Purpose: To determine the gross and histologic configurations of the medial and lateral frontalis muscle.
Methods: After making a midcoronal incision and bluntly dissecting to the orbital rim, the frontalis muscle was marked and measured. A protractor was used to measure the frontalis-orbicularis angle (FOA) and, when present, the angle of central bifurcation (AOB). Three strips of full-thickness forehead soft tissue measuring 0.5 cm × 8 cm were excised 3, 4.5, and 6 cm above the supraorbital notch and analyzed histologically for the presence of skeletal muscle fibers. Data were analyzed using 2-sample t tests, paired t tests, Pearson correlations, and mixed effect models. A p value of ≤ 0.05 was considered statistically significant.
Results: Sixty-four hemifaces of 32 cadavers (16 males) were dissected. All specimens were Caucasian. The average age was 78.2 years (range, 56-102 years). The average FOA was 88.7° (13.0°), and the average AOB was 90.0° (26.4°). A visible midline bifurcation occurred in 28 of 32 subjects (88%) at an average height of 4.7 cm (range, 2.4-7.2 cm) superior to the supraorbital notch. Continuous skeletal muscle fibers were present within the midline bifurcation histologically in 89%, 75%, and 11% of specimens 3.5, 5.0, and 6.5 cm above the supraorbital notch, respectively. In 46% of individuals, skeletal muscle fibers were continuously present microscopically within the gross bifurcation.
Conclusion: While a medial frontalis muscle bifurcation occurs grossly in most senescent Caucasians, muscle fibers exist microscopically within this zone in nearly half of individuals.
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http://dx.doi.org/10.1097/IOP.0000000000000244 | DOI Listing |
Nat Commun
January 2025
Department of Biomedical Engineering, State University of New York at Binghamton, Binghamton, NY, 13902, USA.
Creating durable, motion-compliant neural interfaces is crucial for accessing dynamic tissues under in vivo conditions and linking neural activity with behaviors. Utilizing the self-alignment of nano-fillers in a polymeric matrix under repetitive tension, here, we introduce conductive carbon nanotubes with high aspect ratios into semi-crystalline polyvinyl alcohol hydrogels, and create electrically anisotropic percolation pathways through cyclic stretching. The resulting anisotropic hydrogel fibers (diameter of 187 ± 13 µm) exhibit fatigue resistance (up to 20,000 cycles at 20% strain) with a stretchability of 64.
View Article and Find Full Text PDFJ Cachexia Sarcopenia Muscle
February 2025
Department of Bioactive Material Sciences, Research Center of Bioactive Materials, Jeonbuk National University, Jeonju, Republic of Korea.
Background: The cellular prion protein (PrP), a glycoprotein encoded by the PRNP gene, is known to modulate muscle mass and exercise capacity. However, the role of PrP in the maintenance and regeneration of skeletal muscle during ageing remains unclear.
Methods: This study investigated the change in PrP expression during muscle formation using C2C12 cells and evaluated muscle function in Prnp wild-type (WT) and knock-out (KO) mice at different ages (1, 9 and 15 months).
J Ginseng Res
January 2025
KM Data Division, Korea Institute of Oriental Medicine, Daejeon, Republic of Korea.
Background: A decline in muscle mass and function can impact the health, disease vulnerability, and mortality of older adults. Prolonged use of high doses of glucocorticoids, such as dexamethasone (DEX), can cause muscle wasting and reduced strength. Ginsenoside Rc (gRc) has been shown to protect muscles by activating the PGC-1α pathway and improving mitochondrial function.
View Article and Find Full Text PDFJ Cachexia Sarcopenia Muscle
February 2025
Department of Endocrinology and Metabolism, Qilu Hospital of Shandong University, Jinan, Shandong, China.
Background: Muscle atrophy is associated with Type 2 diabetes mellitus, which reduces the quality of life and lacks effective treatment strategies. Previously, it was determined that human umbilical cord mesenchymal stromal cell (hucMSC)-derived exosomes (EXOs) ameliorate diabetes-induced muscle atrophy. However, the systemic application of EXOs is less selective for diseased tissues, which reduces their efficacy and safety associated with their nonspecific biological distribution in vivo.
View Article and Find Full Text PDFFood Sci Technol Int
January 2025
College of Food Science and Engineering, Shandong Agricultural University, Tai'an, China.
The objective of this study was to investigate the water-holding capacity (WHC) and quality changes of beef during heating at specific temperatures (including 40 °C, 60 °C, 80 °C, and 100 °C), as well as the degradation of proteins and the distribution of water within the muscle at different heating temperatures. The experiment utilized the sirloin section from eight crossbred cattle of and breeds, with four sampling sessions, two cattle per session. Each cattle were divided into 30 beef sirloin samples, each weighing 150 ± 10 g, and each session was completed within 3 days with the following tests.
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