A Preliminary Study On Applied Anatomy Of Medial Malleolus And Its Clinical Purpose

Objective: (1) To study the medial malleolus and measure its amatomic data, to provide amatomic according for selecting operational approachs and internal fixations in future, for inserting internal fixation safely and exactly in the operation, and for designing targeting equipments of medial malleolus fractures.Methods: We selected 20 pairs integrated adult tibia samples at human anatomy division in central south university xiang-ya medical college, 10 males and 10 females, left and right matchedpairs; selected 20 pieces typical medial malleolus obverse-lateral position X-ray plates at xiang-ya three hospital radiology department of zhong-nan university, 10 males and 10 females, left and right matched-pairs. we observed the sharpe of medial malleolus on the whole.We selected seven lines: 1. there were five lines in tibial dorsa view:â‘ tibial central axis ray L₁;â‘¡the horizontal line through tibia inferior extremity joint surface L₂ which parallels with tibial astragaloid joint surface;â‘¢paralle tangent line of medial malleolus lateral surface L₃;â‘£paralleling tangent line of medial malleolus medial surface L₄;⑤paralle line through medial malleolus peak which parallels with tibial astragaloid joint surface L₅; 2,there were two lines in facies medialis tibial view:â‘¥the line between anterior border and posterior border of medial malleolus at tibia inferior extremity articular surface level L₆(I. e line mn);⑦the line through basilar part of medial malleolus point which parallels with tibial astragaloid joint surface L₇.We selected three point:â‘ medial malleolus point o;â‘¡the foremost point of medial malleolus at tibia inferior extremity articular facet level m;â‘¢the postmost point of medial malleolus at tibia inferior extremity articular facet level n.We obtained following medial malleolus parameter through selecting these lines and points:â‘ MA (acute angle made by line L₁ intersecting line L₃, I. e varus angle of medial malleolus, calling for short medial malleolus angle);â‘¡TA(acute angle made by line L₂ intersecting line L₃, I. e tibia angle);â‘¢superior-inferior diameter of medial malleolus I. e height H(actual length between line L₂ and L₅ I. e vertical dimension from point o to line mn);â‘£superior extremity width of medial malleolus W_上(I. e the distance between foremost point and postmost point of medial malleolus at tibia inferior extremity articular facet level mn);⑤inferior extremity width of medial malleolus W_下(the distance of the line L₇ between anterior border and posterior border);â‘¥superior inferior extremity thickness of medial malleolus T_上(thickness of medial malleolus root);⑦inferior extremity thickness of medial malleolus T_下(thickness of basilar part of medial malleolus point);⑧thickness at mean line of medial malleolus T(thickness at half-height of medial malleolus)We fulfiled measuring height H,superior extremity width W_上,inferior extremity width W_下,superior extremity thickness T_上,inferior extremity thickness T_下and thickness T at mean line of medial malleolus bone sample, and fulfiled measuring medial malleolus angle MA at X-ray plates.Results: 1. From up to down medial malleolus becomes tapered narrow in lateral view, being similar to a handstand trapezoid. 2. From up to down medial malleolus gradually becomes thinner, however changes not very. 3. The differences between two sides of medial malleolus parameters are not statistically significant. (p＞0.05). 4. The differences of height H,superior extremity width W_上,inferior extremity width W_下,superior extremity thickness T_上,inferior extremity width T_下and thickness at mean line T between male-female bone sample of medial malleolus are statistically significant (p＜0.05). 5. The differences of medial malleolus angle MA between male-female X-ray plates are not statistically significant (p＞0.05). 6. we measure medial malleolus angle at X-ray plates and find that it relatively permanent, there is a relatively stationary scope.Conelusion: 1. Through the anatomic study and research of medial malleolus, we raise definition and measurements of correlate parametrics of medial maUeolus, specially raise the concept of measure malleolus angle.2. We have obtained reliable amatomic data of correlate parametrics of medial maIleolus, to provide amatomic according for selecting operational approachs and internal fixations in future, for inserting internal fixation safely and exactly in the operation, and for designing targeting equipments of medial malleolus fractures.