 Now, I'm going to again retract the trapezius to show the muscles which are deep to the trapezius And we can see some muscles in front of us So let's first name them From below up this muscle that we see here This is the rhomboidus major the next muscle above that This is the rhomboidus minor and the muscle on the top. This is the libator scapulae Let's say a few quick words about each of them because all these three muscles they act on the pectoral girdle So let's start from the top again. The libator scapulae The libator scapulae takes origin from C1 to C4 and It comes down and here it also forms a part of the floor of the lateral cervical region But of course that we cannot see from here because we are in the posterior aspect and then it comes down and gets inserted Here we can see and this insertion is on the medial border of the scapula above the base of the spinal So this is the insertion of the libator scapulae. What is the action of the libator scapulae? The libator scapulae as the term implies elevates the scapulae Another action of the libator scapulae is Along with the rhomboids minor and major is to rotate the glenoid cavity downwards as opposed to the trapezius Now superior and the inferior fibers which rotated the glenoid cavity upwards these rotate the glenoid cavity downwards Now let's come to the rhomboidus minor rhomboidus minor takes origin from the spinous process of C7 downwards and It also takes origin from the nuclear ligament which is in the back of the neck and It gets inserted onto this portion here Which is the base of the spinal of the scapulae and this is the spinal scapula So it gets inserted into the base of the spinal the medial border of the scapulae rhomboidus major this takes origin from T2 spinous process downwards to T5 and we can see here and The fibers then run down obliquely and they get inserted out of the medial part of the scapula below the spinal Action of the rhomboidus minor and the rhomboidus major is to hold the scapula close to the chest Especially during exertion and it also helps to rotate the glenoid cavity downwards When a person is swinging a sledgehammer The rhomboidus minor and the rhomboidus major are the ones which come into play to hold the scapula to the chest wall So that the person can use force to swing the sledgehammer These three muscles are supplied by the dorsal scapulae nerve. So let's take a look at the dorsal scapulae nerve by This is the dorsal scapula artery The dorsal scapula artery is a branch from the second part of the subclavian artery And we can see it is running and it runs deep to these muscles and when I give exert traction here We can see that it is moving here and accompanying that Are the branches of the dorsal scapula nerve the dorsal scapula nerve arises from the root of the brachial plexus This is the dorsal scapula nerve which comes from C5 root of the brachial plexus And it runs with the branches of the dorsal scapula artery that we can see here and they run deep to the levator scapulae The rhomboidus minor and the rhomboidus major and they supply when there is an injury to the dorsal scapula nerve then the paralysis occurs of these three muscles and we can judge it clinically When we see the patient from behind this needle border of the scapula Will be shifted further away from the midline because of the paralysis of the muscle So that is how we judge the paralysis of the dorsal scapula nerve C5 Thank you very much for watching. Dr. Sanjay Sanyal signing out if you have any questions or comments Please put them in the comment section below. Have a nice day