hello all this is dr alsup and in this video we will be discussing
bone types specifically we will talk through the five main types of bones
and the characteristics and a few examples of each type these characteristics will
sometimes help in understanding the individual function of these bones
all right i always like to start with long bones because i think they are easy to conceptualize
long bones will have a greater length than width so but always with a slight curve particularly
in terms of the the body of the long bones to help absorb stress from body weight and for just
general strength these bones are mostly compact bone in the body region so in this region here
will be mostly compact bone and then the ends of the bone will be made up of mostly spongy bone
the humerus which you see here which is the longest bone of the upper limb
is an example of a long bone as are the the larger femurs as well as the forearms
radius and ulna and the leg bones the tibia and fibula but also some smaller bones in the hand and
feet like metacarpals metatarsals and phalanges which while smaller they're still longer than
they are wide so officially long bones and you can even see some of those over here in this region
short bones are more cube-like with a nearly equal length width and even depth
so such as what you can see here with these carpal bones so we were talking
about how some of these are more long bones over here but your carpal bones are really
excellent examples of sharp of sharp bounds of short bones so carpal bones many of the
tarsal bones that are associated with the ankle region are also short bones these
are almost completely composed of spongy bone except for a thin outer layer of compact bone
flat bones are pretty descriptive in terms of their name they're going to be composed of two
nearly parallel sets two parallel but slightly curved plates or tables these are going to be
made up of compact bone and then you will have spongy bone in the middle region right there
um so the sternum or the breastbone is a good example of a flat bone but many
of the cranial bones as well as even the ribs are considered flat bones
next we have the sesamoid bones which are actually one of my personal all-time favorite types of
bones and these are super neat because they form and develop within certain tendons so remember
tendons are going to connect muscle to bone so you're going to have bone forming within tendons
particularly in areas where there's considerable stress and or friction
or compression these bones may not be completely ossified even into adulthood and the number of
sesamoid bones in the body can vary from person to person so the next time someone says that there
are 206 individual bones in an adult skeleton you can smartly add well if you aren't considering the
possibility of different sesamoid bones and you will be ever so popular at your next dinner party
there are two name types of sesamoid bones there is the patella which you can see here or your
kneecap as well as the pisiform bones in the wrist region which are one of your carpal bones
and there are other common but typically unnamed sesamoid bones in the big toe or your first
toe and your thumb region these are going to be formed in tendons there
the fifth category of bone is for all the other bones that just don't fit into one of the other
four categories and these are the irregular bones these have very complex shapes as you can see here
in the vertebrae which are an excellent example of irregular bones many of the facial bones of
the skull the calcaneus or the heel bone these are all examples of irregular bones all right so
those are the five types of bone when we get to discussing each bone uh in subsequent sessions i
want you to think what type of bone is this and why don't we get started on that right now okay
so this arrow is pointing at the left coxal bone we often refer to this as the hip bone what type
of bone is this just look at it what do you think it is is it flat irregular long sesamoid or short
so take a minute and pause the video if you need to and kind of think through it but when you're
ready let's get let's talk through it together because this one's kind of tricky because really
when you're looking at this particular portion of the coxal bone it is relatively flat but the
inferior and posterior portions which i know you can't see the posterior portion here they don't
fit within the flat category so we're not going to go with flat flat is not going to be the correct
answer the left coxal bone or the right coxal bone either one are certainly not long or short bones
and it's not a sesamoid bone either first off i'll just tell you it doesn't form within a
tendon that would have to be a giant tendon and it's just plain too big to be a sesamoid bone
so if it doesn't fit into any of those four other categories we know that it's going to
always fit in the ever encompassing irregular category so be irregular is the correct answer
yeah hey great job here sometimes the categories aren't very cut and dry
and that's okay but the basic categories will help you understand what the potential function
of the bone is as well as what type of bone organization makes up the bone so
is it more spongy or more compact or a pretty even combination all right thank you for your
time and attention here and please always feel free to reach out with any questions