posterior tibial work together to support the medial arch by giving a supination movement to the foot.
• A debalance of the work of these muscles will lead to a dysfunction of the medial arch that will possibly overload the anterior and posterior tibial.

Transverse arc

• The transverse arc is formed by:
  • The lengths of the metatarsals and tarsi
  • the concave features along the inferior surface of the metatarsals.
• There are two transverse arches:
  • Antérior
    • The heads of the metatarsals create the anterior transverse arch.
    • A debalance of the work of these muscles will lead to a dysfunction of the medial arch that will possibly overload the anterior and posterior tibial.
  • Posterior
    • The posterior transverse arc consists of larger parts of the tarsus and metatarsus.
    • The arch is supported by support formed by the medial and lateral longitudinal arcades, with dynamic support provided by the perennial long muscle.
    • It only creates half of the dome in one foot.
    • The entire dome is made up when the two feet are brought together.
• The arch is supported by support formed by the medial and lateral longitudinal arcades, with dynamic support provided by the perennial long muscle.