The Ankle and Foot Complex Anatomy & Biomechanics

Ankle and Foot Complex

1. THE ANKLE AND FOOT COMPLEX PREPERED BY SOMA BALAJI PT

2. INTRODUCTION Ankle/foot complex analogous to wrist/hand. Primary role is for weight bearing(can accommodate large weight bearing stresses). Provides stability and mobility(static & dynamic). Acts as shock absorbers. Consist of 28 bones that form 25 component joints. They are divided in to 3 segments. Hind foot (T,C) Mid foot (NCC) Forefoot (MP)

3. Joints of Ankle & Foot Complex Proximal & distal tibio -fibular joints. Talocural joint. Talocalcaneal / subtalar joint. Talonavicular joint. Calcaneo cuboid / transverse tarsal joint. Tarsometatarsal joints(5). Metatarsophalangeal joints(5). Interphalangeal joints.

4. Movements in joint

5. Valgus/ varus (calcaneal)

6. Ankle Joint It refers to the talocrural joint. Hinge variety of synovial joint( ). Proximal articular surfaces(distal tibiofibular joint). Distal articular surfaces(body of the talus).  

7. Proximal Tibiofibular Joint Plane synovial joint formed by the articulation of the head of the fibula with posterolateral aspect of the tibia. Proximal tibiofibular joint is surrounded by joint capsule by Anterior Posterior Tibiofibular ligaments The motion at this joint is small. Proximal Articular Surface

8. Distal tibiofibular joint Joint is Syndesmosis Consist of concave surface of distal tibia, tibial & fibular malleoli. These 3 facets forms cave like structure on both sides (comparatively more on lateral side) – forms MORTISE (FLEXIBLE). Ligaments Anterior tibiofibular ligaments Posterior tibiofibular ligaments Interosseous membrane

9. Distal Articular Surface Body of talus forms the distal articulation of the ankle joint. Body of talus has 3 articular surface Large lateral facet Smaller medial facet Trochlear facet The large, convex trochlear surface has central groove that runs slightly angle to head and neck of talus.

10. Capsule and Ligaments Medial collateral ligament or Deltoid ligament Lateral collateral ligament Anterior tibiofibular ligaments Posterior tibiofibular ligaments Calcaneofibular ligament Portions of extensor and peroneal retinacula of ankle are credited with stability.

11. Medial ligaments of Ankle Lateral ligaments of Ankle

12. Axis of ankle

13. Subtalar Joint (Hinge type) Talocalcaneal or Subtalar joint is composite joint formed by 3 separate plane articulations between Talus superiorly and Calcaneus inferiorly . Posterior articulation formed by Concave facet on undersurface of body of talus and convex facet on calcaneus body. Smaller anterior and medial talocalcaneal articulations formed by 2 convex facets on inferior body and neck of talus 2 concave facets on calcaneus.

14. Tarsal canal – funnel shaped tunnel present between the posterior, anterior and medial articulations. Sustentaculum tali – bony projection between tibial and fibular malleolus. Posterior articulation has its own capsule, where as anterior and medial with shared capsule of talonavicular joint . LIGAMENTS Calcaneofibular Lateral talocalcaneal Cervical Interosseous talocalcaneal

15. Movements Movement Non-weightbearing Weight-bearing Supination Calcaneal inversion (varus) Calcaneal adduction Calcaneal plantar flexion Calcaneal inversion (varus) Talar abduction (lateral rotation) Talar dosiflexion Tibiofibular lateral rotation Pronation Calcaneal eversion (valgus) Calcaneal abduction Calcaneal dorsi flexion Calcaneal eversion(valgus) Talar adduction (medial rotation) Talar plantar flexion Tibiofibular medial rotation

16. Transverse Tarsal Joint Also known as midtarsal or chopart joint . Combination of talonavicular & calcaneocuboid joint. Two joints together forms “ S ” shape. Navicular and cuboid bones are immobile in the weight bearing.

17. Talonavicular Joint Proximal – anterior portion of the head of the tallus . Distal – concave posterior aspect of the navicular bone. Subtalar and transverse tarsal joint have a common capsule; this joint’s inferior aspect is formed by plantar calcaneonavicular ligament (Spring ligament). It contains of 3 bands superiomedial , medioplantar , inferoplantar that extends fom sustentaculum tali to inferior navicular bone. Passive/static stabilizer of medial arch of the foot.

18. Calcaneocuboid Joint Proximal – anterior calcaneus. Distally – posterior cuboid bone. They have a reciprocal shape, it makes available motion at the calcaneocuboid joint but it is a restricted type (Have own Capsule).

19. Ligaments Laterally – lateral band of the bifurcate ligament(calcaneocuboid). Dorsally – dorsal calcaneocuboid ligament. Inferiorly – plantar calcaneocuboid & long plantar ligaments.

20. Joint Function Subtalar and transverse tarsal joints are mechanically connected because they share the joint capsule. Any weight bearing motion at sub talar joint causes movement at talonavicular and calcaneocuboid joint to begin supination. It acts as transitional between hind & forefoot.

21. Tarsometatarsal Joint Plane synovial joint. Formed by distal row of tarsal bones (posteriorly at the base of meta tarsals). Attachment 1 st - medial cuniform 2 nd – middle cuniform & sides of medial and lateral cuniforms 3 rd – 3 rd metatarsal and lateral cuniform (shares capsule with 2 nd tarsometatasal joint) 4 th & 5 th – formed by the bases of the fourth and fith metatarsals with bone There is a deep transverse metatarsal ligament that spans the heads of metatarsals on the plantar surface.

22. Joint Function Supination Twist Pronation Twist In relation to weight bearing this joint contribute in regulation of the forefoot.

23. Metatarsophalangeal Joints Condyloid synovial joint with 2 ⸰ of freedom(dorsi/plantar & abd /add). Proximally – convex heads of the metatarsals. Distally – concave base of proximal phalanges. Index minus/Morton’s foot – 2 nd metatarsal is longer than remain.

24. Sesamoidities The sesamoid bones and their supporting structures can become traumatized with excessive loading leading to acute fractures. Inflammatory conditions of the sesamoid which results in pain (generally first meta tarsal head known as sesamoidites ). Stability of the metatarso phalangeal joint is provided by joint capsule, collateral ligaments & plantar plates.

25. Joint Function Flex/Ext & Abd/Add . Hallux rigidus – limited extension ROM at 1 st MTP Joint will interfere with metatarsal break. Hammer Toe Deformity – excessive extension at the metatarsophalangeal joint resulting this position.

26. Interphalangeal Joints Hinge variety of synovial joint – Flex/Ext. Greater toe has only one interphalangeal joint connecting two phalanges. Four lesser toes have 2 interphalangeal joints (proximal and distal ). Toes function to smooth the weight shift to the opposite foot in gait and help maintaining stability by pressing against the ground standing.

27. Arches of Foot Consist of 3 Arches Medial longitudinal arch is the largest arch. Medial longitudinal arch Lateral longitudinal arch Transverse arch

28. Longitudinal arches are anchored posteriorly at the calcaneus and anteriorly at the metatarsal heads. Talus rests at the top of the foot and considerd to be the keystone of the arch. Transverse arch is easily visualized in the mid foot at the level of tarsometarasal joint. Anterior tarsals, middle cuniform bone forms the keystone of the arch. Shape and arrangement of the bones are partially responsible for stability of the plantar arches. Inclination of the calcaneus and 1 st meta tarsals contribute to stability of medial longitudinal arch(in standing). Without support of ligaments and muscles arches may collapse. Support for medial longitudinal arch are Spring ligament. Interosseous talocalcaneal ligament. Deltoid ligament. Plantar aponeurosis.

29. Muscles Dynamic Arch Support Medial Arch Support Intrinsic muscles Tibialis Ant & Post. Peroneus longus & tertius. Flexor digitorum longus Abductor hallucis Flexor hallucis brevis Flexor digitorum brevis Abductor digiti minimi Dorsal interossei Tibialis posterior

30. Supporting structures of the foot arches

31. Function of Arches Stability and mobility. Weight distribution. Suspension

32. Pes Cavus – high arch foot in both weight and non weight bearing. Hallus valgus – associated with reduction in 1 st MTP joint ROM, lead to gradual sublaxation and less weight bearing. Pes Planus – progressive loss of static and dynamic longitudinal arch support.

33. Plantar Aponeurosis/fascia It is a dense fascia, Extends from posteriorly on the medial tubercule of the calcaneus & continues anteriorly to attach plantar platis . Function via tie - rod and truss which forms the triangle.

34. Weight Distribution ( Tallus ) Bilateral stance – 50% Unilateral stance – 100% Standing position – 50%

35. MOVEMENT MUSCLES ROM (In Degree) JOINT INVOLVED Plantar flexion gastrocnemius, plantaris, soleus, tibialis posterior, flexor digitorum longus, flexor hallucis longus, fibularis longus and the fibularis brevis 20-25 Talocrural Dorsiflexion tibialis anterior and the extensor hallucis longus  35-50 Talocrural Abduction Abductor hallucis 10-20 Subtalar & Talocrural Adduction Adductor hallucis 10-20 Subtalar & Talocrural Inversion tibialis anterior and the extensor hallucis longus 0-30 Subtalar and the talocalcaneonavicular Eversion peroneus longus and Peroneus Brevis 0-20 Subtalar and the talocalcaneonavicular