Variant Patterns Of Brachial Plexus – A Cadaveric Study In North Indian Population

Background: The brachial plexus is constituted by the ventral rami of C5-T1 spinal nerves. It forms a network ofterminal nerves that innervate the upper limb. Variations of brachial plexus are common and a better awarenessof variations is very crucial to achieve successful results in its surgical procedures. The aim of present studywas to find the variant patterns of brachial plexus and to discuss their developmental and clinical significance.Materials and Method: 50 upper limbs belonging to 25 formalized and well preserved male cadavers obtainedfrom the Department of Anatomy, constituted the material for the study. These were dissected and roots, trunks,cords and terminal branches of brachial plexus were exposed. The variant patterns were noted and photographed.Results: Out of 50 limbs, 5 limbs showed variations of brachial plexus at different levels.All the variations seenwere unilateral. Out of 5 variant patterns seen, different types of communications between musculocutaneousand median nerve were observed in 4 limbs (8%).Out of 4, in 1 limb (2%) medial cord joined with lateral root ofmedian nerve to form mediano-ulnar nerve which after a distance of 1cm bifurcated into median and ulnarnerve. In one limb (2%), there was no distinction between medial and lateral cord. Instead a single anterior cordwas formed by union of anterior divisions of all the three trunks anterior to axillary artery.Conclusion: The variant patterns of brachial plexus are usually more prone to accidental injuries and entrapmentneuropathies. Knowledge of such variations may provide additional anatomical information for the cliniciansduring diagnosis of unusual clinical symptoms and also for surgeons during surgical exploration of axilla andarm to avoid damage to these nerves.

Re-definition of position and calculation of safe area for axillary nerve in deltoid muscle with its clinical relevance: a cadaveric study / 대한해부학회지

Several authors have made efforts to define the position of the axillary nerve within deltoid muscle and to calculate the so called safe area for this nerve but it still remains a matter of debate. The primary aim of the study was to investigate the acromio-axillary (AA) distance and its correlation with upper arm length. The secondary aim was to re-define the safe area for axillary nerve within deltoid muscle. Sixty shoulders of thirty adult human cadavers were dissected using standard methods. The distance from the anterior and posterior edge of acromion to the upper border of the course of the axillary nerve was measured and recorded as anterior and posterior AA distance respectively. Correlation analysis was done between the upper arm length and AA distance for each limb. The ratios between anterior and posterior AA distance and upper arm length were calculated and mentioned as anterior index and posterior index, respectively. The mean of anterior and posterior AA distance was 5.22 cm and 4.17 cm, respectively. The mean of upper arm length was 29.30 cm. The means of anterior index and posterior indices were 0.18 and 0.14, respectively. There was a significant correlation between upper arm length and both the anterior and posterior AA distance. The axillary nerve was found to lie at variable distance from the acromion. The minimum AA distance was found to be 3.50 cm. So this should be considered as the maximum permissible length of the deltoid split. Upper arm length has strong correlation with both anterior and posterior AA distances. The ideal safe area for the axillary nerve was found to be a quadrangular area above it and the size of which depends on the length of the upper arm.