axial musculature (theory) Flashcards
axial musculature function
- helps position the head and vertebral column
- moves the rib cage
4 axial muscle groups
- muscles of the head and neck
- muscles of the vertebral column
- oblique and rectus muscles (eyes)
- muscles of the pelvic floor
muscle groups of the head and neck
- facial muscles
- extra-ocular muscles
- mastication
- pharynx
- tongue
- neck (anterior)
facial muscle nerve supply
the facial nerve (CN VII)
extra-ocular nerve supply
the extra and intra ocular muscles are supplied by the occulomotor nerve (CN III)
EXCEPT
the lateral rectus (CN VI) and the superior oblique (CN IV)
CN VI
abducens nerve
CN IV
trochlear nerve
mastication nerve supply
trigeminal nerve (CN V)
facial expression muscles
- buccinator
- depressor labii inferioris
- levator labii superioris
- orbicularis oris
- levator anguli oris
- depressor anguli oris
- zygomatic major and minor
- risorius
- mentalis
frontal belly of the occipitofrontalis
helps move the eyebrows
orbicularis oculi
helps close the eye
nasalis
compresses the nose bridge
zygomaticus minor
moves lips up and back
zygomaticus major
has dimples
orbicularis oris
helps with whistling and blowing of the mouth
risorius
helps with smiling
mentalis
wrinkles the chin (pouting muscle)
epicranial aponeuroses
connects the occipitofrontalis and the posterior occipitalis
temporoparietalis
tenses the scalp and moves the ear
procerus
changes the shape of the nostrils and draws the medial eyebrow inferior (line between eyebrows)
levator labii superioris
helps lift lips
buccinator
cheek muscle
the name means “trumpet player”
the buccinator is utilized for blowing air
depressor anguli oris
helps pull the lip down
platysma
a muscle connected the mandible and covers the sternocleidomastoid muscle
this NOT a facial or mastication muscle
it tightens the skin around the neck and can depress the mandible
extra-ocular muscles
controls extrinsic eye movement
- superior and inferior obliques
- superior and inferior rectus
- lateral rectus
- medial rectus
- trochlea
trochlea
a ligamentous sling that the superior oblique passes through, this acts as a pulley
this helps the superior oblique twist the eye down and laterally to the side
superior and inferior rectus
superior = eye looks up
inferior = eye looks down
superior oblique
pulls the eye down and laterally
innervated by CN IV (trochlear nerves)
lateral rectus
innervated by the abducens nerve (CN VI)
this pulls the eye laterally
medial rectus
pulls the eye towards the medial line
eye paralysis example
if you recognize the eye is pointing to the midline and the patient can’t point their eye to the side laterally, there’s likely a problem with the lateral rectus or the abducens nerve (CN VI) that supplies it
levator palpebrae superioris
helps lift the eye lid up
mastication muscles
all mastication muscles are supplied by the trigeminal nerve (CN V)
- masseter
- temporalis
- pterygoids
masseter
elevates the mandible and closes the jaw
also helps protract and retract the mandible
temporalis
elevates mandible, helps retract, moves the mandible side to side
medial pterygoid
elevates the mandible and closes the jaw
lateral pterygoid
depresses the mandible and opens the jaw
trigeminal nerve branches
aside from innervating the mastication muscles, CN V also gives sensation to the face area
there are 3 branches…
1. ophthalmic branch
2. maxillary branch
3. mandibular branch
if a patient can’t feel their maxillae it’s likely a problem with the maxillary branch of the trigeminal nerve
tongue muscles
all are innervated by the hypoglossal nerve (CN XII) EXCEPT for the palatoglossus which is innervated by the vagus nerve (CN X)
bc the tongue can move in complex directions, all tongue muscle fibers intersect and perform similar movements
- genioglossus
- hyoglossus
- palatoglossus
- styloglossus
genioglossus
depression and protraction
hyoglossus
depression and retraction
palatoglossus
elevation and soft palate depression
styloglossus
retraction and side movement
pharynx muscles
all are innervated by the vagus nerve (CN X) EXCEPT for the stylopharyngeus which is supplied by the glossopharyngeal nerve (CN IX)
- tensor veli palatini
- levator veli palatini
- stylopharyngeus
- palatopharyngeus
- superior pharyngeal constrictor
- middle pharyngeal constrictor
- inferior pharyngeal constrictor
tensor veli and levator veli palatini
both elevate the palate
stylopharyngeus and palatopharyngeus
both are laryngeal elevators and shorten the pharynx to help with swallowing
the fibers are arranged longitudinally which help with shortening
pharyngeal constrictors
help constrict the pharynx (shortening the diameter) to help with peristaltic movement
the fibers are arranged circularly
salpingopharyngeus
equalizes the air pressure when swallowing
muscles of the neck
don’t need to know the innervation
most of these muscles elevate and depress the hyoid
- mylohyoid
- geniohyoid
- stylohyoid
- omohyoid
- sternohyoid
- sternothyroid
- thyrohyoid
- sternocleidomastoid
sternocleidomastoid
connects the sternum to the mandible
2 main functions…
- turn the head laterally
- assist in lifting up the clavicle and the sternum in inhalation
mylohoid
elevates the hyoid when we swallow
geniohyoid
elevates the hyoid and depresses the mandible
thyrohyoid
connects the hyoid to the thyroid cartilage
thyroid cartilage
makes up the adam’s apple
cricothyroid
connects the thyroid to the cricoid cartilage
cricothyroidotomy
an emergency procedure to open a patient’s airway
the incision is made between the patient’s cricoid cartilage and thyroid cartilage to gain access to the airway
muscles of the back
there are 3 categories of back muscles…
1. superficial intrinsic
2. intermediate intrinsic
3. deep intrinsic
- trapezius
- latissimus dorsi
- levator scapulae
- rhomboid muscles
trapezius
extends the neck
splenius capitis
extends the neck also
rhomboid minor and major
both help retract the scapulae
serratus posterior (superior and inferior)
superior = helps elevate the ribs during inhalation
inferior = helps with forced expiration
erector spinae muscle group
help to keep us erect when standing
quadratus lumborum
flexes the vertebral column
spinal flexors
anterior, middle and posterior scalenes
the scalene muscles help to elevate the ribs and help the apex of the lung expand during inhalation
oblique muscles (thoracic)
- spinal flexors
- external intercostals
- internal intercostals
- transverse thoracis
pectoralis minor
underneath the pectoralis major
connected to the coracoid process of the scapula
pectoralis major
above the pectoralis minor
helps abduct and flex the arm
fibers of this muscle converge
internal intercostals
help depress the ribs during exhalation
external intercostals
help elevate the ribs during inhalation
the contraction of these muscles increases the transverse diameter of the ribs
external obliques
flexes/rotates the vertebral column
internal oblique
rotates the vertebral column
transverse abdominis
compresses the abdomen
quadratus lumborum
helps the torso with lateral flexion
diaphragm muscle
the main function is to expand the thoracic cavity for inhalation
it has its origin at the L4 (right crus) and L3 (left crus) vertebrae
it has its insertion at the central tendon
it has 3 openings
3 openings of the diaphragm
- esophageal opening
- inferior vena cava opening
- opening for the aorta
rectus abdominus
the abs
this provides anterior flexion of the vertebral column
it has longitudinal divisions (linea alba) and transverse divisions (tendinous inscriptions)
muscles of the perineum and the pelvic floor
the muscles of the pelvis can be divided into two triangles separated by the superficial transverse perineal
- urogenital triangle
- anal triangle
urogenital triangle
- ischiocavernosus
- bulbospongiosus
- external urethra
ischiocavernosus
assists with clitoral erection in females and with penis erection in males
bulbospongiosus
empties the urine and constricts the vaginal orifice
it also helps with ejaculation
external urethra
made up of skeletal muscle and can regulate flow of urine
anal triangle
- anus
- levator ani
- external anal sphincter
- coccygeus
anus
site of defecation
levator ani
circles the anus and helps with defecation
this is a powerful muscle
external anal sphincter
made up of skeletal muscle
coccygeus
supports the levator ani and pelvic visceral organs