 plexus, studying from the neck and going all the way to the axilla. So, let us start off from this place here that we can see this is the skeleton triangle bounded by the skeletonist medius, skeletonist anterior. The inferior boundary is the first strip which is behind the clavicle passing through the skeleton triangle we can see this structure here. This is the upper trunk of the brachial plexus. The upper trunk of the brachial plexus is formed by the C5 root which we have lifted up here and the C6 root. Then we have the next trunk. This is the middle trunk of the brachial plexus. This is formed by the C7 root and then we have the subclavian artery and below the subclavian artery we have the inferior trunk of the brachial plexus. Usually we cannot see the T1 root because it is deep and behind the skeletonist anterior but we can see the inferior trunk. So, in the skeleton triangle usually we see the trunks. The upper trunk, the middle trunk and the lower trunk and the trunks can get compressed here in the scalyan syndrome usually it's the lower trunk. We can see this first branch coming out is the suprascapular nerve. This arises from the herbs point and this is the one which supplies the supraspinitis muscle and the intraspinitis muscle and we can see it is being accompanied by the suprascapular artery and the vein. Now let's trace through the cervical axillary canal and this is the cervical axillary canal where my instrument is located. It's a canal bounded by the clavicle at the first strip and posteriorly by the scapular. The divisions occur in the cervical axillary canal but the divisions are more theoretical than actual in the sense that we cannot really see the divisions. After the divisions we have the cohorts in the axilla. In some places we have used the word trunks inadvertently. And let us take a look at the structures continuity of these structures in the axilla. For that I have reflected up the pectoralis major and the pectoralis minor. This is the axillary artery continuation of the subclavial artery. So therefore this is the lateral cord of the brachial plexus. And continuing the lateral trunk we can see this first branch here. This is the musculocutaneous and then we have the lateral root of the median nerve. Also arising from the lateral trunk we can see this nerve here. This is the lateral pectoral nerve and we can see it is supplying the pectoralis major muscle. Now let us come to the medial trunk. This is the medial trunk of the brachial plexus. And we can see it is giving rise to this branch here. This is the ulnar nerve and this is the medial root of the median nerve and the two unite to form the median nerve here. And incidentally we can also see the medial cutaneous nerve of the arm and the medial cutaneous nerve of the forearm also arising from the medial trunk. Then we come to the posterior trunk. This is the posterior trunk behind the axillary artery. And if you trace the posterior trunk we can see one branch is continuing as the axillary nerve through the quadrangular space and the rest of the nerve is continuing as the radial nerve which enters the arm and enters the radial groove. So we have traced the full continuity of the brachial plexus from the neck from the supraclavicular region to the axilla. From the roots, trunks, divisions, cords and branches. In the supraclavicular fossa we can give a supraclavicular nerve block, inter-skeline nerve block between the skeleton's anterior and skeleton's medias. So these are some places where we can give nerve blocks of the various trunks or the branches of the brachial plexus. The trunks or the roots of the brachial plexus can get compressed and that constitutes a peak syndrome called the thoracic inlet syndrome or the costoclavicular syndrome or the skeleton's anterior syndrome. It can also be compressed by a cervical rib or it can also be compressed by a sagging shoulder girdle in which case it is referred to as a costoclavicular syndrome. Usually the lower trunk is the one which is involved and therefore the most of the symptoms are palpable on the medial side of the hand and the medial side of the forearm. So this is all I wanted to show you about the brachial plexus extending from the neck to the arm. Thank you very much for watching. Talk to Sanjay Sanyal Sanyal. If you have any questions or comments please put them in the comment section below and as soon as the camera person. Have a nice day.