 Hi, I am Dr. Bipinsha, I am a senior consultant radiologist, I am a director as well as a radiologist of the Eklat polyclinic and imaging center in Vileparla, West. I have special interest in musculoskeletal imaging and I am immediate past president of Indian society of musculoskeletal ultrasound. Today I am going to cover the ultrasound technique examination of the ankle joint using a systematic approach from the anterior medial lateral and posterior quadrant based on the protocol suggested by the European society of skeletal radiology. Examination of the ankle joint can be performed by asking the patient to lie down supine on the examination table or asking him to sit up with the knee being bent at about 45 degree and the sole of the foot being flushed with the top of the table. Periarticular soft tissue structures of the ankle joint being relatively superficial in location few millimeters deep to the skin surface. I prefer to evaluate these structures by using high frequency probe. You ideally using the hockey stick probe which ranges in frequency between 8 to 18 megahertz. However, if you do not have an access to this probe, one can also use a linear probe with a small footprint having a frequency range between 6 to 15 megahertz transducer. Anterior quadrant examination of the ankle joint is performed by keeping the transducer along the anterior joint line at the level of the telus and the structure which are evaluated on this quadrant includes anterior tibioteler joint space. Also we look at the extensor tendon of the ankle and also the lateral ligamentus complex. In addition, one can also look at the cartilage covering the tailored dome then these smaller ligaments like telonevicular ligament or the calcaneo cuboid ligament. Anterior telotibular joint space examined by connecting the telus with the lower end of the tibia when transducer is parked in the longitudinal in this plane one can identify anterior telotibular joint space which usually does not contain any fluid but is filled with the fat which distance the joint capsule superiorly. On the top of this structure you can see the extensor tendons by moving the transducer from the medial to lateral aspect entire extent of the joint space is evaluated for any evidence of synovitis or the synovial hypertrophy. By asking the patient to do a planter flexion additional component of the cartilage covering the tailored dome can be visualized. So by doing this examination extending your probe from medial to lateral side almost 80% of the cartilage covering the tailored dome can be visualized. However, one point of caution ultrasound is not the best examination to evaluate osteocondrol injury MRI is the modality of the choice. Once the anterior tibia telotibular joint space is evaluated the next step is to look at the extensor tendon of the ankle joint on the NTA quadrant. So by using the bony acoustic landmark of the medial malleolus which appears as a hyper equic structure one need to move the transducer laterally and the first structure the first tendon that is visualized in the transverse plane is the tibialis anterior tendon which has got a classical speckled appearance on the transverse axis. This tendon can be evaluated all the way distally to its attachment to the medial cuneiform and proximally to its to the level of the musculotendonus junction. Once the transverse examination of the tibialis anterior is complete we need to turn the transducer 90 degrees and visualize this tendon along the longitudinal axis till its insertion over the medial cuneiform bone. So like any other tendons this tendon has got typical fibrillary appearance which is due to a bright echoes coming from the collagen fibers and the dark echoes arising from the intervening connective tissue. So that is the distal attachment of the tendon to the medial cuneiform which can be very well appreciated on the longitudinal ultrasound image. After evaluation of the tibialis anterior the transducer is moved laterally and the next extensor tendon that is identified is includes the extensor helioseus longest tendon which again seen as a speckled structure along the transverse axis and it is almost half the size of the adjacent tibialis anterior tendon. One needs to examine this tendon all along its length till its inserts over the dorsum of the distal phalanx of the graded tube. Once the transverse examination of extensor helioseus tendon is over we need to turn transducer along the 90 degree to look at this tendon in a longitudinal plane and follow this tendon distally all along its way till its attachment over the dorsal aspect of the distal phalanx of the graded toe to evaluate the integrity of this tendon and make it sure that there is no injury to the distal attachment of this tendon over the distal phalanx of the graded toe. The specific examination of this tendon can be performed by doing a passive movement of the graded toe to look at the excursion of this tendon which should happen very smoothly in anterior posterior as well as superior inferior direction. After the extensor helioseus longest is examined we need to move more laterally and between the extensor helioseus longest and the extensor digitorum one can see the neurovascular structure which consists of the anterior tibial artery and the vein as well as the deep peroneal nerve. So, moving the transducer from superior to inferior aspect all these three structures can be evaluated very well. Once the evaluation of the neurovascular structure on the anterior aspect of the joint is over, move the transducer more laterally and the tendon of the extensor digitorum longest can be identified which is surrounded by the thick retinaculum and showing a multiple slips as you go distally the slips are seen diverging towards the each toe of the foot and the dynamic examination can be performed by moving this toes in the flexion and extension. Over the extensor tendon you can see a hypoequic thin structure which shows evidence of anisotropy this is nothing but the extensor retinaculum this is the superior extensor retinaculum and when you move down distally one can also appreciate the inferior extensor retinaculum the main function of this retinaculum is to prevent the bow stringing of the tendons of the ankle. Other structure that can be evaluated while you are on the dorsum of the foot or at the anterior quadrant of the ankle is the telonevicular ligament it is a very small structure which appears as a hypoequic structure connecting these two bones and one can evaluate this structure from medial to lateral aspect for any evidence of injury. Another ligament which can be seen on the lateral aspect includes the calcaneo cuboid ligament this is another small hypoequic structure which connects the calcaneum to the cuboid. Entero inferior tibiofibular ligament can be examined by connecting two bones that is the lateral myliolus on the lateral aspect and the tibia on the medial aspect this ligament appears as a bright ecogenic structure with the compact fibers connecting bone to bone the neuro vascular structures can be seen superior to this ligament. Once this ligament is identified one can move transducer more superficially and can have a look at the introsius membrane which is seen connecting the tibia with the fibula. So in high ankle injuries along with the entero inferior tibiofibular ligament the introsius membrane is also injured. In order to evaluate lower lateral ligament complex structure one need to keep a small bolster under the medial aspect of the ankle so this allows a better contact of the skin surface and patient is asked to move the ankle in a little inward position. By connecting the lateral myliolus and the talus one can easily appreciate the compact ecogenic pattern of the anterior tibiofibular ligament and this ligament can be very visualized from medial to lateral aspect by rocking the transducer. While examining this ligament one can also look at the cartilage covering the tailored dome as well as the fat in the lateral gutter of the ankle. In the patient with the lateral impingement syndrome this structure may show presence of a thick synovitis. The third ligament on the lateral aspect of the ankle that is evaluated includes the calcaneo fibular ligament. So by connecting the lateral myliolus and the calcaneum one can visualize this ligament however because of the obliquity of the ligament in the neutral position there is a significant and isotropic hence the diagnostic dilemma always persists to make it visualize more clearly there is a need to perform dorsiflexion of the ankle. Dorsiflexion of the ankle can be performed by asking the patient to lift the foot above the examination bed. So after achieving dorsiflexion and connecting two bones that is the lateral myliolus and the body of the calcaneum one can visualize very well the calcaneum fibular ligament which appears as a hyper-equic structure. One need to do a various degree of dorsiflexion to visualize this structure. When the ligament is visualized along the longitudinal plane the peroneal tendons are seen along the transverse axis overlying this ligament. By using the booni-acoustic window of the lateral myliolus and moving the transducer in the retro myliolus group two ecogenic structures of the tendon are seen. The one with the musculotendinous belly is the peroneus bravis while the tendinous structure is the peronus longus and on top of this structure you have a peroneal retinaquilum which appears as a hypoequic structure because of the anisotropy. The peroneal tendons being running an oblique course we need to have a good contact between the skin and the examination structure. So lot of amount of jelly needs to be put between the skin and the transducer to avoid any anisotropy and getting a proper isonation of the beam to the examination structure. So one can see in this retro myliolus region the ecogenic peroneal tendons and overlying the hypoequic peroneal retinaquilum. From a retro myliolus region the transducer needs to be moved in a supra myliolus region to examine these two tendons all the way till its level of the musculotendinous junction for any evidence of injury to this tendon structure. From a retro myliolus region we need to move the transducer distally to evaluate these two peroneal tendons in the transverse view distally all along its attachment at the level of the peroneal tubercle while the peronus bravis moves anteriorly, peronus longus moves posteriorly to disappear under the calcaneuquiboid. Boni projection seen at this level is the peroneal tubercle while the peronus bravis appears as a speckled ecogenic structure. Because of the anisotropy the detailed morphology of the peronus longus is not visualized. Once the peronus bravis is identified we need to move the transducer distally and follow it up till its attachment to the base of the fifth metatars. Tendon needs to examine both in the longitudinal and in a transverse plane to look at the integrity of the tendon. At the level of peroneal tubercle the peronus longus is situated posteriorly and by using a proper toggling of the transducer one can evaluate this tendon all along its short axis till it disappears in the calcaneuquiboid tunnel or one can also see sometimes osperoneus within this tendon just distal to the peroneal tubercle. This to the peroneal retinaculum can lead to instability lesions of the peroneal tendons that can manifest either in the form of the subluxation of the tendon during the dynamic examination or a dislocation of the tendon outside the peroneal groove. Dynamic examination of the peroneal tendons is performed by doing dorsiflexion and aversion of the foot to look for any evidence of subluxation or dislocation of this tendons while keeping the transducer fixed in the retromallular region. For the medial ankle examination the structure which are evaluated includes the tibialis posterior tendon, flexor digitorum longus and the flexor halusis longus. In order to visualize tendons better there is a need to put a bolster along the lateral aspect of the ankle. By using medial malleolus as a bony acoustic window the transducer is moved in a retromallular region the first tendon which is identified is the tibialis posterior tendon. This appears as a speckled structure and one need to examine this tendon both in the supramallelar region all the way till its level of the musculotendinal junction. Once that is finished that one needs to move inferiorly and look at this tendon till its attachment to the navicular bone at the distal insertion. Once the tibialis posterior tendon is examined in a transverse view one needs to transducer in 90 degree plane and look at the distal insertion of the tendon to a navicular bone which has got hyperequiprofile occasionally one can also see in os navicular within this tendon suggestive of accessory oscicle. So one need to examine all the way from distal attachment and move proximal attachment till all the level of the supramallelar region of the tendon. So adjacent to the tibialis posterior we have another flexor tendon that is the tendon of the flexor dehytorum longus and this is almost half the size of the tendon of the tibialis posterior and this also needs to be followed distally and proximally in the supramallelar region in a transverse plane. The longitudinal axis sonography views are not very important unless you find some pathology in this tendon then it is necessary to look at this tendon in a longitudinal plane. By moving the transducer more posteriorly the third tendon of the flexor group is identified and this is the tendon of the flexor heliocis longus. This tendon is situated in the groove between the medial and lateral telertivercal. If you want to confirm the presence of this tendon you can do the passive extension and flexion of the greater trove and this tendon can be seen visual seen moving backward and forward that shows the integrity of the tendon. Between the tendon of the flexor dehytorum longus and the flexor heliocis longus one can identify neurovascular structure which is made up of two veins that is the posterior tibial vein one artery that is the tibialis posterior artery and the nerve which is the posterior tibial nerve. The pneumonic which is commonly followed to identify the structure remember the structure is tom, dick and very very nervous hairy that is the order in which the structures are visualized in the posterior medial aspect of the ankle joint. The other structure that is examined on the medial aspect of the ankle includes tarsal tunnel and its contents by turning the color Doppler on one can identify the veins and the arteries in the tarsal tunnel and the posterior tibial nerve which is divided into branches which is the medial and lateral planter calcane and nerve. Components on the medial aspect of the ankle consist of the deltoid ligament which has got three components the t-beow teller component, t-beow calcaneal component and t-beow navicular component. The t-beow teller component can be identified most prominently because of its significant fat content within the fibers of the ligament by asking the patient to do a dorsiflexion and I connect and connecting two bones that is the medial malulus and the tellers you can see a fan strip structure that is the posterior t-beow teller ligament. By connecting the medial malulus and the sustenticulum teller the t-beow calcaneal component of the deltoid ligament is identified by connecting the medial malulus and the navicular bone. One can identify the anterior component of the deltoid ligament that is the t-beow navicular component. The spring ligament or the calcaneal navicular ligament is identified along the long axis lying just below the t-belly's posterior tendon which appears in a transverse view. The ecogenic pattern of this structure can be well appreciated. Keep in mind we can see only the superficial component of this ligament. The structure examined on the posterior quadrant of the ankle joint include tendo-acleus tendon, the retro-calcaneal bursa and the retro-acleus bursa. By using the hyper-echoic bony landmark of the posterior superior calcaneal tuberosity one can identify the distal insertion of the tendo-acleus over the calcaneum which is a fibrocartilaginous attachment. Once this tendon is identified in a longitudinal view move your transducer all the way proximally till the it turns into a myotendinous junction, proximally at the level of the fusion of the eponeurosis of the gastrocnemius and the soleus muscle and tendon. Once the longitudinal examination is over the probe is turned into 90 degree and the tendon is examined again in the transverse plane all the way from its attachment to proximally till it turns into myoponeurotic junction. One needs to look at the entire extent of the tendon both on the lateral aspect as well as medial aspect to look at the any lesion which may be situated at the periphery of the tendon. So, it requires that the entire extent of the tendon should be evaluated on the transverse view while on the transverse view also the AP dimension of the tendon is measured to look for any evidence of abnormal enlargement normally this tendon appears as a flat or a kidney shape structure on the transverse view. Other structures examined at this level is a retrocalcaneal bursa it is a potential space lined by the synovial membrane situated between the distal acleus tendon and the prominence of the calcaneal tuberosity. One needs to toggle the transducer from medial to lateral aspect to look for any evidence of fluid collection or evidence of synovitis. Retrocalcaneal bursa is seen just above the distal tendoacleus between the skin and the paratinon. The tendoacleus is devoid of the synovial sheath but it is covered by the loose areolar tissue which is called the paratinon which marks as a hyper-equic structure which envelops the posterior and the lateral as well as medial aspect of the tendon. This paratinon can also appreciated very well on the transverse imaging covering the tendon both on the posterior as well as on the medial and lateral aspect of the tendon. The other structure that can be evaluated on the posterior aspect is the posterior tibiotellar joint space and the flexor heliocis longus in the longitudinal plane. By moving the transducer medially from the achilles tendon one can visualize the flexor heliocis longus tendon as an ecogenic structure and anterior to that one can also see the posterior tibiotellar joint space and inferior to that one can also see posterior sub-tellar joint space very well. To visualize the tendon on dynamic examination one need to do a flexion and extension of the great toe. So smooth movement of this tendon are visualized when the movements of the toe are performed. Dynamic examination of the tendoacleus is performed by doing a planter flexion and dorsiflexion which shows the smooth excursion of the tendon as well as underlying flexor heliocis muscle belly on the dynamic examination. Planter fascia examination is performed by connecting the hyper-equic cortex of the calcaneum and it is seen as a ecogenic structure leaving the calcaneum and situated deep to the thick heel pad. The thickness of the planter fascia is measured at the level where it exits the calcaneal tuberosity. The normal thickness is approximately 4.5 millimeter. One need to examine this fascia both in the longitudinal plane as well as in the transverse plane for the identification of the pathology affecting this structure. So this concludes the quadrant-based approach of the evaluation of the periarticular soft tissue structures around the ankle and using the protocols which are proposed by the European Society of Skeletal Radiology. Thank you.