 So this is musculocutaneous nerve and we can see it is arising from the lateral cord of the brachial plexus The musculocutaneous nerve immediately as it comes out from the lateral cord it enters into the arm through the insertion of the Coraco brachialis and this is the Coraco brachialis muscle. If you look closely at the point where it enters There is a blood vessel here. This is a humeral nutrient artery Therefore this Coraco brachialis is considered as a landmark muscle because this marks the place where the musculocutaneous Nerve enters the arm and also marks the location of the entry of the humeral nutrient artery in this location the Coraco brachialis rarely the Coraco brachialis can cause entrapment of the brachial artery and or the median nerve But that is not so common musculocutaneous nerve It supplies the coracobrachialis and after that it goes deep and we can see that it supplies the biceps brachial And I am reflecting the biceps brachial to show the rest of the course of the musculocutaneous Nerve and this is the musculocutaneous nerve, which I have lifted up here It supplies the biceps brachialis and then it supplies the brachialis This is the brachialis underneath and it runs between the biceps brachialis and the brachialis Lower down it is between these two muscles and it becomes Cutaneous and we can see the cutaneous portion of the nerve here Here it is known as lateral cutaneous nerve of the forearm and in this position It supplies the skin of the antrolateral aspect of the forearm right up to the base of the thumb This is the full course of the musculocutaneous nerve and that is why it is called the musculocutaneous nerve This musculocutaneous nerve when it becomes cutaneous and becomes known as the lateral cutaneous nerve of the forearm It is accompanied by this cutaneous vein, which we can see This is the cephalic vein this cephalic vein in this location is used quite frequently by nurses and technicians to draw blood And if they do counter puncture and they produce Extravagation of blood and I can score this from not only from my clinical experience But also from personal experience and this extra position of blood can irritate musculocutaneous nerve the cutaneous branch and Produce hummus tingling peristicia in the distribution of the musculocutaneous nerve This musculocutaneous nerve as we can see is rather deep and it goes deep inside the muscles Therefore this musculocutaneous nerve is not so frequently injured However, rarely the musculocutaneous nerve can be injured in a stab injury deep to the arm In which case it will produce paralysis of the Gorago brachialis the biceps brachiae and the brachialis However, it has to be remembered that the brachialis also gets another supply from the radial nerve But the most important disability that will occur in the rare instance if the musculocutaneous nerve is injured is difficulty in friction of the elbow because both the biceps brachiae and the brachialis are flexors of the elbow However, the patient will still be able to weakly flex his elbow because of this muscle here This is the brachioradialis muscle brachioradialis muscle is actually a muscle of the extrinsic compartment and therefore it is supplied by the radial nerve Therefore brachioradialis will take over the function of the flexion of the elbow joint So that is the point to be remembered about the musculocutaneous nerve. This is another cadaver a brown cadaver We are showing the right side posterior aspect. We are showing the ulnar Let's come to the medial side. We can see this septum here This is the medial intramuscular septum which is attached to the medial supra condylar ridge of the humerus And running behind the medial intramuscular septum We can see this nerve here and if you were to trace it here We can find that it is disappeared here that means above this it is in front of the medial intramuscular septum And below this it is behind the medial intramuscular septum This runs on the medial side of the arm and we can see it is disappearing just behind the medial epicondyle This is the medial epicondyle This location where my instrument is located This is called the cubital tunnel. How is this cubital tunnel formed? It is formed by the olecranon process the medial epicondyle a bridge of aponeurosis Which is formed by the aponeurotic expansion of the flexor carpi ulnaris Which bridges over between these two and it fuses with anti-brickle fascia and it fuses with the subcutaneous part of the ulnar So this forms a tunnel and that is referred to as the cubital tunnel And we have split that cubital tunnel here and we can see one margin of the split here And we can see the other margin here and we can see running through the cubital tunnel is the ulnar nerve This ulnar nerve can be injured in fracture of the medial epicondyle But more commonly than that it can also get entrapped in this cubital tunnel And that is referred to as cubital tunnel syndrome Injury to the ulnar nerve will produce numbness tingling peristhesia on the medial side of the hand on the forearm And it will also produce what is known as a radial claw hand and accompanying this ulnar nerve We have seen this is the superior ulnar collateral vessel which participates in the elbow anastomosis That's all for now. 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