Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Non Muscular Anatomy Foot and Ankle Bones Inferior Tibia • Prominent medial malleolus which is continuous with the medial shaft • Inferior surface is smooth for articulation with the talus • Inferior surface continues medial with the malleolar articular surface • Inferior surface turns upward laterally for articulation with the fibula • Anterior surface of smooth • Posterior surface is coarse and grooved by tendons Inferior Fibula • Flattened medially and laterally • Malleolar fossa found posteriorly • Articulates with the talus medially Calcaneus • Inferior to the talus • Forms the heel • Strongly bound to all the tarsal bones by ligaments • Calcaneal tuberosity present posteriorly for Achilles tendon insertion • Sustentaculum tali present medially and superiorly • Support and articulates with the talus superiorly • Provides anchors for ligaments • Helps flexor hallucis longus, tibialis posterior and flexor digitorum longus pass into the foot Talus • Superior to calcaneus • Transmits body weight from tibia to calcaneus and navicular • Split into body and head • Body • Wedge shaped body being wider anteriorly • In between the fibular and tibia • Convex upper surface • Head • Inferior surface articulates with the sustentaculum tali of the calcaneus • Anterior surface articulates with the navicular Navicular • Found anteriorly to the head of the talus • Large tuberosity found inferomedially • Anterior surface divided into 3 triangular areas • Forms articular surface for 3 cuneiform bones Cuboid • Has 6 surfaces • Makes up the transverse arch of the foot with the 3 cuneiform bones • Location • Lateral to lateral cuneiform • Anterior to the calcaneus • Posterior to 4th and 5th metatarsals Cuneiform - Medial • 3 different wedge shaped bones • Makes up the transverse arch of the foot with the cuboid • Medial Cuneiform • Articulates with the navicular posteriorly • Articulates with the 1st metatarsal anteriorly • Articulates with the 2nd metatarsal and Intermediate cuneiform laterally Cuneiform - Intermediate • 3 different wedge shaped bones • Makes up the transverse arch of the foot with the cuboid • Intermediate Cuneiform • Articulates with the medial cuneiform medially • Articulates with the lateral cuneiform laterally • Articulates with the navicular posteriorly • Articulates with the 2nd metatarsal anteriorly Cuneiform - Lateral • 3 different wedge shaped bones • Makes up the transverse arch of the foot with the cuboid • Lateral Cuneiform • Articulates with the cuboid laterally • Articulates with the intermediate cuneiform medially • Articulates with the navicular posteriorly • Articulates with the 2nd and 3rd metatarsal anteriorly Metatarsals • 5 in each foot • All have a shaft, a head distally and a base proximally • Bases articulate with the tarsal bones • Head articulates with the proximal phalanx Phalanges • 2 phalanges in the great toe • 3 phalanges in the other toes • Long bones with a shaft and two extremities • Head of the distal phalanx is flattened on its dorsum and has no articular area Distal Tibiofibular Joint Distal Tibiofibular Joint • Fibrous joint (syndesmosis) • Distal tibia and fibula do not come into contact with each other • Separated by fibroadipose tissue Distal Tibiofibular Joint - Ligaments • • • • • • • • • • Anterior tibiofibular ligament Fibular notch of tibia to lateral malleolus of fibula Posterior tibiofibular ligament Fibular notch of tibia to lateral malleolus of fibula Thicker and broader than the anterior tibiofibular ligament Transverse tibiofibular ligament Deep to posterior tibiofibular ligament Thick and strong From inferior border of tibia to malleolar fossa of fibula Descends below bone posteriorly and forms part of the articular surface for the posterior aspect of the talus Distal Tibiofibular Joint – Joint Capsule and Synovial Membrane • Interosseous membrane • fibrous joint between the tibia and fibula • Does not reach as far as the superior tibiofibular joint • Divides the anterior and posterior compartment of the leg • Synovial-lined recess of the ankle joint cavity extends upwards between the tibia and fibula Distal Tibiofibular Joint – Arthrokinematics • Plantarflexion • Posterior talus moves into anterior part of the tibiofibular socket • Posterior talus smaller than tibiofibular socket • Tibiofibular joint comes together • Lateral malleolus moves medially and inferiorly • Fibula rotates axially (opposite direction to dorsiflexion) Distal Tibiofibular Joint – Arthrokinematics • Dorsiflexion • Anterior talus forced into posterior part of tibiofibular socket • Talus larger than tibiofibular socket • Tibiofibular joint separates • Increases tension in interosseous and transverse ligaments • Fibula rotates axially • Lateral malleolus moves laterally and superiorly Talocrural Joint Talocrural Joint • Synovial hinge joint between tibia, fibula and talus • Allows plantarflexion and dorsiflexion Talocrural Joint - Ligaments • Deltoid Ligament • From tibial malleolus to navicular bone anteriorly and talus/calcaneus distally/posteriorly • Very strong ligament • Valgus force may avulse tibial malleolus before tearing deltoid ligament • Primary function is to control medial distraction and calcaneal eversion • Anterior parts limit plantarflexion • Posterior parts limit dorsiflexion Talocrural Joint - Ligaments • Plantar calcaneonavicular (spring) ligament • Short thick wide ligament • Connects the anterior sustentaculum tali of the calcaneus to the plantar surface of the navicular bone • Supported by tibialis posterior • Blends with the deltoid ligament • Helps to support medial longitudinal arch Talocrural Joint - Ligaments • Anterior talofibular ligament • Anterior margin of the fibular malleolus then passes medially and anterior to the lateral talus • Resists anterior translation of the foot in relation to the shin • Resists plantarflexion • Resists talus internal rotation • Commonly injured with lateral inversion ankle sprains • Posterior talofibular ligament • Almost horizontal from malleolar fossa of the lateral malleolus to the posterior surface of the talus • Resists dorsiflexion • Calcaneofibular ligament • Narrow cord • Lateral malleolus downwards and slightly backwards to the lateral surface of the calcaneus • Covered by the tendons of peroneus longus and brevis • Resists adduction Talocrural Joint – Joint Capsule and Synovial Membrane • Fibrous capsule • completely surrounds the joint • attaches to the articular margins of the tibia and fibula superiorly and talus inferiorly • thickened medially and laterally by ligaments • Synovial Membrane • Lines the capsule Talocrural Joint – Arthrokinematics Subtalar Joint Subtalar Joint • Synovial joint • Allows inversion and eversion of the foot • Space between the talus and calcaneus is the sinus tarsi space • This space is filled with connective and adipose tissue richly innervated with mechanoreceptors and free nerve endings Subtalar Joint - Ligaments • All ligaments provide subtalar stability with calcaneal parts of medial and lateral talocrural ligaments • Ligaments can be split into • Extrinsic • Calcaneofibular ligament • Deltoid ligament • Intrinsic • Talocalaneal ligament • Interosseous ligament • Cervical ligament Subtalar Joint - Ligaments • Interosseous (talocalcaneal) ligament • Thick strong band • Main subtalar ligament providing most stability • Runs through the sinus tarsi • Made up of an anterior and posterior band • Cervical Ligament • Inside the sinus tarsi • Strong ligament providing stability • Talocalcaneal ligament • Made up of anterior, posterior, lateral and medial components Subtalar Joint - Ligaments • Interosseous (talocalcaneal) ligament • Thick strong band • Main subtalar ligament providing most stability • Runs through the sinus tarsi • Made up of an anterior and posterior band • Cervical Ligament • Inside the sinus tarsi • Strong ligament providing stability • Talocalcaneal ligament • Made up of anterior, posterior, lateral and medial components Subtalar Joint - Movements • Calcaneal movement transverse and sagittal movement blocked by ground • Calcaneal movement in frontal plane remains the same • Pronation • Calcaneus eversion, talar plantar flexion and adduction + tibia internal rotation • Gives a wider, flatter foot • Supination • Calcaneus inversion, talar dorsiflexion and abduction + tibial external rotation • Gives a narrower, higher foot Subtalar Joint - Movements • Produced by calcaneus moving on fixed talus and leg • Pronation • Dorsiflexion, abducted and eversion • Supination • Plantarflexion, adduction and inversion Other Structures Plantar Fascia • Thick aponeurosis • Calcaneus tuberosity to the heads of the metatarsals • Longitudinally orientated collagen fibres • 3 distinct components • Medial • Central • Lateral • Continuous with the Achilles tendon Plantar Fascia – Supporting Body Weight • Acts as a truss • Weight goes through talus • Creates a ground reaction force through up through metatarsals and calcaneus • The bones in the foot are compressed between ground reaction force and body weight • Plantar fascia acts as a tie cord between the forefoot and the calcaneus to prevent the arch from collapsing Plantar Fascia – Windlass Mechanism • Windlass mechanism pulls the two ends of the foot together • Compressing the bones and raising the height of the arch • Stabilising the foot • Increases its ability to act as a lever • Toes dorsiflex, wrapping plantar fascia around metatarsal heads • Plantar fascia pulls tight, compressing and supinating • The arch rises and foot shortens and becomes rigid Bursae • Retrocalcaneal Bursa • Located between the Achilles and the calcaneus • Subcutaneous Calcaneal Bursa • Located between the skin and posterior aspect of the Achilles tendon Fat Pad • Subcalcaneal fat pad • Underneath the calcaneus • Can be a source of pain Arches • Medial Longitudinal Arch • Higher than the lateral arch • Made up of the calcaneus, talus, navicular, 3 cuneiforms, first, second and third metatarsals • Peaks at the superior articular surface of the talus • Weakest at the joint talonavicular joint • Supported by the plantar calcaneonavicular ligament (spring ligament) • Elastic and aids to restore arch to normal position under deformation • Supported by tibialis posterior, plantar aponeurosis and small muscles in sole of foot Arches • Lateral Longitudinal Arch • Made up of the calcaneus, cuboid and fourth and fifth metatarsals • Strong arch supported by long plantar and plantar calcaneocuboid ligaments • Supported by extensor tendons and short muscles of little toe Arches • Transverse Arch • Made up of the cuboid bone, 3 cuneiform and the base of the metatarsals • Supported by tibialis posterior, tibialis anterior, peroneal longus and plantar fascia Structural Abnormalities Calcaneal (Rearfoot) Varus • • • • Calcaneus inverts Foot is more supinated at heel strike Lack of eversion at the subtalar joint Uncompensated • Calcaneus inverts and navicular raised = supinated • Causes plantarflexion 1st ray and a varus tibia • Compensated • Calcaneus vertical and navicular collapses = pronated • Gait Changes • Pronation occurs at heel strike and continues until heel rise • After heel rise the foot supinates for normal propulsion Forefoot Varus • • • • • Causes many problems Forefoot inverted (big toe higher than 5th toe) Subtalar joint and calcaneus are in neutral Causes pronation Uncompensated • uncommon • Calcaneus vertical and navicular raised = supination • Compensated • Calcaneal valgus (eversion) and navicular collapse and forefoot abduction = pronation • Gait Changes • Pronation occurs at heel strike and continues through stances phase • Propulsion occurs with a pronated foot Forefoot Varus Forefoot Valgus • • • • • • More rigid and supinated feet High risk of inversion ankle sprains Forefoot is everted while calcaneus and subtalr joint in neutral Medial tarsal below the calcaneus Can be just the 1st ray plantarflexed or all the toes Uncompensated • Very uncommon • Compensated • Calcaneal varus (inverted) and navicular raised = supinated • Gait Changes • Excessive supination occurs after heel strike due to premature loading of the forefoot • Pronation is insufficient but may occur at end of stance phase Forefoot Valgus