 Hi everyone, my today's tutorial will be a very brief discussion on a particular entity of the ankle joint Achilles tendon tear MRI appearance. Before I go into the details, very few important anatomical facts that you need to know. The Achilles tendon originates in the mid leg and is formed by the two heads of the gastronomias and soleus which forms the main bulk. Plantaris muscle if present has a separate insertion anterior to the calcaneum. The insertion point of Achilles is actually an emphasis with a retrocalcaneal bursa situated anterior to it. This is the only true bursa of the ankle the retro Achilles bursa is not actually a true bursa. The Achilles tendon is a tendon which is completely enclosed by what is called paratinon analogous to synovium it gets all its nutrition from this paratinon. Achilles tendon does not actually allow much motion along its axis and therefore there is no need of lubrication from synovial fluid. Now a very important fact a non-vascular relatively non-vascular region exists 2 to 6 centimeters proximal to the calcaneal attachment site and this is the area which is most prone to tear. The main function of the Achilles tendon is to flex the foot and out of the three muscles the soleus has more stabilizing effect of foot. So muscle atrophy of soleus is more important in determining the fate of tendu- Achilles tear especially which is neglected. This is the pictorial diagram showing the gastronomias heads the soleus how they form the Achilles tendon attaching to the heel and we see the long tendon of the plantaris going along and it has a separate attachment anterior to the Achilles attachment of the heel. Now coming to the normal MRI appearance Achilles tendon is completely dark in all sequences. Now few normal fascicles may be seen which is part of the normal appearance and should not be confused with the tear I will show you pictures later how the fascicles are seen. The girth usually varies depending on how muscular the person is. Average thickness is 6 millimeters tall, well-built, athletes will have a bigger growth. Now on sagittal images the anterior and the posterior margins are parallel below soleus insertion. Axial images the anterior margins a bit concave for most of its course and coronal images the tendon widens as it attaches distally. Now see this is the normal tendu Achilles in sagittal images it has a complete dark signal. Now here we will see a thin intrasubstant signal this is not a tear this is the normal fascicle and we see a thin chunk of fluid in what we call the true bursa of the ankle the retro-calcaneal bursa lying anterior to the Achilles. This is the normal tendu Achilles in axial sections again we see small fascicles which is a part of the normal appearance. Again another normal tendu Achilles in axial sections and as we said that it widens out as it reaches distally this is a coronal section showing this. So we again see a normal video of the normal tendu Achilles the sagittal sequence taken here. Now coming to the clinical features of Achilles Stare usually the tear occurs most commonly as a part of sports injuries especially basketball and squash with a male preponderance and there are certain systemic illnesses which leads to Achilles Stare especially diabetes rheumatoid arthritis gout etc. Usually there is a sudden onset of pain and swelling of the ankle sometimes there is an audible snap and a palpable gap can be felt in the region of the tear by the orthopedic surgeon. Tear types are mainly three interstitial or intrasubstant partial and complete. In acute tears there is definite amount of tendon retraction that can be seen I will come to lot of images later. The common Kuwada classification classifies the tears the type 1 is the partial tear with less than equal to 50% of the tendon involved and usually conservative treatment is tried for these patients. The type 2 is when the gap is less than equal to 3 cm they are also usually conservatively treated the type 3 is where the gap is 3 to 6 cm and these usually need a tendon or synthetic graft and finally where the gap is more than 6 cm degenerated tendon neglected cases and these also require tendon synthetic grafts and many a times gastronomies lengthening procedures may be required in these cases. The MRI features of tendon Achilles in short before I go to the images partial tear usually presents at the tendon swelling a focal swelling more than 70 meters full thickness tear is either right from the insertion there may be an evulsion fracture fragment and otherwise it is a mid substance tear with a tendon gap that we usually measure and the tendon gap is filled with edema and blood filling the gap. We either see a healthy Achilles or degenerated Achilles tendon on either side of the gap and in neglected cases we look for solius and gastronomious atrophy. This is a case of intra substance tear and there is intra substance signal changes in the mid substance mainly. This is a partial tear seen in the coronal section where we see few fibres the tendinous fibres remaining where whereas other part is torn. This is also a redundant tendon seen another near complete tear there is no retraction. This is a mid substance tear with very degenerated appearance of the native tendons. Another fluid filled gap in a mid substance tear. This is another complete tear and see the quality of the health of the tendons it's black it's a healthy tendon with a mid substance tear. But here this is also a complete tear but the tendon really does not look that dark in the signals. Another complete tear again where the native tendons don't look dark and degenerated rather. This is also a chronic case look at the atrophy of the muscles associated. So this is a chronic neglected case with quite an amount of muscle atrophy. This is an example of tear of the Achilles right from its attachment we don't see any Achilles tendon at all towards the calcaneal side. To conclude Achilles tendon is a common injury it is usually a clinical diagnosis MRI is not needed to diagnose the case but why do we need the MRI? To differentiate it between insertional versus mid substance tear a rough idea about the gap the gap on which it depends on the treatment the health of the native Achilles that is what the orthopedic surgeon wants to know because he has to plan his surgery depending on that. If it is a healthy one then they can plan an end to end anastomosis whereas the native Achilles is unhealthy then they have to do a tendon graft they often take it from the flexor halosus longus and also we have to tell about the muscle atrophy in neglected degenerated cases specially looking at the soleus atrophy and of course we have to look for other abnormalities like retrocalcaneal bursitis hagelans deformity and things like this thank you