Extrinsic Back Muscles

Question 1

List the Superficial, extrinsic back muscles

Answer 1

Trapezius
Latissimus dorsi
Levator scapulae
Rhomboideus major
Rhomboideus minor

Question 2

Superficial back muscles are ____ muscles, innervated by ____ rami

Answer 2

Hypaxial
Ventral rami

Question 3

Name the intermediate back muscles

Answer 3

Serratus posterior superior
Serratus posterior inferior

Question 4

Intermediate back muscles are called ____ muscles, and are innervated by ____ rami

Answer 4

Hypaxial
Ventral rami

Question 5

List the deep/intrinsic back muscles

Answer 5

Erector spinae group
Transversospinalis group
Others (occur in groups)

Question 6

Deep/intrinsic back muscles are called ____ muscles and are innervated by ____ rami

Answer 6

Epaxial
Dorsal rami

Question 7

Define Aponeurosis

Answer 7

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

Question 8

Thoracolumbar aponeurosis general structure

Answer 8

• 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

Question 9

thoracolumbar aponeurosis

Anterior layer

Answer 9

• anterior to quadratics lumborum muscle
• ends medically in transverse process of lumbar vertebrae
• combines laterally with aponeurosis of TVA

Question 10

thoracolumbar aponeurosis

Middle layer

Answer 10

• posterior to quadratics lumborum muscle, attaches to TP
• anterior to intrinsic back muscles

Question 11

thoracolumbar aponeurosis

Posterior layer

Answer 11

• covers erector spinae group
• ends laterally in lumbar by blending with aponeurosis of TVA muscle

Question 12

Principle actions of superficial back muscles

Answer 12

Motions of upper limb (scapula & upper limb)

Question 13

Superficial muscles of the back are ____ developmentally , meaning…

Answer 13

Hypaxial
- innervated by ventral rami of spinal nerves
- migrate during development to gain attachment to vertebrae

Question 14

Trapezius is superficial to…

Answer 14

Splenius muscles of neck

Question 15

What forms the subtrapezial plexus on deep surface of muscle?

Answer 15

CN XI and C3/4 fibers

Question 16

Describe the route of CN XI accessory

Answer 16

• spinal root leaves cranium via jugular foramen
• pierces SCM muscle, continues to trapezius

Question 17

Latissimus dorsi general structure

Answer 17

• 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

Question 18

General structure of levator scapulae

Answer 18

• Superior 1/3 lies deep to sternocleidomastoid muscle
• inferior 2/3 lies deep to trapezius

Question 19

Both Rhomboideus major and minor lie deep to ____

Answer 19

Trapezius
(R. Minor is more superior of 2)

Question 20

Rhomboideus major is ____ as wide as R. Minor

Answer 20

Twice as wide

Question 21

What is the triangle of auscultation?

Answer 21

thin tissue covering ribs where sounds of thorax are audible

Question 22

name the intermediate back muscles

Answer 22

serratus posterior superior
serratus posterior inferior