hi um let's talk about Forum um forum is uh the function of forum is to fine-tune the position of the hand so that uh we can use our hand to manipulate object for our valued um um occupations um it has one degree of Freedom U which is pronation superation and you may argue uh there or there are two joints uh the proximal radio on a joint and the distal u u radio on a joint yes um but these two joints are typically seen as one when we look at the pronation superation okay so again um typically we see form as uh uni um actual joint which is uh one degre of Freedom joint okay so if we look at the proximal radio on the joint again uh it's the radial hair kind of move around the radial not um so it's between um oner joint and uh the radi I'm sorry the owner bone and the radial bone and uh what you need to see is here um the anular ligament it's kind of um secure um the radio head right here the radio ahead um so that uh it can of spin so that that means that it doesn't really allow the the radio head to move around I mean at the proximal oner I'm sorry the proximal radio oner joint right here okay um and uh if we if we go more uh distal we see this uh interus membrane it's a a broad a flat membrane between the radio bone and the bone it kind of holds the bones out together and provide a surface uh for the form to to function okay and then when we go more dist we see here uh the distal radio owner joint right here it's um it's the head of the owner kind of arcul I'm sorry articulate with the owner Notch right here okay it's very um stable um because you see here there are so many um ligaments to stabilize the joint and we will talk more about that when we um talk about wrist joint or wrist complex okay and most family um I'm sorry most famous um ligaments is called U triangular fibral C uh cartilage um complex um AKA tfcc um again we will um revisit this U tfcc when we talk about wrist so you can kind of see that this uh disto radial joint is kind of um stable and the movement of the forarm is pration superation um it's really when you kind of draw a um a a virtual line um from the radio head to the owner head right here this is the axis of um from motion and um uh because the uh the radar head is really kind of spinning at one place mostly so what you see is really the uh radial head going to move onto the the oner I'm sorry the radial bone going to move onto the owner head and going to go come back but that doesn't mean that the owner bone have no movement it does but it's really tiny like you know normal uh no more than 3° so again so what we typically see uh is uh the radial bone going to move uh on the owner bone okay the normal range of pronation superation is 0 to 80° again zero means neutral okay from neutral position uh um pronate um for 80° and supernate for 80° and the functional range of for poration superation is 0 to 50 so there's a difference between there's a difference because the arts for the normal Ral motion is60 and the functional range is it's just 100° so this is this is interesting because um especially for um people who um break their bone especially um the radial bone right there and U distal um radial bone um often times uh people will lose range of motion of poration superation but they barely complain about it because you know they can still function right it just doesn't feel uh good when you cannot turn or you know peration or super Nation to um uh compared to before the injury but again when you look at the functional um perspective they're okay okay so the prime mover for pronation of the Forum is uh the pronator quadratus you see this huge uh square shape muscle in uh in disty U so this muscle kind of kind of kind of um move um the forarm into pronation and another prime mover is pronat Terrace you can see that it's kind of round shape but um tiny muscle um it it it's not really as strong as the uh quadras and it it it's it's most efficient when we have when we having a fast pronation um then this pronat terrorist will be in place to do um its job for example oh oh um or when we kind of pronate to against of resistance for example uh when we turn a door knob okay or uh we uh bring back the hand to the face okay um and superator um biceps Breaky ey uh like when we talk about elbow uh it's a huge uh a very strong uh superator um it's most uh efficient when the elbow is in U flexion of 90° okay and supernat right here you can see that um it's it's not as big as spine saps and it doesn't it doesn't um allow uh too much Movement Like elbow joint I me I'm sorry like the biceps muscle okay so uh if you look at the muscle right here it's not hard to imagine that the best function of the superator is when the elbow is in extension because in this uh when elbow is in extension um it puts the muscle in a better um um M arm um for muscle contraction okay so again um what we see um um um the prime mover there are secondary movers and again uh we uh only want to focus on the the the primary mover of uh a joint so uh but you do need to know that they cannot do their job without um um assistance from other muscles okay so here's a summary of muscle actions that may feel uh confused uh sometimes so um I I I make this slide for you just for you to focus so when we look at the uh elbow flexion we see uh biceps Breaky eye uh Breaky Alice bracho radialis are the prime movers for elbow flexions um and tricep brachi and um anones um is um the prime mover for elbow extension when we think about pronation of the forarm is a pronator quadratus and pronator teras and superator uh we have biceps break ey and the superator okay so overall uh what what are the common elbow inform um pathologies here uh what I didn't talk about and when we uh visit the elbow complex is the Epicon because I'm going to talk about it um when we talk about um wrist so uh but roughly lateral Epicon of the humorus are the common origin site for extensors and the medial eond of the humorus is a common site of an origin for flexors and um these These are the these mus when these muscle is damaged um typically um we have um the lius uh which is U the in uh information so uh when we uh the common sides for elbow injury is the lateral epic uh C I'm sorry lateral epicondilitis um AKA table it's mostly back we overuse our extensors of the wrist and hand and the medial Epicon deltis is also aka the golfer elow it's more like a overuse of the flexors of the wrist and the fingers what it's um difficult or uh hard to see is the pulled elbow also called nurse maze elbow it's most seen in the young children that's um that's the uh anular ligament God traction or tear like when the adult kind of you know uh when you see um an adult kind of hold uh a young kid's hand and cross the uh the busy road when the green lights on and the adult kind Rush the young kid to go and often times we may pull too hard that uh will sub loock um the anal ligament and that's uh when we hurt um the kid's um elbow and that's what we call the pulled um elbow okay and um a lot of time well because it's it's elbow is a it's a quite stable joint it's we don't see that much I mean uh the dislocation much but it's uh most um seen in uh accident like you know the fall or C accident that or doing a sport um we may dislocate uh the elbow and um the AL nerve um kind of travel to the back of the the elbow um and when the on nerve uh got um compression or in trapped at the elbow um it's it's uh that's uh what we call the cubito Turnal syndrome okay cubito means elbow okay so and it's the second common scen nerve compression syndrome in human body the F uh well the first one is carpotonal syndrome at the wrist okay so it's medium nerve compression at the wrist and the second one is on nerve compression at the elbow um which called cubito Turnal syndrome and we will uh talk more about that um in phys disc course okay so these are the common pathologies that we see uh at the El okay