Ch 11

Skeletal muscles of the body can be
subdivided into:

axial and appendicular musculature

Axial musculature

muscles that position the head and vertebral column

muscles that move the rib cage

Appendicular musculature

muscles that stabilize or move the appendicular skeleton

Amount of skeletal muscles

over 600

What moves skeletal muscles?

motor neurons

How are skeletal muscles controlled/ innervated?

one neuron controls the action of that muscle

How are muscles innervated?

nerves

Four groups of the axial muscles

1. head and neck

2. vertebral column

3. rib cage, lateral walls of the abdominal and pelvic cavities

4. pelvic floor

Muscles of head and neck (general)

face, tongue, larynx, eyes

Muscles of the vertebral column (general)

flexors and extensors of the axial skeleton

Muscles of the rib cage, lateral walls of the abdominal and pelvic cavities (general)

respiration and separation of cavities

Muscles of the pelvic floor (general)

control the movements of material

Components of muscles of the head and neck

➢Muscles of facial expression
➢Extra-ocular muscles
➢Muscles of mastication
➢Muscles of the tongue
➢Muscles of the pharynx
➢Anterior muscles of the neck

Function occipitofrontalis

rises eyebrows and wrinkles forehead

O occipitofrontalis

epicranial aponeurosis

I occipitofrontalis

skin of eyebrows, bridge of nose

Function occipitalis

tenses and retracts scalp

O occipitalis

superior nuchal line

adjacent region of mastoid of the temporal bone

I occipitalis

epicranial aponeurosis

Function temproparietalis

moves auricle of ear

*more superficial than temporalis

O temporoparietalis

fascia around external ear

I tempororparietalis

epicranial aponeurosis

CN VII

Cranial Nerve VII, also known as the facial nerve, controls the muscles of facial expression and provides taste sensations from the anterior two-thirds of the tongue.

Function orbicularis oculi

closes eyes

O orbicularis oculi

medial margin of orbit

I orbicularis oculi

skin around eye lids

Function corrugator supercilii

wrinkles eyebrows

O corrugator supercilii

medial end of the supericiliary arch

I corrugator supercilii

eyebrow

Function procerus

wrinkles and move nose, horizontal wrinkles frowning

O Procerus

lateral nasal cartilages

I Procerus

aponurosis at bridge of nose and forehead

Function nasalis

dilate nostrils

O Nasalis

maxilla and alar cartilage of the nose

I nasalis

bridge of nose

Function orbicularis oris

compresses and purses lip

O orbicularis oris

maxilla and mandible

I orbicularis oris

lips

Function buccinator

compresses cheeks

O buccinator

alveolar processes of the maxilla and mandible

I buccinator

into fibers of orbicularis oris

Function risorious

contracting with smiling

O risorious

fascia surrounding parotid salivary gland

I risorious

angle of the mouth

Function zygomaticus

smiling

O Zygomatic major

zygomaticotemporal suture

I zygomatic major

skin at corners of the mouth

O zygomaticus minor

zygomaticomaxillary suture

I zygomaticus minor

skin at corners of the mouth

Function platysma

thin superficial muscle

open mouth, tenses skin of neck

O platysma

fascia covering the superior parts of the pectoralis major and deltoid

I platysma

mandible and skin of cheek

Function mentalis

protrudes lower lip

O mentalis

incisive fossa of mandible

I mentalis

skin of chin

Muscles of facial expression: raised eyebrows/ wrinkled forehead

frontal belly of epicranius

Muscles of facial expression: angry eyebrows

corrugator supercilii

Muscles of facial expression: blink

orbicularis oculi

Muscles of facial expression: tense neck

platysma

Muscles of facial expression: pout

mentalis

Muscles of facial expression: pucker

orbicularis oris

Muscles of facial expression: smile

zygomaticus major

Extra-ocular muscles also known as

oculomotor or extrinsic eye muscles

O extra-ocular muscles

orbit of the eye

I extra-ocular muscles

sclera

Diagram of extra-ocular muscles

All the extra-ocular muscles

1. superior rectus

2. superior oblique

3. lateral rectus

4. medial rectus

5. inferior oblique

6. inferior rectus

Movement of superior rectus

upward

Movement of superior oblique

down and laterally

Movement of medial rectus

medially

Movement of inferior rectus

downward

Movement of inferior oblique

up and laterally

Movement of inferior oblique

up and laterally

Movement of lateral rectus

laterally

Which nerves control the eyes?

III, IV, VI

CN III

oculomotor

controls almost all eye muscles

CN IV

trochlear

superior oblique

CN VI

abducens

lateral rectus

What muscle movement of oblique eye muscles?

opposite of the names

Muscles of mastication

1. temporalis

2. masseter

3. pterygoids

Function temporalis

elevates mandible and closes jaw

O temporalis

temporal lines (parietal bone)

I temporalis

coronoid process of the mandible and anterior border of the mandible

Function masseter

synergistic muscle with mandible

crosses TMJ

clench teeth

O masseter

zygomatic arch

I masseter

lateral surface and angle of mandibular ramus

CN V

trigeminal nerve responsible for sensation in the face and motor functions such as biting and chewing.

Function pterygoids

medial and lateral are antagonists

move mandible side to side

ie. chewing gum

Function medial pterygoid

closes jaw

O medial pterygoid

medial pterygoid plate and portions of palatine bone and maxilla

I medial pterygoid

medial surface of the mandibular ramus

Function lateral pterygoid

opens jaw

O lateral pterygoid

surface of the lateral pterygoi and greater wing of the sphenoid

I lateral pterygoid

mandibular condyle

Function of intrinsic tongue muscles

move the tongue

Parts of intrinsic muscles of the tongue

1. longitudinal (superior and inferior)

2. transverse

3. vertical muscles

O and I of intrinsic tongue muscles

inside the tonuge

Function extrinsic tongue muscles

speech, move food

O extrinsic tongue

outside of tongue

I extrinsic tongue

tongue