The lateral inframalleolar fat pad: a poorly recognized anatomical structure

The authors carried out an anatomical histological study of the lateral inf ramalleolar region in order to improve knowledge of a fat pad of the latera l aspect of the ankle which is not mentioned in most anatomical texts. Twen ty-four ankles, from 12 cadavers, free of any local pathology or malformati on, were studied. Twenty ankles were dissected, of which, five had samples taken for histological examination. Colored latex was injected into the joi nt cavities of the last four ankles before anatomical cuts were made in thr ee planes. This study allowed the description of the fat pad which we have called the lateral inframalleolar fat pad (LIMFP). It is oval and made up o f a classical unilocular fatty tissue which is clearly distinct from the su bcutaneous plane. We have defined its relationships and in particular, the neurovascular ones. The sural nerve which supplies cutaneous sensation to p art of the 5(th) toe runs over the surface of the fat pad. It is accompanie d on this part of its course by the short saphenous vein which gives off a medial perforator which traverses the LIMFP. Because of these neurovascular relationships, the LIMFP may play a role in the pathophysiology of neuralg ias of the lateral aspect of the 5(th) toe or of the 4(th) digital interspa ce. It should be recognized before any operations on the lower limbs, in pa rticular, before any plastic surgical liposuction, in order to optimize the resection volume to prevent inaesthetic over correction or under correctio ns which are often confused with residual edema.