BME320 - Biomechanics I - Ankle Joint (PDF)

BME320 - Biomechanics I of freedom - I degree Dr Mazin Sirry Assistant Prof. of Biomedical Engineering...

BME320 - Biomechanics I of freedom - I degree Dr Mazin Sirry Assistant Prof. of Biomedical Engineering 1  3 The hip joint Joints > - load bearing Overview > - To Knee joint The AnkleJoint with d stand > -  Anatomy (Articulations). Movement. Amain function of the joints : > - carry weight. it for movement can * it isn't essential ,  Stability. * Ankle joint requires more support. add stability to the joint. ↳ soft tissues - ->  Kinematics. displacement angle" > - of motion" "range  Kinetics. ↳ forces joint - that affecting the 2 Biomechanics of Ankle Joint 3  complex. Foot > - The second Highly complex dynamic organisation and construction. Less sophisticated than & hand. #1. gligg 26 bones - 30 muscles 21 functional joint Over 100 ligaments ↓ movement slight 4  Foot The main functions of the foot during upright posture and ambulation are: R The arch of the Fort & > - ef the Sta Shock absorption - The shape Cushioning Stability of the body it looks Propulsion during locomotion & like a whistle. din Wement G the heat to it isn't connected the leg 5  Ankle cross section Image Lout ① of the. Joint complex consists of 3 articulations: Tibio-talar joint 1Tuo-Tibidar. E O The midial bone O : - " one "the big Fibulo-talar joint/Talo-fibular midim Distal tibio-fibular joint malldieu maledus & :Y S O The lateral bor "The thin One" : Roles of ankle joint: movement" Participate in kinematic functions"related to weight. of the body Load bearing. > - "It carries the 6  Ankle (Anatomy) additional The shaping gives Stability & D 7  Ankle (stability) ↳ I degree of freedom to make Inherently stable joint (stable structural arrangement). inherent joint stable. & hape-geometry) it L - (S morphology. & & The inherent & G stability is conferred Mortise 6The surface of Tibiad by the mortise - tenon Fibular arrangement. Tenon G The surface of the Talus Shape only - comes from the The stability Mort & &G Mortis-Tenon Arrangement. Teno 8  Wedge keystone The addition at support *. Comes from Saudissue & & " - Mortise mid. I hat is 6us * which break first one is ? going to = The mid to deform ↳ it is going the more. (It is absorbing 9 most of the shock".  Soft tissue stability. Ankle (stability) * Collateral ligament most : In addition, the soft tissue maintains the integrity of the joints: system The ligament be is thatto - * help us to Tmy & are stack to Q PifL - Y A sing TFL maintain the affected mortise surface each. other Deltoid. ⑨ whe bones. Tibia betwee ↑ Evid - - fibula ② & & - d twisting. Tibia & - C FL A lateralest & end zibi attached - - ↳ - = > - to the tibia -- of the Cute sc T & fibula and fibula - a - Interosseous and tibiofibular ligaments Hija Medially: deltoid ligament - Laterally: lateral collateral ligament systems (ATFL, PTFL, CFL) Joint capsule Synovial fluid A it has - a 10. morable joint any freely in T  When you move your foot. & The talus is only moving weekness Ankle (stability). most most strength Ple & stability volurab. max /S increasing The mortise is maintained by the shape of the - ② talus, resulting in a tight fit between the fibula and tibia and the interosseous membrane. full anteriorly wider than posteriorly full Dorsiflexion. * - 6 · - The talus narrows posteriorly (wedge).. approx ¼ ↳ stable most. · plantar Flexion. posteriorly - The talus translate ↳ least Stable. wider anteriorly than posteriorly. Cit back) to the - & Full backed anteriorly leaving · & moves -. The talus translate = & eleust Dorsiflexion: ankle is most stable (close packed – some space. E packed. - There isNo space left - g 2-D · ~. & wider portion of body of talus between malleoli). - ↳s9 = -5 a , - Anterior talar injury happens. Plantarflexion: ankle is unstable (least pack – * translation during ↳ because When there is a is movement narrow portion of body between malleoli). plantarflexion > There space - With increasing plantarflexion there is more anterior talar translation. Stability is created by soft - tissue. - ant. post. 11  posteriorly. is lower slighting fibuke tibia Ankle (Kinematics) deviate Ian the it up The ankle functions as a uniplanar hinge (1 dof), with & not horizontal deviation it has motion of the talus primarily in flexion/extension - about a medio-lateral axis: Axis of ankle joint & Deviates superiorly from the transverse plane of the foot - lightly on the medial side. coronal anteriorly. * deviates posteriorly from the frontal plane of the foot on top - - the lateral side. mid. later. Axis of rotation of the ankle joint to pass through the distal tips of the medial and lateral malleoli. Clinically, this axis is located by palpation.(medical examination) & - - Y angular - displacement angular 2 * velocity anyular 3 A acceleration 12  anatomial > - go Ankle (Kinematics) - & ↳ withoutforce lanter flexion more p the dorsiflexion. of it Range of motion most flexion. than tur > planter - Approx. 80° in total, although this varies from individual = to individual, as well as with age. Approx. [20 – 30° in dorsiflexion --- Approx.* - 50– 60° in plantarflexion 13  rotationChangeent Center Ankle (Kinematics) ↳ a the falues it lies on - T Surface joint motion Mainly tibio-talar and fibulo-talar articulations (surfaces). In normal ankle: instant centres of rotation fall within the talus, but their ⑧ positions change with ankle motion. This confirms that the axis of rotation does not remain constant with motion. - 14  Ankle (Kinematics) Surface joint motion stability mex least most of stability S prese d engury- /L dry vrlnurable Full plantarflexion Full dorsiflexion Start End * Distraction of joint Bone gliding Jamming of joint Ebring things - re s e together. GreDo, 15  forces most of pain in joint joint reaction > - forces affecting igt the. * & - Ankle (Kinetics) creating (affecting) SRJ weight. * - weight & & , muscle muscles Statics analysis > - here. will sit T lymuscle Simple static analysis reveals that - The strong standing on tip-toes on one leg can result in forces in the Achilles' & Achilles tendon of approx. 1.2 times body weight. approximately equivalent weightto the. O plantar flexion. At the same time the joint reaction force is approx. 2.1 times body weight. double - the weight. 6 it or can the go down muscle. by either the weight of the foot ? How would forces affect joint from Muscle Contraction additional forces Come. where are from ? # jrF A they coming = w & weight , GRF > All muscle contraction - , of JRF = 2XW them generates "internal Forces" JRF & 16  Ankle (Kinetics) comes from additional source of forces ↑ Dynamics acceleration -. Because of acceleration, ankle joint reaction force can reach up to 5 ② times - body weight during walking (x13 during running). 𝑭𝒐𝒓𝒄𝒆 = 𝒎 × 𝒂 = Force Compared to the hip or knee, the (body weight) joint stresses are lower because of & the relatively large (11 – 13cm2) load-bearing surface area of the talus for load bearing. % of cycle 𝒇𝒐𝒓𝒄𝒆 (stance phase) 𝑷𝒓𝒆𝒔𝒔𝒖𝒓𝒆/𝑺𝒕𝒓𝒆𝒔𝒔 = 𝒂𝒓𝒆𝒂 17  Ankle (Kinetics) Ankle load distribution The ankle joint responds poorly to changes in alignment which could be the result of sprains or other instability. If uncorrected, the talar shift will lead to significant biomechanical alterations in the joint. Early degenerative changes in the ankle joint are likely because of increased stresses. 18