Morphometric description of the subfascial intermuscular adipose tissue of anterior compartment of the leg

Abstract

Objectives: To describe the morphological characteristics of subfascial intermuscular adipose tissue (IMATS) in the anterior compartment of the leg, considering its developmental and functional relationship with the crural fascia. Methods: In twenty formalin-fixed cadaveric legs (13 males, 7 females), after removal of the skin and crural fascia, the IMATS was exposed and classified into four types according to its shape. Leg length was divided into eight regions. The length, width at the widest point, closest distances of the upper and lower ends to the intermalleolar line and the anterior margin of the tibia, as well as the thickness of the skin-subcutaneous tissue complex, limb and leg lengths were measured for IMATS. Results: The most common type of IMATS was the short-large type. The largest point of IMATS was located in zone 3 or 4, and this point was located in the two zones closest to the lower end of IMATS in 75% of cases. In all cases, one to three connecting vessels piercing the crural fascia (80% were in zones 2, 3 or 4) connected to the IMATS in a slightly lateral to medial oblique course of the IMATS from top to bottom. The IMATS was superficially located in the tendinous and muscular parts of the extensor digitorum longus and/or tibialis anterior muscles, loosely attached to the muscles and crural fascia, but not between the muscle fibers. Although the largest point (p=0.041) and the distance from the distal end to the anterior margin of the tibia were found to be greater in males (p=0.049), the gender difference disappeared when normalized for limb length. Conclusion: No data on IMATS morphometry could be found in the literature. A remarkable finding of the study, which is open to interpretation in terms of the function of the IMATS, is that the location of the IMATS overlaps with the crural fascia region, which is reported to be biomechanically stiffer in the transverse direction. Our data that a connecting vessel is always connected to the IMATS by a fixed spatial relationship strengthens the argument that the developmental history of both structures may intersect.

Keywords

• anterior compartment of leg
• crural fascia
• extensor digitorum longus
• fat pad
• intermuscular adipose tissue
• tibialis anterior muscle

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