Toes and ankle pt 1

Anatomy of the Foot

• The foot structure includes various bones essential for mobility and stability.

Tarsal Bones

• There are 7 tarsal bones in the foot:

  • Cuneiforms (1st, 2nd, 3rd)

    • 1st: Medial Cuneiform

    • 2nd: Intermediate Cuneiform

    • 3rd: Lateral Cuneiform

  • Cuboid: Located laterally; articulates with the calcaneus.

  • Navicular: Sits slightly superior to the cuboid.

  • Talus: Sits atop the sustentaculum tali and helps support it.

• The arch is formed along the instep of the foot.

Metatarsals and Phalanges

• The numbering of phalanges in the foot is opposite to that of the hand:

  • Phalanges are labeled 1 through 5 from medial to lateral.

• Metatarsals are found between the tarsal bones and phalanges.

• Distal phalanges are numbered 1, 2, 3, 4, 5 while middle phalanges are 2 through 5. The big toe only has proximal and distal phalanges.

Common Injuries

Jones Fracture

• A Jones fracture occurs at the base of the 5th metatarsal.

• Important to note due to frequent appearance in exams.

Joint Architecture and Movement

• Interphalangeal (IP) joints: Ginglymus (hinge)- flex/ext.

• Metatarsophalangeal (MTP): Modified ellipsoidal (condyloid) Flex/ext., abd/add

• Tarsometatarsal & intertarsal joints: Plane (gliding)

• Ankle joint: Saddle (sellar) dorsiflexion & plantar flexion only

• The ankle is described as a modified ellipsoidal joint, permitting four directional movements:

  • Abduction

  • Adduction

  • Flexion

  • Extension

Ankle Positioning

• The lateral malleolus is positioned posteriorly, while the medial malleolus is anterior.

• A protractor view shows that the fibula is 15 to 20 degrees posterior from the tibia in the lateral view.

Foot Actions

• Inversion: Movement of the plantar surface of the foot towards the midline.

• Eversion: Movement of the plantar surface of the foot away from the midline.

• Stress movements can result in injuries or tears in the ankle joint.

Sesamoid Bones

• Tibial sesamoid and fibular sesamoid are present on the dorsal surface of the foot.

Pathology

• Hallux valgus refers to an abnormality concerning the first metatarsal head and associated osteophyte growth.

• Osteophytes can indicate excessive bone growth typically occurring in conditions like hallux valgus.

• Jones fracture- occurs at the base & shaft of the 5^th MT (tuberosity)

• Pott fracture- complete fracture of distal fibula with major injury to ankle joint, including ligament damage and frequently fractured distal tibia

• Gout- a form of arthritis in which uric acid appears in excessive quantities in the blood & joints (common in 1st MTP