An unusual occurrence of a four-headed psoas major: a case report

BACKGROUND

While many structures within the human body demonstrate anatomical variations, this is not typically the case for the iliopsoas muscle complex. However, the present paper describes a case of an anomalous psoas major composed of four different muscular heads in a 78-year-old male cadaver.

MATERIALS AND METHODS

During a routine dissection of the right posterior abdominal wall, an unusual psoas major was observed, measured and photographed.

RESULTS

The psoas major was found to possess four muscular heads, otherwise the anatomy of the wall was normal.

CONCLUSIONS

The presence of so many heads could interfere with the functions of the psoas major muscle. Therefore this anatomical variation merits further study.

Never undescribed four - headed plantaris muscle

The plantaris is a small muscle of the superficial posterior compartment of the leg. It originates at the lateral supracondylar line of the femur and the knee joint capsule, from where it continues distally, forming a long and slender tendon distally attached to the calcaneal tuberosity. During standard anatomical dissection four-headed plantaris muscle was found and all of its heads connected to each other as a single muscle belly passing into tendinous structure which was distally attached as a standard plantaris muscle. The first head originated from the popliteal surface of the femur. The second one was originated from distal Kaplan fiber. In turn, the third and fourth heads were proximally attached to the lateral femoral epicondyle. Knowledge about morphological variations is necessary because of its potential clinical significance, which means not only neurovascular compressions, but also surgical procedures.

Immunohistochemical Analysis of the Ligamentum Mucosum is the Key to Understand its Clinical Usefulness

Ligamentum Mucosum(LM) is a ligamentous structure within the synovial layer of the knee joint capsule. For a long time LM was perceived as the vestigial remnant from the embryological development of the knee. Being treated as an irrelevant structure LM was often the first victim of shaver during arthroscopy. However, last years have shown increased interest in this structure due to its potentially significant clinical role. Our aim was to classify LM based on its morphological characteristics and examine its microanatomy using immunohistochemical analysis to reveal the potential clinical value for surgeons. We have examined sixteen fresh frozen lower limbs, 6 females (mean age 83.1 ± 3.4 years) and 10 males (mean age 84.2 ± 6.8 years). Classical histological H+E stain was routinely conducted. Subsequently, CD31 antibody (DAKO, Monoclonal Mouse Anti-Human, Clone JC70A) was used to mark vascular epithelium. Monoclonal Mouse Anti-Human Neurofilament Protein (NFP) antibody (DAKO, Clone 2F11) was used to expose the nerves. Moreover, we have conducted arthroscopic visualizing and suturing LM to the torn ACL during routinely performed arthroscopic suturing of the ACL. The dissection process has revealed that LM was present only in 75% of cases. Histological examination confirmed the presence of longitudinal collagen fiber bundles in all samples. Tiny nerves were confirmed by NFP, along the subsynovial layer in all samples. CD-31 immunostain revealed the presence of many vascular vessels along the entire ligament, especially well developed at its distal end. Our study has revealed that LM contains rich vascular network. Thus, it may be a donor for the revascularization process after ACL tear or reconstruction which may improve the recovery. Another great advantage of the LM is the presence of nerves along the subsynovial layer, hopefully they may serve as the source of reinnervation and hence better clinical outcome. Based on our results we believe that seemingly irrelevant LM may be very useful during surgical procedures in the knee region. Suturing LM to the ACL may not only prevent the infrapatellar fat pad from subluxation but also improve the blood flow and reinnervation of the injured ACL. Until now there are only a few studies examining microanatomy of the LM. This basic knowledge may serve as the foundation for surgical procedures. Hopefully our findings may be useful for surgeons while planning surgical procedures or clinicians while diagnosing patients who suffer anterior knee pain.

An assessment of the variation of the intramuscular innervation of the gracilis muscle, with the aim of determining its neuromuscular compartments

Some muscles present neuromuscular compartments, one of which is the gracilis muscle. The aim of the present study is to determine the number of compartments present within the gracilis muscle based on its intramuscular innervation patterns; such knowledge could be of value in free functional muscle transfer. The study comprised 72 gracilis muscles (38 women, 34 men), fixed in 10% formalin solution. The muscles were removed and then stained using Sihler's method. When sufficient transparency was achieved, some measurements were made. Three different types of intramuscular innervation were distinguished. Type I (70.8%) was featured by at least one direct proximal nerve branch. Type II (23.6%) presented at least one indirect proximal nerve branch. Type III (5.6%) did not possess any proximal nerve branch. The median of descended nerve branches was five. Considerable anatomical variation is possible within the intramuscular innervation of the gracilis muscle. The muscle presents neuromuscular compartments, but the exact number depends on the type of its intramuscular innervation and the number of the main descendent nerve branches. All three types seem to be appropriate for free functional muscle transfer. Our findings may be of great value for surgeons carrying out complex reconstructions with the use of the gracilis muscle.

The ligamentum mucosum: A new classification

The ligamentum mucosum (LM) is a ligamentous structure within the synovial layer of the knee joint capsule. For a long time LM was perceived as the vestigial remnant from the embryological development of the knee. However, last years have shown increased interest in this structure due to its potentially significant clinical role. Fifty-one, 12 females (mean age 83.1 ± 3.4 years) and 39 males (mean age 84.2 ± 6.8 years) fixed in 10% formalin were examined. Upon dissection, the following morphological features of the LM were assessed: the types of LM, morphometric measurement and histological analysis of each type. The LM was present in 66.7% of all examined specimens. Three different types were recognized: Type I (55.9%)-single band with attachment to the intercondylar notch, Type IIa-bifurcated ligament with attachment to the anterior cruciate ligament, Type IIb-bifurcated ligament with both attachments to the intercondylar notch, Type III-double ligament with two independent bands and attachments to the intercondylar notch and to the knee joint capsule. The LM is variable and probably evolutionary changes are the reason. In our study we propose the new clinically useful classification supported by its anatomical and histological characteristics. Type IIa seems to be the most important from the clinical point of view, as it may be responsible for clinical issues and should be paid attention while diagnosing patients suffering from anterior cruciate ligament torn or anterior knee pain.

Localization of the gracilis muscle motor points - key considerations for botulinum neurotoxin injection and electrical stimulation

INTRODUCTION

Muscle motor points are considered the best sites for electrode positioning in electrical stimulation and, by some researchers, for botulinum neurotoxin injections. The aim of this study is to locate the motor points in the gracilis muscle to improve muscle function maintenance and treatment of spasticity.

MATERIAL AND METHODS

Ninety-three gracilis muscles (49 right, 44 left), fixed in 10% formalin solution, were subjected to the research. All nerve branches running towards the muscle were precisely traced to each motor point. Specific measurements were collected.

RESULTS

The gracilis muscle presents multiple motor points (median of 12), all of which were localized on the deep (lateral) side of the muscle belly. Generally, motor points of this muscle were spread between 15% and 40% of the reference line length.

CONCLUSION

Our findings may help clinicians identify appropriate locations for electrode placement during electrical stimulation of the gracilis muscle; they also deepen our understanding of the correlation between motor points and motor end plates and improve the application of botulinum neurotoxin injections.

Classification of the popliteofibular ligament

PURPOSE

The purpose of this study was to characterize the morphological variations in the distal attachment of the popliteofibular ligament (PFL) and create an accurate classification for use in planning surgical procedures in this area and in evaluating radiological imaging.

METHODS

One hundred and thirty-seven lower limbs of body donors fixed in 10% formalin solution were examined for the presence and course of the popliteofibular ligament.

RESULTS

The PFL was present in 88.3% of cases. We propose the following three-fold classification: type I (72.3%), the most common type, characterized by the attachment onto the apex of the head of the fibula, type II (8.7%), characterized by a bifurcation, with the dominant band inserting on the anterior slope of the styloid process of the fibula and the smaller band onto the posterior surface of the styloid process of the fibula and type III (7.3%), characterized by a double PFL: the first PFL (main) originated from the popliteus tendon and inserted onto the anterior slope of the styloid process of the fibula, while the second originated from the musculotendinous junction of the popliteus muscle and inserted on the posterior surface of the styloid process of the fibula.

CONCLUSION

The PFL was characterized by high morphological variation, as reflected in our proposed classification. This variation may present clinical and biomechanical issues for both medical personnel and researchers. Our proposed classification may be valuable for clinicians who evaluate and perform surgical procedures within the knee joint area.

Impact of plantaris ligamentous tendon

There are countless morphological variations among the muscles, tendons, ligaments, arteries, veins and nerves of the human body, many of which remain undescribed. Anatomical structures are also subject to evolution, many disappearing and others continually emerging. The main goal of this pilot study was to describe a previously undetected anatomical structure, the plantaris ligamentous tendon, and to determine its frequency and histology. Twenty-two lower limbs from 11 adult cadavers (11 left, and 11 right) fixed in 10% formalin were examined. The mean age of the cadavers at death was 60.1 years (range 38–85). The group comprised six women and five men from a Central European population. All anatomical dissections of the leg and foot area accorded with the pre-established protocol. Among the 22 lower limbs, the PLT was present in 16 (72.7%) and absent in six (27.3%). It originated as a strong fan-shaped ligamentous tendon from the superior part of the plantaris muscle, the posterior surface of the femur and the lateral aspect of the knee joint capsule. It inserted to the ilio-tibial band. Histologically, a tendon and ligament were observed extending parallel to each other. A new anatomical structure has been found, for which the name plantaris ligamentous tendon is proposed. It occurs around the popliteal region between the plantaris muscle, the posterior surface of the femur, and the ilio-tibial band.

The plantaris muscle - Anatomical curiosity or a structure with important clinical value? - A comprehensive review of the current literature

PURPOSE

Although the plantaris muscle is vestigial in humans, it is far too important to remain omitted. The aim of this study is to provide a comprehensive review of the existing literature focused on plantaris muscle clinical value, grafting usefulness and its morphological variations. Hopefully this study will be of great use for every medical practitioner due to its clarity and conciseness despite such broaden scope of this article.

MATERIAL AND METHODS

The article is written based on 100 studies published since 1868 until 2020. During careful selection process 12 papers were dismissed due to their insufficient sample size, wrong methods used or results that were previously discovered.

RESULTS

Many aspects concerning the plantaris muscle are already well examined, summarized and described. However this study has shown how much we still do not know and which fields require further investigations.

CONCLUSION

The anatomical variations of plantaris muscle morphology may cause mid-portion Achilles tendinopathy, tennis leg syndrome or increase the risk of failure while harvesting the tendons.

"Popliteofascial muscle" or rare variant of the tensor fasciae suralis?

Anatomical variations are routinely encountered during dissections of muscles and in clinical practice, so anatomists and clinicians need to be aware of them. One such muscle is the tensor fascia suralis, a very rare muscle located in the popliteal fossa. It can originate from any of the hamstring muscles and it inserts into the fascia of the leg. This report presents a case of a variant muscle located very deep to the biceps femoris; it originated from the posterior surface of the femur and inserted into the fascia of the leg. It is unclear whether this is a rare variant of the tensor fascia suralis or a completely new muscle.

Case report of a bifurcated fibular (lateral) collateral ligament: which band is the dominant one?

BACKGROUND

The fibular collateral ligament is a permanent and extracapsular ligament of the knee joint. It is located on the lateral aspect of the knee and extends from the lateral epicondyle of the femur to the lateral surface of the head of the fibula. As one of the main knee joint ligaments it is a stabilizer of the posterolateral corner of the knee and resists varus stress. The case report displays the bifurcated variant of the fibular collateral ligament. The aim of this study is to determine which of those bands should be considered dominant.

MATERIALS AND METHODS

Classical anatomical dissection was performed on the left knee joint. The fibular collateral ligament was thoroughly cleansed around its origin, distal attachments, and course. Appropriate morphometric measurements were collected.

RESULTS

A bifurcated variant of the fibular collateral ligament with inverted proportions of its two bands (main and accessory one) constitutes our findings. It originated on the lateral epicondyle of the femur. Then it divided into two bands (A1 and A2). Band A1 inserted to the head of the fibula. A bony attachment of band A2 was located on the lateral aspect of the lateral condyle of the tibia.

CONCLUSIONS

Although the fibular collateral ligament is a permanent structure it presents morphological variations. It is important to constantly extend morphological knowledge for all scientists concerned in anatomy.

Possible effect of morphological variations of plantaris muscle tendon on harvesting at reconstruction surgery-case report

Purpose

Seemingly a well-known, weak, and vestigial plantaris muscle should not be a revelation. However, recent studies have shown that this structure is incredibly underestimated and perceived only as an infirm flexor of the talocrural joint, the knee joint or a great source of graft tissue. Usually, the origin of this inconspicuous muscle begins at the lateral supracondylar line of the femur and the knee joint capsule. It continues distally, forming a long and slender tendon. In most cases, it inserts onto the calcaneal tuberosity on the medial side of the Achilles tendon. However, many morphological variations have been discovered during anatomical dissections and surgical procedures. Nevertheless, according to the present literature, no other studies presented such a complex insertion variant, with indisputable clinical value and significant proof of development of this forgotten muscle.

Methods

The dissection of the right thigh, knee, crural and talocrural region was performed using standard techniques according to a strictly specified protocol.

Results

Four different insertion points were observed. The first band (A) inserted near to the tarsal canal flexor retinaculum. The second band (B) bifurcates into two branches—B1 and B2. B1 is located on the medial side and B2 is located on the lateral side of the calcaneal tuberosity. The third band (C) is inserted into the superior nonarticular calcaneal surface of the calcaneus anteriorly to the Achilles tendon.

Conclusion

A differently shaped plantaris tendon could be considered a cause of harvesting procedure failure. In the light of new case reports perhaps what we are now witnessing is remodeling and transformation of the Plantaris muscle. If so, the awareness of the influence on the onset of Achilles midportion tendinopathy or a potential role in tibialis posterior conflict can be crucial for every clinician.

A highly complex variant of the plantaris tendon insertion and its potential clinical relevance

The body is home to a number of unique and intriguing anatomical structures, plenty of which concern the muscles and their tendons. Of these, the plantaris muscle is reported to present a particularly high range of morphological variations. The muscle, passing distally throughout the length of the lower leg, consists of a small muscle belly and a long, thin tendon. It originates, traditionally, on the popliteal surface of the femur and the knee joint capsule, and then inserts to the calcaneal tuberosity. It has been suggested that mid-portion Achilles tendinopathy may be caused by certain plantaris tendon morphologies. This case report describes a new anomalous plantaris tendon insertion, closely related to the Achilles tendon. It comprise four distinct insertions and one direct merge with the calcaneal tendon. The current classification should be extended to accommodate such ‘rare cases’ to facilitate more successful Achilles tendinopathy treatment.

Proposal for a new classification of plantaris muscle origin and its potential effect on the knee joint

PURPOSE

The plantaris muscle (PM) is typically characterized by a short, slim and spindle-shaped muscle belly and long, thin tendon. It is situated posterior to the popliteal muscle, and anterior to the lateral head of the gastrocnemius muscle (GM). Little information exists regarding the high variability of origin of the PM. The main aim of the study was hence to characterize the morphology of the PM and its place of origin, classify it and evaluate its prevalence.

METHODS

Classical anatomical dissection was performed on 142 lower limbs (77 left, and 65 right) fixed in 10% formalin solution. The morphology of the origin of the PM and its prevalence was evaluated.

RESULTS

The PM was present in 128 lower limbs (90.1%). Six types of origin were observed, the most common being Type I (48.4%). This type was divided into two subtypes (A-B): subtype A attaching to the lateral head of the GM, lateral femoral condyle and to the capsule of the knee joint, and subtype B, attaching to the lateral head of the GM, the lateral femoral condyle, knee joint capsule and the popliteal surface of the femur. The second most common type was Type II (25%), attaching to the capsule of the knee joint and, indirectly, to the lateral head of the GM through the lateral femoral condyle. The third most common type was Type III (10.15%), attaching to the lateral femoral condyle and the knee joint capsule. Type IV (6.25%), the rarest type, attached to the lateral femoral condyle, knee joint capsule and to the iliotibial band. Type V (8.6%) originated only from the lateral condyle of the femur. Type VI (1.6%) contains only "rare cases".

CONCLUSION

The PM presents high morphological variability, and its status as a residual muscle should be reconsidered. Our presented classification of its types of origin is a valuable addition for both clinicians and anatomists. Level of Evidence - II Basic Science Research.

Intramuscular innervation of plantaris muscle evaluated using a modified Sihler's staining protocol - Proposal for a new classification

PURPOSE

The plantaris muscle is a morphologically variable structure with regard to both its origin and insertion, and the course of the tendon. We here determined the pattern of branching and distribution of intramuscular nerves of the plantaris muscle to determine its usability for autologous transplantation. No information exists on the innervation of the plantaris muscle using Sihler's staining technique, and hence its intramuscular nerves. The main purpose of the work is to determine the pattern of branching and distribution of the intramuscular nerves of the plantaris muscle. Is the plantaris muscle a good transplant candidate?

MATERIALS AND METHODS

Eighty lower limbs from cadavers (40 left, 40 right, 40 male, 40 female, age range 41-94 years) were fixed in 10% formalin solution and examined macroscopically as well as morphometrically with regard to the innervation pattern of the respective plantaris muscle. Afterwards Sihler's staining was used in all 80 plantaris muscles to identify the exact distribution of the muscular branch originating from the main nerve trunk in the muscle belly.

RESULTS

Two patterns of branching and nerve distribution could be intensified in the plantaris muscle: Type I, with a single pattern entire up to the muscle and then divided into superior and inferior intramuscular branches.; type II with a double innervation pattern (superior and inferior). The superior and inferior pattern were not connected to each other.

CONCLUSION

The plantaris muscle reveals variability with two different innervation patterns. Type II is ideally suited for autologous transplantation. New classifications of innervation are desirable for individual muscles rather than a generalized approach.

A proposal for a new classification of the fibular (lateral) collateral ligament based on morphological variations

BACKGROUND

The fibular collateral ligament (FCL) is subject to varus forces at all knee flexion angles and is also resistant to external rotation near extension. It originates on the lateral epicondyle of the femur and inserts on the lateral surface of the head of the fibula. However, its anatomical characteristics are inconsistent. Recent publications have focused on morphological variations concerning mainly femoral and fibular attachments, as well as morphometric measurements. Less attention has been paid to the morphology of the FCL and its relationship to the antero-lateral ligament (ALL).

QUESTION/PURPOSES

The aim of this paper is therefore to introduce the first complete classification of the FCL that includes all important aspects of morphological variability.

METHODS

Classical anatomical dissection was performed on 111 lower limbs (25 isolated and 86 paired) fixed in 10% formalin solution. The lateral compartment of the knee was investigated in detail.

RESULTS

The fibular collateral ligament was present in all specimens. The FCL originated most commonly (72.1% of cases) from the lateral femoral epicondyle, and the inserted on the lateral surface of the head of the fibula (Type I). In addition, bifurcated (Type IIa - 12.6%) and trifurcated (Type IIb - 0.9%) ligaments were also found with two and three distal bands, respectively. A double FCL was also found (Type III - 6.3%), as was fusion of the FCL and ALL (Type IV - 8.1%).

CONCLUSION

The FCL is characterized by high morphological variability. Knowledge of these variants is essential for surgeries performed in this region concerning the FCL and the ALL.

CLINICAL RELEVANCE

Distinguishing FCL from the FCL-ALL Complex is necessary when planning surgical procedures.

The Anterolateral Ligament of the Knee: A Proposed Classification System

The anterolateral ligament (ALL) is a potential stabilizer of the knee and cooperates with the anterior cruciate ligament (ACL). It originates on the lateral epicondyle of the femur, to which it is mainly posterior and proximal; insertion is posterior to Gerdy's tubercle. Its anatomical characteristics vary. Recent publications have focused on morphological variations concerning mainly the femoral and tibial attachments, and on morphometric measurements. Histological and cystochemical examinations have also been performed. Classical anatomical dissection was performed on 111 lower limbs (25 isolated and 86 paired) fixed in 10% formalin. The knee region was dissected using traditional techniques and the morphological features of the ALL were assessed: morphometric measurements and the types of ALL. The ALL was present in 70 individuals (37 woman and 33 men). In 30 cases, it was absent symmetrically, and in 11, it was present on just one side (P = 0.0011). The ALL was morphologically very variable. In type I (the most common form - 64.3%), a single band traveled parallel to the fibular collateral ligament (FCL); in type II the band crossed it. In type III, the origin was located on the lateral epicondyle of the femur and also on the lateral-posterior surface of the joint capsule, and the insertion was in the deep fascia of the leg: this type could be called a capsule. Type IV was characterized by a double ALL, type IIb by ligaments that bifurcated, and type V by the ALL starting directly from the FCL rather than the femoral epicondyle. The ALL is characterized by high morphological variability, both in its femoral and in its tibial attachments and in its course. Clin. Anat. 31:966-973, 2018. © 2018 Wiley Periodicals, Inc.