Morphology of the aortic arch branching pattern in raccoon dogs (Nyctereutes procyonoides, Gray, 1834).

BACKGROUND: Aortic arch (AA) branching patterns vary among different mammalian species. Most previous studies have focused on dogs, whereas those on raccoon dogs remain unexplored. OBJECTIVES: The objective of this study was to describe the AA branching pattern in raccoon dogs and compare their morphological features with those of other carnivores. METHODS: We prepared silicone cast specimens from a total of 36 raccoon dog carcasses via retrograde injection through the abdominal aorta. The brachiocephalic trunk (BCT) branching patterns were classified based on the relationship between the left and right common carotid arteries. The subclavian artery (SB) branching pattern was examined based on the order of the four major branches: the vertebral artery (VT), costocervical trunk (CCT), superficial cervical artery (SC), and internal thoracic artery (IT). RESULTS: In most cases (88.6%), the BCT branched off from the left common carotid artery and terminated in the right common carotid and right subclavian arteries. In the remaining cases (11.4%), the BCT formed a bicarotid trunk. The SB exhibited various branching patterns, with 26 observed types. Based on the branching order of the four major branches, we identified the main branching pattern, in which the VT branched first (98.6%), the CCT branched second (81.9%), the SC branched third (62.5%), and the IT branched fourth (52.8%). CONCLUSIONS: The AA branching pattern in raccoon dogs exhibited various branching patterns with both similarities and differences compared to other carnivores.

Considerations on the morphology of the thyroid ima artery.

PURPOSE AND BACKGROUND: Detailed knowledge of the thyroid ima artery is essential for surgeons consequently we conducted an analysis investigating the arterial vasculature of the thyroid gland in 290 cases by dissection of formalin-fixed cadavers and by studying computed tomography angiographies. METHODS: Our study was conducted on 82 cases obtained from the dissection of formalin-fixed cadavers while 208 cases were computed tomography angiographies. The following aspects were observed: the frequency of the thyroid ima artery, its origin, course, and diameter. All were studied, comparing right to left and according to sex. RESULTS: Following the study of thyroid gland vasculature on a number of 290 cases, the thyroid ima artery was discovered in 16 cases (5.52% of cases), from which 3.45% of cases were in male subjects, and 2.07% of cases in female subjects. Of these, 4.14% of the total cases were left thyroid ima artery, and 1.38% of cases were on the right, found only in female subjects. In 5.17% of the total cases, the thyroid ima artery originated from the aortic arch, of which 3.45% were in the male sex and 1.72% were in the female sex. In one case only (0.35%) in the female sex did the thyroid ima artery originate from the brachiocephalic trunk. In 2.76% of cases, the thyroid ima artery existed with a left-sided inferior thyroid artery originating from the subclavian artery, either directly or from a thyrocervical trunk. CONCLUSIONS: The thyroid ima artery has proven to be one of the highly variable arteries in terms of its presence and origin and the knowledge surrounding it is useful for surgical interventions.

Topographic anatomy and vascularization of the glandula thyroidea in rats.

Topographical anatomy and detailed measurements of the glandula thyroidea (thyroid gland) and the glandula parathyroidea (parathyroid gland) were determined in rats, with significant differences identified between the sexes. In the rats (N = 10 male, 10 female), the glandula thyroidea were positioned at the level of the C1 and C2 vertebrae. One glandula parathyroidea was present in each glandula thyroidea lobe, localized in the cranial part of the lateral lobes in 60% of the animals. There was no glandula thyroidea left lobe in one female and no isthmus in two females. Both the A. thyroidea cranialis and the A. pharyngea ascendens originated from the A. carotis externa, which acted as a common trunk. On the left, the A. thyroidea caudalis originated from the truncus brachiocephalicus in all rats and on the right side was found to originate from both the truncus costocervicalis and the A. subclavia dextra in three females, and only from the truncus costocervicalis in seven females. The V. thyroidea cranialis opened into the V. jugularis interna in the neck region and at the level of the apertura thoracis cranialis, and the V. jugularis interna united with the V. thyroidea caudalis. In addition, on the right, the V. thyroidea cranialis joined the V. jugularis interna, at the level of the A. subclavia. The veins on both sides opened into the V. cava cranialis. Significant differences were observed between the sexes and detailed anatomical analysis of the glandula thyroidea and the glandula parathyroidea, and related vasculature and innervation, have been described in this paper.

Morphology of aortic arch branching patterns in the Eurasian Otter (Lutra lutra, Linnaeus, 1758).

In this study, we investigated the aortic arch (AA) branching pattern in the Eurasian otter (Lutra lutra). We performed arterial silicone casting of the AA of 18 Eurasian otters (8 males and 10 females). We analyzed the AA branching pattern at three levels: the AA, brachiocephalic trunk (BCT), and subclavian artery (SB), using different classification methods at each level. We introduced new criteria for classifying the SB branching pattern applicable for Eurasian otter and other carnivores based on the sequence of the four main branches: vertebral artery (VT), internal thoracic artery (IT), costocervical artery (CCT), and superficial cervical artery (SC). In all Eurasian otters, two major branches emerged directly from the AA, i.e., the BCT and left SB. The BCT branched off the left common carotid artery and terminated in the right common carotid artery and right SB in 17 of 18 Eurasian otters; the BCT formed a bicarotid artery in the remaining case. The SBs showed various branching patterns, with the main branching pattern involving branching to the VT and IT at the same position, followed by the CCT and SC. The SB branching pattern in the Eurasian otter differed from that in dogs in that the two first branching arteries were VT and IT, rather than VT and CCT. Here, we present the anatomical characteristics of the AA branching patterns in the Eurasian otter and new analysis methods applicable for comparative studies of other carnivores.

Morphology of the pattern of branching of the aortic arch (Arcus aortae) in Syrian hamsters (Mesocricetus auratus).

The branching patterns of the aortic arches of 28 adult male and female Syrian hamsters (SH) were thoroughly examined under a stereomicroscope for the first time by using latex injection and corrosion casting to determine their general arrangements and morphological variations as well as their differences and similarities to other rodents and rabbits. Three major arteries, namely, the brachiocephalic trunk (BC), left common carotid artery (CC) and left subclavian artery (SA), originating from the aortic arch (AR), were uniformly noted in SH. The BC was consistently divided into the right SA and the right CA. SA in SH normally releases the internal thoracic, deep cervical, dorsal scapular, vertebral, superficial cervical and supreme intercostal arteries. The costocervical trunk typically consisted of supreme intercostal and internal thoracic arteries and a common trunk for dorsal scapular and deep cervical arteries. To comprehend the comparative morphology of the pattern of branching of AR more completely, our results were compared with previous studies in rodents and rabbits. (1) The general morphology of the great arteries from AR in SH was similar to that in mole rats, rats, mice, porcupines, and gerbils but was essentially different from that in rabbits, guinea pigs, red squirrels, ground squirrels, pacas and chinchillas. (2) The typical pattern of the branching of the subclavian arteries in SH was similar to that in guinea pigs, rats, and rabbits but was different from that of the reported rodents regardless of the origins of the bronchoesophageal and internal thoracic arteries and the composition of the costocervical trunk.

Two cases of variations in inferior thyroid arterial pattern and their clinical implications.

Vascular variations are the most common ones in humans. Inferior thyroid artery arises from the thyrocervical trunk in 90.5%, from subclavian in 7.5%, and very rarely from the common carotid, aortic arch, brachiocephalic, internal thoracic, pericardiacophrenic, or vertebral. Thyroid ima artery is more common variety found in up to12.2% of the population. Two cadavers dissected in the anatomy department are presented with variations in the blood supply of the thyroid gland. The first case was a 61-year-old man with middle thymothyroid artery arising from the common carotid on the right side and inferior thyroid as a branch of the common carotid on the left. The second case was an 85-year-old female without inferior thyroid arteries bilaterally, replaced by thyroid ima arising from brachiocephalic artery. The awareness of such arterial pattern is crucial for the specialists in imaging and preoperative diagnosing and escaping eventual iatrogenic complications of thyroid gland.

The thyrocervical trunk: an analysis of its morphology and variations.

The number of studies on the variations of the branching of the TT is scarce, and those works that treat about the different types of the said trunk are oftentimes inconsistent. Therefore, the authors of the present study would like to propose a set of five types of TT, which were created based on observations of 41 computed tomography angiographies (82 TTs). To establish the anatomical variations, their prevalence, and morphometrical data regarding the TT and its branches, a retrospective study was performed. The results of 55 consecutive patients who underwent neck and thoracic computed tomography angiography (CTA) were analyzed. The analysis was performed on a total of 82 TTs of 41 patients, aged 15 to 82 years (mean age: 46 years; SD: 18.4), of which 16 (39.0%) were females, and 25 (61.0%) were males. Initially, 11 types of variations were evaluated, of which types 1-4 constituted 89.0%. Furthermore, a new method of classification of the anatomical variations of the TTs has been established. In this study, the variety of the branching and morphology of the TT was presented, proposing its novel classification based on the five most commonly prevalent types. Types 1 and 2 were the most common, with a prevalence of 26.8% each. This work also provides physicians with crucial data about the morphology of the TT and its branches, which can surely be of use when performing endovascular or reconstructive procedures in the cervical region.

The costocervical trunk: A detailed review.

The number of studies on the anatomy of the costocervical trunk (CCT) is scarce, and the actual prevalence of this structure is unknown. Therefore, the authors of the present study would like to propose a set of four types of CCT, which were created based on observations of computed tomography angiographies (75 CCTs). A retrospective study was conducted to establish variations and the morphometric properties of the CCT. The results of 55 consecutive patients who underwent neck and thoracic computed tomography angiography (CTA) were analyzed in March 2022. The analysis was performed on a total of 75 CCTs. Of these, 32 were from women (42.7%) and 43 were from men (57.3%). Branching variations of each CCT were thoroughly analyzed. A classification of the branching pattern of the CCTs was made and consisted of four types. In the present study, the variety of branching and morphology of CCT was analyzed, proposing its novel classification based on the four most frequently observed types. Type 1 was the most prevalent (76.1%), having a similar origin and branching pattern as described in the major anatomical books. CCT was found to be absent in 23.94% of the cases, making it a somewhat less consistent branch of the SA. Understanding the variability of the anatomy of the CCT can be a great tool for physicians performing endovascular procedures in the cervical region.

Aberrant branches of the subclavian artery and their relationship with the phrenic nerve and the brachial plexus / Ramas aberrantes de la arteria subclavia y su relación con el nervio frénico y el plexo braquial

SUMMARY: Variations in subclavian artery branches are relatively common and may impact surgical procedures and effects. During educational dissection of a male cadaver, we encountered an extremely rare variation of the right subclavian artery branches. The internal thoracic artery, the thyrocervical trunk, and the costocervical trunk arose from the third part of the right subclavian artery. In addition, the phrenic nerve displaced remarkably laterally by the thyrocervical trunk, and the course of the costocervical trunk was between the upper trunk and the middle trunk of the brachial plexus. These variations may pose a potential risk for nerve compression and increase the risk of arterial and nerve puncture. This case report would bring attention to the possibility of other similar cases, and early detection of these variations through diagnostic interventions is helpful to reduce postoperative complications.

RESUMEN: Las variaciones en las ramas de la arteria subclavia son relativamente comunes y pueden afectar los procedimientos y efectos quirúrgicos. Durante la disección educativa de un cadáver masculino, encontramos una variación extremadamente rara de las ramas de la arteria subclavia derecha. La arteria torácica interna, el tronco tirocervical y el tronco costocervical nacían de la tercera parte de la arteria subclavia derecha. Además, el nervio frénico se desplazaba lateralmente por el tronco tirocervical, y el trayecto del tronco costocervical se encontraba entre el tronco superior y el tronco medio del plexo braquial. Estas variaciones pueden suponer un riesgo potencial de compresión nerviosa y aumentar el riesgo de punción arterial y nerviosa. Este reporte de caso llamaría la atención sobre la posibilidad de otros casos similares, y la detección temprana de estas variaciones a través de diagnósticos es útil para reducir las complicaciones postoperatorias.

Evaluación morfológica del músculo subclavio en una muestra de material de autopsia: inferencias clínicas / Morphological evaluation of the subclavian muscle in a sample of autopsy material: clinical inferences

RESUMEN: El músculo subclavio (MS) guarda estrecha relación con las estructuras neurovasculares (ENV) en el tercio medio de la región clavicular, situación de suma importancia para la realización de procedimientos invasivos de esta región. Pocos estudios han determinado la distancia desde el MS hacia la vena subclavia (VS), arteria subclavia (AS) y plexo braquial (PB). El propósito de este estudio fue valuar la expresión morfológica del MS y su relación con las ENV en una muestra de especímenes cadavéricos frescos. Estudio descriptivo en el que se realizó disección anatómica sobre la región clavicular de 30 especímenes de cadáveres humanos frescos no reclamados del Instituto Nacional de Medicina Legal y Ciencias Forenses, Colombia. Se realizó la caracterización cualitativa y cuantitativa del MS y se determinó la relación del MS con las ENV en la región clavicular. El MS presentó una longitud de 102,4±10,3 mm, con un espesor anteroposterior de 8,8±1,9 mm y superoinferior de 7,0±1,9 mm. El MS se caracterizó así: tipo I en 12 (40 %) especímenes, tipo II en 18 especímenes, tipo IIa: 10 especímenes. No encontramos tipos III y IV. La VS, AS y PB se relacionaron con el MS en el tercio medial y medio de su longitud a una distancia desde el margen superior del MSde 9,4±2,2 mm, 11,3±2,1 mm y 12,0±1,5 mm respectivamente. Los MS se relacionaron con las ENV de la región clavicular en una zona comprendida entre el 36,2±3,6 % y 89,4±4,8 % de su longitud total. Los hallazgos cualitativos y morfométricos de este estudio enriquecen los conceptos anatómicos subclaviculares y son de utilidad para el manejo quirúrgico de fracturas de clavícula.

SUMMARY: The subclavian muscle (MS) is closely related to the neurovascular structures (VNS) in the middle third of the clavicular region, and is critical when performing invasive procedures in this region. Few studies have determined the distance from the MS to the subclavian vein (VS), subclavian artery (AS) and brachial plexus (PB). The purpose of this study was to evaluate the morphological expression of MS and its relationship with VNS in a sample of fresh cadaveric specimens. The study involved the anatomical dissection in the clavicular region of 30 specimens of fresh unclaimed human cadavers from the National Institute of Forensic Medicine and Sciences, Colombia. The qualitative and quantitative characterization of the MS was carried out and the relationship of the MS with the VNS in the clavicular region was determined. The MS presented a length of 102.4 ± 10.3 mm, with an anteroposterior thickness of 8.8 ± 1.9 mm and a superoinferior thickness of 7.0 ± 1.9 mm. The DM was characterized as follows: type I in 12 (40 %) specimens, type II in 18 specimens, type IIa: 10 specimens. We did not find types III and IV. The SV, AS and PB were related to the MS in the medial and middle third of its length at a distance from the upper edge of the MS of 9.4 ± 2.2 mm, 11.3 ± 2.1 mm and 12.0 ± 1,5 mm respectively. The MS were related to the VNS of the clavicular region in an area between 36.2 ± 3.6 % and 89.4 ± 4.8 % of its total length. The qualitative and morphometric findings of this study enrich the subclavicular anatomical concepts and are useful for the surgical management of clavicle fractures.

Effects of the Vertebral Artery Ostium/Subclavian Artery Angle on In-Stent Restenosis after Vertebral Artery Ostium Stenting.

METHODS: Between January 2016 and October 2018, sixty-four consecutive patients who underwent a total of 66 stenting procedures were screened for symptomatic and asymptomatic atherosclerotic VAOS. Of these patients, 57 had complete follow-up data. The baseline patient demographics and morphological features of the VAO were recorded. Potential factors influencing ISR, including conventional cerebrovascular disease risk factors, were assessed, together with outcome events including recurrent transient ischemic attack (TIA), stroke, and vascular-related mortality. RESULTS: The average follow-up period was 13.2 ± 4.6 months. Technical success was achieved in all interventions. The degree of stenosis was reduced from 77.2 ± 6.1% to 13.7 ± 8.9% after the procedure. ISR was detected in eight treated vessels (14.0%) and occlusion in two (5.3%) arteries. Of the 57 patients, one had an ischemic stroke and 5 had TIAs. The angle of the VAO at the subclavian artery was associated with the risk of restenosis (preoperative, P = 0.04; postoperative, P = 0.02). CONCLUSIONS: Stenting is a feasible and effective treatment for VAOS. The angle of the VAO at the subclavian artery may contribute to the development of ISR.

A systematic classification of the left-sided aortic arch variants based on cadaveric studies' prevalence.

INTRODUCTION: Typical branching pattern of the left-sided aortic arch consists of the brachiocephalic trunk (BCT), the left common carotid artery (LCCA) and the left subclavian artery (LSA). Variant patterns have been associated with a broad spectrum of pathologies. The meticulous knowledge of potential aortic arch variants is of utmost importance to radiologists, interventional cardiologists, vascular and thoracic surgeons. The current systematic review collects all aortic arch branching patterns and their frequency as published by various cadaveric studies, calculates prevalence taking into account the gender and the different people background, as well. All extracted variant patterns are classified into types and subtypes according to the number of emerging (major and minor) branches (1, 2, 3, 4 and 5) and to the prevalence they appear. In cases of similar prevalence, total cases were taken into consideration; otherwise the variants were classified under the title "other rare variants". METHODS: A systematic online search of PubMed and Google books databases was performed only in cadaveric studies. RESULTS: Twenty studies with typical (78% prevalence) and variable (22%) branching patterns were included. Types 3b, 2b, 4b, 1b and 5b had a prevalence of 81%, of 13%, of 5%, 0% and of 0%, respectively. Common variants were the brachiocephalico-carotid trunk (BCCT, 49% prevalence), the aberrant left vertebral artery (LVA, 41%) and the aberrant right subclavian artery (ARSA, 8%). LVA of aortic origin was detected in 32%, the bicarotid trunk (biCT) in 5% and the bi-BCT trunk in 3%. Thyroidea ima artery, a minor branch emerging from the aortic arch was found in 2%. Coexisted variants were detected in 4% (ARSA with a distinct RCCA and LCCA origin), in 3% (BCCT with a LVA of aortic origin), in 2% (ARSA with a biCT and a vertebrosubclavian trunk). CONCLUSION: No significant gender or ethnic differences exist among the 5 branching types. The proposed classification scheme aims to become a valuable and easy to use tool in the hands of all physicians involved in diagnosis and treatment of aortic arch pathology. It could be also useful in anatomical education, as well.

Left non-recurrent inferior laryngeal nerve in a patient with right-sided aortic arch and aberrant left subclavian artery.

Non-recurrent inferior laryngeal nerve (NRILN) is rare but one of the important anatomical variations in thyroid and parathyroid surgery. Almost all cases were observed on the right side with aberrant right subclavian artery and left NRILN have been reported in only five cases so far. Here, we reported a 38 year-old Japanese male with left NRILN accompanying adenomatous goiter. He was referred to our hospital for the surgical treatment of left thyroid goiter. Preoperative computed tomography revealed right-sided aortic arch and aberrant left subclavian artery with no signs of complete situs inversus viscerum, suggesting possible left NRLN. Left hemithyroidectomy was performed using nerve monitoring system. Intraoperatively, left recurrent laryngeal nerve was not identified along tracheoesophageal groove, but directly originated from vagal nerve and was running horizontally to larynx. Mobility of vocal cords were not impaired and postoperative course was uneventful. During thyroid surgery for the patients with right-sided aortic arch, meticulous care should be taken using nerve monitoring system to avoid nerve injury.

Anatomy and Embryology of the Thoracic Outlet.

The thoracic outlet is the space between the thorax and axilla through which the subclavian vein, subclavian artery, and brachial plexus travel from their central origins to their peripheral termini. Its bounds include the clavicle, first thoracic rib, insertion of the pectoralis minor muscle onto the coracoid process of the humerus, and the sternum. It contains three areas: the scalene triangle, the costoclavicular space, and the subcoracoid or pectoralis minor space. Aberrant anatomy is common in the thoracic outlet and may predispose patients to compression of the neurovascular bundle and development of clinical thoracic outlet syndrome (TOS). Much of this aberrancy is explained by the embryologic origins of the structures that comprise the thoracic outlet. A thorough understanding of this anatomy and embryology is therefore critical to the understanding of TOS.

Aberrant right subclavian artery in a dog - case report / [Ectopia de artéria subclávia direita em cão - relato de caso]

The brachiocephalic trunk and the left subclavian artery originate from the aortic arch, and both supply blood to the head, neck, and thoracic limbs. Anatomical variations, such as an aberrant right subclavian artery, are congenital conditions rarely observed in dogs, Thus, the objective of the present report was to describe a case of aberrant right subclavian artery in a 9-year-old Dalmatian. However, this anomaly was a finding in which the patient was asymptomatic during its 9 years of life and only at this age did he exhibit signs including sialorrhea, vomiting, hyporexia, and noisy deglutition. Blood count, biochemical profile, and thoracic radiography led to a diagnosis of megaesophagus and aspiration pneumonia. Despite the recommended treatment, the patient did not respond well; as such, the owner elected to euthanize the animal. On necropsy, the right subclavian artery originated directly from the aortic arch, followed a route from left to right dorsally to the esophagus, and then formed an impression of the vascular path over the muscular wall of the esophagus. The esophagus, in turn, exhibited a flaccid wall and dilation in the caudal portion to the vascular path made by the ectopic position of the right subclavian artery.(AU)

O tronco braquiocefálico e a artéria subclávia esquerda emergem do arco aórtico e são responsáveis por fazerem o suprimento sanguíneo para cabeça, pescoço e membros torácicos. Variações anatômicas, como a ectopia da artéria subclávia direita, são alterações congênitas raramente encontradas em cães, cujas alterações do sistema digestivo acontecem em pacientes recém-desmamados e não em adultos. Assim, o objetivo deste relato é descrever um caso de ectopia da artéria subclávia direita em uma cadela, Dálmata, de nove anos de idade. No entanto, essa anomalia foi um achado do qual o paciente foi assintomático durante os nove anos de vida e somente com essa idade apresentou sinais como sialorreia, vômito, hiporexia e deglutição ruidosa. O hemograma e os perfis bioquímicos, associados à radiografia torácica, levaram a um diagnóstico de megaesôfago e pneumonia aspirativa. Mesmo seguindo o tratamento recomendado, houve piora clínica do quadro e o animal foi submetido à eutanásia. À macroscopia, a artéria subclávia direita originava-se direto do arco aórtico, fazia um percurso da esquerda para a direita dorsalmente ao esôfago e, então, formava uma impressão do trajeto vascular sobre a parede muscular do esôfago. O esôfago, por sua vez, apresentava parede flácida e dilatação na porção caudal ao trajeto vascular feito pela posição ectópica da artéria subclávia direita.(AU)

Applicability of a standardized thoracic endograft with a single branch for the left subclavian artery to treat aortic disease involving the distal arch.

OBJECTIVE: Coverage of the left subclavian artery (LSA) origin during thoracic endovascular aortic repair (TEVAR) is associated with increased neurologic complications. Our group is involved in the development of an off-the-shelf (OTS) thoracic endograft incorporating a left common carotid artery (LCCA) scallop and a retrograde inner branch for LSA perfusion. This study aimed to evaluate the arch morphology of patients treated by TEVAR and requiring LSA coverage to determine the applicability of this OTS device. METHODS: The preoperative anatomy of consecutive patients from three separate cohorts treated with TEVAR with LSA coverage was studied. High-quality preoperative computed tomography angiography images were analyzed on an imaging workstation. Location of the origin of the supra-aortic trunks and their anatomic relationship were depicted in all patients; the LCCA origin was set as reference point. We determined the proportion of arch morphology in our cohort of patients eligible for this OTS device configuration. RESULTS: There were 196 patients included in this study, 132 in the dissection cohort and 64 in the aneurysm cohort. The median length from the lower margin of the LCCA to the proximal aspect of the pathologic process was 25.0 mm (18.2-35.2 mm), with 68.4% (n = 134) of our cohort presenting with a proximal sealing zone length >20 mm. The median LCCA-LSA distance was 20.8 mm (16.6-25.4 mm). The median clock position of the LSA from the LCCA was -10 minutes (-30 to 0 minutes). In total, 127 patients (64.8%) could have been treated with the current OTS branched TEVAR configuration; 59 were excluded for proximal neck length distal to the LCCA <20 mm and 10 because of the clock position of the LCCA, and 9 first required a vertebral artery transposition. CONCLUSIONS: The low variability of LSA and LCCA locations in patients with distal aortic arch disease offers wide applicability of a new standardized thoracic branched endograft.

A novel case of multiple variations in the brachial plexus with the middle trunk originating from the C7 and C8.

The brachial plexus is an important nervous structure from which all major nerves to the upper limb arise. It typically originates from the anterior rami of the C5-T1 spinal nerves. As it passes laterally, the roots are successively organized into three trunks, six divisions, and three cords. The BP is susceptible to injury during the perinatal and postnatal periods, as well as in adulthood. Its structure can show considerable variation, and there is a wealth of literature describing its variations, providing indispensable information to neurosurgeons. Here, we report a novel unilateral variant of the brachial plexus found in an adult Japanese male cadaver. In this case, the middle trunk arose from the C7 and C8 spinal nerves, and the inferior trunk continued from the T1 alone. At the interscalene triangle, the subclavian artery was situated between the C8 and T1 nerves. The posterior cord arose from the posterior divisions of the superior and middle trunks, while the root from the T1 nerve/inferior trunk was absent. The anterior division of the middle trunk gave independent roots to the musculocutaneous and median nerves, without completely establishing the lateral cord. A communicating branch arose from the musculocutaneous nerve to join the median nerve. Some branches from the roots and cords also deviated from typical configurations. This case represents a rare combination of variations in the trunks, divisions, cords, and the median nerve and offers a valuable addition to the literature regarding variations in the brachial plexus.

New findings of branching variations in subclavian arteries and supra-aortic arteries in Felis catus.

The branching of blood vessels around the heart is varied in each animal. Three branching patterns of the brachiocephalic trunk in cats have been reported. However, supra-aortic arteries in the hearts of cats have never been investigated. In this study, we hypothesized that the variations of the aortic arch, supra-aortic arteries, and vena cava were observed in domestic cats. Sixty-one hearts obtained from the cadavers of domestic cats (Felis catus) were analyzed in terms of anatomical characteristics, size, and the length of these supra-aortic vessels by using a 3D scanner. New variations of the left and right subclavian arteries were observed using the location of the internal thoracic (ITA) and vertebral artery (VA) as the criterion to group the varying patterns. We found four patterns of the left subclavian artery, which included ITA budding contralateral before VA (5%), VA budding opposite to ITA (75%), VA budding contralateral before ITA (13%) and ITA budding ipsilateral before VA (7%). In contrast, only three patterns were found in the right subclavian artery, which included VA budding opposite to ITA (20%), VA budding contralateral before ITA (19%), and ITA budding contralateral before VA (61%). Moreover, although an average vascular diameter in male cats was higher than in female subjects, the supra-aortic blood volume in both sexes was not different. The findings of this study could help fill the existing gap of knowledge on the anatomical variations of supra-aortic arteries in cats and could be used in clinical applications based on relevant anatomical data.

Transradial Approach as the Primary Vascular Access with a 6-Fr Simmons Guiding Sheath for Anterior Circulation Interventions: A Single-Center Case Series of 130 Consecutive Patients.

OBJECTIVE: In coronary intervention, the transradial approach (TRA) is increasingly used as the primary vascular access because of its numerous advantages over the transfemoral approach. However, in neurointerventions, conventional TRA with a straight-shaped guiding system is used as an alternative vascular access because transradial carotid cannulation can be technically challenging for right common carotid artery (CCA) lesions with steep angulation to the right subclavian artery or left CCA lesions with a nonbovine origin. The purpose of the present study was to evaluate the feasibility and safety of TRA as the primary vascular access with a pre-shaped Simmons guiding sheath for anterior circulation interventions. METHODS: Between June 2018 and September 2019, 130 consecutive patients (75 carotid artery stenting and 55 cerebral aneurysm coiling cases) who underwent TRA as the primary vascular access were included in this study. A 6-Fr Simmons guiding sheath was introduced into the target CCA by selecting a cannulation technique based on preprocedural image assessment. We retrospectively analyzed the carotid cannulation success, procedural success, and periprocedural or vascular access site complications. RESULTS: Carotid cannulation (69 right CCA, 6 left CCA with a bovine origin, and 55 left CCA with a nonbovine origin) and the subsequent procedure were successfully performed for all 130 patients without periprocedural or vascular access site complications. CONCLUSIONS: TRA with a 6-Fr Simmons guiding sheath for anterior circulation interventions is highly successful and safe for all target CCAs and aortic arch types. This method can be utilized as the primary vascular access for anterior circulation interventions.

The brachial plexus - explaining its morphology and variability by a generic developmental model.

In classic anatomy teaching, the brachial plexus generally features as an enigmatic rote-learned structure, leaving the student with a feeling of complexity. The notion of complexity may increase in dissections, where plexuses significantly differing from the standard plexus model are readily found. This raises questions: what determines the existence and prevalence of variants and to what degree should they be considered anomalous? A model linking brachial plexus morphology and its variability to causative morphological parameters which would also standardize plexus description and teaching would be beneficial. The present study aims to provide such a model by analyzing the context of plexus development and applying this model in the analysis of plexus variability in anatomical specimens. Based on a thorough literature review, a generic developmental model was formulated and different factors of variability defined. In 56 plexuses, the proposed generic principles of plexus variability were found consistent with the variations encountered. Summarized, the modeled generic principles are as follows. Brachial plexus axon bundles grow out into an environment of chemical tracer paths in which constraints and obstacles are present: the geometry of the arm bud, cartilaginous bone precursors and vessels. The overall constancy of these factors generates a gross plexus outline, while the variability in these factors gives rise to typical plexus variations. The usefulness of the model derives from the fact that the variability of the main morphologically determining factors is not random but is the expression of the possibilities of the embryological substrate. Within the model, the major plexus morphological determinant is the segmental position of the subclavian artery, which is determined by the segment level of the intersegmental artery from which it develops. Normally, the subclavian artery develops from intersegmental artery i7. However, the subclavian artery can develop from inferior or superior segmental levels, from intersegmental artery i8 or i6, and possibly also from i9 or i5. Each of these arterial variants creates a typical, morphologically distinct, predictable plexus configuration. Superimposed on these basic plexus configurations, the underlying embryological substrate may develop further variability by integrating remnants of other intersegmental arteries into the arterial network. The resulting plexus configurations are further modified by local factors, e.g. the splitting of outgrowing axon bundles around vessels. A large split in the lateral cord around a large vein or veins crossing from lateral to medial, tangentially cranially over the subclavian artery was found in 54% of the 56 investigated BP and therefore might be added to plexus teaching. The distinct plexus morphologies associated with the subclavian artery segmental levels were further found associated with, among others, typical variations in the pectoral nerves and their ansas; these associations were also modeled. The presented models could allow brachial plexus rote learning to be replaced by a more insightful narrative of formative principles suitable for teaching. Clinically, improved understanding of the relationship between plexus variability and the local anatomical environment should be relevant to brachial plexus surgery and reconstruction.