In vivo and in vitro Examination of the Tendinous Inscription of the Human Semitendinosus Muscle

Abstract

The aim of this study was to examine the tendinous inscription (TI) of the human semitendinosus (ST) muscle using dissection (cadavers) and ultrasound (in vivo). Ultrasonography (US) scans were taken in 18 young males at rest and at maximum voluntary contraction (MVC). Further, the ST was dissected and removed from its origins in 10 cadaveric specimens (5 cadavers). The cadaveric long arm of the TI was 6.67 ± 0.64 cm (6.45 ± 1.21 in US) while the shorter arm was 2.39 ± 0.38 cm (1.99 ± 0.75 in US). The angle formed by the two TI arms ranged from 53.19 (US) to 56.05° (cadavers) while more superficial fascicles intersected the inscription at significantly higher angles (range 31.98 ± 6.15 to 34.69 ± 7.71°) compared with deeper fascicles (p < 0.05). Fascicle length did not differ between compartments, but it was significantly smaller in superficial compared with deeper layers (p < 0.05). With the exception of the angle between the TI arm and the deep aponeurosis, all measured angles as well as the length of the long arm of the TI increased significantly from rest to MVC (p < 0.05). The role of the TI probably lies in the local interconnections with the fascicles of either compartment, which upon contraction is such that the ST muscle contracts as one muscle. However, the TI arm morphology changes from rest to MVC, indicating a nonuniform displacement of the TI, mainly between the superficial and deeper layers of the muscle.

Freehand three‐dimensional ultrasound to assess semitendinosus muscle morphology

“…No differences in fascicle lengths between distal and proximal compartments were found, except for the most distal fascicles at both compartments ('fasc d ). Similar fascicles lengths within the two compartments (Wickiewicz et al 1983;Woodley & Mercer, 2005;Kellis et al 2012), as well as shorter fascicle lengths in the proximal compared with the distal compartment (Markee et al 1955), have been reported. However, comparison of the results between the present data and those of previous studies regarding differences in fascicle lengths within and between compartments is hampered by a lack of standardization of the location of the measured fascicles or differences in the dissection plane.…”

“…; Woodley & Mercer, ; Kellis et al. ), as well as shorter fascicle lengths in the proximal compared with the distal compartment (Markee et al. ), have been reported.…”

“…The ST is divided by a tendinous inscription (also referred to as raphe) into a proximal and a distal compartment (Markee et al 1955;Lee et al 1988;Woodley & Mercer, 2005;Kellis et al 2012;van der Made et al 2013). Fascicles in both ST compartments are arranged in series and exert force at a small angle with the aponeuroses (Kellis et al 2009;Ward et al 2009).…”

Reliability of biceps femoris and semitendinosus muscle architecture measurements obtained with ultrasonography

“…The authors found SEM below 10%. In vivo, high intrarater and interrater reproducibility was reported to semitendinosus pennation angle (ICC > 0.83) (Kellis et al, 2011). This study is the first to describe the in vivo muscle thickness and fascicle length measurements reliability for the semitendinosus muscle using ultrasound.…”

Hamstring Elongation Quantified Using Ultrasonography During the Straight Leg Raise Test in Individuals With Low Back Pain

“…The ST muscle is characterized by the presence of a tendinous inscription (TI), which consists of 2 arms that intersect along the midway of the muscle length. The inscription is highly visible on the ultrasound image, especially during changes in hamstrings length [29]. For this reason, we monitored the TI position during the SLR as an index of hamstring muscle−tendon extensibility [29] (Figure 1).…”