Muscle and Joint interaction of trunk

best trunk flexors

rectus abdominis/abdominal muscles

best trunk extensors

SLI, multifidi (best IMA)

best lateral flexor of trunk

iliocostalis

best rotator of trunk

rotatores (brevis) - horizontal orientation

intrinsic muscular stabilizers

transversospinal and short segmental groups all control fine tuned movement, with the ability to stabilize across a few segments

without the level to level control of intrinsic back muscles

spine is subject to large, gross movements

extrinsic muscle stabilizers

muscles of anterior-lateral trunk (abd), erector spinae, quadratus lumborum/psoas major, hip muscles - provide gross control over larger regions of body

coactivation of trunk flexors and extensors

creates stability

first muscles to activate with any task, in order to stabilize

transversus abdominis and obliques (keep posture stable) (cue core tightening with movement)

in a crunch

rectus abdominis activates to flex spine, wants to posterior tilt, hip flexors slightly activates to resist

anytime you activate any abdominal muscle

you're activating all of them

in a sit up

there is full hip flexion along with trunk flexion, a crunch is better for abdominals, sit up is better for hip flexors

when you rotate your trunk to the left, lateral flexion will

be offset by contralateral external and internal obliques

what slows down hip extension

hip flexors, pulling pelvis into anterior tilt until rectus abdominis resists - weak abds would cause extreme lumbar lordosis

when slowly lowering your chin what is all happening

anterior roll/posterior slide at skull/C1, forward tilt at C1/C2, anterior/superior slide at C3-C7, gravity is doing motion and extensors are eccentrically slowing movement

at the level of the skull, neck musculature contains

very few neck flexors

muscles of anterior-lateral craniocervical region

SCM, scalenes, longus colli and capitis, rectus capitus anterior and lateralis

sternocleidomastoid OI

sternal head at anterior/superior manubrium, clavicular head at medial/superior clavicle both to mastoid provess

action of SCM

contralateral rotation and ipsilateral flexion, upper cervical extensor, lower cervical flexor (chicken head with bilateral activation)

nerve SCM

CN XI

ideal neck posture has muscles

in a passive position to keep straight

forward head

bilateral tightness of SCM causing upper cervical extension and lower cervical flexion

neck muscle tightness can be a source of

headaches - keep chin tucked

unilateral tightness of SCM

torticollis (idiopathic or via back to sleep initiative) - treat with ipsilateral rotation and contralateral lateral flexion, and extension of cervical spine to loosen muscle (chin tuck)

scalene muscles all

help elevate ribs when you breath

scalenus anterior OI

anterior tubercles of TP C3-C6 to inner border of 1st rib

scalenes medius OI

posterior tubercle of TP C2-C7 to upper border of 1st rib

scalenes posterior OI

posterior tubercles of TP C5-C7 to external surface of 2nd rib

nerve of all scalenes

ventral rami of nearby nerve roots

scalenes actions

ipsilateral lateral flexion (no flexion/extension), return you back to middle from a rotated position, stabilize ribs 1 and 2

brachial plexus travels between

anterior and medial scalenes (tightness can pinch nerve plecus)

scalenes dont attach to

skull

longus capitus OI

anterior tubercle of TP of middle/lower cervical vertebrae to basilar part of occipital bone

longus captius nerve

ventral rami C1-C3

longus capitus action

flexor

longus colli OI

anterior aspect of T1-T3 VB and all cervical vertebrae to anterior arch of C1 and TP/VB of all cervical vert

longus colli is known as

dynamic anterior longitudinal ligament

longus colli nerve

ventral rami C2-C8

longus colli action

flex neck

with a whiplash injury

longus capitus and colli are stretched and partially torn (can lengthen up to 56% before tear)

rectus capitis anterior OI

TP of C1 to occiput just anterior to condyles

rectus capitis anterior action

flexion, ipsi lateral flexion

rectus capitis anterior and lateralis nerve

ventral rami C1-C2

rectus capitis lateralis OI

TP of C1 to occiput just lateral to condyles

rectus capitis lateralis action

ipsi lateral flexion

splenius muscles simulate a

splint - up and out fiber direction

splenius capitis OI

inferior 1/2 ligamentum nuchae and SP C7-T4 to mastoid process

splenius capitis action

extend, ipsi lat flex, ipsi rotation

splenius capitis nerve

dorsal rami C2-C8

splenius cervicis OI

SP T3-T6 to posterior tubercles of TP C1-C3

splenius cervicis action

extend, ipsi lat flex, ipsi rotation

splenius cervicis innervation

dorsal rami C2-C8

suboccipital muscles

rectus capitis posterior major and minor, obliquus capitis superior and inferior

suboccipital muscles act to

fine tune for head position

rectus capitus posterior major OI

SP C2 to lateral end of inferior nuchal line

RCP major action

extends, lateral flexion at skull, extension and ipsi rotation at AAJ

rectus capitus posterior minor OI

posterior tubercle of C1 to posterior to foramen magnum (most medial)

RCP minor action

extends and lateral flex skull

obliquus capitus inferior OI

C2 SP to inferior margin of C1 TP

OBC inferior action

extend, ipsilateral rot of AAJ

obliquus capitus superior OI

superior aspect of TP C1 to lateral end of superior and inferior nuchal lines

OBC superior action

extend and lateral flex of skull

best AOJ flexor

rectus capitus anterior

best AOJ extensor

RCP major and OBC superior

best AOJ lateral flexor

OBC superior

best AAJ extensor

RCP major

best AAJ rotator

OBC inferior

with a chin tuck, SCM, scalenes, semispinalis capitus and levator scap

all passively support and stabilize the spine