Download Back Muscles

Back Muscles
Splenius capitis
Origin:
Insertion:
Innervation:
Action:
Splenius cervicis
Origin:
Insertion:
Innervation:
Action:
arises from nuchal ligament and spinous process of C7-T3
mastoid process, superior nuchal line
posterior rami of spinal nerves
unilaterally- laterally bend to side of active mm
Bilaterally- extend head and neck
arises from nuchal ligament and spinous process of C7-T3
transverse process of C1-C3
posterior rami of spinal nerves
unilaterally- laterally bend to side of active mm
Bilaterally- extend head and neck
Spinalis (thoracis, cervicis, capitis) –Erector spinae
Origin:
iliac crest, sacrum, and supraspinous ligament
Insertion:
spinous process of thoracic region to skull
Innervation:
posterior rami of spinal nerves
Action:
unilateral- laterally bend to side of active mm
Bilaterally- extend the vertebral column and head
Longissimus (thoracis, cervicis, capitis) –Erector spinae
Origin:
Iliac crest, sacrum, and supraspinous ligament
Insertion:
transverse process in thoracic and cervical region, mastoid process
Innervation:
posterior rami of spinal nerves
Action:
unilaterally- laterally bend vertebral column to side of active mm
Bilaterally- extend vertebral column and head
Iliocostalis ( lumborium, thoracis, cervicis) –Erector spinae
Origin: Iliac crest, sacrum, and supraspinous ligament
Insertion:
angles of lower ribs and transverse processes
Innervation:
posterior rami of spinal nerves
Action:
unilaterally- laterally bend vertebral column to side of active mm
Bilaterally- extend vertebral column and head
Semispinalis (thoracis, cervicis, and capitis) –Transversospinalis
Origin: arises from thoracic and cervical transverse processes
Insertion:
fibers run superomedially and attach to occipital bone and spinous processes in
thoracic and cervical regions, spanning 4-6 segments
Innervation:
posterior rami of spinal nerves
Action:
unilaterally- rotate head and neck contralaterally
Bilaterally- extend head and thoracic cervical regions, stabilizes
Multifidus (lumborum, thoracis, cervicis) –Transversospinalis
Origin:
arises from sacrum and ilium, transverse process of T1-L5 and articular
processes of C4-C7
Insertion:
fibers pass superomedially to spinous process spanning 2-4 segments
Innervation:
posterior rami of spinal nerves
Action:
unilaterally- rotate head and neck contralaterally
Bilaterally- stabilizes vertebrae during local movements of vertebral column
Rotatores (thoracis and cervicis) –Transversospinalis
Origin:
arise from transverse process of vertebrae, best developed in thoracic region
Insertion:
pass superomedially and attach to junction of lamina and transverse process of
vertebrae of origin or into spinous process above their origin, spanning 1-2
segments.
Innervation:
posterior rami of spinal nerves
Action:
unilaterally- rotate head and neck contralaterally
Bilaterally- stabilizes vertebrae and assist with local extension and rotary
movements
Latissimus dorsi
Origin:
spinus process of inferior 6 thoracic vertebrae, thoracolumbar fascia, iliac crest,
and inferior 3-4 ribs
Insertion:
intertubercular sulcus
Innervation:
thoracodorsal nerve (C6-C8)
Action:
extends, adducts, and medially rotates humerus
Serratus posterior superior
Origin:
nuchal ligament, spinus process of C7-T3
Insertion:
2nd-4th ribs
Innervation:
2nd-5th intercostal nerves
Action:
elevate ribs
Serratus posterior inferior
Origin:
spinus process of T11-L2
Insertion:
8th-12th ribs
Innervation:
anterior rami of T9-T12 nerves
Action:
depresses ribs
Levator scapulae
Origin:
nuchal ligament, transverse processes of C1-C4
Insertion:
superior angle of scapula
Innervation:
dorsal scapular (C5)
Action:
elevates scapula
Rhomboid major
Origin:
spinous process of T2-T5
Insertion:
medial border of scapula, level of spine to inferior angle
Innervation:
dorsal scapular (C4-C5)
Action:
retracts scapula
Rhomboid minor
Origin:
nuchal ligament, spinus process of C7-T1
Insertion:
medial border of scapula, level of spine to inferior angle
Innervation:
dorsal scapular (C4-C5)
Action:
retracts scapula
Deltoid
Origin:
lateral third of clavicle(anterior), acrominon(middle), and spine of
scapula(posterior)
Insertion:
deltoid tuberosity of humerus
Innervation:
axillary nerve (C5-C6)
Action:
anterior- flexes and medially rotates arm
Middle- abducts arm
Posterior- extends and laterally rotates arm
Trapezius
Origin:
superior nuchal line, occipital protuberance, nuchal ligament, spinus process of
T7-T12
Insertion:
clavicle, acromion, and spine of scapula
Innervation:
spinal accessory nerve (CN XI)
Action:
elevates, retracts, and rotates scapula
External intercostal
Origin:
inferior border of ribs
Insertion:
superior border of ribs below
Innervation:
intercostal nerve
Action:
elevate ribs
Internal intercostal
Origin:
inferior border of ribs
Insertion:
superior border of ribs below
Innervation:
intercostal nerve
Action:
depresses ribs
Serratus anterior
Origin:
Insertion:
Innervation:
Action:
Infraspinatus
Origin:
Insertion:
Innervation:
Action:
Quadratis lumborum
Origin:
Insertion:
Innervation:
Action:
1st -9th ribs
Anterior surface of medial border of scapula
Long thoracic nerve (C5-C7)
Protracts scapula
Infraspinous fossa of scapula
Greater tubercle
Suprascapular nerve (C5-C6)
Laterally rotates arm
12th rib and lumbar transverse processes
Illiolumbar ligament and iliac crest
Anterior rami of T12-L4 nerves
Extends and laterally flexes vertebral column, fixes 12 th rib during inspiration,
“hip hiking”
Teres major
Origin:
inferior angle of scapula
Insertion:
lesser tubercle
Innervation:
lower subscapular (C6-C7)
Action:
adduct and internal rotation
Sternocleidomastoid (SCM)
Origin:
Mastoid process, superior nuchal line
Insertion:
Sternal head- manubrium
Clavicular head- medial third of clavicle
Innervation:
Spinal accessory nerve (CN XI)
Action:
unilaterally- laterally flexes neck to side of active muscles
Bilaterally- flexes cervical
Teres minor
Origin:
lateral border of scapula
Insertion:
greater tubercle
Innervations:
axially nerve (C5-C6)
Action:
laterally rotates arm
Anterior Scalene
Origin:
transverse processes of C4-C6
Insertion:
1st rib
Innervation:
cervical spinal nerves C4-C6
Action:
flexes head
Middle scalene
Origin:
posterior tubercles of transverse processes of C2-C7
Insertion:
1st rib
Innervations:
anterior rami of cervical spinal nerves
Action:
flexes neck laterally, elevates 1st rib
Posterior scalene
Origin:
posterior tubercles of transverse processes of C2-C7
Insertion:
2nd rib
Innervations:
anterior rami of cervical spinal nerves C4-C8
Action:
flexes neck laterally