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Ribs 3 through 9 are typical ribs. They have a similar
structure where the rib starts in the back
by the spine and the head of the rib is going to articulate
with the vertebrae and then you’re
going to have the tubercle attached to the vertebrae above
where the head is and then come around,
curved. Again start at, let’s say, rib 6, T6 attached to T5
as well. It will then come down
and then come up but not as far as it would be from where it
starts. That's the general structure of
the typical rib and the neck and the tubercle articulate
with the transverse process and
costovertebral ligaments and the ligaments cement the head
of the rib in place and the tubercle is
tightly held next to the vertebrae. Again, this is why in a
trauma you are at risk for fracturing
or injuring the ligaments and these are not easy to image
and not easy to see on x-rays or CAT scans
or MRIs. So, the flat curved nature of the ribs is effective
for motion but it does have some
downsides and that it's susceptible to trauma, susceptible
to rapid changes and speed or motion.
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Here is another example of typical rib just so you can see
what they look like and again they
get larger as you get down to T10. T10, T11 and T12 are
atypical ribs. So the atypical ribs.
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What does it mean? They’re part of the rib cage, they’re
part of the structure that encases the chest
wall cavity. The first rib is the shortest rib. It’s got the
greatest curvature, it’s also flat
without an angle or costal groove and it has a single facet
so it articulates only with T1. It
doesn't go up to C7. It doesn't attach to anything but T1.
The second rib, the costal cartilage,
has 2 demifacets that attaches to the manubrium and that's
going to also move a little bit
differently and when we talk about motion, we'll talk about
the pump handle motion of the upper
ribs. Part of that has to do with the structure of the ribs
at top that dictate the motion. 10
through 12 also will only have one facet and attach only to
the one level of vertebrae. So it
isn’t stabilized, it isn’t braced and the motion has more
____ is more likely to change. T11 and
T12 have no necks, no tubercles, no attachment to the rib
above. Again another picture of an
atypical rib showing where the subclavian vessel will be and
the muscle attachments that will move
and stabilize the bone. The atypical ribs will include the
upper and the lower ribs, ribs 1 and 2;
ribs 10, 11 and 12. Rib 1 is where the thoracic inlet is and
you have to be very conscious of
that because you'll see a lot of complaints, a lot of issues
with neuromuscular dysfunctions. The
manubrial attachment is usually rib 2. Again, rib 2 still
comes down a little bit and comes back
up and attaches by the manubrium. Rib 10 is typical in
structure with the atypical articular facet
again attaching to 1 vertebra and not always attaching to
the vertebrae above it. 11 and 12
are floating ribs with no anterior attachment. It’s going to
have caliper motion, it’s not going to
have the pump handle of the upper ribs or the bucket handle
of the lower ribs that we’ll talk about
a little later. So each rib again has a slope and this is
meant to slow down. Think about the
rib cage and understand that when you’re looking at the body
there's somewhat of a forward bending
slope to it, somewhat of an asymmetry in the body. We get
used to looking at people like this
because people hold their ribs the same way they hold their
chest the same way and in looking
at it again higher in the back, lower and then coming up.
There is some smoothness to it but if
you trace a single rib it will be helpful. So take a second,
trace your rib from the back to the
front and get a good sense of the curvature. Then turn the
patient around and trace the rib again
from the back coming down and then coming back up and do
this with palpation, feel the rib,
feel where it's coming to and get a sense of how the change
occurs. Why is this important when we
get to inhalation lesions? Someone breathes in and they
can't fully exhale. it's restricted that’s
going to matter and understanding the normal is going to
help. Getting the attachments will
help with the motion. The manubrium is at the level of T3/T4
because again it's coming down and not
coming back as far up. You are going to have the jugular
notch there, you’re going to have the
you’re going to have the clavicular notch where the clavicle
attaches and you’re going to have
the costal cartilage of the 1st rib and the clavicle
attaching to the manubrium. When you get
to the sternum, you want to notice the angle of Louis. By 30
years of age, that’s set. You are
going to have some hypertrophy, bony enlargement after that
but you’re not going to have the same
trabecular matrix of the bone, you’re not going to have the
same sponginess to the bone. It is
more likely to fracture, more likely to separate and more
likely for people to have medical issues
after 30 years of age and the sternal angle, the angle of
Louis, will give you a sense of is it
formed, is it solidified, has the organs stopped developing
and what age is it? When we talk about
aging, yes the sacrum, the size and shape is one of the most
sensitive but the manubrium also has a
different size and shape in men and women. The sternum
larger, thinner and narrower than the
manubrium so it starts to taper down from level 5 to 9 and
then when you get to the xiphoid it
gets even smaller. Originally, the sternum is in 4 separate
pieces but again it ossifies by 30 years
of age and we call the sternal pieces sternebrae. I want to
talk a little bit more about the
sternomanubrial junction because again we look at it all the
time, we notice it, it's very evident
and it does give us some information. It does tell us what’s
going on with that joint, how good
is the motion, how fluid is the motion, how stuck is the
motion, how likely is this person to
develop breathing problems because their rib cage is not
healthy, not easily moving, not smoothly
moving. So, you look at the sternomanubrial junction and we
often test and check the sternoxiphoid
junction to see if the articulation has solidified and is
moving or not. While the xiphosternal
junction is cartilaginous, it is a synchondrosis of
bone-on-bone joint that moves somewhat but
not very much and the sponginess, the motion, is a general
sign of how easily it is to move and
how healthy the joint is. In older people again, once it's
ossified the motion is going to be less
and you may feel some crepitus, you may feel decreased
motion and even some tenderness to
the musculature when you try and move. Let’s examine the
xiphoid process now because it's the bottom
of the sternum, it's the smallest part of the sternum and
it's also variable, it's thinly elongated,
it sometimes bends inward, it sometimes has extra pieces,
sometimes you get ossicles formed but you
can tell if it's tender or if it's easily moving or not
easily moving. It tends to ossify by 30,
sometimes 40 years of age and tends to stop changing as
rapidly after that and doesn't have as much
of an organ function. So it's just something to be aware of.
It will give you a clue as to whether
or not there’ll be breathing problems, breathing sticking or
breathing ease. It's also a marker
for checking the liver, checking the stomach and seeing
where organs are and for reproducibility
of the exam and when you think of the thorax again we tend
to look at the rib cage but the strut of
having the clavicle and the sternum also affects motion and
mobility, it affects comfort levels
and it also connects to the sternum which is part of how it
affects motion and breathing.