Increased knowledge of the rich innervation of the deep fascia and its anatomical organization indicates the need to reevaluate maps of the dermatome according to the new findings. The authors present a distinction between dermatome and fasciatome, basing their approach to the literature on nerve root stimulation and comparing dermatomeric and myomeric maps. The former represents the portion of tissue composed of skin, hypodermis, and superficial fascia supplied by all the cutaneous branches of an individual spinal nerve; the latter includes the portion of deep fascia supplied by the same nerve root and organized according to force lines to emphasize the main directions of movement. The dermatome is important for esteroception, whereas the fasciatome is important for proprioception. If they are altered, the dermatome shows clearly localized pain and the fasciatome irradiating pain according to the organization of the fascial anatomy. Clin. Anat. 32:896–902, 2019. © 2019 Wiley Periodicals, Inc.

The fascia can be defined as a dynamic highly complex connective tissue network composed of different types of cells embedded in the extracellular matrix and nervous fibers: each component plays a specific role in the fascial system changing and responding to stimuli in different ways. This review intends to discuss the various components of the fascia and their specific roles; this will be carried out in the effort to shed light on the mechanisms by which they affect the entire network and all body systems. A clear understanding of fascial anatomy from a microscopic viewpoint can further elucidate its physiological and pathological characteristics and facilitate the identification of appropriate treatment strategies.

Aging of human skeletal muscles is associated with increased passive stiffness, but it is still debated whether muscle fibers or extracellular matrix (ECM) are the determinants of such change. To answer this question, we compared the passive stress generated by elongation of fibers alone and arranged in small bundles in young healthy (Y: 21 years) and elderly (E: 67 years) subjects. The physiological range of sarcomere length (SL) 2.5–3.3 μm was explored. The area of ECM between muscle fibers was determined on transversal sections with picrosirius red, a staining specific for collagen fibers. The passive tension of fiber bundles was significantly higher in E compared to Y at all SL. However, the resistance to elongation of fibers alone was not different between the two groups, while the ECM contribution was significantly increased in E compared to Y. The proportion of muscle area occupied by ECM increased from 3.3% in Y to 8.2% in E. When the contribution of ECM to bundle tension was normalized to the fraction of area occupied by ECM, the difference disappeared. We conclude that, in human skeletal muscles, the age-related reduced compliance is due to an increased stiffness of ECM, mainly caused by collagen accumulation.

Although the number of Ultrasound (US) imaging studies investigating the fascial layers are becoming more numerous, the majority tend to use different reference points and terminology to describe their findings. The current work set out to compare macroscopic and microscopic data of specimens of the fascial layers of the thigh with US imaging findings. Specimens of the different fascial layers of various regions of the thigh were collected for macroscopic and histological analyses from three fresh cadavers and compared with in vivo US images of the thighs of 20 healthy volunteers. The specimens showed that the subcutaneous tissue of the thigh is made up of three layers: a superficial adipose layer, a membranous layer/superficial fascia, and a deep adipose layer. The deep fascia is composed of an aponeurotic fascia, which envelops all the thigh muscles and is laterally reinforced by the iliotibial tract and an epimysial fascia, which is specific for each muscle. The morphometric measurements of the thickness of the superficial fascia were different (anterior: 153.2 ± 39.3 µm; medial: 128.4 ± 24.7 µm; lateral: 154 ± 28.9 µm; and posterior: 148.8 ± 33.2 µm) as were those of the deep fascia (anterior: 556.8 ± 176.2 µm; medial: 820.4 ± 201 µm; lateral: 1112 ± 237.9 µm; and posterior: 730.4 ± 186.5 µm). The US scans showed a clear picture of the superficial adipose tissue, the superficial fascia, and the deep adipose tissue, as well as the deep fasciae. The epimysial and aponeurotic fasciae of only some topographic areas could be independently identified. The US imaging findings confirmed that the superficial and deep fascia have different thicknesses, and they showed that the US measurements were always larger with respect to those produced by histological analysis (p < 0.001) probably due to shrinkage during the processing. The posterior region (level 1) of the superficial fascia had, for example, a mean thickness of 0.56 ± 0.12 mm at US, while the histological analysis showed that it was 148.8 ± 33.2 µm. Showing a similar pattern, the thickness of the deep fascia was as follows: 1.64 ± 0.85 mm versus 730.4 ± 186.5 µm. Study results have confirmed that US can be considered a valid, non‐invasive instrument to evaluate the fascial layers. In any event, there is a clear need for a set of standardised protocols since the thickness of the fascial layers of different parts of the human body varies and the data obtained using inaccurate reference points are not reproducible or comparable. Given the inconsistent terminology used to describe the fascial system, it would also be important to standardise the terminology used to define its parts. The difficulty in distinguishing between the epimysial and aponeurotic/deep fascia can also impede data interpretation.