Module 4B: Axial Skeletal Muscles Flashcards
what do axial muscles attach to?
the axial skeleton
- some have their impact on limbs in the appendicular skeleton
what is the one large muscle on the neck?
the sternocleidomastoid
what is the origin of the sternocleidomastoid?
- clavicle
- sternum (point of manubrium)
what is the insertion of the sternocleidomastoid?
mastoid process of the temporal bone
what is the actions of the sternocleidomastoid?
- lateral flexion of the head and neck
- rotation of head
what contracts both the left and right sternocleidomastoid?
moving your head to your chin
what are the three muscles that comprise the erector spinae muscle group from medial to lateral? (trunk muscles)
medial: spinalis
- longissimus
lateral: iliocostalis
what are your postural/standing up muscles? (control movement of the vertebral coloumn)
- spinalis
- longissimus
- iliocostalis
where is the origins of the erector spinae muscle group?
- iliac crest
- sacrum
- lumbar and lower thoracic spinous processes
what is the insertions of the erector spinae muscle group?
- ribs
- transverse/spinous processes of cervical/thoracic vertebrae
what is the actions of the erector spinae muscle group?
- back extension (if you contract the left and right group together)
- lateral flexion of back (only one side contracts)
what are the thoracis and lumborum parts of the trunk muscles important for?
because they behave more regionally vs by the actual muscle
what are your pars lumborum?
- iliocostalis lumborum
- longissimus lumborum
- spinalis lumborum
what are your pars thoracis?
- iliocostalis thoracis
- longissimus thoracis
- spinalis thoracis
what are the differences between the pars thoracis vs pars lumborum?
- have different lines of action
- different lengths of tendons so they can act to support the trunk by keeping upright posture and resisting the forward movement of the trunk when you tip or bend your trunk forward
which portion of the trunk muscles have the greatest mechanical advantage? why?
- the pars thoracis portions of the muscles
- due to having the longest “moment arms”??? i cant understand what she said
when is the pars thoracis and pars lumborum system that supports the spine only functioning?
if you keep a neutral lordotic curve in your spine
where is the quadratus lumborum?
- a deep trunk muscle (deep to the abdominal muscles that wrap around the torso as well as the erector spinae muscles)
- squarish shape
what is the origin of the quadratus lumborum?
the iliac crest
what are the insertions of the quadratus lumborum?
- inferior border of rib 12
- L1-L4
what is the action of the quadratus lumborum?
- lateral flexion of back (only if it contracted only on one side)
- very strong muscle
- back extension if both sides are contracted
- will also help to stabilize the pelvis if the trunk is stationary
what does intercostal mean?
between ribs
what muscle group is the internal and external intercostals part of?
the thorax muscle
how many layers are there of intercostal muscles
three layers
where does the external intercostal muscles run?
external thorax
- run down, medial and forward from the rib to the rib below
where does the internal and innermost intercostals muscle run?
internal thorax
- they run up, medial and back from the rib below to the rib above
what muscles are involved in respiration?
the thorax muscles
what is the AIO of the external intercostals?
A- inspiration (acts lifts the ribs when you breath) (pulls up on the bottom rib to the top rib)
I - rib below
O- rib above
what is the AIO of the internal and the innermost intercostals?
A- expiration (act to lower ribs when you take a breath out) (when you contract muscles, you pull down on the top rib toward the bottom rib to help with expiration)
I- rib above
O- rib below
where is the diaphragm located?
at the bottom of the ribs, the bottom of the thorax
what muscle is responsible for most of the action of breathing?
the diaphragm
what is the origin of the diaphragm?
- lumbar vertebrae
- inferior ribs
- xiphoid process
what is the insertion of the diaphragm?
- central tendon - its some big dome shaped structure that’s deep to the ribs
what is the action of the diaphragm?
- increases vertical dimensions of thorax (for inspiration)
what sits on top of the diaphragm?
the lungs
- when we take a breath in, the diaphragm is contracting to pull down(moving towards it origin) so the lungs can fill with air
contractions typically bring the _______ closer to the ________.
insertion closer to the origin
what is medial to the external oblique?
the rectus abdominis
what is deeper to the external oblique?
the internal oblique
what is the deepest abdominal muscle?
the transversus abdominis
what do the abdominal muscles perform?
trunk flexion
what are the abdominal muscles antagonist to?
the erector spinae muscle group
between the four abdominal muscles, what direction are the fibers moving in?
all directions
the abdominal muscles support and protect?
support the trunk and protect your organs
your external, internal oblique and transversus abdominis all attach to?
an aponeurosis
- a big broad tendon that is connective tissue that connects muscle to bone
which muscle has a big tendon running down the middle and small little tendons running horizontally?
the rectus abdominis
what is the origin of the rectus abdominis?
pubis bone
what is the insertion of the rectus abdominis?
- xiphoid process
- lower ribs
what is the action of the rectus abdominis?
- trunk flexion
- increases intra-abdominal pressure.
the rectus abdominis has divisions by what?
tendinous intersections
why does the rectus abdominis have divisions by tendinous intersections?
for stability to the middle of the muscle but also stops the muscle from bowing so that the muscle produce greater force
- prevents the rectus abdominis from being torn apart due to hoop stresses
- they limit the bulk when you shorten the muscle and they permit lateral transmission of force from the oblique muscles to help make a continuous loop around the abdomen
- tendinous intersections look a lot like ab lines!!!
because of what is why the rectus abdominis stabilizes the pelvis during running or walking or when you raise your legs?
the origin on the pubis bone
the rectus abdominis is deep to?
the external oblique
do we have a 6 or an 8 pack?
an 8 pack (bottom two are the hardest to showcase)
what direction does the fibers of the external oblique run in?
down and forward
is the external oblique deep or superficial to the rectus abdominis?
external oblique is superficial to the rectus abdominis
what is the origin of the external oblique?
outer surface of ribs
what is the insertion of the external oblique?
- linea alba
- inguinal ligament
what is the action of the external oblique?
- trunk flexion (if both sides are contracted)
- trunk lateral flexion (one side contracted)
- trunk rotation (one side contracted)
- increases intra-abdominal pressure (one side contracted)
what runs vertically between the left and right rectus abdominis muscle?
the linea alba
what runs along the perimeter of the rectus abdominis?
the inguinal ligament
what direction does the fibers run in the internal oblique?
down and backwards
where is the internal oblique in regards to the rectus abdominis muscle?
deep
what is the origin of the internal oblique?
- lumbar fascia (on back)
- iliac crest
what is the insertion of the internal oblique?
- linea alba
- lower ribs
what is the action of the internal oblique?
- trunk flexion (if both sides are contracted)
- trunk lateral flexion (one side contracted)
- trunk rotation (one side contracted)
- increases intra-abdominal pressure (one side contracted)
what is the deepest abdominal muscle?
the transversus abdominis
how do the fibers of the transversus abdominis run?
horizontally
what is the origin of the transversus abdominis?
- lumber fascia (on the back)
- iliac crest
- inguinal ligament
what is the insertion of the transversus abdominis?
- linea alba
what is the action of the transversus abdominis?
- increases intra-abdominal pressure
where is the inguinal ligament?
attaches to the superior anterior iliac crest and goes down to almost the pubis symphysis (tech stops at the superior ramus of the pubis)
what is intra-abdominal pressure?
- drawing in of the abdomen
- squeezes and compresses the abdomen
- compresses the abdominal contents which helps to keep your organs safe
- provides postural support with the muscles of your back
- it is an action for ALL your abdominal muscles
can you strengthen your transversus abdominis alone?
no
- do not target this muscle alone
- instead: target exercises that are for all of the abdominal muscles together like planks
