Relevant Anatomical Variations Research Articles

Clinically Relevant Anatomical Variations in the Brachial Plexus.

Anatomical variation in the brachial plexus may result in a variety of clinically relevant patterns, including various neuralgias of the upper extremity and differing nerve territories. Some conditions can be debilitating in symptomatic patients, resulting in paresthesia, anesthesia, or weakness of the upper extremity. Others may simply result in cutaneous nerve territories that deviate from a traditional dermatome map. This study evaluated the frequency and anatomical presentations of a large number of clinically relevant brachial plexus nerve variations in a sample of human body donors. We identified a high frequency of various branching variants, of which clinicians, especially surgeons, should be aware. The medial pectoral nerves in 30% of the sample were found to originate from either the lateral cord, or both the medial and lateral cords of the brachial plexus rather than exclusively from the medial cord. The dual cord innervation pattern greatly increases the number of spinal cord levels traditionally believed to innervate the pectoralis minor muscle. The thoracodorsal nerve arose as a branch of the axillary nerve 17% of the time. The musculocutaneous nerve sent branches to the median nerve in 5% of specimens. The medial antebrachial cutaneous nerve shared a common trunk with the medial brachial cutaneous nerve in 5% of individuals and derived from the ulnar nerve in 3% of specimens.

Determination of Standard Values for Knee Version in a Healthy Population

Background: Different measures are used to describe relevant anatomic variations that can result in patellofemoral instability and disorders. Knee version, the relative rotational alignment between the femur and tibia in the axial plane at the level of the knee, may have a decisive effect on the kinematics of the patellofemoral joint. However, data regarding the values of knee version are currently lacking. Purpose: This study aimed to determine standard values for knee version in a healthy population. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 100 healthy volunteers (50 male and 50 female) without patellofemoral disorders or lower extremity malalignment were included in this study and underwent knee magnetic resonance imaging. The torsion values of the femur and tibia were independently measured using the Waidelich and Strecker method. Knee version, defined as static rotation of the tibia with respect to the femur in full extension, was determined by measuring the angle between the tangent lines to the dorsal femoral condyle (DFC) and the dorsal tibial head (DTH; defined by the posterior point of the proximal tibial plateau). Supplementary measurements were obtained as follows: (1) femoral epicondylar line (FEL), (2) tibial ellipse center line (TECL), (3) tibial tuberosity–trochlear groove (TT-TG) distance, and (4) tibial tuberosity–posterior cruciate ligament (TT-PCL) distance. Results: In 200 analyzed legs of 100 volunteers (mean age, 26.5 ± 5.8 years [range, 18 to 40 years]), we identified a mean internal femoral torsion of −23.8°± 9.7° (range, −46.2° to 1.6°), external tibial torsion of 33.2°± 7.4° (range, 16.4° to 50.3°), and external knee version (DFC to DTH) of 1.3°± 3.9° (range, −8.7° to 11.7°). Other measurements were as follows: FEL to TECL, −0.9°± 4.9° (range, −16.8° to 12.1°); FEL to DTH, −3.6°± 4.0° (range, −12.6° to 6.8°); and DFC to TECL, 4.0°± 4.9° (range, −12.7° to 14.7°). The mean TT-TG distance was 13.4 ± 3.7 mm (range, 5.3-23.5 mm), and the mean TT-PCL distance was 11.5 ± 3.5 mm (range, 6.0-20.9 mm). Female participants had significantly greater external knee version than male participants. Conclusion: Coronal- and sagittal-plane alignments of the knee have a well-known effect on the biomechanics of this joint. Additional information about the axial plane may result in new decision-making algorithms for managing knee disorders. This study is the first to report standard values of knee version in a healthy population. As a subsequent step building on this work, we advocate for the measurement of knee version in patients with patellofemoral disorders, as this parameter may assist with new treatment guidelines in the future.

Learning the Hidden Signature of Fetal Arch Anatomy: a Three-Dimensional Shape Analysis in Suspected Coarctation of the Aorta

Neonatal coarctation of the aorta (CoA) is a common congenital heart defect. Its antenatal diagnosis remains challenging, and its pathophysiology is poorly understood. We present a novel statistical shape modeling (SSM) pipeline to study the role and predictive value of arch shape in CoA in utero. Cardiac magnetic resonance imaging (CMR) data of 112 fetuses with suspected CoA was acquired and motion-corrected to three-dimensional volumes. Centerlines from fetal arches were extracted and used to build a statistical shape model capturing relevant anatomical variations. A linear discriminant analysis was used to find the optimal axis between CoA and false positive cases. The CoA shape risk score classified cases with an area under the curve of 0.907. We demonstrate the feasibility of applying a SSM pipeline to three-dimensional fetal CMR data while providing novel insights into the anatomical determinants of CoA and the relevance of in utero arch anatomy for antenatal diagnosis of CoA.Graphical abstract

Pre-FESS Imaging of Paranasal Sinuses and Nasal Cavity: Using Multi-detector Computed Tomography (MDCT) in Understanding Normal Anatomy and Anatomical Variations: Tips and Tricks.

With the advent of Multi-detector Computed Tomography (MDCT), imaging evaluation of paranasal sinuses (PNS) and nasal cavity has witnessed a paradigm shift. Submillimetric slice thickness with superior quality multiplanar reconstructions in orthogonal as well as non-orthogonal planes have resulted in better understanding of the intricate details of complex sino-nasal anatomy and their normal variations. Sagittal plane images have gained increasing acceptance among the sinus surgeons for understanding frontal sinus drainage pathway as well as lateral nasal wall. Analyzing the axial volume dataset in three dimensions has become a routine both for the radiologists as well as sinus surgeon. Besides default window settings, customized window settings enable better appreciation of air containing structures and their boundaries. Mandatory scan check list and template based structured reporting helps the sinus surgeon in better pre-operative planning. Regular mutual interaction between radiologists and sinus surgeon helps better understanding of the surgically relevant anatomy and anatomical variations.

Anatomical variations of the ethmoid sinuses and their association with health or pathology of the ethmoid and maxillary sinuses in a Southern Chinese population: An analysis using cone-beam computed tomography.

PurposeThe aim of this study was to evaluate the prevalence of clinically relevant anatomical variations of the ethmoid sinuses and their potential association with ethmoid and maxillary sinus pathologies on cone-beam computed tomography (CBCT) scans. Additionally, potential associations with different sides and demographic factors, including age and sex, were evaluated.Materials and MethodsIn total, 273 CBCT scans with complete ethmoid and maxillary sinuses were analyzed to determine the prevalence of Agger nasi cell, supraorbital ethmoid cell, Haller cell, Onodi cell, and ethmomaxillary sinus. In addition, the health or pathology of the ethmoid and maxillary sinuses was also recorded to assess correlations with the aforementioned variations.ResultsThe prevalence of Agger nasi cell was found to be the highest (95.6%) in this study, followed by Onodi cell (60.4%), Haller cell (29.3%), and supraorbital ethmoid cell (19.4%). Ethmomaxillary sinus was the least common finding (16.5%). Males and persons above 61 years of age had a significantly higher frequency of supraorbital ethmoid cell and Onodi cell, respectively. However, no significant relationships were noted between anatomical variations of the ethmoid sinus and pathologies of the ethmoid or maxillary sinus.ConclusionThere was a high prevalence of ethmoid sinus variations in this Southern Chinese population. The prevalence of Agger nasi cell and Onodi cell was higher than that of other anatomical variations of the ethmoid sinuses. Anatomical variations of the ethmoid sinuses were not associated with ethmoid or maxillary sinus pathologies in this patient cohort.

Surgical Relevance of Pediatric Anterior Clinoid Process Maturation for Anterior Skull Base Approaches.

Removal of the anterior clinoid process (ACP) can expand anterior skull base surgical corridors. ACP development and anatomical variations are poorly defined in children. To perform a morphometric analysis of the ACP during pediatric maturation. Measurements of ACP base thickness (ACP-BT), midpoint thickness (ACP-MT), length (ACP-L), length from optic strut to ACP tip (ACP-OS), pneumatization (ACP-pneumo), and the presence of an ossified carotico-clinoid ligament (OCCL) or interclinoid ligament (OIL) were made from high-resolution computed-tomography scans from 60 patients (ages 0-3, 4-7, 8-11 12-15, 16-18, and >18 yr). Data were analyzed by laterality, sex, and age groups using t-tests and linear regression. There were no significant differences in ACP parameters by laterality or sex, and no significant growth in ACP-BT or ACP-MT during development. From ages 0-3 yr to adult, mean ACP-L increased 49%, from 7.7 to 11.5 mm. The majority of ACP-L growth occurred in 2 phases between ages 0-3 to 8-11 and ages 16-18 to adult. Conversely, ACP-OS was stable from ages 0-3 to 8-11 but increased by 63% between ages 8-11 to adult. Variations in ACP morphology (OCCL/OIL/ACP-pneumo) were found in 15% (9/60) of scans. OCCL and OIL occurred in patients as young as 3 yrs, whereas ACP-pneumo was not seen in patients younger than 11 yrs. The ACP demonstrates stable thickness and a complex triphasic elongation and remodeling pattern with development, the understanding of which may facilitate removal in patients <12. Clinically relevant ACP anatomic variations can occur at any age.

Variant Anatomy and Its Terminology.

Variant anatomy, which is an integral part of anatomical science, is related to abnormalities in the human body structure. Our understanding of variant anatomy is based on thousand years of anatomical experience. These abnormalities generally do not interfere with the function of the human body and do not typically manifest as pathological nosological units. However, under certain conditions, these abnormalities can worsen existing pathological states or even evoke new ones. Understanding variant anatomy is a basic skill not only of mere anatomists, but also of clinicians who work in fields involving both diagnostic techniques and therapeutic interventions. To gain and retain a good knowledge of the most frequent and clinically relevant anatomical variations, a simple, clear, and exactly defined nomenclature of variant structures is needed. A list of items comprising variant anatomy, which have been incorporated into the internationally accepted nomenclatures Terminologia Anatomica (1998) and Terminologia Neuroanatomica (2017), is described and analyzed. Examples of the most common anatomical variations related to terminology are mentioned, and variant anatomy as a whole and its role in understanding current anatomy are discussed.

Extrahepatic Biliary Tract Anatomy: A Review

Laparoscopic cholecystectomy is one of the most common surgical procedures in general surgery. Significant gaps in knowledge still exist and even with clinical expertise, there might be limitations. Some of these are exploration restrictions during laparoscopic approach, visualization impairments and distortion of the usual arrangement of structures because of local inflammation, among others.Given the wide variability in anatomical presentation and considering that even in 56% of the population there is a close relationship to main vascular structures, intraoperative injuries might occur leading to higher rates of complications, longer surgical time and increased morbidity.Our aim is to describe the most common and relevant anatomic variations in the extrahepatic biliary tract (EBT). A systematic review of the literature was pursued using the MeSH terms: “Biliary Tract/abnormalities”, “Bile Ducts and Extrahepatic/abnormalities”. Only articles written in Spanish and English and limited to the last 20 years were considered.The anatomical structure considered normal for the EBT is described in roughly 60% of the population. The most variable structures according to included manuscripts are the left and right biliary ducts and the most prevalent variations are: posterior branch of the right hepatic duct draining into the left hepatic duct, triple confluence of the intrahepatic ducts, and anterior or posterior branch of the right hepatic duct draining into the common hepatic or cystic duct.As mentioned before the awareness and comprehension of EBT variations is crucial in avoiding complication, morbidity and achieving optimal outcomes in diagnostics and therapeutic procedures as reducing intraoperative iatrogenic injuries and considering the need of noninvasive techniques for EBT identification for a better surgical planning.

Computer Simulation and Maxillary All-on-Four Surgery.

Maxillary all-on-four implant reconstruction requires training beyond normal dental implant training. It conjoins technical surgical acumen, anatomic and complex spatial relationship understanding, thorough awareness of dental prosthodontic principles, and excellent patient management skills. Acquisition of appropriate training to the level of competence in an era of greater patient expectations and increased vigilance for patient safety and overall quality of care is limited. Repeated purposeful practice in performing complex psychomotor tasks is of paramount importance in achieving competence. Surgical simulation may assist surgical learners to acquire familiarity with relevant anatomic variations, instrumentation, surgical techniques, and management of intraoperative and postoperative complications.

Analysis of maxillary sinus septa by cone-beam computed tomography

Abstract Introduction Pneumatization of the maxillary sinus may make it impossible to insert implants directly in the posterior region of the maxilla, and in these cases, the solution is to submit the patient to maxillary sinus floor augmentation surgery. The most common complication of this surgery is sinus membrane perforation. Anatomical variations of the internal space of the sinus, such as the bone septa, may further hamper detachment of this membrane. Objective To evaluate the prevalence and characteristics of sinus septa in patients from the Zona da Mata Mineira (Minas Gerais, Brazil), to offer relevant information for a safer planning of surgeries involving this region. Material and method A total of 120 patients (240 sinuses) were analyzed using cone-beam computed tomography (CBCT) images, verifying the presence of sinus septa and classifying them for size and anteroposterior location. Result Of the 120 patients analyzed, 45 (37.50%) had sinus septa, 66 septa in total. Of these, 33 (50%) were present in the middle region of the maxillary sinus and the mean septum size was 7.23 mm. There was no significant difference in the septum size between the genders or between the right and left sides. Conclusion The high rates of incidence of sinus septa justify their study, which should be based mainly on accurate exams, such as CBCT, since they represent one of the most relevant anatomical variations for the cases of sinus surgeries.

Torsional Anatomy of the Lower Limb: The Appearance of Anatomy in Hemispastic Position.

The aim of the study was to determine whether there are relevant anatomical variations to the typical injection sites for antispasticity procedures in the lower limb. Sonographic images were obtained at traditional injection locations for spasticity in the lower limb. Images were recorded in neutral and contracted postures. Doppler imaging was obtained for sites that contained vasculature. The images were analyzed, and schematics were created that highlighted relevant findings. The adductor longus in commonly used injection sites was close to vasculature making accidental injection of the latter a higher risk. The sciatic nerve was vulnerable to injections at the proximal biceps femoris injection side if injected too deeply. Hamstring injection sites can be adjusted to the midline to improve accuracy. The proximity of the tibial nerve to the flexor hallucis longus and the deep fibular nerve to the extensor hallucis longus puts these nerves at risk for accidental injection. Contracted posture results in altered positions of lower extremity muscles that could lead to inadvertent neurovascular injection or decreased efficacy with injections. Findings in this study may be helpful for planning and executing injections to reduce spasticity in the lower extremity. Sonographic imaging allows a better localization of muscles associated with spasticity and can instruct the clinician to alter usual injection pathways. This article documents visual evidence that previous assumptions for injection strategies require updating.

Surgically Relevant Bony Anatomical Variations in Paraclinoid Aneurysms-Three-Dimensional Multi-Detector Row Computed Tomography-Based Study.

Objective:To evaluate the proportion of surgically relevant anatomical variations such as caroticoclinoid foramen, interclinoid osseous bridge, and anterior clinoid pneumatization in patients with paraclinoid aneurysms based on computed tomography (CT) cerebral angiography studies.Materials and Methods:Fifty-four CT cerebral angiography studies showing paraclinoid aneurysms involving the cavernous, clinoid, and supraclinoid internal carotid artery (ICA) were retrospectively evaluated. Source images were processed for three-dimensional reconstructions to evaluate the presence and type of caroticoclinoid foramen, interclinoid osseous bridge, and multiplanar reconstructions with bone algorithm to study the type of pneumatization.Results:The study included 30 female and 24 male patients with mean age of 45.61 (10.47) years. Among the 108 sides studied in 54 patients, caroticoclinoid foramen was seen in 24 cases (22.22%), interclinoid osseous bridge was seen unilaterally in 1 case (0.9%), and pneumatization of anterior clinoid process occurred in 12 cases (11.11%). Incomplete caroticoclinoid foramen (11 cases) and Type I pneumatization (7 cases) were seen to be predominant subtypes. There was no statistically significant gender difference in the occurrence of caroticoclinoid foramen and anterior clinoid pneumatization. Seventy-four aneurysms were detected in 54 patients. Based on their location, 46 aneurysms involved supraclinoid ICA, 18 aneurysms in the clinoid segment, and 10 aneurysms in the cavernous segment. Caroticoclinoid foramen was most prevalent in clinoid aneurysms with 12 cases occurring in the clinoid segment.Conclusion:Notable proportions of caroticoclinoid foramen and pneumatization occur in cases of paraclinoid aneurysm. Radiological reports should emphasize on these surgically relevant bony anatomical variations.

The anterior jugular veins: preliminary study

The jugular venous system is responsible for the head and neck drainage. The anterior jugular vein has the smallest caliber when compared with the other jugular veins. Near to the superior thoracic opening, the anterior jugular veins run sideways, deep to the sterno bone. Above the sterno bone, the anterior jugular veins run side by side lateral to the midline and they can communicate to each other through an arch – the jugular venous arch. There are many relevant anatomical variations among the anterior jugular veins. Therefore, an anatomical pattern study about these veins have a relevant clinical importance for the enhancement of the surgical technique and improvement of post‐operative cares for procedures done in the anterior region of the neck like thiroidectomies and trachoestomiesObjectiveDescribing the anterior jugular veins relations in the infrahyoid area and comparing possible variations with anthropometric characteristics.MethodTo study the anterior jugular veins positions, Using a form, previously elaborated, the anterior jugular veins are observed according to the following characteristics: the number of veins, caliber, position, path, distance between the middle line, presence and anastomoses location, presence and jugular venous arch location. The cadavers' anthropometric characteristics. had been collected.ResultsThese are the preliminary results : 5 cases with 2 anterior jugular veins;4 cases with only one anterior jugular vein e one case with 3 anterior jugular veins. Fifty per cent of the cases showed the anterior jugular veins near to the midline plan (1cm or less). The veins' caliber were 5 mm or less in 60% of the cases. There are many variantions talking about the arch.Conclusionsas a preliminary study we are able to state that there are many relevant anatomical variations in number of veins and their caliber

Ultrasound-guided central venous catheterization: A review of the relevant anatomy, technique, complications, and anatomical variations.

Central venous catheterization is a commonly used and important intervention. Despite its regular use it is still associated with a high incidence of complications especially infection and catheter tip embolization. Addition of ultrasound guidance to the technique has shown great improvement to the time and number of attempts for successful catheterization. The preference of vein depends greatly on the situation; subclavian vein is the preferred method overall but internal jugular vein is preferred in patients undergoing cardiac or thoracic surgery. This is especially true for pediatric patients in whom femoral vein catheterization is still preferred despite it carrying a higher risk than other locales. Addition of ultrasound guidance greatly reduces the incidence of arterial puncture and subsequent hematoma formation regardless of location. This is because it allows for visualization of anatomical variation prior to intervention and continual visualization of the needle during the placement. It is noteworthy however, that addition of ultrasound does not prevent complications such as catheter tip embolization as this may occur even with perfect placement. The value of ultrasound usage is undisputable since all studies assessing the difference between it and landmark based methods showed preferable outcome. Reduction of time and number of attempts is sufficient argument to make ultrasound guidance standard practice. Clin. Anat. 30:237-250, 2017. © 2017 Wiley Periodicals, Inc.

Clinical significance of circumportal pancreas, a rare congenital anomaly, in pancreatectomy

BackgroundCircumportal pancreas is a rare congenital pancreatic anomaly. The aim of this study was to clarify the clinical characteristics of patients with circumportal pancreases undergoing pancreatectomy. MethodsThe medical records of 508 patients who underwent pancreatectomy were retrospectively reviewed. The prevalence of circumportal pancreas and related anatomical variations were assessed. Surgical procedures and postoperative outcomes were compared in patients with and without circumportal pancreas. ResultsCircumportal pancreas was observed in 9 of the 508 patients (1.7%). In all nine patients, the portal vein was completely encircled by the pancreatic parenchyma above the level of the splenoportal junction, and the main pancreatic duct ran dorsal to the portal vein. The rate of variant hepatic artery did not differ significantly in patients with and without circumportal pancreas. Pancreatic fistula developed more frequently in patients with than without circumportal pancreas (44% vs. 14%, p = 0.03), but other clinical parameters did not differ significantly in these two groups. ConclusionsDespite being rare, circumportal pancreas may increase the risk of postoperative pancreatic fistula in patients undergoing pancreatectomy. However, a prospective, large-cohort study is necessary to determine the real incidence of relevant anatomical variations and the definitive clinical significance of this rare anomaly.

Lymphatic Intervention for Various Types of Lymphorrhea: Access and Treatment.

Traumatic lymphorrhea is a rare but potentially life-threatening complication. Postoperative lymphorrhea is the leading cause of traumatic lymphorrhea and can arise anywhere within the lymphatic system. Leaks arising from the aortoiliac region to the thoracic duct (TD) and from hepatic lymphatics can be identified with intranodal lymphangiography and transhepatic lymphangiography, respectively. Therefore, an appropriate lymphangiography technique is essential for identifying the sources of leaks. Chylothorax resulting from damage to the TD can be serious because the TD transports large amounts of lymphatic fluid from the gastrointestinal, hepatic, and aortoiliac regions. Percutaneous TD embolization-comprising access to the TD followed by embolization-has recently become a minimally invasive alternative to surgical TD ligation for high-output chylothorax. The selection of access routes to the TD depends on its anatomy. If the TD cannot be approached by such means, other options include TD needle interruption or drainage of lymphatic fluid adjacent to the leakage point followed by sclerotherapy. Most cases of abdominal lymphorrhea arise from the aorta-iliac lymphatic system, and lymphangiography alone or computed tomography-guided sclerotherapy might be useful. Rarely, leakage may arise from hepatic lymphatics due to a damaged gastroduodenal ligament and can be visualized and embolized transhepatically. This article comprehensively reviews clinically relevant anatomic TD variations, lymphangiography techniques and criteria for their selection, and treatment strategies for lymphorrhea. ©RSNA, 2016.

Clinically relevant anatomical variations of neural and vascular structures of the neck

Clinically relevant anatomical variations of neural and vascular structures of the neck

AIUM Practice Parameter for the Performance of Selected Ultrasound‐Guided Procedures

AIUM Practice Parameter for the Performance of Selected Ultrasound‐Guided Procedures

AIUM Practice Parameter for the Performance of Selected Ultrasound-Guided Procedures

AIUM Practice Parameter for the Performance of Selected Ultrasound-Guided Procedures

Stereoscopic vascular models of the head and neck: A computed tomography angiography visualization.

Computer-assisted 3D models are used in some medical and allied health science schools; however, they are often limited to online use and 2D flat screen-based imaging. Few schools take advantage of 3D stereoscopic learning tools in anatomy education and clinically relevant anatomical variations when teaching anatomy. A new approach to teaching anatomy includes use of computed tomography angiography (CTA) images of the head and neck to create clinically relevant 3D stereoscopic virtual models. These high resolution images of the arteries can be used in unique and innovative ways to create 3D virtual models of the vasculature as a tool for teaching anatomy. Blood vessel 3D models are presented stereoscopically in a virtual reality environment, can be rotated 360° in all axes, and magnified according to need. In addition, flexible views of internal structures are possible. Images are displayed in a stereoscopic mode, and students view images in a small theater-like classroom while wearing polarized 3D glasses. Reconstructed 3D models enable students to visualize vascular structures with clinically relevant anatomical variations in the head and neck and appreciate spatial relationships among the blood vessels, the skull and the skin.