Additional head of the rectus femoris muscle: a case report.

PURPOSE: The aim of the present case is to describe an interesting variation of the additional head of the rectus femoris. METHODS: A male body donor, 81 years old at death, was subjected to routine anatomical dissection for research and teaching purposes at the Department of Anatomical Dissection and Donation, Medical University of Lodz, Poland. RESULTS: We have found an example of an accessory head of the quadriceps femoris, a double-headed rectus femoris in which the proximal attachment is connected to the rectus femoris muscle originating from the anterior inferior iliac spine. The muscle belly of this additional structure is separate but fused distally with the vastus lateralis muscle. It then passes into the patellar ligament inserted into the tibial tuberosity. CONCLUSIONS: Knowledge of the possible occurrence of an additional head is nevertheless important for clinicians, especially for orthopedists performing reconstructive surgeries. It could also be significant for physiotherapists arranging rehabilitation plans after such surgeries because it could potentially help to achieve faster recovery.

Anatomical variation of co-existing bilaminar tensor of the vastus intermedius muscle and new type of sixth head of the quadriceps femoris.

BACKGROUND: We present a case report of quadriceps femoris (QF) with co-existing bilaminar tensor of the vastus intermedius (TVI) muscle and new type of sixth head. MATERIALS AND METHODS: Cadaveric dissection of left thigh of a 72-year-old man was performed for research and teaching purposes at the Department of Anatomical Dissection and Donation, Medical University of Lodz. The left lower limb was dissected using standard techniques according to a strictly specified protocol. Each head of the muscle was photographed and subjected to further measurement. RESULTS: During dissection, an unusual type of TVI muscle was observed. It consisted of two surfaces, superficial and deep. In addition, sixth head of QF muscle grew out from the vastus medialis muscle. CONCLUSIONS: The knowledge of the existence and possible variations of additional heads of QF muscle is necessary during diagnostic process of muscle strains. Moreover, according to course of tendons that heads may take part in patella stabilisation.

The development of the tensor vastus intermedius during the human embryonic period and its clinical implications.

The tensor vastus intermedius (TVI) is a newly discovered muscle located in the anterolateral thigh area and is considered the fifth component of the quadriceps femoris muscle. There have been several papers describing its anatomical and morphological features in detail; however, many features of this muscle, such as its ontology or kinetic functions, remain unknown. The purpose of this study was to determine the initial appearance of the TVI muscle in human embryonic development and to investigate its growth and development. Histological observations were performed on 30 lower limbs of 15 human embryos from Carnegie stage (CS) 21, 22, and 23 (with crown-rump length ranging from 18.7 to 28.7 mm). Myocyte clusters of the TVI were observed between the vastus lateralis and intermedius muscles in 7 out of 10 limbs in CS 22, indicating that the TVI arises during this stage. In CS 23, the TVI was clearly present in all specimens except one. However, neither the aponeurosis nor the tendonous structure of the TVI were observed in these embryonic stages. Formation of the conventional four components of the quadriceps muscle is completed within CS 21; therefore, our results suggest that the TVI is the last element to develop in the quadriceps femoris complex. It is posited that after the embryonic period, the TVI continues to grow, while forming the tendinous structure toward the patella and receiving vascular supply from certain vascular branches. The clinical significance of these findings is that orthopedists and plastic surgeons who perform surgical procedures within the anterolateral thigh (ALT) area should be aware of the anatomy and development of the TVI in order to reduce surgical complications. Our present research aims to contribute to a deeper understanding of the morphogenesis of the TVI and the other femoral extensor muscles.

Tensor vastus intermedius: a review of its discovery, morphology and clinical importance.

BACKGROUND: This review aims to summarise the relevant literature surrounding the tensor vastus intermedius, a newly discovered muscle, and to discuss its morphology and potential clinical importance. No such review currently exists in the literature. MATERIALS AND METHODS: A comprehensive literature search regarding the tensor vastus intermedius was performed using PubMed and Google Scholar in July 2020. Principles of Evidence-Based Anatomy and the Anatomical Quality Assessment Tool were employed to ensure a high-level review. All relevant papers were included and citation tracking was performed to uncover further publications. RESULTS: The tensor vastus intermedius is found in the anterior compartment of the thigh and has a similar morphology to the other vasti muscles. It has four main variations and a consistent neurovascular supply. The muscle has been implicated in a number of case reports and surgical procedures, which are described in detail in this paper. CONCLUSIONS: In the 4 years since the tensor vastus intermedius was formally described, a significant amount of work has been done to help us understand its structure and function. Further efforts are needed to gain a full picture as to its clinical importance. As such, it is recommended that this muscle should be acknowledged in anatomical education.

Unusual case report of seven-headed quadriceps femoris muscle.

PURPOSE: We present a case of a seven-headed quadriceps femoris (QF) muscle and a systematic review of the literature concerning this anatomical variation. METHODS: During a routine dissection of the lower limbs of a 72-year old cadaver, a QF with supernumerary heads was identified. Each head of the muscle was photographed and subjected to further measurement. RESULTS: In addition to the four traditional heads of the QF muscle, we found a tensor of the vastus intermedius (TVI) muscle and two additional muscle bellies composed of tendons. Attachments of the TVI tendon and additional tendons were localized on the superior medial border of the patella. CONCLUSION: It is important to be aware of morphological variability of the quadriceps femoris muscle. The described case assists clinicist with avoiding misdiagnoses around the knee.

Triceps, quadriceps or pentaceps femoris? Need for proper muscle definition.

INTRODUCTION: Over the last years, the definition of quadriceps femoris (QF) has evolved somewhat and some authors now define a fifth head: the tensor of vastus intermedius (TVI). Descriptions of the different components of QF in textbooks and recent findings remain confusing. Therefore, the aim of this study is to obtain more information on this possible fifth head. MATERIALS AND METHODS: Twenty lower limbs of 10 embalmed cadavers, six females and four males, were investigated by macro-dissection. The dissection and separation of the different heads were performed with the fingers and a distinction between the different parts of the quadriceps was noted only if it was possible to separate the heads without scalpel to avoid artificial separation of muscle parts. RESULTS: In 9 lower limbs we found a QF as classically described in textbook. TVI was found in only 7 limbs and in 4 cases we were not able to differentiate VI and VM or VI and VL (triceps femoris as described by Testut). These results, and the diversity of descriptions found in the literature have led us to review the definition of an isolated muscle. CONCLUSION: In this study, the presence of TVI was not demonstrated in all limbs unlike previously published studies on the subject. Harmonisation of dissection techniques, but also a clear definition of a muscle is required in order to be able to compare studies and draw clear conclusions.

Magnetic resonance imaging of the tensor vastus intermedius: A topographic study based on anatomical dissections.

The tensor of the vastus intermedius (TVI) is a newly described component of the extensor apparatus of the knee joint. The objective of this study was to evaluate the appearance of the TVI on magnetic resonance (MR) imaging and its association with the adjacent vastus lateralis (VL) and vastus intermedius (VI) muscles and to compare these findings with the corresponding anatomy. MR images were analyzed from a cadaveric thigh where the TVI, as part of the extensor apparatus of the knee joint, had been dissected. The course of the TVI in relation to the adjacent VL and VI was studied. The anatomic dissection and MR imaging revealed a multilayered organization of the lateral extensor apparatus of the knee joint. The TVI is an intervening muscle between the VL and VI that combined into a broad flat aponeurosis in the midthigh and merged into the quadriceps tendon. Dorsally, the muscle fibers of the TVI joined those of the VL and VI and blended into the attachment at the lateral lip of the linea aspera. In this area, distinguishing between these three muscles was not possible macroscopically or virtually by MR imaging. In the dorsal aspect, the onion-like muscle layers of the VL, TVI, and VI fuse to a hardly separable muscle mass indicating that these muscles work in conjunction to produce knee extension torque when knee joint action is performed. Clin. Anat. 30:1096-1102, 2017. © 2017 Wiley Periodicals, Inc.

New insight in the architecture of the quadriceps tendon.

BACKGROUND: Published data regarding the structure of the quadriceps tendon are diverse. Dissection of the quadriceps muscle group revealed that beside the rectus femoris, vastus lateralis, vastus intermedius and vastus medialis a fifth muscle component- named the tensor vastus intermedius consistently fused into quadriceps tendon. It can be hypothesized that all these elements of the extensor apparatus of the knee joint must also be represented in the quadriceps tendon. This study investigated the multi-layered quadriceps tendon with special emphasis on all components of the quadriceps muscle group including the newly discovered tensor vastus intermedius. METHODS: Ten cadaveric lower limbs were dissected. All muscle bellies of the extensor apparatus of the knee joint were identified and traced distally until they merged into the quadriceps tendon. Connections between the different aponeurotic layers of each muscle were studied from origin to insertion. The fusing points of each layer were marked. Their distance to the patella and the distances between the fusing points were measured. RESULTS: Six elements of the quadriceps muscle group form a tri-laminar structure of the quadriceps tendon. The intermediate layer could be further sub-divided. The elements of the quadriceps tendon are 1. lateral aponeurosis of the vastus intermedius, 2. deep and 3. superficial medial aponeurosis of the vastus intermedius, 4. vastus lateralis, 5. tensor vastus intermedius and 6. rectus femoris. Even with differences in fiber direction - these elements join each other a certain distance proximal to the patella. All elements were fused over a region measuring 13 to 90 mm proximal to the patella. Lateral parts of the vastus intermedius formed the deepest layer of the quadriceps tendon. The superficial and deep layer of the medial vastus intermedius aponeurosis fused 56 mm (range, 30 to 90 mm) and 33 mm (range, 13 to 53 mm) above the patella with the aponeurosis of the tensor vastus intermedius and vastus lateralis respectively. Together they built the two-layered intermediate layer of the quadriceps tendon. The tendon of the rectus femoris forms the superficial layer. The vastus medialis inserts medially in all layers of the quadriceps tendon. Fibers of the lateral muscle components were oriented towards the medial, and fibers of the medial muscle components were oriented towards the lateral femoral condyle. CONCLUSIONS: The three-layered quadriceps tendon is formed by six elements. These are 1. lateral aponeurosis of the vastus intermedius, 2. deep and 3. superficial medial aponeurosis of the vastus intermedius, 4. vastus lateralis, 5. tensor vastus intermedius and 6. rectus femoris. These elements of the extensor apparatus join each other proximal to the patella in a complex onion-like architecture. Its two-layered intermediate layer shows variable fusions points. The vastus medialis contributes to the quadriceps tendon with its medial insertion into all layers of the quadriceps tendon.

A newly discovered muscle: The tensor of the vastus intermedius.

The quadriceps femoris is traditionally described as a muscle group composed of the rectus femoris and the three vasti. However, clinical experience and investigations of anatomical specimens are not consistent with the textbook description. We have found a second tensor-like muscle between the vastus lateralis (VL) and the vastus intermedius (VI), hereafter named the tensor VI (TVI). The aim of this study was to clarify whether this intervening muscle was a variation of the VL or the VI, or a separate head of the extensor apparatus. Twenty-six cadaveric lower limbs were investigated. The architecture of the quadriceps femoris was examined with special attention to innervation and vascularization patterns. All muscle components were traced from origin to insertion and their affiliations were determined. A TVI was found in all dissections. It was supplied by independent muscular and vascular branches of the femoral nerve and lateral circumflex femoral artery. Further distally, the TVI combined with an aponeurosis merging separately into the quadriceps tendon and inserting on the medial aspect of the patella. Four morphological types of TVI were distinguished: Independent-type (11/26), VI-type (6/26), VL-type (5/26), and Common-type (4/26). This study demonstrated that the quadriceps femoris is architecturally different from previous descriptions: there is an additional muscle belly between the VI and VL, which cannot be clearly assigned to the former or the latter. Distal exposure shows that this muscle belly becomes its own aponeurosis, which continues distally as part of the quadriceps tendon.