The distal most joint of the upper limb that we're going to discuss is your wrist joint and more
properly referred to as your radiocarpal joint now what's important here is we're talking radio- so
meaning that we're talking about your radius not your ulna the ulna is not actually involved in your
wrist joint it plays such a big role in terms of the elbow joint it actually doesn't extend
all the way down to the wrist so just the distal radius is playing a role here so let's look at the
bony parts of the joint so we're talking distal distal radius and actually if you were to look
at a completely distal view of the radius you would see this nice shallow area that's able to
actually fit with this proximal row of your carpal bones now remember in our discussion of the carpal
bones you have two different rows you have your proximal row which is composed of four different
bones as well as a distal row another four bones the proximal row is made up of your scaphoid bone
which is your most lateral the lunate the triquetrum and then also your pisiform right here and if
you recall your pisiform is actually an example of a sesamoid bone which is formed in your flexor
carpi ulnaris tendon and the pisiform is not actually included within this radiocarpal joint
so it's not actually articulating with the radius just the other three bones the more lateral bones
now the radiocarpal joint is an example of a condyloid joint and we don't talk about
condyloid joints very much because there's not really that many in the body but this is a nice
example of one and in a condyloid joint you had the capability of flexion extension adduction
or abduction which we also refer to as radial deviation so you think about abduction moving
on the radial side of the wrist where as ADduction or adduction is moving on the ulnar
side of the wrist now because you have flexion extension abduction and adduction you're capable
of circumduction that complex movement of those four so let's actually get those in the wrist
joint we'll start with flexion and extension so we have flexion is the movement anteriorly
extension moving back into anatomical position and you actually have quite a range of motion in terms
of hyperextension so past anatomical position now if you look at abduction and adduction you can
see with a ABduction or radial deviation you're moving away from the body and then Adduction
back so it's back towards the ulnar side now in this area you're also going to have the distal
radio-ulnar joint so we discussed the proximal radio-ulnar joint which is closely associated
with the elbow now the distal radio-ulnar joint is more closely associated with the wrist so this is
an additional area for pronation and supination now recall as we discussed that when we're talking
about pronation and supination the moving bone is the radius the radius is the part of the
bone that's actually moving or rotating along the ulna so you have the radius moving along the ulna
and importantly muscles that are going to affect pronation and supination are actually only going
to attach or have it's more distal attachment on the radius now that concludes our discussion in
terms of joints of the upper limb now let's move to the joints at the lower limb which we'll find
have very close connections and very close associations as you have with the upper limb