The lateral inframalleolar fat pad: a poorly recognized anatomical structure.

The authors carried out an anatomical histological study of the lateral inframalleolar region in order to improve knowledge of a fat pad of the lateral aspect of the ankle which is not mentioned in most anatomical texts. Twenty-four ankles, from 12 cadavers, free of any local pathology or malformation, were studied. Twenty ankles were dissected, of which, five had samples taken for histological examination. Colored latex was injected into the joint cavities of the last four ankles before anatomical cuts were made in three 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 of a classical unilocular fatty tissue which is clearly distinct from the subcutaneous plane. We have defined its relationships and in particular, the neurovascular ones. The sural nerve which supplies cutaneous sensation to part of the 5th toe runs over the surface of the fat pad. It is accompanied 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 neuralgias of the lateral aspect of the 5th toe or of the 4th digital interspace. It should be recognized before any operations on the lower limbs, in particular, before any plastic surgical liposuction, in order to optimize the resection volume to prevent inaesthetic over correction or under corrections which are often confused with residual edema.