Muscles of the Back

Question 1

Three layers of back muscles

Answer 1

1) superficial layer
2) intermediate layer
3) deep layer

Question 2

Function of the superficial layer of back muscles

Answer 2

move upper extremity (arm)

Question 3

Function of the intermediate layer of back muscles

Answer 3

respiratory muscles (insert to rib)

Question 4

Functions of the deep layer of back muscles

Answer 4

move trunk and back; support body weight

Question 5

Where do almost all back muscles take their origin from?

Answer 5

vertebrae

Question 6

What bone in the back is free floating and attached to vertebrae by muscles (no direct joint)

Answer 6

scapula

Question 7

Only bony link of scapula to skeleton

Answer 7

clavicle

Question 8

scapula articulates with humerus at _____ joint (ball and socket)

Answer 8

glenohumeral

Question 9

paralysis of some muscles (e.g. serratus anterior) produces unstable scapula. name of this condition

Answer 9

winged scapula

Question 10

Most frequently broken bone in body

Answer 10

clavicle

Question 11

“Point of shoulder”

Answer 11

Acromion (lateral end of the scapular spine)

Question 12

Attaches head of humerus to the scapula

Answer 12

glenoid fossa

Question 13

superficial group of back muscles (5)

Answer 13

1) trapezius
2) latissimus dorsi
3) levator scapulae
4) rhomboid minor
5) rhomboid major

Question 14

Origin of the trapezius (midline or lateral)

Answer 14

midline

Question 15

Insertion of the trapezius (midline or lateral)

Answer 15

lateral

Question 16

Innervation of the trapezius

Answer 16

Accessory Nerve (Cranial nerve XI)

Question 17

Fascia covering the deep muscles of the back

Answer 17

Thoracolumbar fascia

Question 18

Actions of the latissimus dorsi (3)

Answer 18

Adducts, extends, and medially rotates arm

Question 19

Nerve that innervates levator scapulae, rhomboid minor, and rhomboid major

Answer 19

dorsal scapular nerve

Question 20

Overlies 6th intercostal space; floor has no large muscles; medial to scapula

Answer 20

Triangle of auscultation

Question 21

Boundaries of the triangle of auscultation (inferior, superior, and lateral)

Answer 21

Inferior - Lat. Dorsi
Superior - Trapezius
Lateral - Rhomboid Major

Question 22

intermediate group of back muscles (3)

Answer 22

1) levatores costarum
2) serratus posterior superior
3) serratus posterior

Question 23

Action of the levatores costarum

Answer 23

raise ribs in inspiration

Question 24

Three subgroups in the deep group of back muscles

Answer 24

1) splenius
2) erector spinae
3) transversospinalis

Question 25

All deep group of back muscles are innervated by...

Answer 25

dorsal primary rami of spinal nerves

Question 26

Sensory and motor axons to region of back; sensory to skin of back and posterior neck. Motor axons to deep muscles of back and neck

Answer 26

Dorsal ramus

Question 27

sensory to skin of extremities (arm, leg) and anterior and lateral regions of trunk; motor muscles of extremities and anterior and lateral regions of trunk

Answer 27

ventral ramus

Question 28

Area of skin innervated by a single spinal nerve

Answer 28

dermatome

Question 29

Actions of the splenius capitis and splenius cervicis (2)

Answer 29

extend neck and head; rotate in unilateral action

Question 30

Three muscles in the erector spinae (ordered from medial to lateral)

Answer 30

spinalis, longissimus, iliocostalis

Question 31

Actions of transversospinalis (2)

Answer 31

extend trunk in bilateral action; rotate unilaterally

Question 32

How are transversospinalis angled?

Answer 32

angled up and in toward spines

Question 33

Innervation of transversospinalis muscles?

Answer 33

dorsal primary rami of spinal nerves