Variation in the Branches of Arch of Aorta in Patients Undergoing Contrast Enhanced Multidetector Computed Tomography in a Tertiary Centre, Nepal.

INTRODUCTION: Variations in the branching pattern of the Arch of Aorta (AoA) are common in patients undergoing contrast-enhanced Multidetector Computed Tomography, the identification of which is crucial in managing patients undergoing cardiovascular/neck surgeries and interventions. METHODS: This prospective cross-sectional study involved 513 patients who were sent to the Department of Radiology for evaluation of various pathologies of chest and neck between August 2018 and July 2019. After approval from the Institutional Review Committee {Reference No: 11(6-11) E2/075/076}, contrast-enhanced computed tomography images were evaluated with variations in branches of the left-sided arch of the aorta and symptoms associated. RESULTS: Variations in branches of the arch of aorta were seen in 69 (13.45%; 95% CI: 10.60%-16.71%) of cases, left common carotid artery and brachiocephalic trunk having common origin or common trunk was 51(9.94%). The mean age was 52.4±20 years (Range 3 months to 92 years) with male to female ratio of 1.3:1. CONCLUSIONS: Contrast-enhanced computed tomography is the modality of choice for the detection of the variations in branches of AoA, recognition of which is crucial in vascular intervention and surgical procedures to reduce the postoperative morbidity and mortality of the patients.

Thyroidea Ima Artery in Cadavers of a Medical College in Nepal: A Descriptive Cross-sectional Study.

INTRODUCTION: Thyroidea ima artery is a variant arterial branch of arch of aorta supplying the thyroid gland. Understanding the anatomic variances and correctly identifying the thyroidea ima artery is crucial to preventing serious complications both before and after neck surgery. The aim of this study was to find out the prevalence of thyroidea ima artery in cadavers of a medical college in Nepal. METHODS: A descriptive cross-sectional study was carried out at the department of anatomy in Janaki Medical College, Dhanusha, Nepal from 27 December 2022 to 30 June 2023 after ethical clearence from the same institution. Origin of thyroidea ima artery was observed, recorded and photographed. Convenience sampling method was used. Data was analyzed using Microsoft Excel. RESULTS: Out of 35 cadavers, thyroidea ima artery was present in 2 (5.71%), arising from brachiocephalic trunk just proximal to its bifurcation and there was absence of inferior thyroid artery. CONCLUSIONS: Findings from our study showed that thyroidea ima artery originated from brachiocephalic trunk with absence of inferior thyroid artery.

A thyroidea ima artery variation providing collateral circulation to the mediastinum.

The thyroidea ima artery (TIA) is a highly variable arterial deviation of the blood supply to the thyroid gland with critical implications for surgical neck procedures such as tracheostomy. Though relatively common in the population at large (~ 4%), most TIA variations are related to the origin of the artery and whether it emerges from the common sites of the brachiocephalic trunk, aortic arch, and right common carotid artery, or another more unique vessel-as opposed to its dispersion pattern. TIA variants generally supply the thyroid gland, occasionally co-occurring with absent thyroid arteries. Here, we report on a unique case of a four-pronged variation of the TIA discovered during an anatomy laboratory dissection of first-year medical students. This variant originated from the brachiocephalic trunk and had three branches terminating in the thyroid gland and a fourth branch traveling into the thorax to provide accessory circulation in the mediastinum. Specifically, small arterial branches from the inferior TIA branch supplied the anterior pericardium and surrounding adipose tissue, in addition to normal pericardiacophrenic circulation. We discuss the potential embryological and clinical relevance of this unique variation and voice further support for imaging as a requirement before surgical neck procedures to prevent catastrophic bleeding in the event of a TIA variant.

Anatomical and positional variants of the brachiocephalic trunk in a Mexican population.

BACKGROUND: Brachiocephalic trunk (BCT) variants may have a clinical impact during surgical procedures, some of which could be fatal. The objective of this study was to classify height positions of the BCT and report their prevalence in a Mexican population. METHODS: Patients: A retrospective, descriptive, observational, and cross-sectional was performed using computed tomography angiography (CTA) of adult (> 18 years of age) patients, without gender distinction, of Mexican origin. Measuring techniques were standardized using the suprasternal notch to analyze linear and maximum heights, linear and curved lengths, and the vertebral origin and bifurcation levels of the BCT. RESULTS: A total of 270 CTA were obtained (66.7% men and 33.3% women). A high position of BCT was present in 64.81% (n 175/270). The mean linear medial height was 0.58 ± 1.91 cm, the maximum height of the free edge was 3.85 ± 2.04 cm, side length of the midline at the maximum height of the free edge was 1.46 ± 2.59, linear length 3.72 ± 0.70, and a curve length 3.99 ± 0.79. The BCT origin was most predominant at the T3 (57.9%) and T4 (27.0%) vertebral levels, with the bifurcation at T2 (57.9%) and T1 (36.2%). CONCLUSIONS: There is a high prevalence of high position BCT in our population. Patients should be assessed before any procedures in the area, due to the potential risk of complications.

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.

Chest X-Ray to Predict Difficult Right Transradial Cardiac Catheterization Due to Vascular Tortuosity: A Retrospective Study.

Tortuous brachiocephalic artery may lead to procedural difficulties among patients undergoing right transradial cardiac catheterization. By prospectively identifying patients with this anatomic barrier, operators may choose an alternate catheterization site to avoid complications from switching midway. To assess brachiocephalic artery tortuosity, 23 patients who underwent challenging diagnostic coronary angiography by right transradial access were compared to a control group of 29 patients who lacked brachiocephalic artery tortuosity. Preprocedural, plain chest x-rays were analyzed for measurable anatomic parameters and assessed for statistical significance between groups. The vertebrocarinal distance-the distance in centimeters between the spinous process of the first thoracic vertebra (T1) and the most caudal point of tracheal bifurcation, measured at and parallel to the midline-was the most reliable and statistically significant radiographic predictor of brachiocephalic artery tortuosity. Using this novel concept reduces procedure duration and radiation exposure by decreasing transradial cardiac catheterization failure rates.

Geometric Pattern of Proximal Landing Zones for Thoracic Endovascular Aortic Repair in the Bovine Arch Variant.

OBJECTIVE: The aim was to investigate whether the "bovine" aortic arch (i.e. arch variant with a common origin of the innominate and left carotid artery (CILCA)) is associated with a consistent geometric configuration of proximal landing zones for thoracic endovascular aortic repair (TEVAR). METHODS: Anonymised thoracic computed tomography (CT) scans of healthy aortas were reviewed to retrieve 100 cases of CILCA. Suitable cases were stratified according to type 1 and 2 CILCA, and also based on type of arch (I, II, and III). Further processing allowed calculation of angulation and tortuosity of the proximal landing zones. Centre lumen line lengths of each proximal landing zone were measured in a view perpendicular to the centre line. All geometric features were compared with those measured in healthy patients with a standard arch configuration (n = 60). Two senior authors independently evaluated the CT scans, and intra- and interobserver repeatability were assessed. RESULTS: The 100 selected patients (63% male) were 71.4 ± 7.7 years old. Type 1 CILCA (62/100) was more prevalent than type 2 CILCA (38/100), and the two groups were comparable in age (p = .11). Zone 3 presented a severe angulation (i.e. > 60°), which was greater than in Zone 2 (p < .001), and a consistently greater tortuosity than Zone 2 (p = .003). This pattern did not differ between type 1 and type 2 CILCA. A greater tortuosity was also observed in Zone 0, which was related to increased elongation of the ascending aorta (i.e. Zone 0), than the standard configuration. The CILCA had an overall greater elongation, and Zone 2 also was specifically longer. When stratifying by type of arch, reversely from Type III to Type I, the CILCA presented a gradual flattening of its transverse tract, which entailed a consistent progressive elongation (p = .03) and kinking of the ascending aorta, with a significant increase of Zone 0 angulation to even a severe degree (p = .001). Also, from Type III to Type I, Zone 2 presented a progressively shorter length (p = .004), which was associated with increased tortuosity (p < .05). Mean intra- and interobserver differences for angulation measurements were 1.4° ± 6.8° (p = .17) and 2.0° ± 10.1° (p = .19), respectively. CONCLUSION: CILCA presents a consistent and peculiar geometric pattern compared with standard arch configuration, which provides relevant information for TEVAR planning, and may have prognostic implications.

[Anatomical relations in innominate artery compression syndrome: retrospective case-control study]. / Relaciones anatómicas en el síndrome de compresión traqueal por la arteria innominada: estudio de casos y controles retrospectivo.

OBJECTIVE: To compare the anatomical relations between brachiocephalic trunk (BT), trachea, spine and sternum in patients with Innominate Artery Compressing Syndrome (IACS) and control patients. METHODS: Retrospective case-control study of patients diagnosed with IACS in our center, in whom vascular computerized tomography (CT) was performed. The CT were compared with those of control patients free of obstructive respiratory pathology, without congenital heart disease and free of deforming thoracic mass, in whom CT was performed due to other reason. Each case was paired with three controls per case, in similar age groups. The significance value was set as p<0,05. RESULTS: Nine cases were included (7 boys and 2 girls) with their 27 respective controls (20 boys and 7 girls). The BT origin position with respect to the trachea, thought as a clock face, was 01:30 (00:30- 03:00) in cases and 01:30 (00:30-02:30) in controls. No differences were observed (p=0.72). The relation between anteroposterior/transversal tracheal diameters was 0.44 (0.184-0.6) in cases, 0.885 (0.64-1.16) in controls. The sternum-trachea/sternum-vertebra relation was 0.685 (0.6-0.76) in cases, 0.67 (0.49-0.79) in controls. No differences were observed (p=0.75). The angle of thoracic kyphosis was 29º (9º-34º) in cases, 24º (4º-33º) in controls. There were no statistically significant differences (p=0.45). CONCLUSIONS: We found no differences between the two groups in the BT origin in relation to the trachea. In all cases, the origin was on the left side of the body. Therefore, we question the premise that IACS is due to a more left origin of BT.

OBJETIVO: Analizar las distintas relaciones anatómicas entre el tronco braquiocefálico (TB), la tráquea, la columna vertebral y el esternón en pacientes diagnosticados de síndrome de compresión de la arteria innominada (SCAI) y compararlas con las de los pacientes controles. METODOS: Estudio retrospectivo de casos y controles de los pacientes diagnosticados de SCAI en nuestro centro, a los que se realizó una tomografía computarizada con contraste (TC) y/o resonancia magnética (RM). Se compararon con pacientes controles, elegidos entre enfermos sin malformación cardiaca ni masa torácica deformante, y a los que se les había realizado una TC vascular torácico por distintos problemas respiratorios no obstructivos. Por cada caso, se seleccionaron tres controles, agrupándolos por grupos de edades. Se estableció pp<0,05 como valor de significancia estadística. RESULTADOS: Se incluyeron 9 casos (7 niños y 2 niñas) y 27 controles (20 niños y 7 niñas). Se estudió en cortes transversales de la TC la posición horaria del nacimiento del TB respecto a la tráquea, resultando en los casos una posición mediana correspondiente a las 01:30 (00:30- 03:00) y en los controles a las 01:30 (00:30-02:30), sin hallarse diferencias significativas (p= 0,72). Se midió el ratio entre el diámetro anteroposterior/diámetro transverso de la tráquea, este fue de 0,44 (0,184-0,6) en los casos y 0,885 (0,64-1,16) en los controles (p=0,00001). El ratio de la distancia esternón-tráquea/esternón-columna fue 0,685 (0,6-0,76) en los casos y 0,67 (0,49-0,79) en los controles (p=0,75). El ángulo de la cifosis torácica fue 29º (9-34) en los casos y 24º (4-33) en los controles (p=0,45). CONCLUSIONES: No observamos la existencia de diferencias en el nacimiento del TB en pacientes con SCAI respecto a la población general. El TB nace en todos los niños en el lado izquierdo del cuerpo, poniendo en duda que el SCAI sea debido a un nacimiento más izquierdo del TB.

Imaging of the age-related anatomical relationship between the innominate artery and the trachea.

PURPOSE: To measure the age-dependent changes of anatomical positions and relations between the trachea, cricoid cartilage (CC), and innominate artery (IA) in adults by computed tomography (CT). METHODS: A retrospective cohort reviewing images of 127 consecutive adult patients who underwent CT angiography (CTA) of the neck. The trachea-to-IA (T-IA) distance was measured as the minimal horizontal distance between them. The vertical distance between the CC and the IA was measured between the axial section, demonstrating the CC's inferior border to the axial section at the level of the T-IA measurement. RESULTS: Images of 125 patients (median age 53 years, range 18-89; 74 males) were reviewed. The mean T-IA distance was 2.3 ± 1.1 mm for males and 1.7 ± 0.9 mm for females (P = 0.002). The vertical C-IA distance was 44.2 ± 11.4 mm and 49.5 ± 12.5 mm for males and females, respectively (P = 0.01). Age correlated negatively with the vertical C-IA distance (P < 0.0001) and positively with the T-IA distance (P < 0.0001). The rate of IA variants was 23.2%, with no significant difference between the measurements of distances among patients with or without IA variants. CONCLUSIONS: This is the first description of the relationships between the trachea, CC, and IA distances in adults as depicted on CTA. The T-IA distance becomes larger while the T-CC distance becomes shorter with age.

Various branching patterns of the aortic arch in the Siberian roe deer (Capreolus pygargus, Pallas, 1771) on Jeju Island.

This study examined and compared the branching pattern of the aortic arch (AA) and its major branches in the Siberian roe deer (Capreolus pygargus) on Jeju Island (Jeju roe deer [JRD]) with those in the roe deer of the Korean peninsula (mainland roe deer [MRD]). Seven of the nine expected types was observed in the arterial silicone casts of 29 deer (10 males, 19 females). The JRD was identical to the MRD in that absence of the typical pattern; however, the main three pattern types differed between the two. This difference resulted from differences in the branching patterns of the right subclavian artery and costocervical trunk. In conclusion, the JRD has different type of AA from the MRD.

Prevalence and Types of Aortic Arch Variants and Anomalies in Congenital Heart Diseases.

RATIONALE AND OBJECTIVES: Aortic arch (AA) variants and anomalies are important to recognize in patients with congenital heart disease (CHD) before surgery or intervention. The aim was to study the prevalence of AA anomalies and variants in patients with CHD compared to a control group. The secondary outcome was to report the associations between common variations of AA and specific types of CHD. MATERIALS AND METHODS: After institutional review board approval, computed tomography studies of 352 CHD patients and control group of 400 consecutive computed tomography scans of the thorax were evaluated. The AA was assigned to one of seven common types, and their distribution was compared between CHD and control. The distribution of the AA anomalies and variants was evaluated as regard specific types of CHD and the visceroatrial situs. RESULTS: Normal three-vessel branching pattern was the commonest in both groups, but was present in only 50.5% in the CHD compared to 68.5% in the control group, p < 0.00001. Right AA and aberrant right subclavian artery were significantly more common in CHD than control group (18.1% versus 0.25%, p < 0.00001) and (4.5% versus 0.25%, p = 0.0001), respectively. Direct aortic origin of left vertebral artery was insignificantly more common in CHD group (4.2% versus 2.7%, p = 0.258). Brachiobicephalic trunk was significantly more common in control than CHD group (27.7% versus 19.3%, p = 0.007). CONCLUSION: Normal three-vessel AA was significantly less common in CHD. AA anomalies (right arch and aberrant right subclavian) were more common in CHD than control, while AA variants (brachiobicephalic trunk and direct aortic origin of left vertebral artery) were not.

Anatomical variations of the aortic arch branches in a sample of Chinese cadavers: embryological basis and literature review.

OBJECTIVES: The aim of this study is to determine the incidence and explore the types of aortic arch branch variations found in our cadavers. METHODS: The types and incidence of aortic branch variations in 120 cadavers were analysed after careful dissection. RESULTS: One hundred and six of 120 cadavers had normal aortic arch branches and gave rise to usual branches, namely the brachiocephalic trunk, the left common carotid artery and the left subclavian artery. The remaining 14 cadavers had 2 basic types of branch variations, thus accounting for an incidence of 11.67%. A total of 9 aortic arches emitted 4 branches; the brachiocephalic trunk, the left common carotid artery, the left vertebral artery and the left subclavian artery (incidence 7.5%). The second subgroup of 5 cadavers also emitted 4 aortic branches: the right common carotid artery, the left common carotid artery, the left subclavian artery and the right subclavian artery (incidence 4.16%). In this group, the right subclavian artery sprung as a distal branch of the aortic arch (descending), thus making a vascular ring that takes a superoposterior course round the back of the trachea and the oesophagus to reach the right side. There was a single cadaver, different from the other 4 aortic branches of the second group which had a common origin for the common carotid arteries, while the left subclavian artery and distally placed right subclavian artery were present. We did not observe any Kommerell's aortic diverticula. CONCLUSIONS: The variations of aortic arch branching are complex and diverse due to varied possible alterations in the embryological processes. There is an imperative need for further research on these variations to elucidate the possible relationships with clinical diagnostic or surgical events.

[Data on ultrasonographic anatomy of precanal segment of the vertebral artery]. / Dannye po ul'trazvukovoi anatomii dokanal'nogo segmenta pozvonochnoi arterii.

Described in the article are the results of using ultrasonographic duplex scanning for studying anatomical peculiarities of the precanal segment of the human vertebral artery. PATIENTS AND METHODS: Ultrasonographic duplex scanning (USDS) of the extracranial portions of brachiocephalic vessels was performed in a total of 215 inpatients without haemodynamically significant stenoses of the arteries of the vertebrobasilar basin. The patients found to have pathological alterations in the vertebrobasilar basin were excluded from the examined group. We studied the first segment of the vertebral artery from the origin to its entry into the canal of the transverse processes of cervical vertebrae (V1 segment according to the ultrasonographic nomenclature). We measured the diameter of the vertebral artery, assessing the pattern the vessel's passage, presence of pathological tortuosity, topographic interrelations between the V1 segment of the vertebral artery and structures of the neck, as well as analysing age-specific alterations in the anatomy of the vertebral artery. RESULTS: By means of duplex scanning we in a non-invasive manner managed to gain a deeper insight into the anatomical peculiarities of the passage and structure of the initial portion of the human vertebral artery, as well as the differences in the structure between the contralateral vertebral arteries. We determined the average values of the diameters of the vertebral artery, its area, topographical relationships with the surrounding anatomical reference points along the length of the precanal segment, available for visualization by this method of study, and age-related peculiarities of the anatomy of the vertebral artery. CONCLUSIONS: Ultrasonographic duplex scanning of the extracranial portions of brachiocephalic vessels in humans is an effective, available and accurate technique making it possible to assess the anatomy of the initial portion of the vertebral artery. The average values of the diameters and area of the transverse section of the left vertebral artery turned out to be significantly greater than similar values of the right vertebral artery in the overwhelming majority of cases. Due to structural peculiarities of the aortic arch branches, in particular, independent origin of the left subclavian artery from the aortic arch, the left vertebral artery has, as a rule, greater length than the right one and differs by the topographical correlations with the surrounding structures on the neck, which is confirmed by the ultrasonographic method of study. The ultrasonographic method of study makes it possible to sufficiently effectively assess the difference in depth of the passage of the trunk of the vertebral artery in tissues of the fascial spaces of the neck in representatives of various types of the body-build. We also revealed a tendency towards a tortuous passage of the vertebral artery in the precanal segment in 35-44% of cases irrespective of the body-build, age and gender.

[Significance of the definition and detailing of the central neck compartment in the treatment of thyroid carcinoma].

The cervical lymph node metastasis is a risk factor for the high recurrence rate and low survival rate in patients with thyroid carcinoma (especially for age ≥45 years old), which is the most common head and neck carcinoma. The neck lymphatic metastasis, mostly occurring in the central neck compare, is diagnosed among 20%-90% of patients with differentiated thyroid carcinoma. To definite the anatomic boundaries of the central lymph nodes and their subgroups is significantly important for thyroid carcinoma, such as the determination of surgical extent, the evaluation of prognosis and the choice of different treatment strategies. This paper aims to describe the anatomic boundaries and the components of the central neck compartment and the role of individual subgroups in thyroid carcinoma. We think that the central neck compartment is bounded superiorly by the hyoid bone, inferiorly by the innominate artery on the right and the corresponding axial plane on the left, laterally by the carotid arteries. The superior mediastinal lymph nodes should be the important subgroups of the central neck compartment in thyroid carcinoma. When the prophylactic central lymph node dissection for involved lymph nodes is performed in thyroid carcinoma, we should pay more attention to the superior mediastinal lymph nodes.

High-riding brachiocephalic (innominate) artery during surgical tracheostomy.

Two cases of a high-riding innominate artery, which were found during routine surgical tracheostomy. A cartilage flap was applied to cover the significant vessel to prevent the life-threatening complications. These two cases were followed up for 2 months without any adverse events. We discussed the related vascular anatomy, imaging studies and brief literature review.

The Branching Pattern of the Brachiocephalic Trunk in the Donkey (Equus asinus).

Donkeys are a member of the horse family (Equidae) and share a common ancestor. However, in morphological terms, donkeys and horses are regarded as two separate subgenus. Given variations in the branching pattern of the brachiocephalic trunk (BCT) in different species of animals and the use of donkeys in anatomy courses at colleges of veterinary medicine, we conducted this study in order to investigate the branching patterns of BCT and to describe detailed morphological information regarding donkeys. Seventeen mature donkeys were examined following euthanasia by exsanguination from the common carotid artery under general anaesthesia. Thirteen donkeys were embalmed and injected with coloured latex from BCT origin for better visualization of vessels. Four other donkeys were freshly studied without the embalming procedure. In all cases, the BCT was the only branch of the aortic arch and branched into the left subclavian (LSb) artery, the right costocervical trunk, the right subclavian (RSb) artery and the bicarotid trunk. The main branching pattern of the RSb was the costocervical trunk, the vertebral artery, the internal thoracic artery and the superficial cervical artery. The deep cervical artery branched from the costocervical trunk. The major branching pattern of the LSb was the vertebral artery, the internal thoracic artery and the superficial cervical artery. In donkeys, the external thoracic artery branches from the internal thoracic artery. Results obtained from this study indicate that BCT branching in donkeys has some similarities and differences as compared to that in horses and in the Caspian miniature horse.

Unilateral occurrence of five different thyroid arteries-a need of terminological systematization: a case report.

This article highlights an unusual and unilateral variation in the blood supply to the inferior portion of the thyroid gland observed on the right lobe during anatomy dissection course. The rare variation of the occurrence of two anomalous arteries: the middle thyroid artery and the aberrant accessory inferior thyroid artery, and one uncommon variant, the thyroid ima artery, was detected in an adult female cadaver. The two generally constant arteries, the superior thyroid artery and the inferior thyroid artery, have been found in their usual anatomical location. Both the middle thyroid artery and aberrant accessory inferior thyroid artery arose from the right common carotid artery. The middle thyroid artery coursed as a very short branch ventromedially to enter the inferior lateral portion of the right lobe of the thyroid gland. It was at the same level, in which the inferior thyroid artery reached the lateral border of the thyroid gland. The aberrant accessory inferior thyroid artery originated similarly, from the ventromedial surface of the right common carotid artery and passed to supply the inferior pole of the right lobe. The thyroid ima artery was found to arise from the brachiocephalic trunk, entering the isthmus of the thyroid gland. Information about the embryological background might be helpful to clarify why such a type of variation occurs. It is necessary to understand the possible existence of this anomaly, to carry out successful radical neck dissection and to minimize the risk of postoperative complications in patients.

Rare anatomical variation of the brachiocephalic trunk encountered in tracheostomy.

Tracheostomy is a common procedure in head and neck surgery and emergency medicine to secure a patent airway. Surgeons should always be aware of anatomical variants of the branches of the aortic arch, which could lead to life-threatening complications. Open tracheostomy is the safest emergency procedure.

Risk assessment of high-lying innominate artery with neck surgery.

CONCLUSION: A high-lying innominate artery (the upper edge of the innominate artery across the anterior midline of the trachea located 2 cm above the suprasternal notch), a rare situation, may produce disturbance to related anterior cervical tracheal surgery and even cause serious complications. OBJECTIVES: High-lying innominate artery is a high risk factor in anterior cervical tracheal surgery. Pre-operative assessment via imaging technique can help to familiarize the artery and reduce the related disturbance to the surgery. METHODS: A total of 829 patients were selected. Cervical computed tomography (CT) examination was conducted before surgery. The distance between the upper edge of the innominate artery across the anterior midline of the trachea and the suprasternal notch was measured. The exposure of innominate arteries in these cases during surgery was recorded. RESULTS: The upper edge of the innominate artery was located above the suprasternal notch in 26.4% (219/829) of patients. The upper edge of the innominate artery across the anterior midline of the trachea was 2 cm above the suprasternal notch in 18 cases, accounting for 2.2% of all cases, and innominate arteries were exposed in 11 cases (61.1%) during surgery.

Ramos colaterais do arco aórtico e suas principais ramificações no cachorro-do-mato (Cerdocyon thous) / Collateral branches of the aortic arch and its main rami in crab-eating fox (Cerdocyon thous)

O cachorro-do-mato (Cerdocyon thous) pertence à família Canidae, encontra-se amplamente distribuído pela América do Sul. Devido à escassez literária a respeito da morfologia desta espécie objetivamos colaborar com o conhecimento da anatomia do arco aórtico e seus ramos colaterais. Foram estudados quatro animais, sendo 2 machos e 2 fêmeas oriundos da Mina de Bauxita, Paragominas, Pará, Brasil/Terra Ltda, sob autorização da SEMA-PA nº 455/2009, que morreram por causas naturais. O sistema arterial foi preenchido com látex corado em vermelho e fixado em solução aquosa de formoldeído 10%. O arco aórtico de Cerdocyon thous apresentou em sua origem apenas dois vasos, o tronco braquiocefálico e a artéria subclávia esquerda. Do tronco braquiocefálico originou-se o tronco bicarotídeo, que se bifurcou nas artérias carótidas comum direita e esquerda, e artéria subclávia direita. Das artérias subclávias ocorreu a formação do tronco costocervical, artéria vertebral, artéria torácica interna, artéria cervical superficial e ao atingir o espaço axilar passa a ser chamada de artéria axilar em ambos os antímeros. Concluímos que o arco aórtico de Cerdocyon thous é similar ao de outros animais domésticos com relação ao número de ramificações em sua origem.(AU)

Crab-eating fox (Cerdocyon thous) belongs to the Canidae family distributed in South America. Due to literary scarcity regarding the morphology of this species, we objectifiked to collaborate with description of the anatomy of the aortic arch and its collateral branches. We studied four foxes, 2 males and 2 females, from Mina Bauxita, Paragominas, Pará, Brazil/Terra Ltda, under authorization of SEMA-PA nº 455/2009, that died of natural causes. The arterial system was filled with red latex and fixation with 10% formaldehyde solution. The aortic arch of Cerdocyon thous showed that in its origin are two vessels, brachiocephalic trunk and left subclavian artery. From brachiocephalic trunk originates the bicarotid trunk, bifurcated into left and right carotid common arteries, and right subclavian artery. The subclavian arteries originates the costocervical trunk, vertebral artery, internal thoracic artery, superficial cervical artery, to reach the axillary space, and passes to be called axillary artery on both sides. We conclude that the aortic arch of Cerdocyon thous is similar to the one in other domestic animals regarding the number of ramificastions at its origin.(AU)