Aponeurosis

The human triceps surae (two gastrocnemii and soleus) has aponeuroses in the proximal and distal aspects, the latter of which insert into the calcaneus by sharing the common Achilles tendon. These tendinous tissues are known to have elasticity and upon muscle contraction the aponeurosis is stretched both longitudinally (along the muscle's line of action) and transversely. Higher aponeurosis transverse deformability has been documented, but there is a paucity of information on the morphology and mechanical properties of human aponeurosis. This study aimed to identify morphological and mechanical characteristics of the human triceps surae aponeuroses. Twenty-five triceps surae muscle-tendon units were procured from 13 human donors (formalin fixed, 6 males, 7 females) aged 67-91 years. Specimens of aponeuroses were excised from the eight regions (posterior and anterior regions of the gastrocnemius medialis and lateralis, medial and lateral parts of soleus; proximal, middle, and distal sites each, 2-4 cm × 2-4 cm). Aponeurosis thickness was measured using a digital caliper. Uniaxial tensile tests were implemented to determine the mechanical properties of specimens loaded longitudinally (along the muscle's line of action) and transversely. The aponeurosis thickness showed significant differences between muscles and sites, while Young's modulus showed direction-dependent (longitudinal vs. transverse) differences within sites. Results show different morphology and mechanical properties of aponeuroses between synergist muscles. The reason for site-dependent differences in stiffness is due to a reduced aponeurosis thickness rather than a reduction in the material property. The anisotropic elastic feature (differences between longitudinal and transverse directions) of the aponeuroses was more pronounced than previous in vivo findings, suggesting inherent material design of the aponeurosis that matches three-dimensional contractile behavior of muscle fibers.

Background and objectivesThe underlying anatomical mechanism of the ultrasound-guided fascia iliaca compartment (FIC) block for anaesthesia and analgesia in the lower limb has not been illuminated and numerous variations were attempted to achieve an optimal needle placement. This study aimed to define the fibrous configuration of the FIC.MethodsA total of 46 adult cadavers were studied using dissection, latex injection, epoxy sheet plastination and confocal microscopy.Results(1) The fascia iliaca originated from the peripheral fascicular aponeurotic sheet of the iliopsoas. (2) The FIC was a funnel-shaped adipose space between the fascia iliaca and the epimysium of the iliopsoas, had a superior and an inferior opening and contained the femoral and lateral femoral cutaneous nerves but not obturator nerve. (3) The estimated volume of the FIC in the cadavers was about 23 mls, of which about one third was below the level of the anterior superior iliac spine.ConclusionsThis study revealed that the fascia iliaca was aponeurotic and may be less permeable for the local anesthetics.ConclusionsThe FIC contained only the femoral and lateral femoral cutaneous nerves and communicated with the extraperitoneal space and femoral triangle adipose space via its superior and inferior opening, respectively.

PurposeWe established a detailed sonographic approach to the bicipital aponeurosis (BA), because different pathologies of this, sometimes underestimated, structure are associated with vascular, neural and muscular lesions; emphasizing its further implementation in routine clinical examinations.MethodsThe BA of 100 volunteers, in sitting position with the elbow lying on a suitable table, was investigated. Patients were aged between 18 and 28 with no history of distal biceps injury. Examination was performed using an 18-6 MHz linear transducer (LA435; system MyLab25 by Esaote, Genoa, Italy) utilizing the highest frequency, scanned in two planes (longitudinal and transverse view). In each proband, scanning was done with and without isometric contraction of the biceps brachii muscle.ResultsThe BA was characterized by two clearly distinguishable white lines enveloping a hypoechoic band. In all longitudinal images (plane 1), the lacertus fibrosus was clearly seen arising from the biceps muscle belly, the biceps tendon or the myotendinous junction, respectively. In transverse images (plane 2) the BA spanned the brachial artery and the median nerve in all subjects. In almost all probands (97/100), the BA was best distinguishable during isometric contraction of the biceps muscle.ConclusionWith the described sonographic approach, it should be feasible to detect alterations and unusual ruptures of the BA. Therefore, we suggest additional BA scanning during clinical examinations of several pathologies, not only for BA augmentation procedures in distal biceps tendon tears.

BackgroundAbdominal wall hernia is a common disease, with an incidence of around 20%. Recent studies have shown the benefits of using stem cells, especially mesenchymal ones, to improve tissue healing.AimsEvaluate the use of mesenchymal stem cells derived from adipocytes adhered to a suture filament to enhance tensile strength and collagen formation in aponeurosis.MethodsHuman stem cells derived from adipocytes were adhered to a suture filament. Thirty-seven rats of the species Sprague Dawley were divided into three groups: Group 1 was the control group, Group 2 used only a regular suture filament to close abdominal aponeurosis, and Group 3 used a suture filament with stem cells. These animals were evaluated seven, 14, and 56 days after the intervention.ResultsRupture occurred at the semilunar line and the midline. All animals from Groups 2 and 3, submitted to incision and closure, evaluated at D7 and D14, showed a rupture in the midline. However, all animals evaluated at D56 (all groups) ruptured at the semilunar line. Furthermore, tensile strength was significantly lower at D7 in Groups 2 and 3 compared to Group 1 (p0.05). Collagen histologic analysis showed that animals from Group 3 had the highest values in all time points, and Group 2 had higher values than Group 1 in all time points (p>0,05). In graphical analysis, Groups 2 and 3, on D7, had an increase in collagen, but on D14 showed a decrease, with a similar level on D56 (p>0,05).ConclusionsThis study do not support the use of mesenchymal stem cells to improve the healing of a midline abdominal incision in healthy subjects. However, an option for future studies is to employ this filament, combined with matrices for reconstructive purposes, in areas requiring extensive repair, such as large hernias where the aponeurosis is insufficient for defect correction.