4.3 Muscles of back/ vertebral column Flashcards
what are the muscle groups involved in head movements?
muscles groups involved in trunk extension?
- Anterolateral neck muscles: move head
- Intrinsic muscles of the back: extend trunk and maintain posture
what are the anterolateral neck muscles
*muscles of head movement and trunk extension
- Sternocleidomastoid and scalenes
Sternocleidomastoid
sterno = breastbone, cleido = clavicle, mastoid = mastoid process
- two headed muscle located deep to platysma on anterolateral surface of neck
*key muscular landmark in neck
O: manibrium and clavicle
I: temporal bone and occipital bone
*flexes and laterally rotates the head -simultaneous contraction of both muscles flexes neck, rotates head toward shoulder on opposite side
Scalenes
*scalene = uneven
- anterior, middle and posterior
- located more laterally than anteriorly; deep to platysma and sternocleimastoid
- O: cervical vertebrae
I: first two ribs
*elevate first two ribs (aid in inspiration)
splienius
*intrinsic muscle of the back
*splenion = bandage, caput = head, cervi = neck
- has capitis and cervicis portions
- broad bipartite superficial muscle extending from upper thoracic vertebrea to skull
- capitis protion known as bandage muscle bc it covers and holds down deeper neck muscles
O: ligamentum nuchae and certebrea C7 - T6
I: temporal bone and occipital bone (capitis), C2-c4 vertebrae (cervicis
*extend and hyperextend the head, when splenius on one side activated, head rotates and bends laterally to same side
Iliocostalis
contains: lumborium, thoracis and cervicis (part of erector spinae)
- most lateral muscle group of erector spinae
Lumborium: O: iliac crest I: ribs
Thoracis: O: ribs, I: ribs
cervicis: ribs I: cervial certebrae
*extend and laterally flex the vertebral column
longissimus
*longissimus = longest
- has thoracid, cervicis and capitis parts
- intermediate muscle group of erector apinae
O: lumbar and cervical vertebae
I: thoracic or cervical vertebae, ribs
*capitis inserts into temporal bone
*thoracis and vercivis act to extend and laterally flex vertebral column
*capitis extends head and turns face towards same side
ligamentum nuche
- ligament extening from occipital bone of skull along the cervical vertebrae
- inhibits excessive head and neck flexion
semispinalis
has thoracis, cervicis and capitis regions
*capitis interacts w/ head)
- forms deep layer of intrinsic back muscles, extends from thoracic region to head
O: C7-T12
I: Occipital bone (capitis), cervical (cervicis), thoracic vertebrae (thoracid
*extends vertebral column and head and rotates them to opporsite side
Quadratus lumborum
- intrinsic muscle of back
- fleshy muscle forming part of posterior abdominal wall
O: iliac crest
I: lumbar
*laterally flexes vertebral column, assists in forced inspiration
What are the intrinsic muscles of the back?
splenius, Erector spinae (iliocostalis, longissimus, spinalis), semisphinalid, quadratus lumborum
semispinalis
- intrinsic muscle of back
- thoracis, cervicis and capitis regions
- forms part of deep layer of intrinsic back muscles, extends from thoracic region to head
O: C2-T12
I: occipital bone (capitis), cervical (cervicis) and thoracic vertebrae T1-T4 (thoracis)
*extends vertebral column and head and rotates them to opposite side
Quadratus lumborum
- fleshy muscle forming part of posterior wall
O: iliac crest
I: lumbar
- laterally flexes vertebral column, forced inspiration
Multifidus: origins around transverse process, and insert 2-3 vertebrae up on spinous process
Rotators= origin around transverse provcess, insert 1 vertebra up on spinous process
Key role in stabilization
