Axial Muscles Innervation & Actions

Superior Rectus

Elevate, ADDuct the eye

CN III Oculomotor n.

Inferior Rectus

Depress, ADDuct eye

CN III Oculomotor n.

Medial Rectus

ADDuct eye

CN III Oculomotor n.

Lateral Rectus

ABduct eye

CN VI Abducens n. (nerve exception)

note: ABD and ABD

Superior Oblique

Depress, ABduct eye (exact opposite of superior rectus)

CN IV Trochlear n.

• bc it goes through the trochlea

Inferior Oblique

Elevate, ABDuct eye

CN III Oculomotor n.

What nerve innervates ALL muscles of facial expression?

CN VII Facial nerve

Frontalis

Raise eyebrows

Corrugator supercilli

Furrows eyebrows

Brings eyebrows medially and inferiorly

Orbicularis oculi

Orbital part: forcefully shuts eyes

Palpebral part: softly shuts eyelids

Levator labii superioris

Elevates upper lip

Zygomaticus major

Raises corners of lips

Depressor labii inferioris

Depresses lower lip

Depressor anguli oris

Lowers corners of lips

Risorius

Extends corner of lips laterally

Buccinator

Brings cheeks inwards

Mentalis

wrinkle chin

Orbicularis oris

Pucker lips

Platysma

Tenses skin of neck

Temporalis

Closes mouth

CN V3 Mandibular n.

Masseter

Closes mouth

CN V3 Mandibular n.

Medial Pterygoid

Closes mouth

• deep to masseter

CN V3 Mandibular n.

muscle of mastication (all CN V3)

Lateral pterygoid

Opens mouth

CN V3 Mandibular n.

Hyoid bone

Function: Attachment point for muscles that assist in swallowing

• move the Larynx during phonation (speaking)

Genioglossus

Protrude tongue

“i’m a genius :p”

CN XII Hypoglossal n.

Styloglossus

Raise, retract tongue

“style:” mewing by putting tongue on roof of mouth

CN XII Hypoglossal n. (all 3 tongue)

Hyoglossus

Lower tongue

“i’m high blehhhh”

• heavy tongue lowered lol

CN XII Hypoglossal n.

Sternocleidomastoid

1) Sternal belly

2) Clavicular belly

Actions: Flexion of neck

Lateral rotation of head to contralateral side

CN XI Accessory n. (i will SCreaM if i don’t have accessories)

Scalenes

1) Anterior Scalene

2) Middle Scalene

3) Posterior Scalene

Actions: Anteriorly and laterally flex neck

Raise rib cage, aid in respiration

No innervation necessary

Name the suprahyoid muscles

• Digastric

  • anterior belly (CN V3 mandibular n.)

  • posterior belly (CN VII facial n.)

• Stylohyoid (CN VII facial n.)

• Mylohyoid (CN V3 mandibular n.)

• Geniohyoid (deep to mylohyoid)

“Don’t Sweat My Guy”

Action of all: elevate the Hyoid during swallowing.

top V: CN V3 Mandibular n.

bottom strands: facial n.

Digastric: Anterior belly

Suprahyoid Muscle

Elevate the hyoid bone during swallowing

CN V3 Mandibular n.

Digastric: Posterior belly

Elevate the hyoid bone during swallowing

CN VII Hypoglossal n.

Stylohyoid

Elevate the hyoid bone during swallowing

CN VII Hypoglossal n. (-HY-)

Mylohyoid (action & innervation)

Elevate the hyoid bone during swallowing

myle: molar/jaw

CN V3 Mandibular n. (part of the thick V shape, so V3)

Geniohyoid

Elevate the hyoid bone during swallowing (action of all Suprahyoid Muscles (DSMG))

nrv not tested for this muscle

Name the infrahyoid Muscles

“i TOSS” no order (infrahyoid TOSS)

Sternohyoid

Sternothyroid

Thyrohyoid

Omohyoid (superior and inferior bellies)

• omo = shoulder

Actions of all: depress the Hyoid during swallowing

Innervation of all: Ansa Cervicalis

Diaphram (action & innervation)

Action: Breathing

Innervation: Phrenic n. (diaPHRENIC nrv.)

External Abdominal Obliques what is the striation direction?

inferomedial

Rectus abdominis (striation direction)

Striation direction: saggital plane (up & down)

Internal abdominal obliques (striation direction)

Striation Direction: Superomedial (up and in towards heart)

Transversus abdominis (striation direction)

Striation direction: transverse plane

Name the deep back muscles

Splenius Capitis

Splenius Cervicis

Erector Spinae (Iliocostalis, Longissimus, Spinalis)

Quadratus Lumborum

Splenius Capitis (action)

Extend head/neck

Splenius Cervicis

Extend head/neck

Erector Spinae

lateral to medial

1. Iliocostalis

2. Longissimus

3. Spinalis

• along the spine

Extend vertebral column

“I C Lol So Quirky”

Quadratus Lumborum (action)

deep back muscle

action: Flex, laterally bend the vertebral column

• lower back

Name the pelvic floor muscles & their action & innervation

• Levator ani

  • Puborectalis m.

  • Pubococcygeus m.

  • Iliococcygeus m.

• Coccygeus m.

Action: support pelvic viscera

nrv: Pudendal n.

Name muscles in the Perineum (& their innervation)

• Superficial transverse perineal muscle

• Deep transverse perineal muscle

Erectile muscles:

• Ischiocavernosus m.

• Bulbospongiosus m.

Innervation: Pudendal n.

What muscles are innervated by the Pudendal n.?

Pelvic Floor muscles

• levator ani

  • puborectalis m.

  • pubococcygeus

  • iliococygeus

• coccygeus

Perineum muscles

• superficial transverse perineal

• deep transverse perineal

• ischiocavernosus

• bulbospongiosus

What are the erectile muscles?

1. ishiocavernosus (walls of the cavern)

2. bulbspongiosus (muscles surrounding the pp or hole)