hello anatomy colleagues this is dr alsup and welcome to station number 22 where we are talking
all things ribs and so just to review basic the basic structure of the thoracic
cage you are going to have the sternum which is right here in the midline and then you will
have the 12 pairs of ribs that are going to be kind of lateral and posterior to the sternum
and these ribs are going to be attached to the sternum via these costal cartilages and some of
these ribs will have their own individual costal cartilage and some will share a costal cartilage
for its attachment to the sternum and where the kind of end of the shared costal cartilage
where it ends is going to be referred to as the costal margin or the costal arch
and this is something that you can palpate on yourself it is basically kind of the end
region and then you're heading into the wall of the abdomen at that point and so you don't have
any bony structures on the anterior portion you're kind of left with this cartilaginous
structure here and then it's all musculature from here on in the anterior portion the space
between the ribs and the costal cartilages are going to be these intercostal spaces and during
life these would be filled with intercostal musculature as well as neurovasculature
there's two major structures that i want you to be able to identify on a rib these are going to
be the head and the tubercle so i'm going to show you these on the first rib which i have
over here separately because it's such a unique rib and the fact that it is relatively short
as well as the fact that it's a bit more robust specifically on its superior side because you're
going to have that anterior scalene as well as the middle scalene having an attachment here
but you can see this um the head is going to be the most posterior portion of the um rib with the
tubercle that is just going to be a bit kind of lateral to that structure and you can see if we're
looking at this is the posterior view here you can see all these spinous processes you can see that
the head is kind of heading towards the body of the vertebrae and that's where it will articulate
whereas that tubercle is going to articulate with the transverse process of certain vertebrae and
what are those certain vertebrae which level are going to have the articulation with the ribs think
about it for a moment and hopefully you're landing on the fact that these ribs are articulating not
only with the sternum as we saw in this image but with the thoracic vertebrae in the most more
posterior portion and that's what really forms this full cage as these ribs are filling that gap
between the sternum and the vertebral column and the posterior portion so the head is going to be
this kind of nice rounded region the tubercle is articulating with the transverse processes
and here you have this very unique first rib which is going to be significantly curved and
small as the other ribs will continue excuse me to get larger as we kind of move down the rib cage
until you get to the 12th and 11th ribs which don't have this associated costal cartilage
and they're not nearly as curved and that makes sense because they are not going to have that
articulation with the sternum so it doesn't need that curvature anteriorly alright so those are
the structures that we want you to identify on the ribs for the practical setting take your time to
kind of review these and find those areas that you're still having some questions on and make
sure to ask any of those questions early and often and i thank you for your time and attention here