TWO CASES OF AZYGOS LOBE WITH NORMAL AND ANEURYSMAL AZYGOS VEIN ON COMPUTED TOMOGRAPHY.
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Azygos vein
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ABSTRACT 1. The nephridial system of Hirudinaria consists of a series of seventeen pairs of nephridia metamerically arranged in somites VI to XXII. The first six pairs occur in the pretesticular segments (VI-XI), while the remaining eleven pairs lie in the testicular segments (XII-XXII). 2. A typical nephridium consists of the following parts: (i) the initial lobe, (ii) the apical lobe, (iii) the inner lobe, (iv) the main lobe, (v) the vesicle-duct and the vesicle. All the nephridia in the testicular region possess ‘funnels’ (ciliated organs) which are enclosed within the ampullae of the perinephrostomial sinus. There is no continuity or connexion of these ‘funnels’ with the nephridia in the adult leech. 3. The inner end of the initial lobe is directed towards the testis-sac and either ends freely within the connective tissue without coming in contact with the testis-sac, o r is embedded in fibrous tissue in external contact with the wall of the sac, or becomes incorporated within the outer wall of the perinephrostomial sinus. 4. The initial lobe (testis-lobe) forms a very long coiled string of cells round the apical lobe and part of the inner lobe. The inner lobe (the ‘recurrent lobe’ of Bourne) forms a distinct strip of nephridial tissue enclosed between the two limbs of the main lobe besides a small piece which runs alongside the apical lobe. The inner lobe canals serve to connect the intra-cellular canals of all the lobes with one another. 5. The cells of the different lobes of the nephridium are tunnelled through by intra-cellular canals and canaliculi which form a continuous branching network throughout the body of the nephridium. Besides, there is an intra-cellular central canal which makes If ‘rounds’ through the various lobes of the nephridium and opens into the vesicle. The intra-cellular canals and canaliculi open directly or indirectly into the central canal. 6. The vesicle has no muscular layer, and its wall is not contractile. The evacuation of the contents of the vesicle is brought about by the contraction of ventro-Iateral muscles of the bodywall that extend across all the vesicles. The vesicle and the terminal excretory duet do not develop from the rudiments of the true nephridium, but are formed from an ingrowth of the epidermis. 7. A fully developed adult ‘funnel’ (ciliated organ) is a compound structure consisting of (1) a central reservoir and (2) a large number of small independent funnels set on the reservoir and opening into it. The funnels are profusely ciliated. Each funnel is composed of five to six cells, and has the appearance of an ear-lobe with a broad distal and a narrow proximal end. 8. The reservoir is the seat of manufacture of corpuscles which are thrown out of the reservoir through the funnels into the surrounding sinus by the active movements of the cilia of the numerous funnels. 9. The ‘funnel’ is not a degenerate structure. It has, in fact, multiplied into numerous small ciliated funnels, which are much more effective in their ciliary action than a single funnel, even of a large size, could be. Cilia of the funnels show very vigorous movements which keep the fluid in the sinus in constant active circulation. The ciliated organ, instead of serving a renal excretory function, has here become subservient to the sinus-system. 10. The botryoidal vessels are in direct communication with the perinephrostomial sinus. Possibly the corpuscles take up pigment and become the chloragogen cells in the botryoidal vessels. 11. In the embryonic condition the ‘funnel’ is a solid mass of cells which is distinctly continuous with the nephridium by means of a delicate strand of cells. This connexion of the ‘funnel’ with the nephridium snaps later, and the two become discontinuous and discrete structures. In the embryonic solid ciliated organ the funnel-forming cels can be clearly distinguished from the cells of the reservoir. The ‘funnel’ becomes enclosed at an early stage in the perinephrostomial sinus, which is a part of the reduced coelom. 12. The nephridial system of Hirudo is essentially similar to that of Hirudinaria. In Hirudo the initial lobe does not coil round the apical lobe, but forms one mass round the ampullae of the perinephrostomial sinus and another between the apical and main lobes. The inner end of the nephridium is closed as in Hirudinaria. The ‘funnels’ have the same structure and perform the same function as in Hirudinaria.
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Sinus (botany)
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Abstract Bathyergus suillus are subterranean rodents found in the Western Cape of South Africa, where they inhabit sandy, humid burrows. Vertebral venous plexuses around the vertebral column have been implicated in aiding the maintenance of a constant central nervous system temperature via its connections with muscles and interscapular brown adipose tissue. The morphology of the vertebral venous plexuses and its connections in B.suillus were investigated. Frozen ( n = 10) animals were defrosted; the venous system injected with latex and the vertebral venous plexuses, azygos‐ and intercostal veins dissected along the dorsal and ventral aspects of the vertebral column. Specimens ( n = 4) were used for histological serial cross sections of the thoracic vertebrae. Veins drained from the interscapular brown adipose tissue to the external vertebral venous plexus, via a dorsal vein at the spinous process of T2 which might represent the “vein of Sulzer” described in rats. The intercostal veins cranial to the level of T8 drained directly into the ventral external vertebral venous plexus instead of into the azygos vein as seen in rats. The azygos vein was situated ventrally on the thoracic vertebral bodies in the median plane as opposed to most rodents that have a left sided azygos vein. The internal vertebral venous plexus consisted of two ventrolateraly placed longitudinal veins in the spinal epidural space. Veins from the forelimbs entered the internal vertebral venous plexus directly at the levels of C7 and T1 and have not been described in other rodents. Serial histological sections, revealed no regulatory valves in vessels leading toward the internal vertebral venous plexus, allowing blood to presumably move in both directions within the vertebral venous plexus. The vertebral venous plexus of B. suillus shows similarities to that of the rat but the vessels from the forelimbs draining directly into to the internal vertebral venous plexus and the position of the azygos vein and the intercostal veins draining into the external vertebral venous plexus are notable exceptions. J. Morphol., 2011. © 2010 Wiley‐Liss, Inc.
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Plexus
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Objective: To look for a relative region for T4~12 anterior spine surgery assisted by thoracoscopy,and collect anatomical parameters to facilitate the intraoperative localization and the prevention of complications.Methods: 30 normal adult cadavers were selected randomly in the anatomical study.To observe anatomic characteristics of segmental vessels in T4~12 segments,the distance from the right rib head to the azygos vein and to the right sympathetic trunk,the distance from the left rib head to the deputy azygos vein,the accessory deputy azygos vein,the thoracic aorta and the left sympathetic trunk were measured.The distances from adjacent segmental vessels to the superior or inferior border of the intervertebral discs and thedistances among adjacent segmental vessels,were measured on the middle line at the lateral face of T4~12 vertebral body.Results: There was a safe region in which no important vessel and nerve appeared on the both sides of lateral face of T4~12 vertebra,with the biggest and smallest area of(24.25×44.74) mm2 and(19.74×28.43)mm2,and of(29.14×23.22) mm2 and(21.87×7.43) mm2 for the right and left respectively.Conclusions:(1) A relative region locates at the lateral face of the vertebral bodies of T4~12.(2) It is preferred to select the right approach during the anterior thoracic spine operation assisted by thoracoscopy,which is better for exposing and operating.
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Vertebra
Thoracic vertebrae
Sympathetic trunk
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The direct projections of the spinal cord onto the cerebellar cortex were traced using the Nauta method following the placement of cervical or thoracic spinal cord hemisections in six brush-tailed possums. Degenerating fibres reached the cerebellum via typically placed dorsal and ventral spinocerebellar tracts. Although complete differentiation of the terminations of ventral and dorsal tracts was not possible, it was found that the dorsal tract terminates mainly in the ipsilateral anterior lobe vermis and in the pyramis and paraflocculus of the ipsilateral posterior lobe. The ventral tract ends almost entirely in the anterior lobe with the majority of fibres terminating contralateral to the side of the hemisection. Within the anterior lobe, degenerating fibres were distributed fairly symmetrically about the midline in five sagittal rows. Three such rows were found in the posterior lobe. The relatively small number of rows in the anterior lobe (five) may be a characteristic feature of marsupials when compared with eutherian mammals.
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The aim of the research was to study the topography of the liver and to image on computed tomography of the white New Zealand rabbit. We used ten rabbit cadavers. We obtained sagittal frozen cuts. At the level of the plane 10 mm to the left, the left medial lobe was cranial to the left lateral lobe. Caudally were the spleen, the left kidney and parts of the small and large intestines. At the level of the plane 20 mm to the left, the left lateral lobe touched caudally the stomach fundus and body, the papillary process was dorsal to the stomach fundus. At the level of the plane 10 mm to the right, the right lobe was cranially situated to the other lobes. Between the right lobe and caudate lobe were fundus and body of the stomach. Caudate process was caudal to the fundus of the stomach and dorsal to the cranial part of duodenum and ascending colon. It had anatomical contact with the right kidney. Papillary process covered the dorsal part of the stomach. At the level of the plane 20 mm to the right, the right lobe was cranial to the other lobes of the liver. The left medial lobe was covered partially by quadrate lobe. Gall bladder did not reach the ventral border of the liver. The left medial lobe was cranial to the body of the stomach. Caudate lobe touched the muscles of the spine.
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Fundus (uterus)
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Background: The azygos lobe is a rare anomaly of the lung that is separated from the rest of the upper lobe by an azygos fissure. The lobe is encountered mostly in the right lung but a few cases have also been described in the left lung. It occurs at a frequency of 0.25-1% and has surgical and radiological importance. For example it can give rise to opacity on the X-ray that can mimic lung pathology. Observations: The azygos lobe was observed in the upper lobe of the right lung from a 45 years old male cadaver during dissection. The apex of the lung contained a vertical fissure that isolated medially the azygos lobe. The lobe appeared columnar in shape and it measured 4.7cm long and 3.7cm wide; its posterior border contained a notch. In addition to the azygos lobe the right lung also contained an incomplete horizontal fissure and therefore was divided by an oblique fissure into two lobes. Conclusion: The current observation has documented the co-existence of an azygos lobe with incomplete horizontal fissure and two lobes on the right lung. The findings have added knowledge on the morphology of the azygos lobe and have also raised awareness that it can occur with other fissural anomalies. Keywords: Lung, Azygos lobe, Azygos fissure, Horizontal fissure Lobes, Anomalies Tanzania Medical Journal Vol. 21 (1) 2006: pp. 17-19
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Lobe
Fissure
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The present work was carried out on 50 chick embryo of Dandarawi chicken collected from Assiut University Farm at a 3, 7, 9, 11, 13, 15, 17 and 19 day of prehatching life. At the 3 rd day of incubation, the hepatic diverticulum gave dorsal and ventral parts in relation to the ductus venosus. At the 7th day, the dorsal and ventral parts became the left and right lobes respectively where the gall bladder was located on visceral surface of the right lobe and a transverse fissure dividing the left lobe into dorsal and ventral parts. Also, the vitelline veins caudal to the liver anastomosed together forming the portal vein, which gave off left portal branch to the left lobe of liver and continued as right portal branch to the right lobe. At the 9th day, the right lobe was longer and higher than the left one where the right lobe was in contact dorsally with the mesonephros and the left one was separated from the mesonephros by the glandular stomach. At the 11th day, the interlobar fissure was occupied mainly by the umbilical vein. At the 13th day, the parietal surface of the two lobes was related to the heart and body wall and the gall bladder increased in size and extended laterally. At the 15th day, the cranial end of the right lobe had three processes dorsal, middle and ventral but the cranial end of the left lobe had two processes dorsal and ventral. The duct system of the right lobe was hepatocystic and cystoenteric, but that of the left was hepatoenteric duct.
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Ductus venosus
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Azygos vein
Lobe
Hilum (anatomy)
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The azygos lobe, also commonly referred to as an accessory lobe of the azygos vein, is located at the apicomedial portion of the right lung and is separated from the remainder of the upper lobe by a fissure. It usually has no significant clinical implications and is an incidental finding in radiographic studies. We report a patient with recurrent hemoptysis who had no obvious explanation for bleeding. At surgery the posterior segment of the right upper lobe was tucked behind and compressed by the azygos lobe. This suggested that the recurrent bleeding was due to the azygos lobe.
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Lobe
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Mesenchyme
Lobe
Respiratory tract
Histology
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