Fetal Development of Fasciae around the Arm and Thigh Muscles: A Study Using Late Stage Fetuses

Abstract

To obtain a better understanding of multi-laminar deep fascia covering skeletal muscles, we examined nondecalcified histological sections of the arm and thigh of 20 human fetuses aged 25-33 weeks. Morphologies of the fasciae varied between sites and specimens, but the initial morphology was most likely to be a thin and loose sheet on the external surface of the muscles (fascia-1 or F1). When the F1 became wavy, thick and tight, it was detached from the muscle surface. Beneath the F1, the second lamina of fascia (F2) appeared on the muscle surface and it was also detached. In this manner at 25-33 weeks' gestation, fasciae covering the triceps and vastus lateralis muscles had a three-layered configuration (F1, F2, and F3). Due to significant individual variations, this process was not correlated to the ages and sizes of specimens. Muscle contractions might facilitate the detachment. In these muscles, the intramuscular tendon joined the F2 or F3 and the latter became thick and aponeurotic. Along the finally developed lamina, muscle fibers carried a desmin-positive spot for insertion. Increased laminae were accompanied by a reduced number of CD68-positive macrophages and, nerves were absent, near the developing fascia. In contrast to skin ligaments or superficial fasciae showing de novo development in loose tissue, a deep or muscle-covering fascia seemed to originate from the skeletal muscle itself at the surface, and this process was repeated to produce multi-layered fascia. Depending on sites, collagen fibers were added by the intramuscular tendon. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc.

Fetal Fascial Reinforcement Development: From “a White Tablet” to a Sculpted Precise Organization by Movement

“…As has been reported by other studies examining the deep fasciae of the forearm, thigh and lower back during fetal development [12][13][14][15][16], also in the retinacula in weeks 24-29, an irregular connective tissue runs parallel to the skin below the subcutaneous adipose tissue, with an organization in layers that appears at around 29-36 weeks in the ankle and 38 weeks in the wrist. The extensor retinacula of the wrist and ankle showed different developmental behaviors; the former had a huge thickness at the 40th week (735.3 ± 44.26 μm), much higher than the second (185.3 ± 94 μm).…”

“…Despite the fact that fascial reinforcement seems to play a key role in motor coordination and proprioception, there is no clear evidence about their ontogeny. To date, there have been few studies on the embryogenesis of the fascial layers, but no studies have focused on the retinacula [12][13][14][15]. Blasi et al described, in a histological study, in a qualitative and morphometric manner the thickness of the connective tissue between subcutaneous adipose tissue and the underlying muscle (without a differentiation between superficial and deep fasciae) in the gestation period between the 22 and 39 weeks, showing the presence of connective tissue that is topographically and morphologically equivalent to adult deep fasciae [12].…”

“…Abe et al realized the histological examination of thoracolumbar fascia in 25 embryos and fetus at 6-37 weeks, highlighting, within the prenatal life, the drastic change which occurs in interfascial connections and their topographical relation to muscle [13]. Cho et al examined, in a descriptive manner, non-decalcified histological sections of the arms and thighs of 20 human fetuses aged 25-33 weeks [14], highlighting that the advanced lamination of deep fasciae did not usually accompany an increase in the thickness of the subcutaneous tissue: both seemed to be independent [14].…”

Suboccipital myodural bridges revisited: Application to cervicogenic headaches

“…Using late‐stage human fetuses near full term, we have previously investigated the fascial configuration in the limbs (Cho et al, ,b), neck (Katori et al, ; ), and retroperitoneal region (Kinugasa et al, ; Matsubara et al, ). At the stage, collagen and elastic fibers are well differentiated and can be easily discriminated using routine staining techniques (Kinoshita et al, ; Kinugasa et al, ).…”

Subsynovial connective tissue development in the rabbit carpal tunnel

“…A study on myofascial development in older human fetal tissue (25–33 weeks) shows a cyclic process of fascia depositions, originating from the skeletal muscles themselves, then thickening, and subsequently detaching. The repetition of the process produced multilayered fascia (Cho et al., 2018). Hypothetically, a similar process could be present in the CT, where tendinous fibroblasts create layers of collagen matrix deposits in areas where friction is present (closest to the tendon), which would explain why the SSCT in the juvenile rabbits contained fewer layers and interconnecting fibrils compared to the adult rabbits.…”