muscles of the back Flashcards
trapezius origin
occipital protuberance and medial superior nuchal line, the ligamentum nuchae, and thoracic spines
trapezius insertion
lateral 1/3 of the clavicle, acromion, and spine of the scapula
trapezius actions
suspend/steady the shoulder
elevate and depress the scapula
upward rotation of the scapula
adduction/retraction of scapula
trapezius innervation
spinal accessory nerve (cranial nerve XI)
latissimus dorsi origin
spines of the lower thoracic vertebrae lumbar and sacral vertebrae posterior iliac crest outer surfaces of the lower ribs, inferior angle of scapula
latissimus dorsi insertion
humerus- floor of the intertubercular groove
latissimus dorsi actions
extends, medial rotate, and adduct the scapula
latissimus dorsi innervation
middle subscapular (thoracodorsal) nerve
levator scapulae origin
transverse processes of the upper 4 cervical vertebrae
levator scapulae insertion
upper, medial border of the scapula
levator scapulae actions
helps control the position and movements of the scapula
elevates the scapula
assists pec minor in rotation of scapula downwards
levator scapulae innervation
dorsal scapular nerve
rhomboid minor and major origin
lower part of the ligamentum nuchae
spines of upper thoracic vertebrae
rhomboid minor and major insertion
medial border of the scapula
rhomboid minor and major action
adduct/retract scapula
“squaring of the shoulders”
assist with scapula elevation and downward rotation
rhomboid minor and major innervation
dorsal scapular nerve
splenius origin
from ligamentum nuchae
spines of lower cervical, upper thoracic vertebrae
splenius (capitus and cervicis) insertion
cap: onto the skull
cervicis: transverse process of the upper cervical vertebrae
splenius action
- extend the head straight backwards with bilateral contractions
- flex the head and neck to the ipsilateral side in unilateral contractions and slightly rotates the head, thus turning the face to the same side as the contracting muscle
splenius innervation
posterior rami of segmental spinal nerves
posterior layer thoracolumbar fascia
is attached to the spines of the lumbar and sacral vertebrae, including supraspinous ligament
middle layer thoracolumbar fascia
attached to the lumbar transverse processes; iliac crest
anterior layer thoracolumbar fascia
covers quadratus lumborum and is attached to lumbar transverse processes
3 muscles in the erector spinae muscle complex
iliocostalis,
longissimus,
spinalis
origination of iliocostalis
posterior sacrum, posterior iliac crest, spines of the lumbar vertebrae and the lower 2 thoracic spines
iliocostalis insertion
onto the ribs and transverse processes of hte cervical vertebrae
longissimus origin
posterior sacrum, posterior iliac crest, spines of the lumbar vertebrae and the lower 2 thoracic spines
longissimus insertion
onto the transverse processes and the skull
spinalis origin
posterior sacrum, posterior iliac crest, spines of the lumbar vertebrae and the lower 2 thoracic spines
spinalis insertion
onto spinous processes of the vertebrae
the superior portion blends with semispinalis
erector spinae complex action
extension of the vertebral column
also functions in forward and lateral flexion when acting against gravity (eccentric contractions to control the motions)
transversospinalis muscles:
semispinalis
multifidus
rotatores
semispinalis origin
from the articular, transverse, or mammillary processes of the vertebrae
semispinalis (capitis and cervicis) insertion
4-6 segments higher onto the spinous processes of cervical vertebrae and upper thoracic vertrbrae
multifidus origin
from the articular, transverse, or mammillary processes of the vertebrae
multifidus insertion
2-4 segments higher on the spinous processes of cervical, thoracic, and lumbar vertrbrae
best observed in the lumbar region
rotatores origin
from the articular, transverse, or mammillary processes of the vertebrae
rotatores insertion
inserts 1-2 segments higher onto the spinous processes
best developed in the thoracic region
transversospinalis function
- extend the vertebral column
- extension of the head (bilateral contractions)
- help rotate vertebral column to the contralateral side (unilateral contraction)
interspinales
attached to the spines of adjacent vertebrae
levatores costarum
arise from transverse process of vertebra above (C7 to T11) and insert near tubercle of rib below
elevates the rib
4 sub-occipital muscles
rectus capitus posterior major
rectus capitis posterior minor
obliquus capitis superior
obliquus capitis inferior
rectus capitus posterior major
from C2 spine to occipital bone
rectus capitis posterior minor
from C1 posterior tubercle to occipital bone
obliquus capitis superior
from C1 transverse process to occipitial bone
obliquus capitis inferior
from C2 spinous process to C1 transverse process
