Background: Keeping in mind the frequency at which the surgical procedures are performed in the axilla, the organization and branching of brachial plexus and its topography becomes clinically significant and it is extremely complicated. Brachial plexus is the seat of explorations for oncosurgeons operating for breast carcinoma, schwannoma, neurofibroma, Anesthesiologists performing brachial plexus block, Plastic surgeons harboring myo-cutaneous flaps, Orthopedicians dealing with shoulder arthroplasty, humeral and clavicular fractures and for clinicians to explain the inexplicable signs of nerve compressions. The clinical importance of the variations in posterior cord is discussed in the light of various medical scenarios.

Background: The azygos venous system represents an accessory venous pathway supplying an important collateral circulation between the superior and inferior vena cava. The azygos vein is a collateral venous pathway, becoming a vital shunt if major pathways of venous return are obstructed.

Lower subscapular nerves in studied population display a wide range of variations. Anesthesiologists administering local anesthetic blocks, clinicians interpreting effects of nerve injuries of the upper limb and surgeons operating in the axilla should be aware of these patterns to avoid in advertent injury.

INTRODUCTIONThe brachial plexus is a complex network of nerves which extends from the neck to the axilla and supplies motor, sensory and sympathetic fibres to the upper extremity.The brachial plexus is formed by platuing of ventral rami of the lower four cervical and the first thoracic nerves.The plexus extends from the inferior lateral portion of the neck downward and laterally over the first rib, posterior to the clavicle and enters the axilla. The brachial plexus is divided into supraclavicular part and infraclavicular part. The infraclavicular part consists of three cords-lateral, medial and posterior. The posterior cord runs posterior to the second part of the axillary artery behind the pectoralis minor muscle and gives off the following branchesupper subscapular nerve, thoracodorsal nerve, lower ABSTRACTBackground: Purpose of current study was to describe the variations in the origin of the thoracodorsal nerve of the posterior cord of brachial plexus and its distance of origin from mid-clavicular point in the South Indian population. These variations are important during surgical approaches to the axilla and upper arm, administration of anesthetic blocks, interpreting effects of nervous compressions and in repair of plexus injuries. The patterns of branching show population differences. Data from the South Indian population is scarce. Methods: Forty brachial plexuses from twenty formalin fixed cadavers were explored by gross dissection. Origin and order of branching of axillary nerve and its distance of origin from mid-clavicular point was recorded. Representative photographs were then taken using a digital camera (Sony Cybershot R, W200, 7.2 Megapixels). Results: In forty specimens studied, 72.5% of thoracodorsal nerves originated from posterior cord, which was predominant (75%) on the left side, 15% arose from axillary nerve which was observed in 20% of the right sided specimens and 12.5% had origin from the common trunk which was significant (15%) on the left side. In 32.5% of specimens, thoracodorsal nerve had origin at a distance of 4.1-4.5 cm, in 32.5% at a distance of 4.6-5.0 cm, in 17.5% at a distance of 5.1-5.5 cm, in 12.5% at a distance of 3.6-4.0 cm and in 5% at a distance of t more than 5.5 cm from mid-clavicular point. Conclusion: Majority of thoracodorsal nerves in studied population display a wide range of variations. Significant number of thoracodorsal nerve also takes origin from axillary nerve and from common trunk at various distances from a fixed point. Anesthesiologists administering local anesthetic blocks, clinicians interpreting effects of nerve injuries of the upper limb and surgeons operating in the axilla should be aware of these patterns to avoid inadvertent injury and this study provide the necessary insight into the branching pattern of the thoracodorsal nerve and its distance of origin. Further study of the origin of thoracodorsal nerve of posterior cord of brachial plexus and its distance of origin from mid-clavicular point is recommended

Background: The humerus forms the longest bone of appendicular skeleton of upper limb. The nutrient arteries form major blood supply to the long bones, which enters the bone through the nutrient foramina. Materials and Methods: The present study was undertaken on 200 dry normal adult humerus bone obtained from the Department of Anatomy, SSIMS & RC, Davangere. 100 humeri belong to right and 100 belong to left side. Results: After the completion of this particular study on the vascular foramina, especially the nutrient foramina on 200 dry humeri, it was able to arrive at following conclusions: Among the segments, upper end shows maximum density of vascular foramina indicating the highest intensity of blood supply. The shaft being, supplied mainly by nutrient artery, the location and direction of nutrient foramina was thus important to find out. The position of nutrient foramina in most cases is found to be in the middle 1/3 rd of the anteromedial surface of the shaft and the direction of nutrient foramina was towards the elbow. Middle 1/3 rd of anteromedial surface is more vulnerable to surgical or traumatic injuries that may damage nutrient artery, thus highlights its significance. Discussion and Conclusion: Nutrient foramina plays vital role in nutrition and growth of the bones. Majority of the nutrient arteries follow the rule, 'to the elbow I go, from the knee I flee' but they are very variable in position. Their number, location, direction & its importance in the growing end of long bones were studied in the long bones of upper limb. The present study has variations in the position & direction. The study of nutrient foramina is important for surgeons operating on humerus, it is not only of academic interest but also in medico-legal practice in relation to their position. The present study also emphasizes importance of length of humerus. With the observation and information of variations in the vascular foramen, placement of both external and internal fixation devices on humerus can be appropriately done.