okay so let's talk about hand so Hand um is really complex so that uh that can help this person to uh move and you know doing uh value activities and it's really a good connection from the per uh from this person to interact with the environment and um for a value occupation so on the hand has three main functional component that uh we can kind of simplify the hand um to you know there down it to be three component um the first one is thumb so the thumb um mainly uh it function is um to do opposition okay when a thumb um pair with index and the middle finger is more uh when this person is doing precision grip like a pinch or pick up something or manipulate something it's more like a Precision grip when um the three fingers and then add in the ring finger and then the little finger which is the five digits so the ring finger and little fingers are when they're involved they're typically more involved with power grip so just you know to simplify this thumbs function is more for opposition index middle finger uh it's in uh the that is more for the Precision uh grip and ring finger and midle finger are um are in for the power grip okay so that's the general idea of the hand so when we look at the hand from the surface so uh we uh if we look at our hand um this is this is really important especially uh for um um Hand Therapy that uh we make splint and these are the kind of like a reference or the landmark that we use uh for making a splet so if you look at our hand you see uh we have a lot of quas these cre represent the joint yeah so for example so um this crease at the thumb right here going of represent the IP joint and then another crease right here this is um mCP joint and then the thinner crease right here kind of represent the whole thumb CMC movement okay if you look at here we uh this is distal Palmer crease and then this one is par uh I'm sorry proximal uh Power Mark cras so uh if you connect these two line two dots and then you connect this it's the joint for the mCP joint at the four digit right here so below this crease uh would allow this person to ban the knuckles or to ban the mcps and then here's here's are uh the PIP creas and dip creas okay so these are the creas that you have to know so the thin the creas dto pmer creas uh proximal pmer creas okay oh and then the wrist crease right here that kind of represent a different rows of the um the wrist movement okay like um in um in this model uh this model those clear on the distal and the proximal crease but my hand I have uh another one in between it's called mle wrist crease okay so this is uh the surface anatomy of the hand that uh you have to know okay and if we look at the bones the bones of the hand kind of form uh three uh primary Arch so we have um longitudinal Arch kind of like you know start from the the wrist joint can kind of all the way past the Met met coule bone I'm sorry carpal bone met coule bone proximal beo and distal fings so this going to form the longitudinal um Arch you see it's kind of like a little bit um kind of um it's not a straight line let me put that so this is the longitudinal Arch and then uh we have two uh transverse Arch the uh the proximal transverse Arch kind of form by the couple bones and then the distal transverse arge can of form by the mid couple bones so these are the three main arches of the hand so if you uh look at your hand uh when you make a fist you see your knuckles so so remember that shape and then you kind of grasp harder or make a power power grip you see that the fourth and the fifth knuckle kind of goes down that means uh that's because the the Min coule bone going to move a little bit right down here that would that would change change the shape of the distal transverse Arch we want to preserve uh these arge so that this person can remain a good hand function so and a lot of time we may ignore that the dist transvers may change um you know according to different task required so fail to allow uh the this transver to kind of change that that this person will lose ability to do power power grip okay and I want to introduce you another arch called obl Arch it's uh it's a it's not a New Concept because well it's been 10 more years but again uh it's not widely uh uh recognized about this and the uh the upli arch um is really uh the concavity formed by um the thumb and the four digit something that you're holding a a comb of an ice cream that kind of an obl arch so you have this Arch this Arch this Arch and this Arch and form U an obl arch like that this is quite important especially um uh when this person's thumb is involved okay so when we talk about longitudinal Arch transverse and proximal and this to transvers AR the thumb is not involved right so when a thumb is involved we have to consider the OB Arch uh right here which is the opposition of the thumb to uh each four digit each of the four digits okay so that's from the surface of uh the hand