Axillary Nerve

00:01 So, finally then, let's look at the axillary and the long thoracic nerves.

00:07 So, first of all, let's look at the axillary nerve and remind ourselves of the course.

00:11 We can see it's coming off the posterior cord really once the posterior cord is giving rise to the radial nerve, the axillary nerve quickly comes off and passes through the quadrangular space of the axilla to enter the posterior compartment of the arm.

00:26 Here, it runs alongside the posterior circumflex humeral artery which form that important anastomosis around the surgical neck of the humerus.

00:34 Here, we can see teres minor muscle and we can see deltoid muscle to help orientate ourselves.

00:40 The axillary nerve is important in supplying the cutaneous aspect around the shoulder.

00:45 So, here, we can see the area of skin that the axillary nerve supplies.

00:50 If you were to have a lesion around the fracture of the surgical neck or compression of the quadrangular space due to muscle hypertrophy, so, weightlifters increasing muscle mass can compress this space and can compress the nerve.

01:05 That leads to paralysis of the deltoid muscle which the axillary nerve supplies and also, when we spoke about teres minor.

01:12 You'll therefore be unable to abduct beyond 15 degrees where we have deltoid muscle contributing to this.

01:19 Remember, the first 15 degrees is supported by supraspinatus.

01:25 If we then look, we'd have the concomitants and sensory loss here of that distribution.

01:30 It's quite widespread here and it's usually around like an army badge as one would have on a military uniform. That sort of location on the lateral aspect of the arm.