Gross anatomic evidence of partitioning in the human fibularis longus and brevis muscles

Peroneus Longus Graft Harvest Does Not Affect Ankle Biomechanics: A Narrative Review

The peroneus longus graft has gained much attention in recent years as a reliable autograft for primary ACL surgery. Critics have voiced concerns related to its impact on ankle biomechanics. The current review aims to synthesize the available literature on ankle biomechanics after peroneus harvest. The quantum of evidence available shows that PL harvest does not significantly impact ankle eversion or plantarflexion strength. Its impact on gait needs to be studied more deeply before any significant conclusions can be drawn.

Individuals with chronic ankle instability show altered regional activation of the peroneus longus muscle during ankle eversion

Individuals with chronic ankle instability (CAI) present muscular weakness and potential changes in the activation of the peroneus longus muscle, which likely explains the high recurrence of ankle sprains in this population. However, there is conflicting evidence regarding the role of the peroneus longus activity in CAI, possibly due to the limited spatial resolution of the surface electromyography (sEMG) methods (i.e., bipolar sEMG). Recent studies employing high-density sEMG (HD-sEMG) have shown that the peroneus longus presents differences in regional activation, however, it is unknown whether this regional activation is maintained under pathological conditions such as CAI. This study aimed to compare the myoelectric activity, using HD-sEMG, of each peroneus longus compartment (anterior and posterior) between individuals with and without CAI. Eighteen healthy individuals (No-CAI group) and 18 individuals with CAI were recruited. In both groups, the center of mass (COM) and the sEMG amplitude at each compartment were recorded during ankle eversion at different force levels. For the posterior compartment, the sEMG amplitude of CAI group was significantly lower than the No-CAI group (mean difference = 5.6% RMS; 95% CI = 3.4-7.6; p = 0.0001). In addition, it was observed a significant main effect for group (F1,32  = 9.608; p = 0.0040) with an anterior displacement of COM for the CAI group. These findings suggest that CAI alters the regional distribution of muscle activity of the peroneus longus during ankle eversion. In practice, altered regional activation may impact strengthening programs, prevention, and rehabilitation of CAI.

Task-related differences in peroneus longus muscle fiber conduction velocity

It has been identified that the peroneus longus presents a regional activity. Specifically, a greater activation of the anterior and posterior compartments has been observed during eversion, whereas a lower activation of the posterior compartment has been reported during plantarflexion. In addition to myoelectrical amplitude, motor unit recruitment can be inferred indirectly from muscle fiber conduction velocity (MFCV). However, there are few reports of MFCV of the regions that make up a muscle, and even less, MFCV of the peroneus longus compartments. This study aimed to analyze the MFCV of peroneus longus compartments during eversion and plantarflexion. Twenty-one healthy individuals were assessed. High-density surface electromyography was recorded from the peroneus longus during eversion and plantarflexion at 10%, 30%, 50%, and 70% of maximal voluntary isometric contraction. The posterior compartment presented a lower MFCV than the anterior compartment during plantarflexion, and both compartments did not show differences in MFCV during eversion; however, the posterior compartment showed an increase in MFCV during eversion compared to plantarflexion. Differences observed in the MFCV of the peroneus longus compartments could support a regional activation strategy and, to some extent, explain different motor unit recruitment strategies of the peroneus longus during ankle movements.

Case report of unusual insertion of the fibularis brevis muscle

The fibularis brevis and fibularis longus muscles belong to the lateral compartment of the leg. The fibularis brevis is morphologically variable, especially in the number of tendons and place of insertion. Its type of insertion is correlated with the presence of a fibularis digiti quinti, which is also anatomically variable. We present a case study based on dissection of a seventy-three-year-old female cadaver with an unusual insertion of the fibularis brevis muscle. The tendon had three bands inserting into the fifth metatarsal bone. There was a coexisting fibularis digiti quinti, which was fused with the fibularis tertius muscle. Awareness of such anatomical variation could be useful during reconstructive surgery and planning rehabilitation protocols.

Contribution of the peroneus longus neuromuscular compartments to eversion and plantarflexion of the ankle

Compartmentalization of animal and human skeletal muscle by multiple motor nerve branches known as the neuromuscular compartment (NMC) has been observed primarily in muscles that participate in a plane of motion. In this context, the peroneus longus muscle contributes to eversion and plantarflexion of the ankle and the presence of NMCs has been reported. However, no research has reported the selective activation of the compartments of the peroneus longus during the performance of different ankle movements. The purpose of this research was to determine the contribution of peroneus longus NMCs, through multi-channel surface electromyography (sEMG), to eversion and plantarflexion movements. Multi-channel sEMG was recorded from the peroneus longus muscle by using an electrode grid during eversion and plantarflexion of the ankle at 10%, 30%, 50%, and 70% of maximal voluntary isometric contraction (MVIC). The root mean square and displacement of the center of mass position in the X (COMx) and Y (COMy) components were calculated. The primary finding was that eversion showed significantly higher sEMG amplitude than plantarflexion in the posterior compartment in low, moderate, and high percentages of MVIC. However, no significant difference in sEMG amplitude was observed in the anterior compartment between eversion and plantarflexion. In addition, a posterior displacement of the COMx in eversion compared to plantarflexion in all MVIC percentages, with greater topographic distancing of the COMx at higher levels of activation. In conclusion, the peroneus longus muscle presented NMCs; the anterior compartment contributed to both eversion and plantarflexion movements, whereas the posterior compartment mainly contributed to the eversion movement of the ankle in low, moderate, and high percentages of MVIC.

Topography of muscular branches of the superficial fibular nerve based on anatomical preparation of human foetuses

BACKGROUND

The progress of pediatric surgery and increasingly better diagnosis of fetal defects require detailed knowledge of human developmental anatomy. Precise knowledge of the anatomy of innervation of the lower extremities corresponds to this subject and is not only cognitive but also clinically important. The aim of this study was to analyse the anatomy of the topography of the muscular branches of the superficial fibular nerve (NPS) in the prenatal period, which will fill a gap in the literature.

METHODS

The analysis was carried out on 207 human foetuses aged from the 113th day to 222nd day of foetal life. The study material is a part of the collection of the Division of Normal Anatomy of Wroclaw Medical University. The study incorporated the following methods: anthropological, preparational and image acquisition which was acquired with the use of high-resolution digital camera. Statistical analysis was carried out with the use of STATISTICA package.

RESULTS

Based on the research results the number of muscle branches of the examined nerve was determined. It was shown that in more than half of the cases the two nerve branches are responsible for Peroneus Longus innervation and in about 90% of cases one branch is responsible for Peroneus Brevis innervation. Based on the obtained data a unique, new typology of distribution of these branches was created. It has been shown that the bipinnate type is the most common in the examined fetal population. The presence of statistically significant differences in the frequency of occurrence of individual innervation patterns depending on sex and body side were excluded (p > 0.05). There were also no statistically significant changes in the frequency of occurrence of individual types of NPS branch distribution according to fetal age (p > 0.05).

CONCLUSIONS

The created unique typology of NPS branch distribution based on extensive preparation material is an important supplement to the anatomical knowledge and at the same time, due to the peripheral and superficial location of the described structures, it has a relevant clinical significance.

The variations of peroneus digiti quinti muscle and its contribution to the extension of the fifth toe. A cadaveric study

Objectives:

To investigate the origin, prevalence, and possible effects of peroneus digiti quinti muscle (PDQ) on the fifth toe, to find out the variations of PDQ by determining the relationship between peroneus brevis muscle (PB) and PDQ, and to reveal its importance for the applications in foot and ankle surgery.

Methods:

This study was conducted at the Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey between September 2013 and June 2014. The study was a prospective dissection of cadaveric lower limbs. Twenty-five amputated lower limbs were stored in the freezer at -15°C. The legs were dissected; prevalence and variations of peroneus digiti quinti were investigated.

Results:

Peroneus digiti quinti muscle was found in 8 (32%) of 25 dissected lower limbs. However, 2 different tendon extensions were found at 3 (37.5%) of 8, and 5 (62.5%) of them were determined to have a single tendon.

Conclusion:

The incidence, dimensions, length, and insertions of peroneus digiti quinti are important in the evaluation and treatment of functional loss of the fifth toe, lateral foot deformities, and tendon problems behind the lateral malleolus of the ankle.

Anatomical variations of peroneal muscles: a cadaver study in an Indian population and a review of the literature

BACKGROUND

Persistent lateral ankle pain is a common presentation in clinics. Various studies on anatomical variations of the peroneal compartment muscles, including the peroneus quartus muscle, have been reported in different populations. However, such studies are rarely from India. Hence, the present study was undertaken on cadavers in an Indian population.

METHODS

The lateral compartments of the legs were dissected in 70 specimens to study the presence, origin, and insertion of accessory muscles. Different peroneal tendons were observed for tears and splits.

RESULTS

Three of 70 specimens (4.3%) showed prevalence of the peroneus quartus muscle. Twenty specimens (28.6%) had split or tear lesions of the peroneus brevis muscle. Presence of the peroneus quartus muscle in this Indian population was relatively low compared with that in previous reports in English and American populations (6.6%-21.9%).

CONCLUSIONS

Racial differences, cultural variations, and postural habits, along with different stages of evolution, may be factors contributing to different observations. Split lesions of the peroneus brevis tendon were six to seven times more prevalent than was presence of the peroneus quartus muscle, which implies that split or tear lesions of the peroneus brevis tendon are more frequently involved in the manifestation of persistent retromalleolar pain compared with complications arising out of presence of the peroneus quartus muscle. Hence, accurate knowledge of presence of the peroneus quartus muscle in different populations is important because it can also be used in grafting and reconstruction in foot and ankle surgery.

Differences in end-point force trajectories elicited by electrical stimulation of individual human calf muscles

The purpose of this study was to investigate the end-point force trajectories of the fibularis longus (FIB), lateral gastrocnemius (LG), and medial gastrocnemius (MG) muscles. Most information about individual muscle function has come from studies that use models based on electromyographic (EMG) recordings. In this study (N = 20 subjects) we used electrical stimulation (20 Hz) to elicit activity in individual muscles, recorded the end-point forces at the foot, and verified the selectivity of stimulation by using magnetic resonance imaging. Unexpectedly, no significant differences were found between LG and MG force directions. Stimulation of LG and MG resulted in downward and medial or lateral forces depending on the subject. We found FIB end-point forces to be significantly different from those of LG and MG. In all subjects, stimulation of FIB resulted in downward and lateral forces. Based on our results, we suggest that there are multiple factors determining when and whether LG or MG will produce a medial or lateral force and FIB consistently plays a significant role in eversion/abduction and plantar flexion. We suggest that the intersubject variability we found is not simply an artifact of experimental or technical error but is functionally relevant and should be addressed in future studies and models.

Gross morphology of the vastus lateralis muscle: An anatomical review

To understand the role of the vastus lateralis (VL) muscle in the pathogenesis of common knee disorders such as patellofemoral joint syndrome, knowledge of its anatomical structure is essential. The aim of this study was to review currently available information on the gross morphology of VL. A structured literature review was undertaken and 36 references, comprising 22 scientific papers and 14 anatomical textbooks, were included. Results of this literature review show that most of the included studies exhibited methodological limitations, and focused on different parameters of the VL muscle. Hence, reproducibility of these studies and comparison of results was difficult. This review also demonstrates a dearth of information on the muscle architecture, compartmentalization, nerve supply and fusion of VL, and that there has been no investigation of the muscle as a whole unit. Further research is required of the architecture and innervation of the VL muscle to better understand its function.

Hamstring Muscles: Architecture and Innervation

Knowledge of the anatomical organization of the hamstring muscles is necessary to understand their functions, and to assist in the development of accurate clinical and biomechanical models. The hamstring muscles were examined by dissection in six embalmed human lower limbs with the purpose of clarifying their gross morphology. In addition to obtaining evidence for or against anatomical partitioning (as based on muscle architecture and pattern of innervation), data pertaining to architectural parameters such as fascicular length, volume, physiological cross-sectional area, and tendon length were collected. For each muscle, relatively consistent patterns of innervation were identified between specimens, and each was unique with respect to anatomical organization. On the basis of muscle architecture, three regions were identified within semimembranosus. However, this was not completely congruent with the pattern of innervation, as a primary nerve branch supplied only two regions, with the third region receiving a secondary branch. Semitendinosus comprised two distinct partitions arranged in series that were divided by a tendinous inscription. A singular muscle nerve or a primary nerve branch innervated each partition. In the biceps femoris long head the two regions were supplied via a primary nerve branch which divided into two primary branches or split into a series of branches. Being the only muscle to cross a single joint, biceps femoris short head consisted of two distinct regions demarcated by fiber direction, with each innervated by a separate muscle nerve. Architecturally, each muscle differed with respect to parameters such as physiological cross-sectional area, fascicular length and volume, but generally all partitions within an individual muscle were similar in fascicular length. The long proximal and distal tendons of these muscles extended into the muscle bellies thereby forming elongated musculotendinous junctions.

Anatomic survey of the common fibular nerve and its branching pattern with regard to the intermuscular septa of the leg

Compression syndromes of the common fibular nerve and its branches frequently occur primarily as well as secondarily to trauma and surgery. A keen knowledge of the course and the relationship of the deep fibular nerve to adjacent anatomical structures in the proximal leg is mandatory. Previous literature often lacks detailed information on the course of the deep fibular nerve and is based on a limited number of observations. The aim of this study was to investigate the common fibular nerve and its branching pattern with special regard to the relationship between the deep fibular nerve and the anterior intermuscular septum of the leg. Variations in the course of the fibular nerve were demonstrated. The fibular compartments of the leg (n = 111) were dissected in 57 embalmed cadavers and included: 1) investigation of the number of muscular branches; 2) entering passages to the respective compartments of the leg; and 3) the relationship between the fibularis longus muscle and the deep fibular nerve. The most proximal muscular branch of the deep fibular nerve directly "pierced" the anterior intermuscular septum of the leg. Narrow passages within the fibular compartment and, in consequence, areas of possible higher incidence of nerve compression were suggested at the level of the intermuscular septa of the leg, between the two distinct portions of the fibularis longus muscle and the crossing of the supplying vessels. There were hardly ever statistically significant differences between the two sides or male and female gender. According to our results, the anterior intermuscular septum of the leg may be regarded as an important landmark for the surgeon when dissecting the muscular branches of the deep fibular nerve. The variable branching pattern of the deep fibular nerve within the fibular compartment of the leg should be taken into account.