 on muscles of the upper limb. In this session, we will be learning about the muscles of the hand. You see, muscles of the hand, they are in all 20 in number. You can group them into groups of four. There are four 3-nar muscles, four hypotenar muscles, four lumbaricals, four palmar introscii and four dorsal introscii. So, these 20 muscles will be covering in this particular session. So let's start with the 3-nar muscles first. In muscles of the hand, we need not remember all the attachments of the muscles like as we do for the muscles of the forearm, the remaining of the upper limb. In muscles of the hand, we at least need to remember the names of the muscles and the approximate location of those muscles. So, 3-nar muscles, these are four in number, abductor policies, abductor policies, bravis, flexor policies, bravis and opponent policies. So, how we can easily remember these four muscles? We can remember four actions of the thumb. Which four actions? So, you can do these actions as I am speaking. Adduction, abduction, flexion and opposition. These four actions, if you remember, then you can correlate and easily remember the names of the muscles. The muscles are four in number, but these three muscles are together included in the 3-nar eminence. These three muscles are included in 3-nar eminence. Abductor policies, bravis, flexor policies, bravis and opponent policies. Adductor policies is a deep muscle. It's not like included in the 3-nar eminence. So, to identify these muscles, in the superficial part, there are two muscles which are seen. Abductor policies, bravis is on the lateral aspect, flexor policies, bravis is on the medial aspect. When we retract these two muscles in a deeper plane, a muscle will be seen. Here, this is opponent's policies. This is opponent's and horizontal muscle, which is seen here, has got a transverse head and an oblique head. This muscle is adductor policies. We are the 3-nar muscles. Let's try to identify these muscles in the dissected image. This muscle here is abductor policies, bravis. This muscle is flexor policies, bravis. If we retract these two muscles, the muscle lying deep will be opponent's policies. Here, this muscle, which we can see, this is adductor policies, the transverse head and oblique head. This is adductor policies muscle. Now, let's cover the hypothenor muscles as well as the lumbaricals. Hypothenor muscles are seen here on the medial side. In hypothenor muscles, the muscles are towards the little finger. That's why digite minimi comes in the name. That is, abductor digite minimi, flexor digite minimi, opponent's digite minimi. As well as, there is one superficial muscle just beneath the skin in this region. That is, parmaris bravis muscle. So, remember, these muscles also, we can remember, actions of this little finger, abduction, flexion and opposition. So, three muscles are seen in the image and one muscle is just beneath the skin. That is, parmaris bravis. Then, let's see the lumbaricals. Lumbaricals are four in number. They are attached on to the tendons of the flexor digitorum propandus muscle. This is the first lumbaricals, second, third and fourth. If you carefully see, the first and the second lumbaricals are unipinate muscles. The third and the fourth lumbaricals are bipinate muscles. Distal attachment, it goes up to the dorsal digital expansion. Now, supply of lumbaricals is such that the first and the second lumbaricals, which are on the lateral aspect, those are supplied by the median nerve. And the third and the fourth lumbaricals, which are on the medial aspect, those are supplied by the ulnar nerve. Because as you all know, the flexor digitorum propandus muscle, its lateral half is supplied by median nerve and the medial half is supplied by the ulnar nerve. Okay. Similarly, it carries forward for the lumbaricals as well. For hypothenar muscles, all are supplied by the ulnar nerve. Maximum muscles in the hand are supplied by ulnar nerve. Only few of them are supplied by median nerve, which I'll list out at the end of the session. Let's see dissected images of these muscles. Here, these muscles are the hypothenar muscles. This is adductor digitiminimine. This is flexor digitiminimine. Opponents digitiminimine will be a little in a little deeper plane. Okay. And with the skin, the parmaris bravis muscle has been gone. Okay. And these muscles, which you can see, these are the lumbaricals. Lumbaricals means worm-like muscles. Okay. These are the first lumbaricals, second, third and fourth. Lumbaricals, the proximal attachment is on the tendons of the flexor digitorum propandus muscle. Distal attachment, it goes up to the dorsal digital expansion. Now, let's cover the other set of muscles, the parmarintrosiae and the dorsal introsiae. Parmarintrosiae will be seen more clearly on the anterior aspect. Dorsal introsiae will be seen more clearly from the posterior aspect. Okay. In this image, we can see the parmarintrosiae. This first, second, third and fourth. There is no parmarintrosiae which is attached on to the middle metacarpal. Okay. Because this is the axis of movement. The movements caused by these muscles are adduction and abduction. For hand adduction and abduction, the axis is towards the middle finger. Okay. Movement towards the middle finger is adduction. Movement away from the middle finger is abduction. Parmarintrosiae causes adduction. You can remember pad. And dorsal introsiae causes abduction. You can remember dab. Okay. Dorsal introsiae is for abduction. Parmarintrosiae is for adduction. In this image, we can see the dorsal introsiae. Dorsal introsiae are bipinate muscles arising from the adjacent metacarpals. Distal attachment, it goes up to the base of the proximal phylinx as well as onto the dorsal digital expansion. And all muscles are supplied by ulnar nerve. Action of these lumbaricals and introsiae are such that they cause flexion of the metacarpal phylinx joint and extension at the interphylinx joint. Okay. So, when they are paralysed, opposite action occurs which leads to clinical conditions is called as claw hand. In claw hand, there is hyper extension of the metacarpal phylinx joint and flexion of the interphylinx joint. Exactly opposite the actions of these introsiae and lumbaricals. Okay. Let's see the dissected images of parmarintrosiae and dorsal introsiae. These are the parmarintrosiae. As you can see, there is no parmarintrosiae attached down to the middle metacarpal. Okay. And these are the dorsal introsiae. Let's summarize what we have covered in this session. So, in all, as you all know, there are 20 muscles grouped into groups of four, four-thiner, four-hypothiner, lumbaricals, parmarintrosiae and dorsal introsiae. Okay. Each of them are four in number and the nerve supply of these muscles is such that 16 and a half is supplied by ulnar nerve and four and a half is supplied by median nerve. Okay. So, if you remember this four and a half part, then remaining muscles we can add on to the ulnar nerve. So, what is this half-half? Half-half is from the flexor-polisus bravis muscle. Okay. Flexor-polisus bravis is a hybrid muscle supplied by both median nerve and ulnar nerve and which are the other four muscles which are supplied by median nerve. Two are the lumbaricals. First and the second lumbaricals are supplied by median nerve and there are two muscles in the tinar eminence, opponent's policies and abductor policies bravis. Okay. Abductor policies bravis, opponent's policies, these are two other muscles. These two and these two lumbaricals and half of flexor policies bravis. Only this much in the hand is supplied by median nerve. That's all muscles are supplied by ulnar nerve. For lumbaricals, parmarintrosiae actions are very important because they get affected in a clinical condition is called as clump case paralysis. So, actions of lumbaricals, parmarintrosiae and dorsal introsiae are flexion of the metagarpopalangell joint and extension of the interpalangell joint and exactly opposite will occur in a clinical condition is called as claw hand due to the lower trunk of the rachial flexor injury called as clump case paralysis. In claw hand what occurs? Hyper extension of the metagarpopalangell joint and flexion of the interpalangell joint. Okay. So, all these occur in claw hand. So, this was all about this particular session. If you all have any doubts, then you all can ask in the comments section below. Okay. Thank you.