Fat Is Consistently Present within the Plantar Muscular Space of the Human Foot—An Anatomical Study
Tomlinson J, Klima S, Poilliot A, et al (2022)
Fat Is Consistently Present within the Plantar Muscular Space of the Human Foot—An Anatomical Study.
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Background and Objectives: The foot comprises of active contractile and passive connective tissue components, which help maintain stability and facilitate movement during gait. The role of age- or pathology-related degeneration and the presence of fat within muscles in foot function and pain remains unclear. The existence of fat has to date not been quantified or compared between individuals according to age, sex, side or subregion. Materials and Methods: 18 cadaveric feet (mean age 79 years) were sectioned sagittally and photographed bilaterally. Fat in the plantar muscular space of the foot (PMSF) was quantified through the previously validated manual fat quantification method, which involved observing photographs of each section and identifying regions using OsiriX. Fat volume and percentage was calculated using a modified Cavalieri's method. Results: All feet had fat located within the PMSF, averaging 25.8% (range, 16.5-39.4%) of the total PMSF volume. The presence of fat was further confirmed with plastination and confocal microscopy. Conclusions: These findings suggest that fat within the PMSF is a consistent but highly variable finding in elderly cohorts. Fat within the foot muscles may need to be considered a norm when comparing healthy and non-healthy subjects, and for therapeutic interventions to the foot. Further work is required to understand in detail the morphological and mechanical presence of fat in the foot, and compare these findings with pathological cohorts, such as sarcopenia. Additionally, future work should investigate if fat may compensate for the degeneration of the intrinsic muscles of the foot, with implications for both the use of orthotics and pain management. 背景と目的 足部は能動的な収縮組織と受動的な結合組織から構成され、歩行時の安定性の維持と運動の円滑化に寄与している。加齢や病理学的な変性、および筋肉内の脂肪の存在が足の機能や痛みに果たす役割は、まだ明らかになっていない。また、脂肪の存在については、これまで年齢、性別、側面、部位による個人間の定量化や比較は行われていない。材料と方法：18人の死体足（平均年齢79歳）を矢状に切開し、両側から写真を撮った。足底筋腔（PMSF）の脂肪は、以前に検証された手動の脂肪定量法（各切片の写真を観察し、OsiriXを用いて領域を特定する）を用いて定量化した。脂肪量と脂肪率は、修正Cavalieriの方法を用いて算出した。結果 すべての足にPMSF内に脂肪があり、PMSF総容積の平均25.8%（範囲、16.5～39.4%）を占めた。脂肪の存在は、プラスティネーションと共焦点顕微鏡でさらに確認された。結論 これらの知見は、PMSF内の脂肪は、高齢者コホートにおいて一貫しているが非常に多様な所見であることを示唆している。健常者と非健常者の比較や、足への治療的介入を行う際には、足の筋肉内の脂肪を規範と考える必要があるかもしれない。足部における脂肪の形態学的および力学的存在を詳細に理解し、これらの所見をサルコペニアのような病的コホートと比較するためには、さらなる研究が必要である。さらに、将来的には、脂肪が足の固有筋の変性を補うことができるかどうかを調査し、装具の使用と疼痛管理の両方に影響を与える必要があります。 https://gyazo.com/a93e38e25279a5ea3df06cdefab1405d
Figure 1 Foot section, sagittal plane. The region of interest of the plantar muscular space of the foot is highlighted. White lines indicate the anterior and posterior margins; the head of the metatarsal 1–5 (M) and the calcaneus (C). The blue line represents the inferior margin of the space with the plantar aponeurosis inferiorly. The green line indicates the superior boundary, which is the bony margins of the longitudinal arch of the foot. Scale bar = 10 mm. A = anterior; I = inferior; P = posterior; S = superior.
https://gyazo.com/12920aed53cda73d85c52ca7c5542f12
Figure 2 (A) Plastinated sagittal section of a foot with confocal images to demonstrate the adipose tissue. The black square indicates the region shown in (B). Scale bar = 15 mm. A = anterior; C = calcaneus; H = hallux; I = inferior; M = metatarsal; P = posterior; S = superior. (B)