Joints of the Foot and Ankle PDF

The joints of the foot and ankle  Outline Aims Main joints, joint cavities and motions Muscular control of the joints Neurovascular structures supplying the joints  Aims To identify the major joints of the foot and ankle and their cavities. T...

The joints of the foot and ankle  Outline Aims Main joints, joint cavities and motions Muscular control of the joints Neurovascular structures supplying the joints  Aims To identify the major joints of the foot and ankle and their cavities. The motions at the joints and their muscular control. The neurovascular structures that supply the joints. Major joints / cavities of the foot 1. 1. Subtalar (posterior talocalcaneal), Talus, calcaneus Anterior talocalcaneal, Talus, calcaneus Talonavicular, 2. Talocalcaneonavicular Talus, navicular The talonavicular and 3. Calcaneocuboid, calcaneocuboid joints are collectively Calcaneus, cuboid known as the midtarsal joint, despite the fact that they are 2 separate joints with their own membranes & cavities!  Major joints / cavities of the foot 2. 4. Cuneonavicular, Navicular, medial cuneiform Intercuneiforms, Cuneiforms These joints form one Cuneocuboid, Lateral continuous cavity cuneiform, cuboid 5. Medial cuneometatarsal, 1st cuneiform & metatarsal This cavity is itself continuous with the 2 & 3 6. Cuboidometatarsal, 4th & 5th cuneometatarsal joints and (2- metatarsals, cuboid. 4) intermetatarsal joints  Major joints / cavities of the foot 3. Plus, don’t forget: – The ankle (talocrural) Tibia, fibula, talus – Metatarsophalangeal joints Metatarsals and toes – Interphalangeal joints Phalanges of toes Lots aren’t there!  The ankle joint The articulation of the tibia and fibula with the talus. L & M malleoli form a mortice into which the talus fits Synovial joint, with capsule and synovial membrane. Hinge. AKA talocrural joint The true ankle joint – Works as part of a complex with other joints Ankle cross-section  Bones Posterior view of ankle Tibia Distal Fibula tibiofibular joint Tibial plafond Trochlear surface of the talus Lateral Medial malleolus malleolus Talus Sustentaculum tali of the calcaneus Bones Bones Lateral ligaments  Medial ligaments Medial ankle ligaments are collectively known as the Deltoid ligaments, stronger than lateral ligaments.  Posterior View Posterior tibiotalar Posterior talofibular Tibiocalcaneal Calcaneo fibular Anterior(ish) view  Ankle joint motion Primarily – Plantarflexion – Dorsiflexion More plantarflexion than dorsiflexion. Ankle more stable in dorsiflexion than plantarflexion, due to shape of the talus. Some – Inversion – Eversion Minimal – ADduction – ABduction  Muscles & ankle motion Dorsiflexors – Tibialis anterior – Extensor digitorum longus – Extensor hallucis longus Plantarflexors – Gastrocnemius – Soleus – Plantaris – Tibialis posterior – Flexor hallucis longus – Flexor digitorum longus – Peroneus longus – Peroneus brevis  Neurovascular supply of the ankle Blood Nerves – Malleoli supplied – Ankle joint is by malleolar supplied by anastomosis. branches of the – Talus supplied by deep peroneal and branch of dorsalis tibial nerves. pedis to head & neck – Talus vulnerable to interuption of blood supply if fractured.  Subtalar joint Articulation between Gliding and rotary the posterior, inferior motion. talus and the Sinus tarsi and superior calcaneus. canal penetrate AKA: Posterior through the joint. talocalcaneal joint Synovial, plane joint, capsule attaches to margins of articular surfaces.  Subtalar joint This bit is the subtalar joint.  Anatomical variations A: 3 facet B: Transitional 2 facet. C: Simple 2 facet. D: Special 2 facet It is thought that more facets = more stable but less facets = more motion.  STJ ligaments 1. Interosseous talo-calcaneal - limits inversion and eversion 2. Lateral talo- calcaneal (cervical) - limits inversion 3. posterior talocalcaneal - relatively insignificant Hoke’s tonsil! The interosseous ligament, together with it’s accompanying blood vessels and a blob of fat resemble a tonsil. It is sometimes known as Hoke’s tonsil.  STJ motions 2 basic motions at the In OKC the talus acts as STJ: part of the foot. – Pronation In CKC the talus acts as part of the leg. – Supination Tri-planar It depends on – Moves in all 3 body planes whether the foot is on simultaneously. the ground (CKC) or Movement occurs around off the ground (OKC) an ‘axis of motion’. (Will as to how that motion deal with this concept in first lecture of next term.) manifests it’self.  Broadly speaking Pronation Supination – Part of the shock – Assists propulsion absorbency during gait. mechanism. – Helps turn the foot – Allows the foot to into a rigid lever, become a ‘mobile so we can move adapter’ to allow from A to B in a for variation in relatively straight terrain. line.  OKC motion Talus is free to move and acts as part of the foot. Pronation – ABduction – Evertion – Dorsiflexion Supination – ADuction – Inversion – Plantarfelxion  CKC motion Talus is locked between M & L malleoli and acts as part of the leg.  CKC motion 2 Pronation Supination Talus ADducts ABducts Talus Inverts Everts Talus plantarflexes dorsiflexes Internally Externally Tibia rotates rotates  Muscles & STJ motion Pronators – Peroneus brevis – Peroneus longus – EDL – EHL Supinators – Tibialis posterior – Tibialis anterior – FDL – FHL – Gastrocnemius – Soleus Note: Ground reaction force will pronate the foot at the subtalar joint at the moment of heel strike. – Plantaris  Neurovascular supply to STJ Blood supply – Branches of tib post & peroneal supply sinus tarsi & canal. – Also, Ant tib to talus – Anastomosis around the complex. Nerves – Supplied by branches of the deep peroneal, maybe some tibial.  Talocalcaneonavicular Anterior part of joint the talus fits into here and articulates with the navicular Anterior talcalcaneal joint and calcaneus. + talonavicular joint. Spring Front part of talus sits on ligament is integral to the ‘shelf’ of the calcaneal the joint. sustentaculum tali, talus articulates with navicular. Usually we just contemplate the talonavicular part as a component of the MTJ This facet of complex. the calcaneus forms the Has it’s own joint capsule. subtalar joint  The midtarsal joint complex Not one anatomical joint but a pair of joints Talus that kind of act as Calcaneus a functional unit. The articulations Calcaneus of: Navicular Cuboid – Talonavicular joint Cuboid – Calcaneocuboid joint Midtarsal joint  TCN joint ligaments Dorsal talonavicular ligament Plantar calcaneonavicular (spring) ligament, forms integral part of TCN joint, elastic.  Calcaneocuboid joint Articulation between: – Distal calcaneus & proximal cuboid Synovial – Encloses Cuboid capsule Plane joint CC Joint Calcaneus  CC joint ligaments Bifurcated ligament – Y shaped Calcaneonavicular portion Calcaneocuboid portion Dorsal calcaneocuboid Long plantar ligament – Calc to cuboid & base of mets Short plantar ligament – Calc to cuboid Note: See plantar foot notes for LPL & SPL Midtarsal joint motions MTJ motion closely related to ankle and STJ – Talus is common to all 3 joints Broadly – As STJ pronates, MTJ becomes more mobile to accommodate uneven terrain. – As STJ supinates, MTJ locks to allow foot to act as a rigid lever.  MT joint motions 2 Traditional theories suggest that the MTJ complex has two independent axes of motion. – Longitudinal Mainly inversion / eversion. – Oblique Mainly dorsiflexion / plantarflexion with some abduction / adduction. These motions combine to result in pronation / supination around the MTJ. More modern theories challenge the old school view and suggest alternative mechanisms (mainly because the above is rubbish). This will be covered in more detail next term.  Muscles and MTJ motion Pronators – Peroneus longus – Peroneus brevis – Peroneus tertius – Extensor digitorum longus Supinators – Tibialis anterior – Extensor hallucis longus – Tibialis posterior – FHL & FDL – (medial fibres of EDL may supinate)  Neurovascular supply Blood Nerves – Anastomosis from – Branches of deep dorsalis pedis, peroneal, medial medial and lateral and lateral plantar plantar arteries. nerves.  Other inter-tarsal joints Cuneonavicular – 3 joints, articlations of cuneiforms and navicular. Synovial, gliding. Capsule strengthened by strong dorsal & plantar ligaments. Synovium continuous with: intercuneiform jts, cuneocuboid jt, cuneometatarsal jts & intermetatarsal jts.  Other inter-tarsal joints Cuboideonavicular – Fibrous articulation of cuboid and navicular. – Strong dorsal, plantar and interosseous ligaments Other inter-tarsal joints Intercuneiform & cuneocuboid. – Synovial plane joints. – Capsule continuous with cuneonavicular joint. – Bones connected by dorsal, plantar and interosseous ligaments.  Intermetatarsal joints Articulations between metatarsal bases. Synovial, plane joints. Connected by dorsal, plantar & interosseous ligaments.  Tarsometatarsal joints Articulations between tarsal bones and Ouch! metatarsals. AKA Lisfrancs jt Synovial, plane joints. 1st joint has it’s own joint cavity. 2nd joint recessed, v stable Connected by dorsal, plantar & interosseous ligaments.  Rays of the forefoot 1st ray Medial cuneiform & 1st metatarsal. 2nd ray Intermediate cuneiform & 2nd met 3rd ray Lateral cuneiform & 3rd metatarsal 4th ray 4th metatarsal only 5th ray 5th metatarsal only  What are rays? One or more bones acting together as a functional unit as if they are one bone. – E.g. 1st ray plantarflexes as one to assist turning the foot into a rigid lever for propulsion. – 1st and 5th rays work independently – 2nd to 4th rays usually work together  Effects of pronation STJ pronates – MTJ unlocks (making foot wibbly wobbly for shock absorbency and accommodation of uneven terrain) – Ground reaction force pushes 1st ray up (dorsiflexes), reducing ROM at 1st mtpj. – ALSO: as STJ pronates, tibia internally rotates thus unlocking the knee – This allows quadriceps to absorb impact as the knee flexes  Effects of supination STJ supinates – MTJ locks (making the foot a rigid lever for propulsion) – 1st ray plantarflexes, increasing ROM at 1st MTPJ – 1st MTPJ extends during propulsion to facillitate ‘normal’ gait. – ALSO: as STJ supinates tibia externally rotates – This helps to lock the knee as it extends, thus stabilising the knee during push off.  Metatarsophalangeal joints All of the MTP Joints are more or less the same 1st MTPJ is a bit different Metatarsophalangeal joints  Metatarsophalangeal joints 2 Large, convex articular surface to the met head to allow extension & flexion of joints. Articular surface of proximal phalanx smaller and concave. 1st mtpj also articulates with sesamoids. Synovial, condyloid joints. Most motion is extension flexion, some ABduction / ADduction  Muscles that cross the mtpjs Hallux Lesser toes – EHL – EDL – EHB (portion of – EDB EDB) – FDL – FHL – FDB (2 - 4) – PADs (3 - 5) – FHB – DABs (2 - 4) – ADH – Lumbricals – ABH – ABDM (5th only) – FDMB (5th only)  Motions at mtpjs Muscles determine action at the joints. – Primarily: Extension / flexion – Some: ABduction / ADduction – Negligible: Frontal plane rotation (in M TP the normal foot). J oints Ligaments of the mtpjs A tough fibrous capsule surrounds the joints. Thickened at sides to form collateral ligs Thickened on plantar surface to form plantar plate Hallux has: – Intersesamoidal ligament – Plantar sesamoidal ligament Deep transverse Metatarsal Ligaments  Plantar plates Lesser toes only (1st has sesamoid apparatus within FHB tendon) Fibrocartilagenous thickening of joint capsule Attached strongly to proximal phalanx, less so to metatarsal Provides attachment for: – plantar aponeurosis – Flexor sheath – DTML – Collateral ligs – Extensor expansion  Plantar mtpjs Fibrous capsule 1st plantar Plantar plate ligament DTML FHL TADH FHB & OADH  Neurovascular supply Blood Nerves – Dorsal digital – Dorsal digital arteries – Common & proper – Plantar metatarsal plantar digital nerves & digital arteries  Interphalangeal joints Interphalangeal joints Only 1 in 1st toe 2 in lesser toes Synovial, hinge joints Motion, mainly flexion / extension – More flexion than extension – PIPJ moves more than DIPJ  Muscles / tendons that cross the IPJs Cross PIPJ Cross DIPJ too – FDL – FDL – EDL – EDL – FDB – Lumbricals (via – EDB extensor expansion) – Lumbricals (via extensor Cross IPJ of hallux expansion) – EHL – FDL  Extensor expansion Extensor tendons widen and flatten. These blend with a thickening of the fascia Metatarsal surrounding the toes. This splits into 3, central part inserts into intermediate phalanx, longus brevis lateral parts converge and insert into the base of the distal phalanx. Extensor expansion  Flexor sheaths Inferior surface of each toe covered in fascial thickening. Proximal end blends with plantar aponeurosis. Flexor tendons lie Sheaths within synovial sheath in a tunnel between flexor sheath and the bones. Sheath thick over the phalanges but thinner and more lax over the IPJs. Flexor tendons Flexor digitorum brevis splits in order to allow FDL to pass pass through to the distal phalanx.  Neurovascular supply Blood Nerves – IPJs supplied by – IPJs are supplied by plantar and dorsal proper plantar digital arteries. digital and dorsal digital nerves. – Also, the nail is mainly supplied by the plantar nerves due to the way embryos develop.  Neurovascular supply Dorsal Toe neurovascular bundles Phalanx Plantar neurovascular bundles  Summary You should now be able to: – Name the major joints of the foot and ankle. – Be able to identify the main joint cavities of the foot. – Describe the basic motions at the joint and which muscles control those motions. – Name the neurovascular structures that supply the joints.