ANATOMY UNIT B WEEK 6: AXIAL MUSCLE

occipitofrontalis (epicranius)

• facial expression

• FRONTAL BELLY

  • raises eyebrows

• OCCIPITAL BELLY

  • retracts scalp

• NS: facial CN VII

orbicularis oculi

• facial expression

• close or squint eyes

• NS: facial CN VII

zygomaticus major and minor

• facial expression

• smiling

• minor is superior to major

• NS: facial CN VII

risorius

• facial expression

• pull corners of mouth laterally

• NS: facial CN VII

buccinator

• facial expression

• contract cheeks

• deep to risorius

• NS: facial CN VII

levator labii superioris

• facial expression

• elevate upper lip

• NS: facial CN VII

depressor labii inferioris

• facial expression

• pull lower lip down

• NS: facial CN VII

mentalis

• facial expression

• protrude lower lip or wrinkle chin

• NS: facial CN VII

masseter

• mastication

• (PM) mandible elevation

• ORIGIN:

  • temporal bone

• INSERTION:

  • mandible

• NS: trigeminal CN V3

temporalis

• mastication

• mandible elevation/retraction

• NS: trigeminal CN V3

lateral and medial pterygoid

• mastication

• mandible protraction, side to side grinding

• NS: trigeminal CN V3

sternocleidomastoid

• neck

• (PM) head flexion, lateral flexion, rotation

• ORIGIN:

  • sternum, clavicle

• INSERTION:

  • temporal bone

• NS: accessory CN XI

splenius capitis

• neck

• (PM) head extension, lateral flexion, rotation

• SCM antagonist

• ORIGIN:

  • vertebrae

• INSERTION:

  • temporal bone

• NS: cervical spinal nerves

scalenes

• neck

• elevates first 2 ribs (inspiration), head lateral flexion

• SCM synergist

• NS: cervical spinal nerves

suprahyoids

• elevates hyoid

  • MYLOHYOID

  • STYLOHYOID

  • DIGASTRIC

    • anterior belly

    • posterior belly

• NS: trigeminal CN V3, facial CN VII

superficial infrahyoids

• depress hyoid

  • STERNOHYOID

  • OMOHYOID

• NS: ansa cervicalis

deep infrahyoids

• depress hyoid

  • THYROHYOID

  • STERNOTHYROID

• NS: ansa cervicalis

iliocostalis, longissimus, spinalis

• deep back

• 3 muscles of erector spinae

• (PM) torso extension, stabilizes torso upright/erect

quadratus lumborum

• deep back

• flex vertebral column, maintain posture

• ORIGIN:

  • ilium

• INSERTION:

  • lumbar vertebrae, rib 12

trapezius

• superficial back

• move scapula

  • upper fibers elevate

  • middle fibers retract

  • lower fibers depress

• ORIGIN:

  • vertebrae, occipital bone

• INSERTION:

  • scapula, some clavicle)

• NS: accessory CN XI

levator scapulae

• intermediate back

• elevates scapula

• NS: dorsal scapular nervve

rhomboid major and minor

• intermediate back

• retract scapula

• minor superior to major

• NS: dorsal scapular nerve

pectoralis minor

• thoracic

• protracts scapula

• deep to pectoralis major

serratus anterior

• thoracic

• upward rotation, protraction, abduction

• deep to pectoralis major

external intercostals

• deep thoracic

• elevate ribs for inspiration

• lateral

• NS: phrenic nerve

internal intercostals

• deep thoracic

• elevate ribs for inspiration

• medial

• NS: phrenic nerve

diaphragm

• separates thoracic cavity and abdominopelvic cavity

• (PM) inspiration, flattens as it contracts

• ORIGIN:

  • internal rib cage, sternum, lumbar vertebrae

• INSERTION:

  • central tendon

• NS: phrenic nerves

rectus abdominus

• abdomen

• flex torso (vertebral column), maintain posture

• ORIGIN:

  • pubis

• INSERTION:

  • sternum

• NS: intercostal nerves

external obliques

• lateral abdomen

• rotation

• most superficial layer

• NS: intercostal nerves

internal obliques

• lateral abdomen

• rotation

• same layer as rectus abdominus

• NS: intercostal nerves

transversus abdominus

• lateral abdomen

• compress abdomen

• deepest layer of muscle in abdomen

• NS: intercostal nerves

superficial transverse perineal

• superficial perineum

• stabilizes perineal body

• transverse

• NS: pudenal nerve

deep transverse perineal

• deep perineum

• supports pelvic organs

• NS: pudenal nerve

levator ani

• superficial perineum

• stabilize pelvic organs

• NS: pudenal nerve

ischiocavernosus

• superficial perineum

• compress roots of erectile bodies

  • stop blood flow, keep erection

• NS: pudenal nerve

bulbospongiosus

• superficial perineum

• FEMALE

  • close vaginal opening

• MALE

  • empty urethra

• rhythmic contractions during orgasm or ejaculation

• NS: pudenal nerve

trigeminal CN V3

• innervates mastication muscles

• masseter, temporalis

facial CN VII

• innervates all muscles of facial expression (9), some suprahyoid

  • stylohyoid and digastric posterior belly

accessory CN XI

• innervates:

  • sternocleidomastoid

  • trapezius