Lecture 7 - Axial Musculature Flashcards
what are the two main characteristics of axial musculature?
1) innervation by cranial nerves and spinal nerves
2) attachments are found on the axial skeleton, associated organs, and/or soft tissue
what are the five major functions of the axial musculature?
1) aids in vision, hearing, mastication, facial expressions and swallowing
2) upright posture & movement of the back
3) support of abdominal & pelvic viscera
4) aid in respiration
5) aids in urination, defecation, & partuition
what are the four major groups of axial muscles?
1) head and neck
2) back
3) thorax and abdomen
4) pelvis and perineum
the muscles in the head and neck are innervated by:
the cranial nerves
what are the seven muscles of facial expression?
- occipitofrontalis (frontal belly)
- zygomaticus major
- buccinator
- platysma
- orbicularis oris
- orbicularis oculus
- procerus
facial muscle that raises eyebrows, moves scalp, and wrinkles forehead
occipitofrontalis
facial muscle that elevates the corner of the mouth, drawing it laterally; smiling
zygomaticus major
facial muscle that compresses and holds the shape of cheeks; helps with chewing and blowing
buccinator
facial muscle that tenses skin of neck, stretching from the mandible to the skin of the neck (most superficial neck muscle)
platysma
facial muscle that purses lips and aids in chewing, kissing, and whistling
orbicularis oris
facial muscle that closes eyelids (blinking, sleeping)
orbicularis oculi
facial muscle that moves the nose (nostrils), and draws medial side of eyebrow inferiorly
procerus
all of the facial muscles have at least one attachment to bone, and one attachment to ____
the skin
what are the seven extra-ocular muscles?
- levator palpebrae superioris
- superior rectus
- inferior rectus
- medial rectus
- lateral rectus
- inferior oblique
- superior oblique
extra-ocular muscle which elevates the eyelid
levator palpebrae superioris
extra-ocular muscle which helps the eye look up
superior rectus
extra-ocular muscle which helps the eye look down
inferior rectus
extra-ocular muscle which helps the eye perform adduction
medial rectus
extra-ocular muscle which helps the eye perform abduction
lateral rectus
extra-ocular muscle which helps the eye roll up and laterally
inferior oblique
extra-ocular muscle which helps the eye roll down and laterally
superior oblique
why do the superior rectus and inferior rectus contract slightly medially?
to correct for the muscles that want to move laterally (remember that the axis of the eyeball is not the same as the axis of the orbit)
what type of joint is the temporomandibular joint?
an ellipsoid joint (a bicondylar joint that allows both rotation and translation)
what happens at the TMJ when opening the mouth (depression)?
1) rotation of the condyle (inferior compartment)
2) translation of the condyle (superior compartment)
what gives the TMJ its ability to rotate and translate?
the double plated articular disc (fibrocartilage) increases the range of motion
list the four muscles of mastication
- temporalis
- masseter
- lateral pterygoid
- medial pterygoid
muscle of mastication that reaches from the temporal bone to the coronoid process of the mandible
temporalis
muscle of mastication that reaches from the zygomatic arch to the lateral angle of the ramus on the mandible
masseter
elevation of the mandible is closure of the:
mouth
processes with muscle attachments below the sphenoid bone
pterygoid plate
true or false: both the lateral pterygoid and medial pterygoid come from the lateral pterygoid plate
true
muscle of mastication that reaches from the lateral side of the pterygoid plate to the mandibular condyle
lateral pterygoid
muscle of mastication that reaches from the medial side of the pterygoid plate to medial angle of the mandibular ramus (acts like a baby masseter)
medial pterygoid
all of the muscles of mastication are elevators of the mandible, except for the:
lateral pterygoid
where is the centre of rotation of the mandible?
the centre of the condyle
what muscle moves to depress the mandible (mouth opening)?
lateral pterygoid muscle
what muscle moves first to elevate the mandible (mouth closing)?
temporalis
the word glossus refers to the:
tongue
what are the four muscles discussed in class that connect to the tongue?
- palatoglossus (palate to tongue)
- styloglossus (styloid process to tongue)
- hyoglossus (hyoid bone to tongue)
- genioglossus (chin to tongue)
these pharyngeal muscles tense and elevate the soft palate to block the nasal cavity
tensor and levator palatini
this pharyngeal muscle is the first to constrict the pharynx and connects to the mandible
superior pharyngeal constrictor
this pharyngeal muscle is the second to constrict the pharynx and connects to the hyoid
middle pharyngeal constrictor
this pharyngeal muscle is the last to constrict the pharynx and connects to both the laryngeal cartilage and cricoid cartilage
inferior pharyngeal constrictor
why is the order of contraction of the pharangeal muscles significant?
prevents food from coming back up the esophagus
superficial anterior neck muscle which tenses the floor of the mouth during swallowing
mylohyoid muscle
superficial anterior neck muscles which elevates the hyloid (and larynx) and helps to close the airway
suprahyoid muscles
superficial anterior neck muscles stretch from the styloid process to the hyloid, then to the mandible (2 bellies) which assist in depression of the mandible to open the mouth wide
digastric muscles
how are the superficial anterior neck muscles innervated?
by both cranial and spinal nerves (cervical)
list the four steps of swallowing in relation to the pharyngeal and neck muscles
1) contraction of mylohyoid and all tongue muscles (pushes food posteriorly)
2) contraction of tensor and levator veli palatini muscles (blocks nasal cavity)
3) elevation of larynx by suprahyoid muscles (blocks trachea)
4) sequential contraction from the top of constrictor muscles to esophagus
superficial anterior neck muscles which pull down the hyoid bone to stabilize them and bring them back
infrahyoid muscles
superficial anterior neck muscles which has three muscle attachments and turns the head to opposite side of contraction (one side) and together allow for head flexion
sternocleidomastoid
where does the sternocleidomastoid attach to?
sternum, clavicle, and mastoid
how are the deep anterior neck muscles innervated?
by spinal (cervical) nerves
deep neck muscles which connect from the transverse processes on the cervical vertebrae to the first and second ribs
scalene muscles
what is the function of scalene muscles?
lateral flexors of the neck, elevators of ribs 1&2
deep neck muscles which attach from the transverse proccesses to the anterior surface of cervical vertebrae and the occipital bone
longus capitus (head), and longus colli (neck)
what is the function of the longus colli and longus capitis
flexors of the neck and head
what is the main purpose of the superficial and deep back muscles?
to stand upright (posture)
these three muscle groups make up the erector spinae
longissimus, spinalis, iliocostalis
how are the back muscles innervated?
spinal nerves
what is the function of the erector spinae?
extensors of the back (vital to maintain upright posture)
superificial back muscles which connect the transverse processes of the vertebrae and runs from the sacrum to the occipital bone
longissimus
superficial back muscles which connect the spinous processes of the vertebrae and runs from the sacrum to the occipital bone
spinalis
superficial back muscles which connect to the ribs and runs from the illium to the upper ribs
iliocostalis
deep back muscle which attaches to the ilium, transverse processes of the lumbar vertebrae, and the lower ribs
quadratus lumborum
what is the function of the quadratus lumborum?
lateral flexor of the trunk and helps with respiration by bringing the ribs back down
deep back muscle group that attaches from the transverse to spinous processes, allowing for delicate adjustments of the zygopophysial joints
transversospinal group
thoracic muscles with three different layers, that connect between every single rib
intercostal muscles
type of intercostal muscles that elevate the ribs during respiration
external intercostals
type of intercostal muscles that assist in forced exhalation
internal intercostals
type of intercostal muscles that hold the rib cage in place (fixators)
innermost intercostals
relaxation of the intercostals will initiate ____ with abdominals and diaphragm
exhalation
contraction of the _____ will initiate inhalation and increase the volume of the thoracic cavity
external intercostals
muscle which separates the thoracic and abdominal cavities and is the chief muscle of respiration (expands the thoracic cavity and compresses the abdominopelvic cavity)
diaphragm
C3, 4, 5, keeps the ____ alive
diaphragm
what are the three main attachments of the diaphragm
- sternum (xiphoid process)
- ribs 7-12 and associated costal cartilage
- lumbar vertebrae (to central tendon)
contraction of the diaphragm during inhalation brings the ______ down to increase the volume of the thoracic cavity
central tendon
what are the three holes in the diaphragm for?
- inferior vena cava
- esophagus (and vena cava go through the muscle and are squeezed closed when the diaphragm contracts)
- aorta (goes behind the diaphragm and does not get squeezed)
most of the abdominal muscles are continuums of the:
thoracic muscles
what is the function of the rectus abdominis and where does it attach?
flexor of the trunk and can help with respiration, attaches to the ribs, sternum, and pubis
what is the function of the two abdominal obliques?
lateral flexors and rotators of the trunk
what is the function of the transversus abdominus (deepest abdominal mm.)?
stabilizer
forms the pelvic diaphragm/floor and provides support to pelvic viscera
levator ani
how are the pelvic muscles inervated?
sacral spinal nerves
what three muscles make up the levator ani?
pubococcygeus, iliococcygeus, puborectalis
not a part of the levator ani but helps with stabilization of the pelvis
coccygeus
the perineal muscles are innervated by:
sacral spinal nerves
regulates the urethral opening
external urethral sphincter
regulates the anal opening
external anal sphincter
muscles which lie over the erectile tissue. contraction increases blood flow into the erectile tissue.
ischiocavernosus (lateral) and bulbospongiosus (medial)