all right we're looking at an anterior portion of a left hand and you can see putting my hand
right next to it this is going to be the lateral portion and moving more medially so before we
really get into the separate types of bones let's talk about the digits and how we number those
when you're talking about digits you start with the first digit your first digit is going to be
associated with your thumb so first digit is going to be lateral which is different what you what you
have in the foot the first digit is going to be medial associated with your big toe or your great
toe so different in terms of what you have in the upper limb then the lower limb so first digit its
lateral second third fourth and your fifth digits associated with your little finger okay so we'll
talk about the three main areas of bones you're gonna have your carpal bones right here these are
your wrist bones there are eight carpal bones you'll have your proximal row and your distal
row the proximal row is made up of four bones so that's what's actually articulating with the
radius so your radiocarpal joint is going to be the articulation of your scaphoid bone your lunate
bone triquetrum which is going to be the most medial and sitting right on top of the triquetrum
is this little bone right here referred to as the pisiform bone now the pisiform bone is
not actually a part of your radiocarpal joint it is going to be associated with your flexor
carpi ulnaris tendon so this is one example of a sesamoid bone another example the largest of
your sesamoid bone is your kneecap or your patella so sesamoid bones actually form within tendons so
very unique in terms of their bone development so this is your proximal row these are what's
articulating with the radius of your forearm then you're going to have your distal row of carpals so
also four bones you'll have your trapezium trapezoid capitate which is your largest of
your carpal bones and the hamate and you can see this hook right here the hook of your hamate
often fractured you'll have a tendon that's going to be moving right through this region right here
so these are your carpal bones eight and all then you're going to have metacarpals we think of the
metacarpals forming a good portion of the palm of your hand so your metacarpals are going to be here
your carpal bones your metacarpals are going to be right in this region your first metacarpal is
going to be the stoutest it's also the thickest in this region your second third fourth and your
fifth metacarpal the fifth metacarpal is an area of frequent fracture particularly in terms
of individuals that boxed you'll have a fracture in this region now one thing I forgot to mention
when I was talking about the carpal bones is this particularly the proximal row you can have
fractures in this area so you'll have the Colles fractures which are fractures of the distal end of
the radius oftentimes in association with that you can have a fracture of your scaphoid bone so your
scaphoid bone or the most lateral on the proximal row of your carpals this is the most frequently
fractured carpal bone and actually this has a lot of implications if you get a fracture here
often it's not picked up immediately on imaging so usually you'll go in for some type of x-rays a
lot of times you'll be misdiagnosed as a strained wrist you can go back in a couple of weeks later
and because the blood vessel was kind of broken in that region it can lose lead to necrosis or
breakdown of the bone in that region so often it's misdiagnosed but with better imaging this has been
picked up a bit more all right so those are the carpals your metacarpals right here you're gonna
have your metacarpophalangeal joints so between your metacarpals in this proximal row of phalanges
so if I were to show you here what we think of as the knuckles it's going to be these joints right
here so your proximal row of phalanges you'll have five of those so your first second third
fourth and fifth your intermediate row so you're getting a little bit smaller you're only going to
have four intermediate or middle phalanges and it starts with the second digits right these are
intermediate phalanges so note I just said that we do not have an intermediate phalanges associated
with your first digit now in terms of the last row your distal phalanges these are very unique
shaped bone right here so you have five of these you have a lot of sensory nerve endings in this
region so if you think about closing your hand in a car door how painful that can be is because you
have so many of those sensory endings associated with this region of the bone so you have five
proximal phalanges four intermediate phalanges and five distal phalanges so this is why you
have 14 bones associated instead of 15 because you're missing this intermediate phalanges here