Brachial plexus Brachial plexus The brachial plexus is a network of nerves formed by the ventral rami of the lower four cervical nerves and first thoracic nerve (C5, C6, C7, C8, and T1). This plexus extends from the spinal cord, through the cervicoaxillary canal in the neck, over the first rib, and into the armpit. It supplies afferent and efferent nerve fibers to the chest, shoulder, arm and hand. The brachial plexus is divided into five "roots", three "trunks", six "divisions" (three anterior and three posterior), three "cords", and five "branches". There are five "terminal" branches and numerous other "pre-terminal" or "collateral"
Ankle–brachial pressure index ABPI is the ratio of the highest ankle to brachial artery pressure. An ABPI between and including 0.9 and 1.2 considered normal (free from significant PAD), while a lesser than 0.9 indicates arterial disease. An ABPI value of 1.3 or greater is also considered abnormal, and suggests calcification of the walls of the arteries and incompressible vessels, reflecting severe peripheral vascular disease. Provided that there are no other significant conditions affecting the arteries of the leg, the following ABPI ratios can be used to predict the severity of PAD as well as assess the nature and best management of various