muscles of the back Flashcards
3 groups of muscles in the back
superficial
intermediate
deep back muscles
extrinsic muscles function
superficial back muscles - produce/control shoulder movements
trapezius
latissimus dorsi
levator scapulae
rhomboids
latissimus dorsi is a muscle of the ____ extremity
upper (even though it is kind of lower)
action of lats
extends, adducts, and medially rotates humerus
innervation of latissimus dorsi
thoracodorsal nerve - ventral rami c6, c7, c8
action of traps
elevates, rotates, and retracts scapula (shrug shoulders)
innervation of trapezius
receives its motor innervation via the 11th CN - spinal accessory nerve
intermediate muscles of the back
small muscles that aid and assist in respiratory control
- serrates posterior superior (deep to rhomboids)
- serrates posterior inferior (deep to latissimus)
deep back muscles are referred to as ______ back muscles because these muscles all act specifically on moving and or stabilizing the vertebral column
true/intrinsic
paraspinal muscles
deep back muscles because of their position alongside the side of the spinal column
layers of the deep muscles of the back
superficial intrinsic layer - splenius muscles (cervical region)
intermediate intrinsic layer - erector spinae mm complex
deepest intrinsic layer - transversospinalis (deep to spinae)
all deep/intrinsic muscles of the back are innervated by _____ of spinal nerves
dorsal rami
only deep muscles (d for deep)
erector spinae complex
intermediate layer of intrinsic/deep back muscles
divided into 3 mm masses
iliocostalis
longissimus
spinalis
action of erector spinae complex
postural muscles, help extend and stabilize column
transversospinalis mm complex
course from transverse process to spinous process
segments of transversospinalis mm complex
- semispinalis - superficial
- multifidus - intermediate
- rotatores - deepest
