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