Back Muscles Flashcards
what is the action of the superficial muscles of the back?
to act on pectoral girdle on humerus
what muscles are part of the superficial layer of the back, which act on pectoral girdle on humerus?
trapezius, latissimus dorsi, levator scapulae, rhombodideus major, rhomboideus minor
what is the action and innervation of the trapezius?
superior fibers elevate the scapula and rotate it upwards
middle fibers retract the scapula
inferior fibers depress the scapula and rotate it upwards
accessory nerve (CN XI)
what is the action and innervation of the latissimus dorsi?
powerful adduction, extension, and medial rotation of the arm
thoracodorsal nerve (from C6-C8)
what is the action and innervation of the levator scapulae?
elevation and downward rotation of scapula
dorsal scapular (C5)
what is the action and innervation of the rhomboideus major?
scapula retraction
dorsal scapular (C5)
what is the action and innervation of the rhomboideus minor?
scapula retraction
dorsal scapular (C5)
what is the action of the intermediate muscles of the back?
act as accessory muscles of respiration (attach to ribs and vertebrae)
what are the muscles of the intermediate layer of the back that act as accessory muscles to respiration? what innervates them?
serratus posterior superior, serratus posterior inferior, levatores costarum (12 pairs)
ventral rami of spinal nerves
what is the action of the muscles of the deep layer of the back?
act on vertebral column (attach to transverse and spinous processes of vertebrae and act at intervertebral joints)
what muscles are in the deep layer of the back and act on the vertebral column? what are they innervated by?
splenius capitus, splenius cervicis, erector spinae, transversospinalis
dorsal rami of spinal nerve
what is the action the splenius capitus?
extends the head
what is the action of the splenius cervicis?
rotates the head
if both the splenius capitus and splenius cervicis act unilaterally, what action do they produce?
lateral bending of the cervical vertebrae
what are the muscles of the erector spinae? what are their positions in relation to one another?
from lateral to medial: iliocostalis, longissimus, spinalis
*I Love Spaghetti
when the erector spinae muscles act bilaterally what action is produced? unilaterally?
bilaterally: extend vertebral column at intervertebral joints
unilaterally: lateral bending of the vertebral column at the intervertebral joints
what are the muscles of the transversospinalis? what are their positions in relation to one another?
from superficial to deep: semispinalis, multifidus, rotatores
when the muscles of the transversospinalis act bilaterally what action is produced? unilaterally?
bilaterally: extend the vertebral column
unilaterally: rotation of the vertebral column
what is the order of the deep layer muscles of the back?
most superficial: splenius capitus, splenius cervicis
between: erector spinae (with iliocostalis, longissimus, spinalis form lateral to medial)
most deep: transversospinalis (with semispinalis, multifudus, and rotatores from superficial to deep)
what is the action of the suboccipital muscles?
act on atlas and axis for extension at atlanto-occiptal joint (YES) and rotation at atlantoaxial joint (NO)
what are the muscles of suboccipital region? what is their innervation?
rectus capitis posterior minor, rectus capitis posterior major, inferior oblique capitis, superior oblique capitis
dorsal ramus of C1 (suboccipital nerve)
what are the muscles of the rotator cuff?
supraspinatus, infraspinatus, teres minor, subscapularis
*(SITS)
what is the function of the rotator cuff muscles?
rotating the arm at the shoulder and maintaining integrity of the shoulder joint (keep head of humerus closely opposed to the glenoid fossa of the scapula during full range of arm motion)
**see specific actions and innervations in the arm muscle set
