Bilateral absence of the deep brachial artery.

The aim of the following study was to present and comprehensively describe a case of a bilateral absence of the deep brachial artery (DBA). Furthermore, its embryology and clinical significance will also be discussed. During routine dissection, a 71-year-old male cadaver with a bilateral abnormality in the DBA and its branches was found. The first branch of the brachial artery (BA) was found to be the radial collateral artery, which passed behind the radial nerve. Furthermore, the middle collateral artery originated distal to the radial collateral artery and gave off first a singular, minor muscular branch and then the superior ulnar collateral artery. Later, the preceding nutrient arteries of the humerus and the deltoid branch consecutively branched off from the middle collateral artery. Subsequently, the middle ulnar collateral artery, the inferior ulnar collateral artery, the deltoid artery, the radial artery, and the ulnar artery branched off from the BA, as adapted in the current knowledge regarding the anatomy of the upper extremity. Furthermore, detailed measurements of the distances between the mentioned arteries were carried out. In the present study, a bilateral absence of the DBA was demonstrated. Meta-analysis focusing on the anatomy of this artery has shown how variable its characteristics are. However, our case report is the first in the literature to present this extremely rare variation. Having adequate knowledge regarding the anatomy of the arteries of the proximal arm is of immense importance when performing orthopaedic and reconstructive surgeries in this area.

Prevalence of the Onodi cell in the Polish adult population: an anatomical computed tomography study.

BACKGROUND: Onodi cell is a posterior ethmoid air cell with the optic canal bulging into it; the common position of the bulge is into the sphenoid sinus, usually immediately posterior to the posterior ethmoid air cells. Variable pneumatisation patterns lead to various structures of lamellae and sinuses occasionally exposing important nerves and vessels, such as the optic and vidian nerves, internal carotid artery and cavernous sinus. In clinical practice, special imaging techniques are used to navigate through the paranasal sinuses and hence avoid injury to these structures. This study is aimed to determine the prevalence of the Onodi cell in the Polish population and compare it with other reported occurrences. MATERIALS AND METHODS: A retrospective analysis of 296 computed tomography (CT) scans of patients treated in Krakow, Poland, using a Siemens Somatom Sensation 16 spiral CT scanner. No contrast medium was administered. RESULTS: The Onodi cell was found in 31 out of the 296 patients, or approximately 10.5%, consistent with the majority of research reporting on Onodi variants. Additionally, there was one presentation of a bilateral Onodi cell in a male patient. No statistically significant difference was found between the male and female populations with a positive identification of the variant (p = 0.095, Chi2 test). CONCLUSIONS: This study helped approximate the Onodi variant prevalence of 10.47%, falling within a commonly reported range 8-14%. This gives clinicians and surgeons a better understanding of this variant's structure and significance, and therefore an opportunity to improve treatment outcomes and research.

The relationship between the aggrecan VNTR polymorphism and its content in lumbar intervertebral discs.

BACKGROUND: There is a specific polymorphism of the ACAN gene called the variable number of tandem repeats (VNTR), which is particularly interesting in the light of the development of intervertebral disc pathology and associated low back pain. MATERIALS AND METHODS: The nucleus pulposus specimens were harvested from the L5/S1 intervertebral discs. The aggrecan content was determined using enzyme- linked immunosorbent assay (ELISA). Moreover, the VNTR polymorphism in the ACAN gene was evaluated. RESULTS: The genotyping of VNTR polymorphism in ACAN gene was successful in 94 tissue samples (48 homozygotes and 46 heterozygotes). The alleles were divided into four groups, in accordance with the number of tandem repeats in the ACAN gene. No difference between groups in the mean aggrecan mass nor in the mean degree of tissue moisture was observed. CONCLUSIONS: No relationship between the ACAN gene VNTR polymorphism and the aggrecan content was observed in studied Caucasian cadavers. Such a relationship may be a more complex phenomenon and exists in other populations.

A left circumflex aorta with a displaced thoracic duct in a 94-year-old male cadaver: a case report with discussion on embryology.

A left circumflex aorta (LCA) is an extremely rare variation of the thoracic aorta. It is distinguished by a retroesophageal descending aorta that subsequently travels down the right side of the thoracic vertebrae towards the aortic hiatus. Nonetheless, its embryological origin ought not to be overly generalised, but each case should be considered individually due to its unique vascular patterns. This study presents a description of a LCA in a 94-year-old male cadaver. The dissection revealed the descending aorta posteriorly from the trachea and oesophagus and then laterally on the right from the thoracic vertebral bodies. The branching pattern of the aortic arch was typical, so was the course of the left and right recurrent laryngeal nerves. However, the thoracic duct was placed on the right, and drained into the right internal carotid vein. Due to the normal appearance of the ascending part and the arch of the aorta, it is safe to presume that the variation originated from the persistent right dorsal aorta, with the retroesophageal part from the persistent left dorsal aorta. Detailed understanding of the variations of the thoracic aorta, and the anomalies associated with the LCA, can help to improve management of these conditions, and with that, improve patients' overall outcomes. Patients with a LCA, or another vascular ring, can either be asymptomatic or present with oesophageal and/or tracheal compression symptoms. Management of this anomaly consists namely of ligation of the patent ductus arteriosus/ligamentum arteriosum and aortic uncrossing.

Variations in the branching pattern of tibial nerve in foot: a review of literature and relevant clinical anatomy.

Considerable variations have been reported regarding the branching pattern of tibial nerve (TN) close to its termination in foot. In order to comprehend the clinical anatomy of heel pain awareness of all the possible variations in relation to terminal branching pattern of TN (close to the tarsal tunnel) is essential. The present study was conducted to undertake a comprehensive review of the variations in TN branches in foot with particular emphasis on the implications for sensory distribution of these branches. Articles were searched in major online indexed databases using relevant key words. The pattern of termination of TN was noted as either trifurcation or bifurcation. Bifurcation pattern was more commonly observed and is associated with the medial calcaneal nerve (MCN) either arising high or low relative to the tarsal tunnel. The most commonly noted type of bifurcation was proximal to malleolar-calcaneal axis but within the tarsal tunnel. Across all five types of bifurcation reported in literature, the termination points of TN ranged from 3 cm proximal to 3 cm distal to malleolar-calcaneal axis and, therefore, the area beyond this region can be considered as safe zone for performing invasive procedures. MCN showed considerable variations in its origin both in trifurcation and bifurcation pattern pertaining to number of branches (one/two/three) at the point of origin. The origin of inferior calcaneal nerve was observed to be relativelyless variable as it mostly arose as a branch of lateral plantar nerve and sometimes as a direct branch from TN before termination. The frequent variation of MCN in the tarsal tunnel should be kept in mind while undertaking decompression measures in medial ankle region.

Bilateral accessory head of the adductor longus muscle: an anatomical case study.

The adductor longus muscle, with its proximal origin at the pubic bone and distal at the linea aspera, is reported to be one of the most frequently injured groin muscles in contact sports, namely football or ice hockey. Notwithstanding, there is a scarcity of published works regarding the accessory heads of the adductor longus muscle in the existing literature, let alone the clinical significance of the said variant. The following study is a case report describing bilateral accessory heads of the adductor longus muscle in a 97-year-old female cadaver. A routine cadaveric dissection revealed two accessory heads on the right thigh and one on the left thigh of a donor with no known structural or pathological abnormalities of the proximal lower extremity. The anterior division of the obturator nerve provided nerve supply to the variants on both sides. The deep femoral, superficial external pudendal, femoral vessels were responsible for the vascular supply to the accessory heads of the adductor longus. Undoubtedly, extensive knowledge regarding the variant anatomy of the hip adductor muscles is of immense importance to physiotherapists and orthopaedists treating patients for their injury or complete tears. Nonetheless, there is little information regarding the accessory heads of the adductor longus in the existing literature (originating mostly from cadaveric studies) that requires further evaluation in vivo to assess whether this variant might have an impact on a patient's everyday life.

Anatomical description of the perforating cutaneous nerve.

BACKGROUND: The perforating cutaneous nerve/perforating nerve of the sacrotuberous ligament is rarely observed. It usually arises from the posterior division of the sacral plexus or the pudendal nerve and perforates the sacrotuberous ligament. The anatomy of this nerve and its variants is poorly described in the literature, but there are data indicating its role in pudendal neuralgia. MATERIALS AND METHODS: Herein, we present an anatomical study of six formalin-fixed cadavers with descriptions of the topography of spinal nerves S2-S4, the pudendal bundle, the perforating cutaneous nerve and the sacrotuberous ligament. RESULTS: We found three perforating cutaneous nerves and described each of them in detail, with measurements of length and width, and point of perforation of the sacrotuberous ligament. CONCLUSIONS: We distinguished three types of perforating cutaneous nerve on the basis of our findings and previous publications; two of the three types were observed in our study.

The divided zygoma: a meta-analysis of its prevalence with a review of the literature.

BACKGROUND: Divided zygoma (DZ) is an important structure in the midfacial region. The anatomy of DZ is poorly researched, but knowledge about this entity could be useful during posttraumatic facial reconstructions. The aim of this study was to estimate the prevalence and anatomy of DZ in different regions around the world. Therefore, the authors performed a meta-analysis, including all studies that report extractable data on the DZ. MATERIALS AND METHODS: The main online medical databases such as PubMed, EBSCO, ScienceDirect, Web of Science, SciELO, BIOSIS, Current Content Connect, Korean Journal Database and Russian Citation Index, were utilised to gather all studies on anatomical characteristics, prevalence, symmetry, and a number of divisions of zygomatic bone. RESULTS: A total of 20 studies were included in this meta-analysis. Data were grouped and analysed in five categories: (1) prevalence of DZ bone, (2) prevalence of DZ skulls, (3) gender prevalence of DZ with sides, (4) divisions of zygomatic bone, (5) symmetry of DZ. CONCLUSIONS: In conclusion, the authors of the present study believe that this study can be considered an up-to-date meta-analysis regarding the prevalence, divisions, and symmetricity of the DZ. The data provided by the present study may be useful information for physicians in recognizing the DZ of the fracture and may be important information during zygomatic bone osteotomy. Detailed anatomical knowledge of the midfacial region can prevent surgical complications when operating in this area.

Variations in extra-hepatic biliary tree morphology and morphometry: a narrative review of literature with focus on cystohepatic triangle.

The morphometry and morphology of the components of extrahepatic biliary tree show extensive variations. A beforehand recognition of these variations is very crucial to prevent unintended complications while performing surgeries in this region. This study was conducted to analyse the configuration of the extrahepatic biliary tree and its possible variations, as well as measure the components that limit the cystohepatic triangle. Articles were searched in major online indexed databases (Medline and PubMed, Scopus, Embase, CINAHL Plus, Web of Science and Google Scholar) using relevant key words. A total of 73 articles matched the search criteria of which 55 articles were identified for data extraction. The length of left and right hepatic duct in majority of studies was found to be > 10 mm. A wide range of diameters of hepatic ducts were observed between 5 and 43 mm. The average length of cystic duct is around 20 mm. The length and diameter of the common bile duct are 50-150 mm and 3-9 mm, respectively. The most frequently observed pattern of insertion of cystic duct into common hepatic duct is right lateral, rarely anterior, or posterior spiral insertion can present. The results of this study will provide a standard reference range which instead will help to differentiate the normal and pathological conditions.

Extensor digitorum muscle tendon to the index finger from the extensor carpi radialis brevis: a cadaveric case report.

The forearm extensor compartment is known for its wide variability in terms of muscle origin, number of tendons and their distal insertion. The index finger on its dorsal aspect is the typical place of insertion of the two tendons of the extensor digitorum (ED-index) and of the extensor indicis. Being acquainted with their anatomy is of immense importance to orthopaedic surgeons in the treatment of e.g., de Quervain's syndrome. The current report presents a rare finding of the ED-index tendon arising from the extensor carpi radialis brevis (ECRB). A routine dissection revealed their fused course from the lateral epicondyle of humerus, though separate from the extensor carpi radialis longus. The ED-index muscle belly separated from the ECRB, 119 mm distal to the lateral epicondyle. The distal insertion point of the ED-index was located radially to that of the extensor indicis. The deep branch of the radial nerve and the recurrent interosseous artery supplied the ED-index. No other musculotendinous variations were encountered neither on the ipsilateral nor the contralateral upper limb of the cadaver. This study presents in detail a tendon of the ED-index arising from the ECRB, a knowledge that can be applied namely in the lateral epicondylitis treatment or approach to the ulnar nerve at the level of the elbow. Extensive depiction of both the proximal and distal attachment points of the muscles, their course and dimensions is indispensable to attain the best patient outcomes and avoid iatrogenic injuries.

Variations of coronary sinus tributaries among patients undergoing cardiac resynchronisation therapy.

BACKGROUND: In cardiac resynchronisation therapy (CRT), the coronary venous system is used for left ventricular pacing electrode placement. Despite the well- -known anatomy of the coronary sinus and its tributaries, heart failure patients' remodelled and enlarged left ventricles may impede the successful lead placement because of acquired anatomical obstacles. MATERIALS AND METHODS: Fifty-five patients qualified for CRT treatment were divided into ischaemic and non-ischaemic cardiomyopathy. Forty-four control groups without heart failure underwent dual-source computed tomography (CT). Rendered reconstructions of cardiac coronary systems were compared. RESULTS: The presence of main tributaries was comparable in all groups. The left marginal vein, small cardiac vein, and oblique vein of the left atrium were present in 63%, 60%, and 51% of the hearts in all the groups. CRT referred CTs had significantly longer distances between posterior and lateral cardiac veins over the left ventricle (p < 0.05), wider angles of tributaries (p = 0.03), and smaller lumen of coronary sinus (p = 0.03). In the non-ischaemic group, the posterior interventricular and great cardiac veins are more extensive than in the control group. Age-related analysis of vessel size shows a moderate correlation between age and diminishing mean vessel size in all the groups studied. CONCLUSIONS: The general structure of the coronary heart system is consistent in patients with and without heart failure. The variance of the general structure, or the presence of adequate veins, is an individual variation. The use of CT and analysis of the coronary veins allow better planning of the CRT-D implantation procedure and may reduce the risk of ineffective left ventricular electrode implantation.

Gross anatomic relationship between the human left atrial appendage and the left ventricular summit region: implications for catheter ablation of ventricular arrhythmias originating from the left ventricular summit.

PURPOSE: The left ventricular summit (LVS) is a source of difficult-to-treat arrhythmias because of anatomical limitations. The aim of this study was to perform detailed research of the left atrial appendage (LAA) anatomy of cadaveric hearts to analyze their complex anatomy and coverage of the LVS. METHODS AND RESULTS: Eighty human formalin fixed hearts (mean age 44.4 ± 15.5, 27.5% females) were investigated. Each LAA size, type, and its relationship to the LVS were analyzed, as well as possible access sites for mapping/ablating electrode. Four types of LAA were observed over two LVS sites that are either accessible or not. The highest coverage over an inaccessible LVS area was observed in the Broccoli type, followed by the Windsock then the Chicken Wing and finally the Cactus types; over the accessible area of the LVS was observed in the Windsock, then in the Chicken Wing, then in the Cactus, and finally in the Broccoli types. The attainable coverage for electrode access is diminished from 25 to 65% because of the complex pectinate muscles and sharp angles. The highest density of the LAA floor made by pectinate muscles can be found in the Broccoli type (p < 0.005), while the Chicken Wing had the highest number of paper-thin-like pouches. CONCLUSIONS: The LAA appears to be a promising entry for ablation-qualified patients with the LV summit originate arrhythmias. The complex internal structure of the LAA may complicate ablation procedures. More prominent appendages are promising in more extensive mapping areas over the LVS.

A three-headed piriformis muscle: an anatomical case study and narrative review of literature.

The piriformis muscle (PM) is found in the gluteal region, exiting the pelvis through the greater sciatic foramen and dividing it into the suprapiriform and infrapiriform foramina. The piriformis works as part of the hip external rotator muscle group, and is responsible for rotation of the femur upon hip extension and abduction of the femur during flexion of the hip joint. The aim of the present report is to describe a very rare case of the primary three-headed PM. To the best knowledge of the authors, the said variant has not yet been described in the existing literature. The 71-year-old male formalin-fixed cadaver was subjected to routine dissection. After careful removal of the connecting tissue, three separate, primary heads of the PM were identified. The lower head of the PM arose from the middle part of the sacral bone; 87.56 mm long and 9.73 mm wide. The medial head was attached to the internal part of the posterior inferior iliac spine; 121.6 mm long and 20.97 mm wide. The upper head was attached to the external part of the posterior inferior iliac spine; 78.89 mm long and 23.94 mm wide. All heads converged into a common tendon which inserted onto the greater trochanter. The clinical importance of this work comes down to the fact that the aberrant PM may be the reason behind the piriformis syndrome and its associated symptoms. Moreover, knowledge regarding the variant anatomy of the PM is of immense importance to, e.g. anaesthesiologists performing computed tomography- or ultrasound-guided sciatic nerve injection for local anaesthesia, radiologists interpreting imaging studies, and surgeons, especially during posterior approaches to the hip and pelvis.

How to write an umbrella review? A step-by-step tutorial with tips and tricks.

The number of meta-analyses (MA) and systematic reviews (SR) on various medical issues has increased during the last two decades. The MA and SR results may differ from one another due to a number of factors such as inaccurate or diverse searches through the databases, discrepancies in the extraction process or in statistical analysis, among others. Some results may even contradict one another, resulting in confusion among readers. Umbrella reviews (UR) have allowed the collection of all available data on a medical issue into one concise study, making it the source of evidence-based medical knowledge to the highest degree. Furthermore, UR can resolve those problems by collecting all data and taking into account both MA and SR, making it the superior tool for physicians. Although the pros of UR are clear and the overall popularity of these types of study has increased tremendously, there is no available step-by-step guide on how to conduct one. Therefore, the objective of the present study was to provide researchers with a detailed tutorial on how to conduct an UR. UR represent the next major step in the advancement of evidence-based medicine, with great practical potential for physicians looking for the most up-to-date data on their topic of interest. We hope that our step-by-step guide may be a useful tool for researchers conducting UR in the future.

The occipital-vertebral anastomosis revisited.

BACKGROUND: The goal of the study was to provide relevant data about the location and prevalence of the occipital artery-vertebral artery (OA-VA) anastomosis in patients without visible occlusive disease, as well as to thoroughly discuss the clinical significance of these anastomotic channels. Furthermore, the morphometric properties of the OA and its branches were also analysed. MATERIALS AND METHODS: A retrospective study was carried out to indicate anatomical variations, their prevalence, and morphometrical data on the OA and its branches. The study was performed on 55 randomly selected computed tomography angiographies (CTA) of the head and neck region. Each CTA result was analysed bilaterally. Thus, 110 results were originally assessed. RESULTS: The OA median maximal diameter was demonstrated at 4.85 mm (lower quartile [LQ]: 4.11; upper quartile [UQ]: 5.53) and the median maximal diameter of VA at 3.60 mm (LQ: 2.79; UQ: 4.38). The distances between OA and its branches were also measured giving a median result of 21.73, 30.29, 60.84, 34.88, 18.02, 55.16 mm for the lower and upper sternocleidomastoid branch, meningeal branch, mastoid branch, and descending branch, respectively. The median distance between OA and its first anastomosis was set to be 51.15 mm (LQ: 37.20; UQ: 60.10). Moreover, a set of additional measurements was carried out in order to create a three-dimensional anatomical heat-map of the occurrence of the OA-VA anastomosis. CONCLUSIONS: Knowledge about the anatomy of the OA-VA anastomosis might be of immense importance to avoid potentially fatal complications during embolisation of the OA and its branches.

Topographical anatomy of the left ventricular summit: implications for invasive procedures.

BACKGROUND: Recent clinical reports have emphasized the clinical significance of the left ventricular summit (LVS), a specific triangular epicardial area, as the source of ventricular arrhythmias where radiofrequency ablation is of great difficulty. MATERIALS AND METHODS: The macroscopic morphology of the LVS has been assessed in 80 autopsied and 48 angio-computed tomography (CT) human hearts. According to Yamada's equation, the size was calculated based on the distance to the first, most prominent septal perforator. RESULTS: The size of the LVS varies from 33.69 to 792.2 mm2, is highly variable, and does not correlate with body mass index, sex, or age in general. The mean size of the LVS was 287.38 ± 144.95 mm2 in autopsied and angio-CT (p = 0.44). LVS is mostly disproportionately bisected by cardiac coronary veins to superior-inaccessible and inferior-accessible areas. The superior aspect dominates over the inferior in both groups (p = 0.04). The relation between superior and inferior groups determines three possible arrangements: the most common type is superior domination (50.2%), then inferior domination (26.6%), and finally, equal distribution (17.2%). In 10.9%, the inferior aspect is absent. Only 16.4% of the LVS were empty, without additional trespassing coronary arteries. CONCLUSIONS: The difference in size and content of the LVS is significant, with no correlation to any variable. The size depends on the anatomy of the most prominent septal perforator artery. The superior, inaccessible aspect dominates, and the LVS is seldom free from additional coronary vessels, thus making this region hazardous for electrophysiological procedures.

Air spaces of the temporal bone: a morphometric analysis with clinical implications.

BACKGROUND: The main objective of the present study was to analyse the morphological variations of the air spaces of the temporal bone, that is, the pneumatized and air-filled spaces of the temporal bone cavities. MATERIALS AND METHODS: A total of 99 sides were analysed. Temporal bone pneumatic spaces (TBPS) were defined as the free spaces inside the cavities of the temporal bone filled with air, excluding the volume of the structures present in the investigated region. Total volumes of TBPS were calculated as the sum of total volumes of mastoid air cells (MAC), tympanic cavity (TC), and external auditory canal (EAC). Analyses were performed considering the general population and the female and male subgroups. RESULTS: The overall results obtained on Polish population were set as follows: the median total volume of TBPS was demonstrated at 7882.58 mm3 (lower quartile [LQ]: 6200.56 mm3; higher quartile [HQ]: 10393.16 mm3). The median volume of MAC was set at 5813.05 mm3 (LQ: 4224.94 mm3; HQ: 8181.81 mm3). The median of the total volume of the EAC was demonstrated at 1294.36 mm3 (LQ: 1099.68 mm3; HQ: 1627.84 mm3). CONCLUSIONS: In the present study, the morphometric properties of the temporal bone cavities were analysed. The results showed that the total volume of the MAC was, on average, lower in women than in men. This should be taken into account when performing procedures on the mastoid, such as mastoidectomies. It is hoped that the results of this study can help reduce potential surgical complications associated with otological procedures.

The cranio-orbital foramen: a meta-analysis with a review of the literature.

BACKGROUND: The goal of the present study was to provide accurate data on the prevalence and morphometrical aspects of the cranio-orbital foramen (COF), which can surely be of use by surgeons performing procedures on the lateral orbit. Furthermore, the embryology and the clinical significance of this osseous structure were thoroughly discussed. MATERIALS AND METHODS: Major online medical databases such as PubMed, Scopus, Embase, Web of Science, and Google Scholar were searched to find all relevant studies regarding COF. RESULTS: Eventually, a total of 25 studies that matched the required criteria and contained complete and relevant data were included in this meta-analysis. The pooled prevalence of COF was found to be 48.37% (95% confidence interval [CI]: 41.67-55.10%). The occurrence of the COF unilaterally was set to be 71.92% (95% CI: 41.87-96.97%). The occurrence of the COF bilaterally was set at 26.08% (95% CI: 3.03-58.13%). CONCLUSIONS: In conclusion, we believe that this is the most accurate and up-to- -date study regarding the anatomy of the COF. The COF is prevalent in 48.37% of the cases, and it is most frequently unilateral (73.92%). Furthermore, the prevalence of accessory COFs was found to be 16.72%. The presence of these foramina may represent a source of haemorrhage that ophthalmic surgeons should be aware of when performing procedures in the lateral part of the orbit.

An aberrant right subclavian artery in a 63-year-old male cadaver.

An aberrant right subclavian artery (ARSA), also called "arteria lusoria", is described as a right subclavian artery (RSA) with a retro-oesophageal course that most frequently originates as the most distal branch of the aortic arch. The aim of the following study was to present and thoroughly describe a case of an ARSA, its course, branches, and relation to the surrounding anatomical structures and discuss the clinical significance and embryology of this variant. During routine dissection, a 63-year-old male cadaver with an abnormal variant of the RSA was found. The RSA branched off from the aortic arch as the most distal branch. Subsequently, it coursed posteriorly to the trachea and oesophagus at the level of T2 and T3. Abnormalities in the branching pattern of the RSA were also discovered, such as the right vertebral artery originating from the right common carotid artery as its first branch. This study presents a case of an ARSA, which is a rare anatomical variant of the branches of the aortic arch. The course and branching pattern of an aberrant subclavian artery is quite variable, and each variant can be associated with different possible complications. Furthermore, the ARSA is associated with other cardiovascular anomalies, such as the Kommerell's diverticulum. Therefore, knowledge about the possible variations of this anomaly may be of great importance for physicians who encounter this variant in their practice.

The petroclinoid ligament: a meta-analysis of its morphometry and prevalence of mineralization with a review of the literature.

BACKGROUND: The petroclinoid ligament (PCL) is an important structure in the petroclival region. The anatomy of the PCL and its relationship with the surrounding structure is highly variable. The aim of this study was to estimate the morphometry, prevalence of mineralization, and anatomy of the PCL. To achieve this, the authors carried out a meta-analysis, including all studies that report extractable data on the PCL. MATERIALS AND METHODS: Major online medical databases such as PubMed, Scopus, ScienceDirect, Web of Science, SciELO, BIOSIS, Current Content Connect, Korean Journal Database, and Russian Citation Index were searched to gather all studies regarding the anatomical characteristics, morphometry, and relationship with the anatomical surroundings of the PCL. RESULTS: A total of 25 studies were included in this meta-analysis. Data were gathered and analysed in eight categories: (1) mineralization of the PCL, (2) relationship of the abducens nerve with the PCL, (3) relationship of the dorsal meningeal artery with the PCL, (4) shape, number, and continuity of the PCL, (5) PCL anterior attachment, (6) PCL anterior attachment point on bone, (7) PCL posterior attachment point on bone, (8) morphometric features of the PCL. CONCLUSIONS: In conclusion, the authors of the present study believe that this is the most accurate and up-to-date meta-analysis regarding the morphology and mineralization of the PCL. The data provided by the present study may be a useful tool for surgeons performing neurosurgical procedures, such as endoscopic transnasal surgeries. Detailed anatomical knowledge of the petroclival region can surely prevent surgical complications when operating in this area.