Muscles Flashcards
What are the 7 groups of muscles in the head and neck?
1 - cervical muscles 2 - muscles of facial expression 3 - muscles of mastication 4 - hyoid muscle 5 - muscles of the tongue 6 - muscles of the soft palate 7 - muscles of the pharynx
Head and neck musculature
Origin
Insertion
Action
Nerve innervation
Sternocleidomastoid
O - medial portion of the clavicle and sternum
I - mastoid process
A - bilateral flexion of the head “yes”, unilateral rotation of the head “no”
N - CN XI
Trapezius
O - external occipital bone and posterior midline of cervical & thoracic regions
I - lateral 1/3 of clavicle and parts of the scapula
A - shrug shoulders
N - CN XI and cervical nerves 3 and 4 (C3, C4)
Muscles of facial expression
- paired muscles
- originate from surface of skull and insert into dermis
- work in concert
- all innervated by facial nerve (CN VII)
Epicranial muscles
- located in the scalp region, has 2 bellies
Frontal belly of epicranial muscle
- origin: epicranial aponeurosis (large spread-out scalp tendon)
- insertion: skin of eyebrow and nose
- action: raises eyebrows and scalp
Occipital belly of epicranial muscle
- origin: occipital bone and mastoid process
- insertion: epicranial aponeurosis
- action: raises eyebrows and scalp
Eye region: orbicularis oculi
encircles the eye
- origin: orbital rim
- insertion: skin at the lateral region of the eye
- action: close eye and squint
Eye region: corrugator supercilii
- origin: frontal bone (supraorbital area)
- insertion: skin of the eyebrow
- action: draws skin medially and inferiorly, wrinkle glabella (space between eyebrows and above nose), frowning
Mouth region: obicularis oris
- origin: around the mouth (not attached to bone)
- insertion: angle of the lips (corners)
- action: close lips, pouting, kissing, rolling inward (grimacing), thinning (pursing)
Buccinator (deeper) “cheek”
- origin: alveolar process of mandible and maxilla
- insertion: skin at angle of mouth
- action: pulling lips laterally, aids in chewing, forcing food occlusal, suckling, Trumpeter’s muscle (forcibly expel air)
Pteryogomandibular raphe
- extends from hamulus (hook-like projection off medial pterygoid plate) to the mylohyoid line (inner surface of mandible)
- visible in mouth as pterygomandibular fold
Risorius muscle
- superficial to buccinator
- origin: fascia (fibrous tissue) over masseter and parotid
- insertion: angle of mouth
- action: lips stretch laterally (grinning and grimacing muscle)
What do elevator muscles do? How many are there?
elevate upper lip, elevate angle of lip, general function in smiling. 5 total
Levator labii superioris
- origin: infraorbital rim
- insertion: upper lip
- action: elevates lip
LLS Alaeque Nasi
- medial to LLS with attachment to ala (wing of nose) and upper lip
- action: elevation of lip to dilate nose
Zygomaticus major
- origin: zygomatic bone
- insertion: angle of the mouth
- action: elevate and pull laterally (TRUE SMILE)
Zygomaticus minor
- origin: medial to zygomaticus major
- insertion: lateral to LLS
- elevates lip
- action: assist in smiling
Levator anguli oris
- deep to zygomaticus
- origin: canine fossa
- insertion: angle of mouth (deep to zygomaticus major)
- action: elevates lip, assist in smiling
What do depressor muscles do? How many are there?
- lower the lower lip
- lower the corner of the lip
- general function in frowning
2 total
Depressor anguli oris (triangular)
- origin: lower border of mandible
- insertion: angle of mouth
- action: decreases angle of mandible (corner of mouth). frowning
Depressor labii inferioris (deep to DAO)
- origin: border of mandible (mental foramen)
- insertion: lower lip (medial to DOA)
- action: depress lip, expose mandibular incisors
- irony expression
Mentalis
- origin: midline of mandible
- insertion: skin of chin
- action: protrude lower lip
- pouting
- doubt
Platysma (anterior triangle of neck)
- origin: skin superficial to clavicle
- insertion: lower border of mandible and muscles around mouth
- action: wrinkle neck (visible ridges), assist in grimacing (corner of mouth down)
What 12 muscles of facial expression can be seen from the frontal view?
1 - obicularis oris 2 - levator labii superioris alaeque nasi 3 - levator labii superioris 4 - zygomaticus minor 5 - zygomaticus major 6 - levator anguli oris 7 - buccinator 8 - platysma 9 - depressor anguli oris 10 - obicularis oris 11 - depressor labii infererioris 12 - mentalis
What 13 muscles of facial expression can be seen from lateral view?
1 - corrugated supercilii 2 - obicularis oculi 3 - levator labii superioris alaeque nasi 4 - levator labii superioris 5 - zygomaticus minor 6 - levator anguli oris 7 - zygomaticus major 8 - risiorius 10 - depressor labii inferioris 11 - mentalis 12 - depressor anguli oris 13 - platysma
Muscles of mastication
There are 4 pairs of muscles attached to the mandible 1 - masseter muscle 2 - temporalis muscle 3 - medial pterygoid muscle 4 - lateral pterygoid muscle
What nerve controls the mandible?
Mandibular branch of the trigeminal nerve
What are the 5 actions of mastication muscles?
- depression
- elevation
- protrusion
- retraction
- lateral deviation
Temporalis
- fills the temporal fossa
- largest muscle of mastication
- origin: temporal fossa (inferior temporal line is the upper boundary)
- insertion: coronoid process
- action: elevates mandible (posterior fibers - retracts mandible backwards; entire muscle fibres - elevation of the mandible)
Masseter
- 2 heads - superficial and deep
Superficial head of the masseter
- origin: anterior 2/3 of zygomatic arch
- insertion: lateral surface of angle of mandible
- action: elevation of mandible
Deep head of the masseter
- origin: posterior 1/3 of zygomatic arch
- insertion: ramus superior to angle
- action: elevation of mandible
Medial pterygoid muscle
- deep to the masseter (2 heads)
- origin: medial surface of lateral pterygoid plate, palatine bone, and maxillary tuberosity
- insertion: medial surface of angle of mandible
- action: elevation and contralateral deviation
Lateral pterygoid muscle
- more external muscle
- 2 heads (inferior and superior) with slightly different functions
- if only 1 side contracts (unilateral contraction) there will be contralateral deviation
Superior head of the lateral pterygoid
- origin: inferior surface of greater wing of sphenoid (the roof of the infratemporal fossa)
- insertion: with anterior surface of neck of condyle
- action: protrusion
Inferior head of the lateral pterygoid
- origin: lateral surface of lateral pterygoid plate
- insertion: neck of condyle
- action: protrusion, slight depression of mandible
What do hyoid muscles do? How many are there and where are they?
Assist in chewing and swallowing. 8 total - 4 supra hyoid and 4 infrahyoid
Digastric muscles
suprahyoid, has an anterior and posterior belly
- origin: mastoid notch (medial to mastoid process for the post belly)
- insertion: inner symphysis (fossa below genial tubercles)
- action: bellies can work independently or together for swallowing and depressing the mandible
- nerve innervation: anterior belly - trigeminal nerve (CN V), posterior belly - facial nerve (CN VII)
Mylohyoid muscles
looks like a mini trapezius, floor of the mouth
- origin: mylohyoid line
- insertion: left and right meet medially on hyoid bone
- action: hyoid elevation, mandibular depression, elevating tongue
- nerve innervation: mylohyoid nerve (trigeminal nerve of CN V)
Geniohyoid muscles
deep/superior to mylohyoid muscle
- origin: genial tubercles
- insertion: body of hyoid
- action: elevates hyoid bone
- nerve innervation: C1 (cervical nerve)
Stylohyoid muscles
- origin: styloid process
- insertion: body of hyoid (near intermediate tendon)
- action: elevates hyoid
- nerve innervation: facial nerve (CN VII)
Infrahyoid muscles
4 pairs depress hyoid bone, all innervated by C1, C2, C3 except thyrohyoid (only C1)
Sternothyroid muscles
- origin: posterior surface of sternum
- insertion: thyroid cartilage
- action: directly depress thyroid cartilage (indirectly depresses hyoid)
Sternohyoid muscles
superficial to sternothyroid
- origin: post of sternum
- insertion: body of hyoid
- action: depresses hyoid bone
Omohyoid muscles
has superior and inferior bellies
Inferior belly of omohyoid muscle
- origin: scapula, deep to sternocleidomastoid
- insertion: short tendon
- action: depress hyoid (bellies join together by a short tendon)
Superior belly of omohyoid muscle
- origin: short tendon
- insertion: lateral border of body of hyoid
- action: depress hyoid (bellies join together by a short tendon)
Thyrohyoid muscle
deep to omohyoid and sternohyoid
- origin: thyroid cartilage
- insertion: greater Cornu of hyoid bone
- action: depress hyoid
- nerve innervation: just C1
What are the 4 groups of intrinsic tongue muscles?
- longitudinal superior intrinsic muscle
- longitudinal inferior intrinsic muscle
- transverse intrinsic muscle
- vertical intrinsic muscle
What is the action of the intrinsic tongue muscles? What is their nerve innervation?
A - change shape of the tongue (long and narrow, short and thicken)
N - CN XII (hypoglossal)
What is the nerve innervation of the extrinsic tongue muscles? What are the 3 pairs of extrinsic tongue muscles?
innervation: CN XII - hypoglossal
- genioglossus
- styloglossus
- hyoglossus
Genioglossus
- fan shaped, superior to geniohyoid
O - genial tubercles
I - most of the tongue
A - protrusion and depression. prevents tongue from sinking back and obstructing respiration
Styloglossus
O - styloid process
I - lateral apex (top) and lateral border of body/base of tongue
A - retraction (superior and posterior)
Hyoglossus
O - hyoid bone (greater Cornu)
I - lateral surface of body
A - depresses
Muscles of the pharynx
- stylopharyngeus
- pharyngeal constrictor muscles:
- superior
- middle
- inferior
What is the soft palate? What does it do?
located at the roof of the mouth, necessary for swallowing
- moves soft palate superior and posterior to meet the pharyngeal wall that is being moved anteriorly
- seals the opening to the nasopharynx to prevent food from entering the nasal cavity
Palatoglossus
forms the anterior faucial pillar O - median palatine raphe I - lateral surface of tongue A - elevates tongue, depress soft palate N - CN X
Palatopharyngeus
forms posterior faucial pillar
O - soft palate
I - thyroid cartilage
A - major action: move pharynx anterior and superior when swallowing; closing off nasopharynx
Levator veli palatini
O - temporal bone (inferior surface)
I - median palatine raphe (just above the uvula)
A - raises soft palate (closes nasopharynx during speech and swallowing)
Tensor veli palatini
anterior to levator veli palatini O - sphenoid bone (inferior surface) I - median palatine raphe (wraps around hamulus) A - tightens and slightly lowers palate N - mn branch of trigeminal nerve/CN V
Muscle of the uvula
lies within the uvula, broadens posteriorly to change the contour of the posterior portion of the soft palate, helps seal the nasopharynx
Nerve innervation of the soft palate
All muscles of the soft palate are innervated by the pharyngeal plexus (CNIX, X, XI) except Tensor Veli Palatine (mn branch of the trigeminal nerve)
