muscles of the head neck and face Flashcards
sella turcica – location
- inside skull
- intersection of the greater + lesser wings of sphenoid
- saddle-shaped depression in the sphenoid bone
- “turk’s saddle”
sella turcica – function
- protects pituitary gland
- location for optic chiasm (where nerves from L + R eyes cross)
cribiform plate – location
- part of ethmoid bone
- located inside skull, directly above nasal passage
cribiform plate – function
- grooves on either side of the cribiform plate support the olfactory bulb and are perforated by foramina for the passage of the olfactory nerves
crista galli – location
- ridge of bone that projects upward from the middle line of the cribiform plate
- “rooster’s comb”
crista galli – function
- where olfactory cranial nerves extend to nose
cranial nerves vs spinal nerves
- cranial nerves come directly from brain
- spinal lnerves emerge from spinal cord
trachea – aka
“windpipe”
trachea – location
- center of anterior neck
- ribbed, cartilaginous tube roughly 1” diameter
- deep to thyroid gland
trachea – includes
superior to inferior:
- hyoid bone
- thyroid cartilage
- cricoid cartilage
- thyroid gland + isthmus
- tracheal rings
hyoid bone
- horseshoe-shaped bone that does not articulate with any other bone (“hyoid” = U-shaped)
- located parallel to base of mandible (jawline) and C-3 or C-4, superior to thyroid cartilage
- accessible + elevates upon swallowing
- attachment site for suprahyoid + infrahyoid myo
thyroid cartilage
- aka “Adam’s apple”
- located below chin, inferior to hyoid but superior to cricoid cartilage
cricoid cartilage
- the only complete ring of cartilage around the trachea (“cricoid” = ring shaped)
- is slightly larger than other trachael rings
- located just inferior to thyroid cartilage (Adam’s apple)
- attachment site for myo, cartilage + ligaments involved in opening/closing of airway + in speech production
thyroid gland
- two glands (L + R) that are connected by isthmus
- controls how quickly the body uses energy + makes proteins
- controls how sensitive the body is to other hormones
isthmus
- bridge connecting 2 lobes of the thyroid
- located inferior to cricoid cartilage
tracheal rings
- pliable but tough to maintain and open airway
- wraps 3/4 way around trachea (membrane closes at back)
sternocleidomastoid (SCM) – location
- located on lateral, anterior neck
- large belly w/ 2 heads (flate clavicular head + slender sternal head)
sternocleidomastoid (SCM) – origin
- top of manubrium (sternal head)
- medial 1/3 of clavical (clavicular head)
sternocleidomastoid (SCM) – insertion
mastoid proess of temporal bone
sternocleidomastoid (SCM) – action
- laterally flex head + neck to same side (unilaterally)
- rotate head + neck to opposite side (unilaterally)
- flex neck (bilaterally)
(shaking head no + nodding yes; cocking ear to listen)
sternocleidomastoid (SCM) – nerve
spinal accessory nerve (also nerve for trapezius) (aka cranial nerve XI)
(SCM + upper fibers of traps begin as one myo in embryo and split during development)
scalenes – location
- sandwiched b/w SCM + anterior flap of trapezius on the lateral, anterior neck
scalenes – names
- anterior scalene - lies partially tucked beneath SCM
- middle scalene - slightly larger, lies lateral to anterior scalene
- posterior scalene - deeper, smaller, b/w middle scalene + levator scapula
scalenes – origin
- anterior: TVP’s of C-3 to C-6
- middle: TVP’s of C-2 to C-7 (longer)
- posterior: TVP’s of C-6 and C-7 (shortest)
scalenes – insertion
- anterior + middle: 1st rib
- posterior: 2nd rib
scalenes – action
- laterally flex head + neck to same side (unilaterally)
- rotate head + neck to opposite side (unilaterally)
- flex head + neck (bilaterally – anterior scalenes only)
brachial plexus + relation to scalenes
- large branches of brachial plexus (group of nerves) pass thru small gap b/w anterior + middle scalenes, and run down arm (one of the branches, musculocutaneous nerve, goes thru coracobrachialis myo)
- compression or impingement of brachial plexus or one of its nerves can send a sharp, shooting sensation or numbness down arm
subclavian artery + relation to scalenes
- subclavian artery passes thru small gap b/w anterior + middle scalenes, and sends blood to arms
- passes b/w rib 1 + clavicle, so thoracic outlet syndrome could be harmful
masseter – location
- located on side of mandible
- consists of 2 overlapping bellies
masseter – function
- strongest myo in body relative to size
- primary chewing myo
- also used in speaking + swallowing
masseter – origin
zygomatic arch
masseter – insertion
angle + ramus of mandible
masseter – action
elevate mandible (at TMJ)
masseter – nerve
trigeminal nerve - mandibular branch (aka cranial nerve 5)
trigeminal nerve – 3 branches
- opthalmic branch
- maxillary branch
- mandibular branch
temporalis – location
- covers almost all of temporal bone (can palpate at temple area when teeth are clenched)
- fibers reach under zygomatic arch to connect at coronoid process
temporalis – origin
temporal fossa (almost all of temporal bone; some of parietal and frontal bone)
temporalis – insertion
- coronoid process of mandible
- anterior edge of ramus of mandible