Hello everyone, this is my 6th video on motor system examination. Today I am going to tell you how to assess the thumb muscle power. So in this we have to assess the palmar abduction of the thumb, radial abduction of the thumb, palmar and ulnar adduction of the thumb, then apposition of thumb, then thumb flexion and extension movements.
So first is the palmar abduction of thumb. In this we have to keep the forearm supinated palm up position and we have to first tell the child move the thumbs upward at the right angle to the plane of the palm then for against resistance we will keep our finger over the thumb and we will give the downward pressure and child will lift the thumb upward at the right angle to the plane of the palm in this video you can see and the muscle for the palmer abduction of the thumb are APL and APB, abductor pollicis longus and brevis. Abductor pollicis longus is supplied by the C7 to C8 posterior intrusions branch of the radial nerve and abductor pollicis brevis supplied by C8 to T1 median nerve. Now for the radial abduction of the thumb we have to keep the palm in the same position as for the palmar abduction but we have to tell the child to move the thumbs away from the palm.
In the same plane of the palm, so child will move the thumb outward but child will keep the thumb in horizontal position. While in the palmar abduction, thumb is in vertical position and in radial abduction, thumb will be in the horizontal position. position and the muscles for the radial abductions are APL and EPB. APL is the abductor pollicis longus and the EPB is the extensor pollicis brevis. It is supplied by the C7 to C8 posterior intrusions branch of the radial nerve.
After the abduction movement of the thumb we have to perform the adduction movement. In this again palmar adduction and ulnar adduction. So in palmar adduction, adduction will be in the plane at the right angle to the palm.
So the ulnar aspect of the thumb will touch the palmar aspect of second metacarpal and the index finger. So thumbnail will remain at the right angle to the other fingernails. In this video you can see how to perform the palmar adduction.
And the muscle for the palmar adduction is adductor pollicis supplied by the CH2T1 ulnar nerve. Now for the ulna reduction. Adduction will be in the plane of the palm.
So the ulnar aspect of the thumb touches the radial aspect of second metacarpal and index finger. So thumbnail parallel to the other fingernails. In this we have to tell the child to hold a piece of paper tightly between the thumb and hand. Muscle for the ulnar adduction is same as for the palmar adduction.
Adductor pollicis. Now after that we have to perform the apposition or antiposition of thumb. We have to tell the child to touch the tip of the finger to the tip of the little finger. And the muscle for the apposition is opponent's pollicis supplied by CA2T1 median now. Now we have to assess the flexion movement of the thumb.
In this we can separately assess the flexion at the distal interphalanges joint and metacarpophalanges joint. but it is not possible to assist separately proximal interphalanges joint flexion movement of the thumb. So for the flexionate distal interphalanges joint first we have to immobilize the proximal interphalanges joint of the thumb then we have to tell the child to flex the DIP joint of the thumb and for against resistance we have to keep our finger and we have to give the upward pressure and the muscle for the flexionate DIP joint of the thumb is flexor pollicis longus supplied by anterior intrusive branch of median nerve CA2T1. Similarly, we will assist the flexion at metacarpophalanges joint of the thumb.
We will tell the child to extend the thumb and then flex at the MCP joint or we can assist by telling the child to make the fist. In this adduction and the flexion of the thumb occur at the MCP and interphalanges joint. And the muscle for the flexion at metacarpophalanges joint of the thumb is FPV flexor pollicis brevis. There are two head of the FPV, superficial head and the deep head.
Superficial head supplied by the median nerve and deep head supplied by the deep palmar branch of the ulnar nerve. Now we have to perform the extension movement of the thumb. So in this first we will assess the extension at distal interphalanges joint of the thumb. First we will immobilize the proximal interphalanges joint of the thumb and we will keep the distal interphalanges joint flexed and we will tell the child to extend the thumb's distal phalanx and for against resistance we will keep our finger over the distal phalanx of the thumb and we will give the downward pressure and child will try to extend the thumb. Muscle for the extension at distal interphalanges joint of the thumb is EPL.
Extensor pollicis longus supplied by the posterior intrusive branch of radian nerve C7-C8. Now we have to perform the extension at the proximal interphalanges and the MCP joint of the thumb. Muscle for this action is EPB, extensor pollicis brevis supplied by the posterior intrusive branch of radian nerve C7-C8.
In this we will tell the child to extend the thumb at the MCP IP joint. And for against resistance, child will resist the passive flexion of the thumb at the MCP joint. So this is all about the thumb muscle power examination. Thank you so much.