Biomechanical assessment of gastrocnemii and Achilles tendon using MyotonPRO: in vivo measurements, and preliminary in situ measurements using formalin-fixed tissues.

PURPOSE: This study aims to evaluate the reliability and validity of using MyotonPRO to quantify the mechanical properties of the muscle-tendon unit through in vivo measurements and preliminary in situ measurements using formalin-fixed tissues. MATERIALS AND METHODS: The mechanical properties of gastrocnemii and the Achilles tendon of 12 healthy adults (six males and six females, 34.9 ± 5.8 years) were examined for in vivo test twice within a day and once post-24 hours using MyotonPRO, while nine human cadavers (formalin-fixed, 3 males and 6 females, 89.9 ± 5.1 years) were assessed for preliminary in situ test with identical time schedule to evaluate the within-day and inter-day reliability and validity. RESULTS: In vivo tests had very high within-day (ICC: 0.96-0.99) and inter-day reliability (ICC: 0.83-0.96), while in situ tests (formalin-fixed tissues) showed high within-day (ICC: 0.87-0.99) and inter-day reliability (ICC: 0.76-0.98) for the results of tone and stiffness. There was no significant difference in the stiffness of the free part of the Achilles tendon between in vivo and in situ conditions. The stiffness of the lateral gastrocnemius (r = 0.55, p = 0.018), proximal part of the Achilles tendon (r = 0.56, p = 0.015), and free part of the Achilles tendon (r = 0.47, p = 0.048) before removing the skin was significantly correlated with that after removing the skin condition. CONCLUSIONS: The findings of the current study suggest that MyotonPRO is reliable and valid for evaluating tendon stiffness both in vivo and in situ (formalin-fixed tissues).

Thickness of the Medial Pretarsal Adipose Tissue in the Upper Eyelid among the Japanese Population.

PURPOSE: To investigate the medial pretarsal adipose tissue thickness of the upper eyelid in the Japanese population. METHODS: Sixty-two whole upper eyelids were harvested from 35 Japanese cadavers and fixed in paraffin. The samples were cut into 5 µm sagittal microsections and stained with hematoxylin and eosin, as well as Masson's trichrome. Data obtained from images and measurements were taken with Aperio ScanScope and ImageScope software and underwent statistical analysis. RESULTS: The samples were divided into 3 shapes sagittal cross-sections of the eyelid (triangular, rectangular, and flat) corresponding to the shape of the medial pretarsal adipose tissue. Type I (triangular shape, 48.4%) had a ratio of fat thickness at 1/2 tarsal height to peak fat thickness of <0.9, and type IIa (rectangular shape, 30.6%) and IIb (flat shape, 21.0%) had pretarsal adipose tissue thickness to tarsal height ratio of ≥0.2 and <0.2, respectively. The mean values of tarsal thickness at 1/2 tarsal height were 1021 µm for the type I group, 1100 µm for the type IIa group, and 764.4 µm for the type IIb group ( p = 0.01). The mean values of fat thickness at 1/2 tarsal height were 410.6 µm for the type I group, 303.3 µm for the type IIa group, and 242.6 µm for the type IIb group ( p = 0.26). CONCLUSIONS: The thickness of the medial pretarsal adipose tissue was different according to the shape of the sagittal cross-section of the eyelid. Awareness of the medial pretarsal adipose tissue thickness contributes to effective suture placement and safe suture depth during blepharoptosis surgery.

Variation in the origin of the plantar aponeurosis and its relationship to the origin of the abductor hallucis muscle.

The plantar aponeurosis comprises medial, central, and lateral bands, which arise from the calcaneal tuberosity. Descriptions of the origin of the abductor hallucis vary among different textbooks. The central band and abductor hallucis muscles are related to the windlass mechanism. Given the uncertainties regarding the details of the origins of the central band and the abductor hallucis muscle, we examined those origins in 100 feet of 50 cadavers (25 males and 25 females) by dissection. There were three central band patterns, depending on the attachment sites of the origins of the central and lateral bands: Pattern Ia, the central band covers the lateral band completely; Pattern Ib, the central band covers part of the lateral band; Pattern II, the lateral band covers part of the central band. The origin of the abductor hallucis muscle was confirmed. It showed two types of variation: attachment type, originating from the central band; non-attachment type, not originating from the central band. Central band Patterns Ia, Ib, and II were found in 23 feet (17 males, 6 females), 24 feet (25 males, 28 females), and 24 feet (eight males, 16 females), respectively. Pattern Ia predominated in males and Pattern II in females. The attachment and non-attachment types of abductor hallucis muscle were observed in 28 feet (28%) and 72 feet (72%), respectively. The attachment type with Patterns Ia, Ib, and II was shown in 17 feet, 10 feet, and one foot, respectively. Thus, we revealed variation and sex differences in the central band, which could affect foot morphology and the efficacy of the windlass mechanism.

Nerve branches to the anterior tibial artery: Clinical application.

Arteries receive vascular branches (VBs) from peripheral nerves. VBs are thought to be involved in arterial constriction. Although the anterior tibial artery (ATA) receives VBs, information on their branching patterns and distribution areas remains limited. The aim of this study was to investigate the anatomical structures of the VBs reaching the ATA. Forty cadaver limbs were examined to assess the branching patterns and distribution areas of the VBs reaching the ATA. The VBs reaching the ATA ramified from the deep fibular nerve (DFN), and the ATA received two or three VBs in each limb. The following mean distances from the head of fibula to the points at which the VBs reached the ATA were measured: all the VBs, 1st VB, 2nd VB and 3rd VB. The measurements were 51.5 ± 23.2 mm, 33.3 ± 3.7 mm, 53.3 ± 18.6 mm, and 72.2 ± 24.5 mm, respectively. In all limbs, the DFN and the ATA converged after the DFN branched into the 1st VB. The 2nd VB in 38 of 40 limbs and the 3rd VB in 20 of 32 limbs were distributed in the ATA proximal to the convergence point of the ATA and the DFN. These findings revealed that all VBs reaching the ATA ramified from the DFN in all limbs. The ATA received two or three VBs, and all the 1st VBs distributed to the ATA proximal to the convergence point.

Effect of acetamiprid on the immature murine testes.

Neonicotinoids, such as acetamiprid (ACE), a pesticide used worldwide, are believed to be safe for human use. These molecules are structurally similar to nicotine, act as nicotinic acetylcholine receptor (nAChR) agonists, and were shown to be associated with neuromuscular and reproductive disorders, but these experiments were primarily performed in mature animals. In this study, the effects of ACE on the testes of immature mice were examined. The exposure of 3-week-old mice to ACE-containing water for 180 days led to a decrease in body weight and mildly affected spermatogenesis. Additionally, the expression of testosterone-metabolism genes, nAChR subunit genes, and proliferation-associated genes decreased in the testes of ACE-treated mice. Our results show that immature rodents may be less sensitive to ACE than mature ones, that mice may be more likely to accumulate ACE than rats, and that the development of disorders may be affected by the accumulation of ACE in the testes.

Analysis of the posterior ramus of the lumbar spinal nerve: the structure of the posterior ramus of the spinal nerve.

BACKGROUND: Knowledge of neural anatomy is fundamental for safe, efficacious use of regional anesthesia. Spinal column procedures, such as a facet joint block, require an accurate understanding of neural pathways relative to anatomic structure. Since Bogduk's report it has been known that human lumbar posterior ramus of the spinal nerve (PRSN) comprises three, equally sized primary branches. However, inconsistencies and controversy remain over the exact locations and pathways of the peripheral portions of the PRSN branches. In this study, the authors investigated the detailed anatomy of the human PRSN. METHODS: The authors performed ventral dissection in seven cadavers to determine the layout of the PRSN between T10 and L4 spinal segments. They captured three-dimensional images with a laser scanner. For fine detail analysis, specimens from another cadaver were subjected to a modified Spalteholz technique to render all nonnerve tissue transparent. Computer graphics were used to create a three-dimensional structural model. RESULTS: All three PRSN branches emanated from an ipsilateral origin and passed posterior to the transverse process. The medial PRSN branch consistently passed between the mammillary and accessory processes under the mammilloaccessory ligament. The intermediate branch passed between the longissimus and iliocostalis muscles and extended to the skin. The lateral branch traveled far lateral from the origin. CONCLUSIONS: The authors created a 3D model of the PRSN in the lumbar segment, which may be useful for planning surgical approaches to dorsal areas of the vertebral column. In addition, this knowledge may improve the accuracy of procedures involving the spinal column, particularly radiofrequency neurolysis of the facet joint.

Effect of interprofessional education on cadaver dissection seminar.

In 2010, WHO published a "Framework for action on interprofessional education and collaborative practice." Interprofessional education (IPE) is now being conducted in various ways. We have been holding cadaver dissection seminars to provide opportunities for medical students, nursing students, and nurse practitioner (NP) students to learn together. In this study, we investigated the effect of learning about IPE in cadaver dissection seminars. The seminars were held for 5 days each in 2021 and 2022 (the number of days of participation was arbitrary). In the seminars, teams of 3-5 participants with the same theme collaborated to dissect a single donated cadaver. Teams were made up of participants with different departments: 29 medical students, 12 NP students, and 20 nursing students participated in the seminar, and participants were surveyed before and after the seminars. The Readiness for Interprofessional Learning Scale (RIPLS) scores before and after the dissection seminar increased significantly overall. The scores of medical and nursing students increased significantly, but those of NP students did not significantly change. In terms of the number of days of participation, a significant increase in scores was found for participants who participated for ≥ 2 days. Overall, a significant positive correlation was found between intrinsic motivation to learn and RIPLS scores. For medical students, a significant negative correlation was noted between extrinsic motivation and RIPLS scores. Cadaver dissection seminars conducted by medical, nursing, and NP students demonstrated IPE learning effect on medical students and undergraduate nursing students.

Specific acupuncture stimulation of Shenshu (BL23) affects sympathetic nervous activity-associated plasma renin concentration changes.

OBJECTIVE: To examine whether specific stimulation of Shenshu (BL23) affects sympathetic nervous activity (SNA)-associated plasma renin concentration (PRC). METHODS: Eight healthy volunteers participated in three pattern conditions in random order: control (Cont), stimulation of Shenshu (BL23), and stimulation of sham point (Sham). All participants were initially in the supine position for > 60 min, and then remained in the standing position during the experimental procedure to increase SNA. An electrocardiogram was used to calculate low frequency/high frequency (LF/HF) ratio; blood was collected to analyze PRC. RESULTS: The LF/HF ratio was significantly increased in the standing position when compared with the supine position ( 0.01). There was no difference in LF/HF ratio during or after stimulation of Shenshu (BL23) in the standing position when compared with before the stimulation in the supine position; however, the LF/HF ratio was significantly increased in Cont and Sham conditions ( 0.01). There was no difference in PRC after stimulation of Shenshu (BL23) in the standing position when compared with before the stimulation in the supine position; however, there was a significant increase in PRC in the Cont and Sham conditions (Cont 0.05, Sham 0.01). CONCLUSION: Our results demonstrated that specific acupuncture stimulation of Shenshu (BL23) in the standing position decreased SNA-associated PRC, which was not observed during acupuncture stimulation of the sham point.

A Part of the Medial Branch of the Deep Peroneal Nerve Distributes the Dorsal Pedis Artery and Its Distribution Area is Close to the Acupuncture Point LR3 (Taichong).

Cutaneous nerves have vascular branches (VBs) that reach the arteries and are thought to be involved in arterial constriction. We aimed to examine the anatomical and histological relationship between the VBs of a cutaneous nerve in the foot and the acupuncture point LR3 (Taichong), which is a depression between the base of the first and second metatarsal bones on the dorsum of the foot and is a source point of the foot. We examined 40 cadaver feet to assess the distribution areas of the VBs of the medial branch of the deep peroneal nerve (MBDPN). MBDPNs were distally followed to identify the point where the VBs reached the arteries. The distance between the point and LR3 was measured. Sympathetic fibers in the VBs were histologically observed using tyrosine hydroxylase (TH) immunostaining. The VBs of the MBDPNs reaching the dorsal pedis arteries were observed in all specimens (100%). The mean distance between LR3 and the point where the VBs of the MBDPN reached the arteries was 3.2 ± 2.6 mm. Among the VBs, 70% were distributed proximal to LR3. Moreover, TH-positive fibers were present in the VBs. These findings revealed that a part of the MBDPN distributed the dorsal pedis artery and contained sympathetic fibers. We also found that the distribution area of the VBs was close to LR3. Our study provides anatomical evidence that LR3 is a specific area and its stimulation would be useful for treating peripheral circulatory failure.

Recurrent position and innervation pattern of recurrent peroneal nerve: A cadaveric study.

BACKGROUND: The recurrent peroneal nerve (RPN) branches from the common peroneal nerve or the deep peroneal nerve and it innervates to the lower patellar region. It has recently been reported that damage to the RPN causes pain in the lower patellar region; therefore, this study examined the recurrent position and the innervation pattern of the RPN. METHODS: Cases of knee deformity or atrophy were excluded, and 50 legs (25 males and 25 females) of 34 cadavers (15 males and 19 females) were examined to assess the recurrent position and the innervation pattern of the RPN. RESULTS: The recurrent position of the RPN was 27.9 ± 3.6 mm from the tip of the fibula. The RPN innervated to the patellar tendon in five of the 50 legs (10%), to the infrapatellar fat pad in 13 legs (26%), and to both the patellar tendon and the infrapatellar fat pad in 20 legs (40%), and to neither the patellar tendon nor the infrapatellar fat pad in 12 legs (24%). No significant sex differences were observed in the recurrent position and the innervation pattern of the RPN. CONCLUSIONS: In all cases, the recurrent position of the RPN was almost fixed from the tip of the fibula. The RPN frequently innervated to the patellar tendon or the infrapatellar fat pad (76%) in both males and females. These findings would be useful in knee surgery to preserve the RPN or for the diagnosis of pain in the lower patellar region.

Variation of insertion of the pectoralis major in a cadaveric study: A case report.

RATIONALE: Typically, the tendon of the pectoralis major inserts into the crest of the greater tubercle of the humerus. However, anomalous insertion sites of the pectoralis major tendons have been noted. PATIENT CONCERNS: The cadaver of a 95-year-old Japanese man was selected from the bodies used for gross anatomy practice at the Tokai University School of Medicine in 2018. DIAGNOSIS: In this cadaver, the left side of the pectoralis major tendon appeared to insert at the crest of the greater tubercle and lesser tubercle of the humerus, forming a tunnel measuring 2.5 cm in total length. INTERVENTION: We removed the fat and skin around the shoulder joint and upper extremity for observational purposes and carefully examined the structures during gross anatomy. OUTCOMES: The medial side of the insertion of the pectoralis major tendon was not into the humerus but had combined with the tendon of the latissimus dorsi, which then loosely inserted into the humerus. As the roof and both walls comprised the tendon of the pectoralis major and the floor was formed by the tendon of the latissimus dorsi and humerus, the structure formed a tunnel. LESSONS: This study is important for orthopedic and rehabilitation physicians in treating diseases of the long head of the biceps brachii tendon. As part of management, the condition of the tendon of the pectoralis major should be confirmed using magnetic resonance imaging or echocardiography.

Acupuncture Point "Hegu" (LI4) Is Close to the Vascular Branch from the Superficial Branch of the Radial Nerve.

The acupuncture point "Hegu" (LI4) has been used for treating peripheral circulatory failure, which is located in the area covered by the superficial branch of the radial nerve (SBRN). SBRN has branches reaching arteries, so-called vascular branches (VBs), which are thought to be involved in the arterial constriction. The distribution areas of the VBs from the SBRN have been reported, but the positional relationship between these distribution areas and the acupuncture points are not known. To examine the positional relationship between LI4 and VBs from the SBRN, forty hands were examined to assess the positional relationship between the acupuncture points "Erjian" (LI2), "Sanjian" (LI3), LI4, and "Yangxi" (LI5) in the Yangming Large Intestine Meridian of Hand, which are located in the area covered by SBRN, and the VBs from the SBRN. After the VBs were identified, the distances from the acupuncture points (LI2, LI3, LI4, and LI5) to the point where the VBs reached the radial artery or the first dorsal metacarpal artery were measured. VBs reaching the radial arteries were observed in all specimens. The mean distances from LI2, LI3, LI4, and LI5 to the point where the VBs reached the radial artery were 64.2 ± 8.2 mm, 42.0 ± 7.5 mm, 4.3 ± 4.3 mm, and 33.0 ± 4.8 mm, respectively. LI4 was significantly closer than the other acupuncture points (P<0.01). The nerve fibers of the VBs adjacent to the radial artery were confirmed using hematoxylin and eosin staining. Our findings provide anatomical evidence that stimulation at LI4 is used for treating peripheral circulatory failure such as Raynaud's disease. LI4 is significant because it is located at a source point, making it clinically important.

Variation in origin of the long head of the biceps brachii tendon in a cadaver: A case report.

INTRODUCTION: In general, the long head of the biceps brachii (LHB) tendon arises from the supraglenoid tubercle in the shoulder joint, and it has an important stabilizing mechanism for the humeral head in the shoulder joint. This case demonstrates that even if the LHB tendon can be palpated outside of the shoulder joint, it may disappear in the intertubercular sulcus (IS) and in the glenohumeral (GH) joint because of abnormal articulation. PATIENT CONCERNS: This case involved the cadaver of an 82-year-old Japanese man (number 1936, cause of death: hepatocellular tumor), who was selected from the bodies used for gross anatomy practice at the Tokai University School of Medicine in 2017. INTERVENTION: We removed the fat and skin around the shoulder joint for observational purposes and carefully examined the gross anatomy of the structures. DIAGNOSIS: We suspected that the long head of the biceps brachii tendon arose from the lesser tubercle (LT) in the cadaver. In our case, it was found that the upper part of the subscapularis (SSC) tendon was torn first, and the succeeding degenerative changes and rupture of the LHB tendon were intra-articular. OUTCOMES: The long head of the biceps brachii tendon was found to be ruptured in the GH joint, and scar tissue developed between the distal stump of the tendon and the articular capsule, resulting in fusion with the LT. CONCLUSIONS: This case necessitates confirmation that the LHB tendon is present in the IS and in the GH joint to treat cases wherein failure of the dynamic stabilizing mechanism for the humeral head occurs.

Anatomical relationship between BL23 and the posterior ramus of the L2 spinal nerve.

BACKGROUND: The acupuncture point BL23 is located in the region of the posterior ramus of the second lumbar spinal nerve (L2) and has historically been used to treat conditions such as lower back pain, pollakiuria, erectile dysfunction, dysmenorrhoea, tinnitus, and vertigo. Some of these treatment effects have been hypothesised to be mediated by the sympathetic nervous system. It was recently discovered that the posterior ramus of the spinal nerve (PRSN) at L2 forms not two but three branches. OBJECTIVE: To examine the relationship between the acupuncture point BL23 and the L2 PRSN in order to consider the pathways possibly affected by BL23 acupuncture. METHODS: Acupuncture needles were inserted through the skin at BL23 to a depth of 3 cm a total of 13 times in eight donor cadavers (seven right-sided, six left-sided). Leaving the needle in place, ventral dissection was performed to determine the PRSN anatomy between the L1 and L3 spinal segments. In four cadavers, the relationship between the L2 spinal nerve and sympathetic branches was additionally evaluated. Following dissection, three-dimensional (3D) data were acquired using a photo scanner and 3D structural images were created using 3D computer graphics software. One additional (female) cadaver was studied without insertion of an acupuncture needle (due to significant scoliosis). RESULTS: The L2 PRSN was divided into medial, intermediate and lateral branches. The needle inserted at BL23 came to lie in the region of the intermediate or lateral branches in all cases. Rami communicantes were found between the L2 spinal nerve and sympathetic trunk with fibres going on to supply the superior hypogastric plexus. CONCLUSIONS: Our findings suggest that acupuncture needles inserted at BL23 come into close proximity with the intermediate or lateral branch of the L2 PRSN, which could result in stimulation of both the somatic and sympathetic nervous systems.