Axial Musculature (CH. 10)

Question 1

4 Groups

Answer 1

1. Muscles of head and neck
2. Muscles of back (vertebral column)
3. Muscles of thorax (rib cage) and abdominopelvic cavity
4. Muscles of the pelvis and peritoneum

Question 2

FUNCTIONS: Muscles of the head and neck

Answer 2

Vision, mastication, facial expression, swallowing

Question 3

FUNCTIONS: Muscles of the back

Answer 3

Upright posture and movement of the back

Question 4

FUNCTIONS: Muscles of the thorax and abdominopelvic cavity

Answer 4

Respiration (diaphragm and intercostals)

Question 5

FUNCTIONS: Muscles of the pelvis and peritoneum

Answer 5

Support of abdominal and pelvic organs/viscera, urination, defecation, parturition (child birth)

Question 6

Main Characteristics of Axial Musculature

Answer 6

Innervated by
1. cranial nerves
2. OR spinal nerves
Attach on:
1. associated bones of axial skeleton
2. organs of axial skeleton (eyeball)
3. soft tissue (skin)

Question 7

Groups of innervated muscles

Answer 7

1. Extra-ocular – CN III, IV, VI
   
   • oculomotor, trochlear, abducens
2. Facial expression – CN VII
   
   • facial nerve
3. Mastication – CN V3
   
   • trigeminal nerve
4. Tongue – CN XII
   
   • hypoglossal nerve
5. Pharynx – CN X
   
   • vagus nerve
6. Neck – CN XI
   
   • spinal accessory nerve

Question 8

Extra-ocular Muscles

Answer 8

Directly onto eye:
Medial + Lateral rectus
Superior + Inferior rectus
Superior + Inferior oblique
Eyelid:
Levator palpebrae superioris

Question 9

Muscles of Mastication

Answer 9

ALL ATTACHED TO MANDIBLE AND INNERVATED BY CN V
- move temporomandibular joint (TMJ)
1. Masseter
- elevate
3. Temporalis
- elevate
3. Pterygoids (lateral and medial) (both medial to masseter and temporalis)
- depress and elevate (respectively)

Question 10

Facial Expression

Answer 10

ALL INNERVATED BY NC VII
- Occipitofrontalis – raise eyebrows
- Orbicularis oculi – squint, blink
- buccinator – suck, blow
- orbicularis oris – perse lips, kiss
- platysma – (neck) tense when angry/cringe
- corrugator supercilii – between brows

Question 11

Pharynx

Answer 11

INNERVATED BY CN X
- pharyngeal constrictors – superior, middle, inferior
-palatal muscles – tensor/levator veli palatine (tense and elevate soft palate)

Question 12

Anterior Muscles of the Neck

Answer 12

Digastric – depress mandible, open mouth
mylohyoid – tenses floor, hyoid bone moves up
infrahyoid muscles – below hyoid, pull down hyoid (thyrohyoid, omohyoid, sternohyoid)
sternocleidomastoid – turns head

Question 13

Tongue

Answer 13

INNERVATED BY CN XII
- styloglossus – from styloid process
- genioglossus – from chin
- hyoglossus – from hyoid
INNERVATED BY CN X
- palatoglossus

Question 14

Vertebral Column Muscles Layers (3)

Answer 14

Superficial
- move neck
Intermediate
- move vertebral column
Deep
- interconnect vertebrae

Question 15

Superficial Layer of Vertebral Column Muscles

Answer 15

• Longus colli
• Longus capitis
• Scalene (elevate ribs 1 + 2: inhale)

Question 16

Intermediate Layer of Vertebral Column Muscles

Answer 16

Erector spinae
- spinalis (most medial)
- longissimus
- iliocostalis (most lateral)
Extend vertebral column, rotates on ipsilateral side

Question 17

Deep Layer of Vertebral Column Muscles

Answer 17

Transversospinal group
- interconnect vertebrae, cross zygopophyseal joint
- smallest + weakest
- extend + laterally flex vertebral column
- rotate vertebral column to contralateral side

Question 18

Trunk

Answer 18

External/Internal Intercostal
- elevate/depress ribs
Abdominals:
- external/internal obliques – compress abdomen
- transversus abdominis – compress abdomen
- rectus abdominis – depress ribs, compress ab, linea albea
(compress to defecate and give birth)

Question 19

Diaphragm

Answer 19

INNERVATED BY phrenic nerve (C3-C5 of spinal cord)
- separates thoracic and abdominal cavities
- central tendon (where vena cava, esophagus, and aorta pierce through)
- contracts -> lowers -> increase thoracic cavity volume: inhale
- relaxes -> rises -> decrease thoracic cavity volume: exhale

Question 20

Pelvic Muscles

Answer 20

INNERVATED BY PUDENAL NERVE
Divided into 2 triangles:
1. Anal (posterior)
- pelvic diaphragm
- levator ani
- external anal sphincter
2. Urogenital (anterior)
- ischiocavernosus
- bulbospongiosis
- external urethral sphincter