Variation of the origin of the left common carotid artery diagnosed by CT angiography

Introduction

The left common carotid artery (LCCA) is usually a second branch of the aortic arch that arises between the brachiocephalic trunk (BCT) and left subclavian artery; relatively frequently, it also arises from or shares a common origin with the BCT. In patients with LCCA of anomalous origin, transfemoral catheterization into the LCCA is sometimes difficult, and transbrachial or transradial approach may be recommended. We evaluated the prevalence of these variations on computed tomography (CT) angiography.

Methods

We retrospectively reviewed CT angiographic images of 2,357 patients obtained using either of two 64-slice multidetector CT scanners. All patients were Japanese and underwent scanning from the aortic arch to the intracranial region; most had or were suspected of having cerebrovascular diseases.

Results

We evaluated CT angiographic images of 2,352 patients after excluding four patients with LCCA occluded at its origin. The LCCA arose from the BCT in 141 patients (6.0 %) and had a common origin with the BCT in 130 patients (5.5 %). We found 11 aberrant right subclavian artery (0.47 %), and four of the 11 patients (36 %) had LCCA of common origin with the right common carotid artery, forming a bicarotid trunk (prevalence: 0.17 %).

Conclusions

The total prevalence of variations of LCCA origin diagnosed by CT angiography was 11.7 %.     

Aortic arch variation analyzed by using plastination

Different ramification patterns can be observed during the development of the aortic arch. In this study a common trunk (CT), which subsequently branched into the brachiocephalic trunk (BT) and left common carotid artery (LCCA), arose from the aortic arch. The LCCA arose from the CT 10.27 mm above the aortic arch. After crossing the ventral aspect of the trachea and esophagus, the LCCA became situated on the left side of the esophagus. The caliber and length of the main branches of the aortic arch were determined and compared to reports in the literature. This variation was discovered in the context of producing transverse body slices using an E12 plastination process.     

Right vertebral artery as the fourth branch of the aortic arch

The present report describes an anomalous case of the right vertebral artery arising as the last branch of the aortic arch identified in a 76-year-old Japanese male cadaver during dissection in the anatomical laboratory of Kanazawa Medical University. The aortic arch itself coursed normally but the right vertebral artery was uniquely situated at the fourth branch next to the brachiocephalic artery, the left common carotid artery, and the left subclavian artery. The anomalous right vertebral artery branched into the esophageal branch, the prevertebral branch, and the second right posterior intercostal artery, and finally entered the first costotransverse foramen at the thoracic region as it passed upward through the first to the seventh transverse foramina of the cervical vertebra. The left vertebral artery was normal. The development of the right vertebral artery may be described as follows: (i) the distal portion of the right dorsal aorta, which usually disappears, persisted and became united, via post-costal longitudinal anastomosis; (ii) the right dorsal aorta between the seventh and eighth intersegmental arteries lost its connection to the main structure; and (iii) the fusion of the originally paired dorsal aorta extended around the 11th segment, which was two segments away from the normal portion of the structure.     

Persistent left hepatic venous connection with the right atrium and the ductus venosus

An anomalous left hepatic vein opening independently of the coronary sinus into the right atrium was found in the cadaver of an 88-year-old Japanese man. This vein originated from the left lobe of the liver, perforated the diaphragm at the left side of the vena caval foramen and opened into the right atrium. The left hepatic vein anastomosed mutually with the middle hepatic vein at the level of venule. The ligamentum venosum originated from the left branch of the portal vein and was connected directly to the left hepatic vein. The development of the central systemic venous system and a possible explanation for the morphogenesis of this anomaly were reviewed. As a result, the occurrence of this anomalous vein was explained as being due to the persistence of the left vitelline connection with the left sinus horn and the ductus venosus.     

A case of anomalous bronchial artery ramified from coronary artery

There have been no anatomical reports on the origin of the bronchial artery derived from the coronary artery. In a 2006 cadaveric dissection course, an anomalous bronchial artery that reached the middle lobe of the right lung from the left coronary artery was observed in an 88-year-old Japanese man. In this specimen, the circumflex branch of the left coronary artery passed under the left auricle in the coronary sulcus and bifurcated to three branches (left marginal branch, posterior left ventricular branch, atrial branch), which were 3.2–3.4 mm in diameter. The atrial branch intersected on the surface of the great cardiac vein, ran along the oblique vein of the left atrium, and reached the atrial side of the transverse pericardial sinus, and then divided into two branches. One of them led to the right atrium. The other branch passed between two right superior pulmonary veins, which derived from superior and middle lobes of the right lung, respectively, through the hilum of the lung along the right superior pulmonary vein derived from the middle lobe, and finally became the bronchial artery in the middle lobe of the right lung. In the middle lobe, the bronchial artery divided into a thin branch along the pulmonary vein for the lateral segment, ran along the surface of the right middle bronchus, and then reached the medial segment, being wedged between the segmental bronchus and vein.     

A parieto-occipital artery arising from ICA directly and resultant incomplete PCA

A parieto-occipital artery arising from internal carotid artery (ICA) directly was identified in a 46-year old man. The left ICA angiograms showed that a parieto-occipital artery was arising from ICA located between posterior communicating artery (PcomA) and anterior choroidal artery (AchoA). And also, incomplete posterior cerebral artery (PCA) which had not a parieto-occipital branch was arising from prominent PcomA. AchoA arose from ICA located just distal to the anomalous origin of the parieto-occipital artery. The vertebral angiograms showed no contrast filling of left PCA. Herein, we present a very rare case which has an anomalous origin of the parieto-occipital artery and resultant incomplete PCA.     

Vascular anatomy of a dicephalic cat

Summary The arterial and venous systems of the neck and heads of a dicephalic iniodymic monosomic cat are described. In the arterial system, an anomalous lingual branch of the right external carotid formed a large subhyoid arch, extending to the midline between both heads, giving off branches supplying the medial aspect of both heads and terminating in two medial internal carotid arteries each for the right or left head. This vessel was considered as an anomalous supernumerary common carotid artery. In the venous system, each lingual branch of linguofacial veins united and formed an anomalous venous arch. It received rostrally a long midline vein running between both heads and connecting with the medial internal jugular system. This vein received tributaries from the left and right heads and was considered as a supernumerary jugular vein. From these observations, and those of others in the literature, it can tentatively be suggested that, in congenital cephalic duplications in domestic mammals, the arterial blood supply for the medial aspect of both heads tends to come from the lingual branch of the external carotid artery, with an unexplained prevailing contribution of the right external carotid system. Two different venous patterns have been observed. In animal especies exhibiting a hyoid venous arch, such as carnivores, a midline supernumerary external jugular vein draining at the anomalous junction between lingual veins of both heads is formed, whilst in animals lacking a constant hyoid venous arch, such as ruminants, an asymmetrical supernumerary external jugular vein draining into the right normal external jugular vein has been repeatedly described.     

双椎动脉变异的影像学特点及临床意义-附3例报道

报道经血管造影证实的3例双椎动脉变异病例:2例为颅外段的椎动脉开窗畸形,其中1例伴有大脑中动脉分叉处动脉瘤,1例左椎动脉起于主动脉弓的变异;另1例为右侧椎动脉双起源变异,伴旁路血管内血栓形成。结合文献对这一现象的胚胎成因及临床意义进行了讨论。     

Anomalous first septal perforator artery: Anatomic-clinical correlates

The interventricular septum is considered the most densely vascularized portion of the heart, containing important elements of the cardiac conduction system and providing mechanical support for both right and left ventricular function. Anatomically, this structure is perfused by the relatively small caliber anterior and posterior septal perforator branches arising from two large epicardial coronary vessels, the anterior interventricular (descending) branch of the left coronary artery and the posterior interventricular (descending) branch of the right coronary artery, respectively. In cases of significant atherosclerotic disease depriving flow in the major coronary vessels and their septal branches, an anomalous septal perforator artery can take over the task of supporting the function of the interventricular septum by supplementing essential collateral flow. © 1996 Wiley-Liss, Inc.     

Coincidence of a right retroaortic circumflex coronary artery and a right-sided aortic arch with a retroesophageal course of the left subclavian artery (arteria lusoria)

An anomalous branch of the right coronary artery was found in a 71-year-old male cadaver with a right-sided aortic arch. The anomalous artery arose from the proximal portion of the right coronary artery and ran in a retroaortic course, before reaching the posterior wall of the heart. It was recognized as the right-sided variation of the circumflex coronary artery. The aortic arch had as branches the left common carotid, right common carotid, right subclavian, and left subclavian arteries, in that order, and the descending aorta was located in the right thorax. The left subclavian artery arose from a Kommerell's diverticulum and ran behind the esophagus, and the left-sided ligamentum arteriosum was also connected at the diverticulum. Therefore, the right aortic arch was classified as type N according to Adachi-Williams-Nakagawa and type III-B1 in accordance with Stewart-Edwards. The Kommerell's diverticulum in this case seemed to press on the posterior wall of the esophagus.     

Anomalous origins of colic arteries

The topography of the celiac trunk and superior and inferior mesenteric arteries was studied by dissection in 27 embalmed cadavers. Variant vascular patterns were noted in four subjects. These consisted of: (1) an accessory right hepatic artery from the superior mesenteric artery, (2) an anomalous middle colic artery from the proximal segment of the splenic artery, and (3) two instances of an accessory left colic artery originating from the superior mesenteric artery. The precarious course of the middle colic artery (coming from the splenic artery) and its dominance in the formation of the marginal artery were thought to predispose the ascending and transverse colon to an increased risk of vascular damage. These cases also illustrate two variant patterns of formation of the marginal artery. In the case of the anomalous middle colic artery, the only contribution of the superior mesenteric artery to the marginal artery was through the anastomosis of its ileocolic branch with the right branch of the aberrant middle colic artery. In subjects with accessory left colic arteries, the superior mesenteric artery played a dominant role in the formation of the marginal artery by contributing the accessory left colic artery, which supplied the splenic flexure and the proximal part of the descending colon. These arterial variations underscore the importance of doing vascular studies prior to major abdominal surgery. © 1995 WiIey-Liss, Inc.     

Atypical coeliomesenteric anastomosis: The presence of an anomalous fourth coeliac trunk branch

The presence of more than three coeliac trunk branches is a commonly encountered variant. Literature occasionally describes cases of middle or left colic arteries originating from the celiac trunks or its branches; however, the presence of an anomalous arterial connection between the celiac trunk and both the superior and inferior mesenteric arteries (SMA and IMA, respectively) has yet to be reported. Routine abdominal dissection of a male Caucasian cadaver, revealed the presence of an anomalous fourth arterial branch on the 4‐cm long coeliac trunk. The course of this artery was traced, and it terminated by anastomosing with the marginal artery of the mesenteric circulation. The distal termination point of this anomalous fourth coeliac branch was the marginal artery, 5 cm medial of the splenic flexure, anastomosing almost perpendicularly. The diameter of this anomalous artery was comparable with the left gastric artery at their origins. The artery coursed inferiorlaterally toward the splenic flexure, passing immediately posterior to both the pancreas and the splenic vein. The anastomosis point of this artery, near Griffith's Point, is normally considered a watershed region with dual arterial supply from both the SMA and IMA, allowing collateral circulation. This region has a relatively higher susceptibility to irreversible damage in ischemic diseases because of lower perfusion, thus, the anastomosis of atypical coeliac branches represents a rare case for consideration. Awareness of the possibility of embryological variants will minimize the risk of complications in surgical or clinical procedures, and exploration of rare variants will benefit the understanding of vascular embryology. Clin. Anat., 2010. © 2010 Wiley‐Liss, Inc.     

Anomalous lumbrical muscles arising from the deep surface of flexor digitorum superficialis muscles in man.

During anatomy practice in 1999 at Kumamoto University School of Medicine, the anomalous lumbrical muscles originating in the forearm were observed in both arms of a cadaver. These muscles, originating from the intermediate tendon of the deep layer of the flexor digitorum superficialis for the index finger (FDS-II), passed through the carpal tunnel to join the insertion of the first lumbrical muscle, and formed a muscle belly near the origin in the left and at the insertion in the right. The left anomalous muscle was innervated by a branch of the median nerve just proximal to the carpal tunnel. The right one received a twig from the nerve to the first lumbrical muscle. Tracing the nerve fibers by peeling off the epi- and perineurium clarified that the nerve fibers supplying the left anomalous muscle formed a common bundle with the fibers to the first lumbrical muscle. Therefore, these anomalous muscles are considered to be the accessory lumbrical muscles arising from the forearm. The three accessory lumbricalis, including one case reported by Yamada (1986), received branches which had slightly different origins from proximally (nerve to the distal belly of FDS-II) to distally (nerve to the first lumbricalis). Accordingly the position of the muscle belly shifted distally. The occurrence of these unusual accessory lumbrical muscles indicates that the distal belly of FDS-III and the first lumbricalis are derived from a common muscle origin and presents an important clue to the phylogenetic origin of the flexor digitorum superficialis.     

Rare case of myloglossus in Japanese cadaver: anatomical and developmental considerations

The styloglossus is one of the three extrinsic muscles of the tongue; it enters the tongue from behind. During human dissection practice for dental students at the Showa University School of Dentistry in 2006, the authors observed anomalous muscle arising from the inner surface of the mandibular angle and inserting into the tongue bilaterally. This muscle was termed myloglossus by Wood. On the right side, the myloglossus was accompanied by a weak rudimentary styloglossus, but the styloglossus was absent on the left side. The hypoglossal nerve innervated the myloglossus bilaterally, and a small branch of mandibular nerve also entered the muscle on the left side. The styloglossus develops from the styloid process and the mandibular angle as a bicipital muscle, but the segment attached to the mandibular angle generally atrophies during development. The present anomalous muscle was thought to represent persistence of this muscle bundle arising from the inner surface of the mandibular angle. The innervation of the innermost part of the left myloglossus by the mandibular nerve was explained by persistence of a vestigial nerve supplying a small muscle bundle originating from the tensor veli palatini, which had fused to the myloglossus.     

Persistent cervical intersegmental artery and aortic arch coarctation

A 15-year-old girl presented with upper extremity hypertension and continuous precordial murmur. Arteriography revealed aortic coarctation proximal to the origin of the left subclavian artery. An anomalous artery originated from the aortic arch, between the left common carotid artery and the stenosis. It ascended cranially and filled an angiomatous vascular formation on the left side of the neck. The "angioma" drained into the left subclavian artery. The embryological explanation of the described anomaly is difficult, but probably related to hemodynamic alterations following the prestenotic increase in blood pressure. This may have impaired the obliteration of cervical intersegmental arteries, resulting in the persistence of one of the first three intersegmental arteries as the anomalous branch of the aortic arch. The angiomatous vascular formation in the neck could be the consequence of altered development of anastomoses between the muscular twigs of both vertebral and deep cervical artery. The vessel draining the vascular formation was probably the thyrocervical trunk. Since there were no overt collateral channels or signs of left ventricular hypertrophy by electrocardiography and echocardiography, it seems that the aberrant collateral flow was hemodynamically significant and reduced the afterload on the myocardium. Although the pattern of collateral flow in our case might be considered extremely rare, it is important in preoperative planning and interpretation of imaging studies.     

Functional Development of the Coronary Collateral Circulation During Coronary Artery Occlusion in the Conscious Dog

We studied changes in the coronary collateral circulation during coronary artery occlusion in 14 conscious dogs by: a) determining simultaneous changes in peripheral coronary pressure (PCP) and retrograde flow (RF) after abrupt coronary artery occlusion; b) correlating these functional indices with quantitative anatomic indices (AI) of coronary collateral development (Menick et al: Am Heart J 82:503-510, 1971); and c) observing changes in these indices after repeated reocclusions of a coronary artery. These dogs were subjected to left circumflex coronary artery (LCCA) occlusions for 2 hours to 8 days; pressure tubes were implanted in the aorta and LCCA, the latter tube placed distal to an occlusive cuff for PCP and RF measurements. Afterwards the animals were sacrificed, their hearts injected with a modified Schlesinger's gelatin mass, and AI determined. During 2 to 24 hour LCCA occlusions (11 dogs) mean PCP rose to levels 50 to 80% of prevailing aortic pressure. During repreated 2- to 24-hour occlusions (2 dogs) in the same dog, the rate at which PCP rose increased. Retrograde flow was unchanged during 2- to 24-hour occlusions. Anatomic indices of these dogs were in the same range as those observed in unoccluded controls. When LCCA occlusion was maintained for more than 4 days (3 dogs), mean PCP rose during the first 24 hours and then remained stable; RF did not change until 4 days into occlusion and then increased. Anatomic indices of dogs occluded for more than 4 days were significantly greater (P < 0.001) than those of the 2- to 24-hour occlusion groups. Our study shows that: a) the early PCP rise after occlusion is not associated with an increase in RF, b) RF is a better index of collateral function and c) RF correlated well with the anatomic development of the collateral bed.     

Total anomalous origin of the coronary circulation from the right pulmonary artery

Origin of both coronary arteries from a branch of the pulmonary artery is rare and has not been reported as a cause of sudden unexpected death. We report autopsy findings of a 14-day male infant in previously good health who died suddenly. From the proximal right pulmonary artery arose a single coronary artery, which branched into the right and left main coronary arteries. The right proximal coronary artery coursed between the aorta and pulmonary trunk, and the left main traveled along the anterior proximal aorta. The distal course of the coronary circulation was normal. There was concentric subendocardial healing myocardial infarction. No other congenital anomalies were identified. Total anomalous origin of the coronary arteries from the pulmonary trunk or artery should be considered in cases of sudden unexpected death in infants.     

Anomalous origin of the left coronary artery from the right side of the aortic valve in Syrian hamsters (Mesocricetus auratus)

This study describes the coronary artery distribution patterns associated with the anomalous origin of the left coronary artery from the right side of the aortic valve in Syrian hamsters. The hearts of 15 affected animals were examined by means of a corrosion-cast technique, histology and scanning electron microscopy. The hamsters belonged to a laboratory inbred colony with a high incidence of coronary artery anomalies and bicuspid aortic valves. The aortic valve was tricuspid in eight hamsters and bicuspid in the other seven. In all cases, the right coronary artery was normal, whereas the left main coronary artery trunk arose from the right aortic sinus or from the right side of the ventral aortic sinus when the aortic valve was bicuspid. In 12 specimens, the left main trunk crossed the infundibular septum and then divided into the left circumflex branch and the obtuse marginal branch. In another specimen, the course of the left main trunk was ventral to the right ventricular outflow tract; in the remaining two, it surrounded the aorta dorsally. In man, some of these distribution patterns may cause myocardial ischaemia and sudden death. The present findings prove that the origin of the left coronary artery from the right aortic sinus occurs in primitive mammals such as the Syrian hamster, suggesting that the defect may occur in other mammalian species. Its possible occurrence should be borne in mind in domestic animals, especially in those with signs of myocardial ischaemia after strenuous activity.     

Anatomical variations as potential risk factors for ulnar tunnel syndrome: a cadaveric study

The aim of this study was to assess the anatomical variations, especially the anomalous muscles passing through Guyon's canal and the fibrous arch forming the piso-hamate hiatus, which may play a role in ulnar tunnel syndrome. We have also focused on the relation of these structures with specific concern to the ulnar nerve. Nineteen embalmed cadavers (37 hands and forearms) were dissected. A fibrous arch extending between the pisiform and the hook of the hamate was observed in 21 hands. In majority of the cases flexor digiti minimi muscle was found to originate only from this arch. An anomalous muscle was disclosed in six hands with four of them passing through the piso-hamate hiatus with the deep branch of the ulnar nerve. In two of four cases, the superficial branch of the ulnar nerve was also accompanying the deep branch of the ulnar nerve beneath the anomalous muscle and through the piso-hamate hiatus. Because these anomalous muscles were generally found to course through the piso-hamate hiatus with the branches of the ulnar nerve, we conclude that the distal portion of the Guyon's canal has a relatively higher risk for ulnar nerve entrapment. We believe that surgeons operating on this region should take into account these various anatomic structures.