Muscles of the Back Flashcards
Back of the neck is supplied by dorsal rami of the _____ nerves.
cervical
Dorsal rami of C1 and C8 carry _____ axons only.
efferent; no sensory function!
The first layer of the back consists of:
latissimus dorsi and trapezius
The second layer of the back consists of:
splenius muscle, levator scapulae, rhomboid major and minor, serratus posterior superior and serratus posterior inferior muscle
Third layer of the back consists of:
erector spinae muscles
The fourth layer of the back consists of:
multifidus, rotators, intertransversii, and suboccipital muscles
Functionally, only the ____ group is involved in the movement of the vertebral column and maintaining posture.
deep (intrinsic muscles)
Deep (intrinsic) muscles are innervated by:
the dorsal rami of the spinal nerves
All muscles in the superficial group are supplied by
anterior rami of spinal nerves through brachial plexus except trapezius.
Superficial back muscles control ____ ____ movements as well as aid in respiration.
upper limb
The origin is the _____ end.
immovable
Insertion is the _____ end.
movabale
The ____ muscle is a large superficial back muscle that resembles a trapezoid.
trapezius
_____ _____ innervates the trapezius muscle.
accessory nerve
actions of the trapezius:
- retraction of the scapula
- depression of the scapula
- elevation of the scapula
- superiorly rotates glenoid cavity
- neck extension
Actions of the latissimus dorsi:
- medial rotation of shoulder joint
- extension of should joint
- adduction of shoulder joint
innervation of the latissimus dorsi
thoracodorsal nerve
Actions of the rhomboids
retract, elevate the scapula
innervation of the rhomboids
dorsal scapular nerve (C5)
Action of levator scapulae
elevation of the scapular only
innervation of the levator scapulae
dorsal scapular nerve
True muscles of the back and neck: Superficial layer
splenius capitis and splenius cervicis
True muscles of the back and neck: intermediate layer
iliocostalis, longissimus, and spinalis
True muscles of the back and neck: deep layer
semispinalis, multifidus, rotatores breves and rotatores longi
True muscles of the back and neck: deepest layer
interspinales, intertransversarii, levatores costarum
innervation of the true muscles of the back and neck
branches of the dorsal rami of the spinal nerves
functions of the true muscles of the back and neck
maintain posture; control movement of the vertebral column
The most superficial layer of the intrinsic back muscles includes the ____ group of muscles. They extend along the posterior and lateral aspects of the neck and upper part of the thorax.
splenius
Action of the splenius group of muscles
bilateral head extension; unilateralL lateral flexion and rotation of the head
Erector spinae group muscles are ____ muscles of the back.
true
Erector spinae group muscles are supplied by the
dorsal rami of the spinal nerves
Which group of muscles are the chief extensor of the vertebral column?
erector spinae
Transversospinal group consists of:
semispinalis, mulifidus, rotators
action of the transversospinal group
extension and stabilization of the vertebral column
Innervation of the transversospinal group
posterior rami of spinal nerves
Action of the levator costarum
bilateral: extends thoracic spine
unilateral: bends thoracic spine
Triangle of auscultation
A region of the posterior thorax devoid of superficial back muscles, which allows for optimal auscultating lung sounds.
Borders of the triangle of auscultation include:
Laterally: medial border of the scapula (border of rhomboid major)
Medially: ascending fibers of the trapezius
Inferiorly: superior border of the latissimus dorsi.
Inferior lumbar (petit’s) triangle
a region of the lower back devoid of superficial back muscles, which is mildly susceptible to herniation.
Borders of the inferior lumbar triangle include:
laterally: external oblique
medially: latissimus dorsi
inferiorly: iliac crest
