Extrinsic Back Muscles Flashcards
List the Superficial, extrinsic back muscles
Trapezius
Latissimus dorsi
Levator scapulae
Rhomboideus major
Rhomboideus minor
Superficial back muscles are ____ muscles, innervated by ____ rami
Hypaxial
Ventral rami
Name the intermediate back muscles
Serratus posterior superior
Serratus posterior inferior
Intermediate back muscles are called ____ muscles, and are innervated by ____ rami
Hypaxial
Ventral rami
List the deep/intrinsic back muscles
Erector spinae group
Transversospinalis group
Others (occur in groups)
Deep/intrinsic back muscles are called ____ muscles and are innervated by ____ rami
Epaxial
Dorsal rami
Define Aponeurosis
Flat sheet or ribbon of tendon like tissue that anchors a muscle
- takes place of tendon or bone in sheet like muscles having wide area of attachment
Thoracolumbar aponeurosis general structure
- thin, transparent fascia in thoracic region
- thick, strong fibrous CT (contains fibroblasts) in lumbar
- blends laterally with aponeurosis of transversus abdominus muscle in lumbar region
thoracolumbar aponeurosis
Anterior layer
- anterior to quadratics lumborum muscle
- ends medically in transverse process of lumbar vertebrae
- combines laterally with aponeurosis of TVA
thoracolumbar aponeurosis
Middle layer
- posterior to quadratics lumborum muscle, attaches to TP
- anterior to intrinsic back muscles
thoracolumbar aponeurosis
Posterior layer
- covers erector spinae group
- ends laterally in lumbar by blending with aponeurosis of TVA muscle
Principle actions of superficial back muscles
Motions of upper limb (scapula & upper limb)
Superficial muscles of the back are ____ developmentally , meaning…
Hypaxial
- innervated by ventral rami of spinal nerves
- migrate during development to gain attachment to vertebrae
Trapezius is superficial to…
Splenius muscles of neck
What forms the subtrapezial plexus on deep surface of muscle?
CN XI and C3/4 fibers
Describe the route of CN XI accessory
- spinal root leaves cranium via jugular foramen
- pierces SCM muscle, continues to trapezius
Latissimus dorsi general structure
- covers inferior 1/2 of back
- large, wide fan-shaped
- superficial to Serratus posterior inferior, which may adhere deep to surface
- passes from trunk to humerus, acts directly on shoulder joint and indirectly on pectoral girdle
General structure of levator scapulae
- Superior 1/3 lies deep to sternocleidomastoid muscle
- inferior 2/3 lies deep to trapezius
Both Rhomboideus major and minor lie deep to ____
Trapezius
(R. Minor is more superior of 2)
Rhomboideus major is ____ as wide as R. Minor
Twice as wide
What is the triangle of auscultation?
thin tissue covering ribs where sounds of thorax are audible
name the intermediate back muscles
serratus posterior superior
serratus posterior inferior
