INTRODUCTIONThe Greek root zyg refers to a pair. 'A-' means not. Thus, azygos means unpaired. The azygos vein is unpaired in that there is only one in the body, mostly on the right side. While there is the hemiazygos vein and its accessory on the left side of the body, they are considered tributaries of the azygos vein rather than its left-side equivalent.1 The azygos system includes those veins which are straight in course, paravertebral in position, and not accompanied with the corresponding arteries.These veins are provided with valves, and drain most of the blood from the back and from the thoracic and abdominal walls. The azygos system communicates with the vena caval system in front, and with the vertebral venous plexus behind. The terminal veins of this system are the azygos, hemi-azygos and accessory azygos veins. The azygos vein is inconstant in the mode of origin. 2Although there are complete valves in some tributaries of azygos veins, there are usually incomplete valves varying between one and four in the azygos arch. Thus, the azygos vein functions as a collateral for the superior and ABSTRACT Background: The anatomical knowledge of the variability of the azygos venous system is important for the surgical interventions of the posterior mediastinum and also during radiological investigations/diagnosis especially CT and MRI. The variant azygos venous system might be confused with thoracic aorta aneurysms, lymphadenopathy and tumours of posterior mediastinum. Methods: The present study was undertaken on 10 embalmed adult human cadavers irrespective of sex, used for undergraduate dissection from the Department of Anatomy, Mandya Institute of Medical Sciences, Mandya. In this present study, formation, course and termination pattern of azygos system of veins was observed in 10 dissected human cadavers. Out of which 2 cadavers showed different types of variations. Results: In the present study, normal azygos venous system was found in 8 specimens accounting for 80%. Variations were found in 2 specimens (20%); one specimen presented with connection between accessory hemiazygos vein and hemiazygos vein, 3 transverse channels across vertebral column and the other specimen showed absence of accessory hemiazygos vein and shifting of azygos vein towards midline. Conclusions: Accurate knowledge about these kinds of variations is very important to identify, especially in the computed tomography and magnetic resonance imaging of mediastinum. The abnormal azygos venous system may easily be confused with aneurysm, lymphadenopathy and other abnormalities like tumor. It is important to keep these kinds of variations in mind while performing the mediastinal operations or surgery of large vessels.

Introduction: The Clavicle is a modified long bone and only long bone which is placed horizontally and subcutaneously at the root of neck. It transmits the weight from upper limb to the axial skeleton. Nutrient foramen is the largest foramen on the long bones through which nutrient artery for the bones passes. The nutrient artery is the principal source of blood supply to a long bone, particularly important during its active growth period in the embryo and foetus, as well as during the early phase of ossification. The bone has a cylindrical part called the shaft and two ends, lateral and medial. The shaft is divisible into the lateral one-third and the medial two-thirds. The inferior surface of shaft of clavicle presents a subclavian groove. A Nutrient foramen lies at the lateral end of the groove running in a lateral direction. Aims & objectives: To note the position, number and direction of nutrient foramen Materials and Methods: The present study was performed on 100 adult human clavicles of unknown sex and age collected from the department of anatomy, Mysore medical college and research institute, Mysore. Clavicles were examined by direct observation to note the position, number and direction of nutrient foramen. A magnifying lens was used to observe the foramina. Results: The study was conducted on 100 adult human clavicles (50 right and 50 left), and we observed the following results: Nutrient foramina were present in 97 clavicles - 49 clavicles (right) and 48 clavicles (left). Single foramina was present in 80 clavicles, 41 clavicles (right) and 39 clavicles (left) Double foramina were present in 17 clavicles, 8 clavicles (right) and 9 clavicles (left). Absence of nutrient foramina were found in 3 clavicles, 1 clavicle (right) and 2 clavicles (left). All foramina were directed towards the acromial end of the clavicle. Conclusion: The knowledge of anatomical variations of nutrient foramina in clavicles are important for surgeons for performing surgical procedures like bone grafting and microsurgical vascularised bone transplantation. KEY WORDS: Clavicle, Nutrient Foramen, Bone Graft.

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Extrahepatic biliary apparatus comprises of gall bladder, cystic duct, hepatic ducts and common bile duct. Gall Bladder is a pear shaped hollow organ, which are situated in contact with the under surface of right lobe of liver. In adult the length is between 7-10 cm, maximum breadth being 3 cm and with a maximum capacity of 50 ml. The morphological and morphometric variations of gall bladder are common. These variations are well studied and documented by the earlier studies but its precise morphological types and its incidence are utmost important during diagnostic and therapeutic procedures. Hence, comprehensive knowledge of variations of gall bladder will be important to avoid complications during surgical procedures and radiological interventions. The study was carried on 50 liver with Gallbladder specimens obtained from 10% formalin fixed cadavers of age group 50-60 years in the department of Anatomy. The gall bladder was observed, dissected carefully and studied for its parameters i.e. length and breadth using Vernier calipers. The variations in shape, its external morphological features and its position were also noted.52% of the gall bladder specimens had length ranging between 7 – 10cms. 68% of the specimens had transverse diameter ranging between 3 – 5cms. Various shapes observed were Pear shape, Hourglass shape, Retort shape, Cylindrical shape and Flask or Irregular shaped. The commonest shape observed and recorded in this study was Pear shaped in 26 specimens (52%). Folded fundus (Phrygian cap) of gall bladder was found in 2 out of 50 specimens (4%) and Hartmann’s pouch was found in 7 out of 50 specimens (14%).The precise knowledge of the various morphological and morphometric variants of the gall bladder is important for the operating Surgeons and Radiologists. The preoperative diagnosis of these variations helps to reduce the complications like bleeding and biliary leaks.

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