The accessory brachioradialis muscle: prevalence of a rare variant with possible clinical implications.

PURPOSE: The brachioradialis muscle (BRM) belongs to the lateral group of forearm muscles and contributes to the elbow flexion. Accessory brachioradialis muscle (ABRM) or "brachioradialis accessorius" represents an uncommon BRM variant, not been enough studied. The present study investigates the prevalence of the ABRM, along with its origin, insertion, and innervation. MATERIALS: Eighty-three upper limbs were meticulously dissected at the arm, forearm, and cubital fossa to investigate the ABRM presence. When the variant muscle was identified, morphometric measurements were obtained. RESULTS: The ABRM was identified in two upper limbs (2/83, 2.4%), in a male cadaver, bilaterally. Its origin was located along with the typical BRM, and its insertion was identified into the anterior surface of the radius (proximal third). The ABRM was innervated by the radial nerve, coursing posteriorly (deeply). CONCLUSIONS: In the current study, the variant muscle was observed in 2.4%. Radial nerve compression, at the forearm, is not an uncommon entrapment neuropathy. The relationship between the radial nerve and the ABRM could precipitate radial neuropathy.

A Literature Review of the Morphological Variability in the Intrinsic Muscles of the Foot: Traps Awaiting Clinicians during Ultrasound.

Purpose: Like other muscular compartments of the human body, the intrinsic muscles of the foot present considerable morphological variability. The aim of this review was to present variations that can potentially cause problems during surgery but might be detected during an ultrasound examination. Materials and methods: PubMed was searched for relevant articles. The identified papers were listed, and citation tracking was performed. Results: Even though lower limb structure is well studied, the variations associated with the intrinsic muscles of the foot and their related ultrasound examination are not. Conclusions: The muscles and tendons of the foot demonstrate similar degrees of variance as other regions of the human body; however, this subject is not as widely covered in the literature. Further ultrasound studies are needed to build awareness of morphological variability in this region, as the findings could prevent misdiagnosis.

The brachioradialis longus: an unreported accessory form of the brachioradialis muscle.

The brachioradialis muscle (BR) belongs to the lateral forearm muscle. Typically, the radial nerve innervates it. BR morphological variability, such as split muscular belly, split tendon, or accessory BR (ABR), has been described in the current literature. A 68-year-old female donated cadaver was routinely dissected for research and educational purposes. A variant muscle was identified extending at the right arm's lateral and forearm compartments. It originated from the humerus lateral surface between the deltoid and the triceps brachii lateral head, joined the second muscular head from the brachialis muscle, and inserted into the radius styloid process. According to its origin, course, and insertion, the variant muscle probably corresponded to the BR accessory form. However, in the current literature, the ABR morphology corresponds to an accessory muscle originating adjacent to the typical BR and inserted into the radial tuberosity. At the same time, it was defined as "brachioradialis brevis." In the current case, the variant muscle differed significantly from the current literature due to the origin, insertion, length, and relationship with the typical BR; therefore, the term "brachioradialis longus" seemed adequate to describe this variant muscle.

Accessory thoracic muscles in human fetuses.

BACKGROUND: Typically, the anterior thoracic wall musculature is composed of the pectoralis major and pectoralis minor. Embryologically, these two muscles are originated from a common pectoral muscle mass; therefore, disruption of the normal development and differentiation could give rise to an aberrant or accessory muscle. The main aim of this study is to demonstrate and classify the accessory muscles of the pectoralis region in human fetuses. MATERIAL AND METHODS: Fifty spontaneously aborted human fetuses (25 male and 25 female, 100 sides) aged 18-38 weeks of gestation at death, and fixed in 10% formalin solution were examined. Following parental approval, the fetuses were donated to the Medical University anatomy program. The pectoralis major and minor muscle's morphology, the possible occurrence of accessory muscles of pectoral region and its morphology, their origins, and insertions, as well as the morphometric details, were assessed. RESULTS: The pectoralis major and minor were bilaterally found in all fetuses (100 cases). The accessory muscles of pectoral region were found in 16 cases (16%), and four types were differentiated. The Pectoralis Quartus muscle was the most common type of accessory muscles found in this study and occurred in 8 cases. The axillary arch muscle was observed in 3 cases. The chondrocoracoideus muscle was observed in 3 cases. The sternalis muscle occurred in 2 cases, and one of them was bifurcated. CONCLUSIONS: The thoracic region is characterized by a large amount of morphological variations, which are observed not only in adult population, but also among human fetuses. The pectoralis quartus was the most frequent variation in this study. Accessory structures like sternalis muscle, chondrocoracoideus muscle, pectoralis quartus muscle, or axillary arch muscle may have clinical implications, and knowledge about them is very useful for clinicians, especially plastic surgeons, thoracic surgeons, and orthopedics.

The superior thyroid artery origin pattern: a systematic review with meta-analysis.

PURPOSE: The current systematic review with meta-analysis aimed to investigate the pooled prevalence of the superior thyroid artery (STA) pattern of origin (distinct or fused-common origin with adjacent arteries in the form of a common trunk). The standard and uncommon variants were also studied, considering the STA's exact surface of origin and the relationship with the upper border of the thyroid cartilage (TC, reference point), considering the laterality effect. Thus, the STA topographical anatomy was considered. METHODS: An evidence-based systematic review with meta-analysis was performed according to the PRISMA 2020 guidelines. A literature search was conducted in four online databases using specific keywords, the pooled prevalence was calculated using statistical analysis in the R programming language, and multiple subgroup analyses were performed. RESULTS: The most common distinct origin of the STA was from the external carotid artery (ECA) (56.94% pooled prevalence, 95%CI: 50.89-62.89), and the rarest one was from the internal carotid artery (ICA) (< 0.01%, 95%CI: 0.00-0.00). Common trunks were also investigated, with the thyrolingual trunk emanating from the ECA estimated at 0.61% (95%CI: 0.21-1.14), representing the most common. Subgroup analysis based on the nationality, type of study, and sample size, as well as a comparison between left and right sides and males and females, were investigated. CONCLUSIONS: The most common STA origin was estimated as the ECA, the medial surface of origin, and above the TC upper border. Adequate knowledge of STA origin is paramount for surgeons, especially during thyroidectomy, not to cause iatrogenic injury to the external branch of the superior laryngeal nerve.

Identifying iliotibial band graft length and incision site may minimise the potential risk of harming adjacent structures: A novel approach for surgeon guidance.

PURPOSE: The Iliotibial band (ITB) is a fibrous thickening of the fascia lata originating at the iliac crest and inserting at Gerdy's tubercle on the lateral tibia. The ITB significantly contributes to lateral knee stabilisation. Due to its size, tensile strength and easy access, it is widely used in orthopaedic surgery as an autograft during reconstruction procedures. Although ITB harvesting may result in complications, such as reduced knee extension or hip flexion, no safety margins or guidelines have been proposed for the procedure. Our aim was to determine the maximal safe length of an ITB graft, that is, that does not harm the lateral collateral ligament (LCL), tensor fasciae latae (TFL), gluteus maximus (GM) or adjacent structures, and reduce the complication rate. METHODS: The study included 50 lower limbs of 25 human cadavers, previously fixed in 10% formalin solution. The inclusion criterion was the lack of visible signs of surgical interventions in the study region. Forty lower limbs were included in the study: 16 female (mean age 83.1 ± 3.4 years) and 24 male (mean age 84.2 ± 6.8 years). Dissection was performed with a previously established protocol. Morphometric measurements were then obtained twice by two researchers. RESULTS: The mean femur length was 404.8 mm [female (F) = 397.3 mm, male (M) = 409.9 mm, standard deviation (SD): F = 23.8 mm, M = 24.1 mm]. The mean ITB length was 318.9 mm (F = 309.4 mm, M = 325.2 mm, SD: F = 25.7 mm, M = 33.7 mm). Longer femurs were associated with longer ITB (p < 0.05). The mean distance from the insertion of the GM to the myofascial junction of TFL and ITB was 34.6 mm (F = 34.5 mm, M = 34.6 mm, SD: F = 3.2 mm, M = 3.3 mm). The longer femurs or ITBs demonstrated a greater distance from GM insertion to the myofascial junction of the TFL and ITB (p < 0.05). CONCLUSION: ITB grafts longer than 21 cm may contribute to the greater risk of TFL rupture. Based on simple measurements of the femur length, the surgeon may assess approximate ITB length, and thus assess the length of the maximal graft length. Moreover, to avoid harming the LCL, the incision should be performed 5 cm proximal to the articular surface of the lateral femoral condyle or 13 mm proximal to the lateral femoral epicondyle. Such preparation and preoperative planning may greatly reduce the risk of complications during ITB harvesting, while performing, for instance, the over-the-top technique for anterior cruciate ligament reconstruction in skeletally immature patients. LEVEL OF THE STUDY: Basic I.

The quadratus femoris muscle anatomy: Do we know everything?

INTRODUCTION: The purpose of this study was to characterize the morphological variations in the quadratus femoris muscle (QF) and to create an anatomical classification that could be used in the planning of surgical procedures in this area, radiological imaging, and rehabilitation. MATERIALS AND METHODS: Ninety-two lower limbs from 46 cadavers, fixed in 10 % formalin solution, were examined. RESULTS: The QF muscle was present in all specimens. According to morphology, the QF muscle was classified into three types. The most common type was Type I, characterized by one muscular belly (78.3 %), while the second most common type was Type II, characterized by two bellies, was observed in 17.4 % of cases. The rarest type was Type III. It was characterized by three bellies and was found in 4.3 % of the cases. CONCLUSIONS: The current classification system on quadratus femoris morphological variability is novel. Morphological variants may contribute to clinical issues, such as the ischiofemoral impingement syndrome, that could arise from type I quadratus femoris. Hence, the current study may be applicated to planning surgical procedures, imaging, and rehabilitation.

The previously undescribed variant of the thyrohyoid muscle and its potential impact on surgical procedures.

The thyrohyoid muscle belongs to the infrahyoid group located in the carotid triangle. It normally originates from thyroid cartilage and inserts into hyoid bone. Quite often, it is continuous with the sternohyoid muscle. Furthermore, there are variants that have their origin in the cricoid cartilage only, however, this occurs very rarely. During anatomical dissection, a two-headed variant of this muscle was found. One head had its origin in the cricoid cartilage and the other in the thyroid cartilage. This variant of thyrohyoid had not been previously described in the available literature. Therefore, we believe that it may be referred to as the cricothyrohyoid muscle. As the thyrohyoideus is often used as a landmark during surgical procedures in the prelaryngeal area and as a muscle graft, a thorough knowledge of its anatomy and variation is extremely important. We speculate that the two-headed version of this muscle may be problematic during surgical procedures in this region, however, it may also provide more options as a muscular graft.

A bicaudatus sartorius muscle: a rare variant with potential clinical implications.

BACKGROUND: Sartorius muscle (SM) belongs to the thigh anterior compartment musculature. It corresponds to the longest muscle of the human body, while its variations are described rarely. The current case reports aims to describe a distal bifurcation of the SM, forming the bicaudatus SM variant. MATERIALS AND: M: ETHODS: An 84-year-old male cadaver was dissected for educational and research purposes at the Department of Anatomy, National and Kapodistrian University of Athens. RESULTS: On the left lower limb, the SM was typically originated from the anterior superior iliac spine. After 351.22 mm length, it was bifurcated into an anterior and posterior part. Both muscular parts were contributing to the pes anserinus morphology. Femoral nerve branches were providing innervation to the variant muscle, while the saphenous nerve and vein were coursed posteriorly to the variant muscle. CONCLUSIONS: SM morphological variability is described quite rarely. The current case report corresponds to the bicaudatus SM variant. Accessory parts of SM could lead to compression symptoms to the femoral nerve anterior branches, as well as to the saphenous nerve.

A previously unknown variant of the calcaneofibular ligament.

The lateral ankle joint is composed of three ligaments: the anterior talofibular ligament (ATFL), posterior talofibular ligament (PTFL) and calcaneofibular ligament (CFL). The ATFL and CFL demonstrate morphological variation, especially regarding their shape and number of bands. During standard anatomical dissection, an unusual type of triple CFL was observed: the CFL was composed of two bands originating on the lateral malleolus, and the presence of a lateral talocalcaneal ligament (LTC) originating on the talus bone. The insertion point of each band was located on the calcaneal bone. An understanding of these anatomical patterns provides a clearer view of ankle joint biomechanics, and improved the planning and performance of surgical treatment.

Anatomical and Radiological Analysis of Structures of Petrous Part of the Temporal Bone and Their Impact on Area of Anterior Petrosectomy.

BACKGROUND: Anterior petrosectomy (AP) is a commonly recognized approach for accessing tumors located in the petrous apex region. The essence of AP lies in drilling the petrous part of the temporal bone within the Kawase quadrangle. In our study, we conducted radiological and anatomical analyses of the structures within the petrous portion of the temporal bone, evaluating their impact on the surgical field during AP. METHODS: We conducted an analysis of 15 anatomical specimens and 20 3D reconstructions based on computed tomography scans of the middle ear. The analyzed structures included the impression of the trigeminal nerve, the groove of the greater petrosal nerve, the arcuate eminence, and the angle between eminentia arcuata and grove for greater petrosal nerve. RESULTS: The mean surface area measured by radiological methods does not deviate significantly from the mean surface area measured by anatomical methods 276.265mm2 (interquartile range: 217.603-309.188) versus 233.21mm2 (interquartile range: 210.923-255.453) P = 0.051. We established a threshold 195,99mm2 for radiological determination of the surface area at which another approach should be considered. Additionally, we have developed corrections for specific radiological factors to enable a better assessment of anatomical conditions. CONCLUSIONS: Our results indicate that preoperative assessment of anatomical conditions based on 3D reconstructions of computed tomography of the middle ear can be a valuable tool in preoperative planning of surgery on tumors in the petroclival region using the AP. Further studies involving a larger sample size are necessary to validate the findings of our study.

Morphological variability of lateral femoral cutaneous nerve and its potential clinical significance.

BACKGROUND: The lateral femoral cutaneous nerve is derived from the dorsal branches of the L2 and L3 spinal nerves. It travels across the pelvis and heads towards the anterior superior iliac spine. It passes under the lateral part of the inguinal ligament and then divides into two branches, which are responsible for sensory innervation of the anterolateral and lateral skin of the thigh. However, the course of this nerve can vary morphologically. Numerous differences have been observed in its exit from the pelvis and in the number of its main trunks and branches. Additionally, its angle with the inguinal ligament and its placement in relation to other structures (such as the femoral artery, femoral nerve, and the sartorius and iliacus muscles) also vary. All of these variants have potential clinical implications. Therefore, the aim of this review is to present the morphological variability of the lateral cutaneous nerve and to explore how these anatomical differences can introduce clinical concerns. MATERIALS AND METHODS: Presented review of the literature was written based on over 30 studies. Comprehensive literature search was done using PubMed in order to study the morphological variability of lateral femoral cutaneous nerve (LFCN). To be included in this review studies needed to be meet certain criteria: been published before December 2023, present information valuable to this paper (variability of lateral femoral cutaneous nerve/clinical significance). The search included how LFCN vary either among fetuses and adults in the aim of providing more complex information about the variability of this nerve. During the search key words as following were used. No particular references were excluded from the analysis. All relevant studies were included, and citation tracking was used to identify publications. RESULTS: This review presents the description of variability of LFCN and its potential clinical impact. In the review differences in adult and fetuses were considered, morphological variability were divided into 4 groups: the origin of the nerve, the way it leaves the pelvis, the branching pattern, the angle between LFCN and surrounding structures and then, clinical significance were considered basing on available literature.

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.

Possible anastomoses between the long branches of the brachial plexus and their clinical significance.

The brachial plexus consists of nerves that supply the upper limb and some nerves of the back, torso, and neck. It is formed by the ventral rami of C5 to T1 (in some cases, C4 or T2 also contribute). The anterior rami of the spinal nerves unite to the roots, trunks, divisions, cords, and terminal branches that innervate muscles and skin. An example is associated with terminal branches of the long nerves. Knowledge of this variation is necessary for enabling surgeons, orthopedists, and neurologists to avoid injury during surgical exploration in the arm or axilla region, and for achieving correct diagnoses, because such variability can evoke nonspecific responses. Awareness of this anastomosis is also mandatory for anesthetists performing anesthesia in the upper limb region. The aim of this article is to describe anastomoses between long nerves from the brachial plexus and to consider their clinical significance.

A three-headed psoas major muscle: a case report.

BACKGROUND: Multiple anatomical variations, from anomalous courses to additional structures, have been reported in muscles from different compartments of the human body. We report an extremely rare case of a psoas major muscle presenting as a three-headed structure with variable morphology. MATERIALS AND METHODS: During a routine dissection of the posterior abdominal wall of a 82-year-old male cadaver, an anomalous PM muscle with supernumerary head was identified, photographed and subjected to further measurement. RESULTS: Although the anatomy of the dissected posterior abdominal wall structures was typical, a three-headed psoas major muscle composed of superficial, intermediate and deep heads was identified. CONCLUSIONS: It is important to be aware of morphological variability of muscles, especially those considered to be constant, since an anomalous structure might interfere not only with their functions, but also lead to further clinical consequences.

The double-headed accessory iliacus muscle: a case report.

PURPOSE: Numerous accessory muscles are present in the human body, many of which are clinically significant. We present a case of an anomalous accessory iliacus composed of two heads, whose occurrence and anatomical location indicate a high probability of causing femoral nerve compression. METHODS: During a routine dissection of the posterior abdominal wall of a xx-year-old cadaver, a double headed accessory muscle was noted, measured and photographed. RESULTS: In addition to the normal anatomy of dissected structures from the posterior abdominal wall, an accessory iliacus muscle composed of superficial and deep heads was identified. In addition, the inferior roots of the divided femoral nerve located between the heads was found to follow an unusual course. CONCLUSIONS: It is important to be aware of morphological variability around structures such as double-headed accessory iliacus muscle presented in this study, due to their association with neurovascular bundles and hip joint. The reported atypical morphology is not widely known in the literature but might be of great clinical significance, therefore knowledge of such variability might be regarded in order to diagnose properly and introduce accurate treatment.

The morphological variability of the pelvic girdle muscles: a potential trap during ultrasound.

BACKGROUND: The muscles present in the pelvic girdle compartment demonstrate clinically significant anatomical variation regarding both their site of attachment and additions, such as accessory heads, muscles or tendinous slips. Many of those variations might be considered potential traps during ultrasound examination that may result in misdiagnosis. The aim of this study was to raise awareness of such possibility. MATERIALS AND METHODS: A comprehensive search for morphological variations was performed in PubMed and NIH. Relevant papers were listed and citation tracking was accomplished. RESULTS: Although several anatomical variations of pelvic girdle muscles have been presented, few studies have examined their relevance in ultrasound imaging. CONCLUSIONS: The morphological variability of the pelvic girdle muscles does not vary from such incidence in other regions of the human body; however further ultrasound studies are needed of the numerous morphological variants that can be found in this region.

The morphological variability of the piriformis muscle.

BACKGROUND: The aim of the study is to create several classifications of the piriformis muscle (PM): proximal and distal attachments, potential fusions, and the relationship with the sciatic nerve. It is the first comprehensive anatomical examination of this subject. MATERIALS AND METHODS: One hundred and twenty-four lower limbs from 62 cadavers, fixed in 10% formalin, were examined. RESULTS: The piriformis muscle was present in 120 limbs (96.8% of cases). Four types of proximal attachment were described (I-IV). The most common type was Type I, in which the proximal attachment was at the anterior surface of the sacrum, between S2 and S4 (52 lower limbs; 43.3%). The rarest type was Type IV, in which the proximal attachment was at the gluteal surface of the ilium near the margin of the greater sciatic notch and from the gluteus medius (12 cases; 10%). Three types of distal attachment were distinguished. The most common was Type 1, a single tendon. This type comprised two subtypes: A and B (105 lower limbs; 87.5%). The other two types accounted for 12.5% of the total. Fusions were noted between the piriformis muscle and adjacent muscles in 31.7%. Four patterns were observed in which the sciatic nerve ran against the piriformis muscle. The most common variation in the relationship was the common fibular nerve exiting superior to the piriformis muscle and the tibial nerve passing inferior to it (10 cases; 8.3%). CONCLUSIONS: The piriformis muscle is highly morphologically variable in both its proximal and distal attachments and its relationship with the sciatic nerve. There are four types of proximal attachment and three types of distal attachment. The piriformis muscle shows numerous fusions with its adjacent muscles: gluteus medius or minimus or superior gemellus. A new (fourth) type of relationship was demonstrated between the piriformis muscle and sciatic nerve. The piriformis muscle was absent in four cases.

Hypoglossal Nerve Neuropathies-Analysis of Causes and Anatomical Background.

The hypoglossal nerve is the last, and often neglected, cranial nerve. It is mainly responsible for motor innervation of the tongue and therefore the process of chewing and articulation. However, tumors, aneurysms, dissections, trauma, and various iatrogenic factors such as complications after surgeries, radiotherapy, or airway management can result in dysfunction. Correct differential diagnosis and suitable treatment require a thorough knowledge of the anatomical background of the region. This review presents the broad spectrum of hypoglossal neuropathies, paying particular attention to these with a compressive background. As many of these etiologies are not common and can be easily overlooked without prior preparation, it is important to have a comprehensive understanding of the special relations and characteristic traits of these medical conditions, as well as the most common concomitant disorders and morphological traits, influencing the clinical image. Due to the diverse etiology of hypoglossal neuropathies, specialists from many different medical branches might expect to encounter patients presenting such symptoms.