lecture 12

Question 1

what are the intrinsic back muscles?

Answer 1

these include muscles that specifically act on the vertebral column, producing its movements and maintaining posture

Question 2

what are extrinsic back muscles?

Answer 2

these include superficial and intermediate muscles that produce and control limb and respiratory movements

Question 3

what are the innervations of the intrinsic back muscles?

Answer 3

they are innervated by the posterior rami of spinal nerves

Question 4

what are the actions of intrinsic back muscle?

Answer 4

these act to maintain posture and control movements of the vertebral column

Question 5

what are the anatomical locations of the intrinsic back muscle?

Answer 5

these muscles extend from the pelvis to the cranium and are enclosed by a deep fascia that attaches medially to the nuchal ligament, the tips of the spinous processes of the vertebrae, the supraspinous ligaments and the median crest of the sacrum

Question 6

what is the thoracolumbar fascia and its function?

Answer 6

these constitute the thoracic and lumbar parts of the deep fascia. They extend laterally from the spinous process and form a thin covering over the intrinsic back muscles in the thoracic region and a strong thick covering for muscles in the lumbar region

Question 7

how are the intrinsic muscles of the back arranged?

Answer 7

superficial, intermediate and deep layer and this is according to their relationship to the surface

Question 8

what are the superficial layer muscles of the intrinsic back?

Answer 8

splenius muscle broken into splenius cervicis and splenius capitis

Question 9

what are the intermediate layer muscles of the back? what are they collectively called?

Answer 9

spinalis, longissimus, iliocostalis; erector spinae muscles

Question 10

what are the deep layer muscles of the back?

Answer 10

semispinalis, rotatores, multifidis

Question 11

What are the deep muscles of the back collectively called?

Answer 11

transversospinalis

Question 12

why are the superficial layer muscles of the intrinsic back superficial?

Answer 12

they are thick and flat and lie on the lateral and posterior aspects of the neck, covering the vertical muscles somewhat like a bandage

Question 13

why are the intermediate layer muscles of the intrinsic back intermediate?

Answer 13

these lie in a groove on each side of the vertebral column between the spinous processes centrally and the angles of the ribs laterally, there are known as the chief extensors of the vertebral column and are divided accordingly into the named groups as mentioned (iliocostalis, longissimus, and spinalis)

Question 14

why are the deep layer muscles of the intrinsic back deep?

Answer 14

these muscles lie deep to the erector spinae and are obliquely short muscles

Question 15

what are the two intermediate extrinsic back muscle movements?

Answer 15

remember that the extrinsic back mm move the shoulder and arm and these comprise the trapezius, latissimus dorsi, levator scapulae and the rhomboids collectively referred to as the superficial extrinsic back muscles and then you have the intermediate extrinsic back muscles comprised of the serrates posterior muscles

Question 16

that are the two intermediate extrinsic back mm and their functions?

Answer 16

the serratus posterior superior and serrates posterior inferior; functions of

Serratus posterior superior, deep to rhomboid mm:

Proximal - lower ligamentum nuchae, C7 – T3

Distal-ribs 2-5

Innervation-intercostal nn

Artery - posterior intercostal aa. 1-4

Action-elevates ribs 2-5

Serratus Posterior Inferior, beneath latissimus dorsi:

Attachments: Prrximal-11 – L3

Distal-o ribs 9-12.

Innervation:-intercostal nn

Artery – lowest posterior intercostal a., subcostal a., first two lumbar aa.

Action- depresses ribs 9-12

*Both may also provide proprioception

Question 17

what are origin, insertion and pathology due to loss of function (pathology) for the rhomboids?

Answer 17

origin: nuchal ligament and C7-T5 spinous processes
insertion: medial border of the scapula

Action - retracts scapula

Innervation - dorsal scapular nerve (C5)

Artery – dorsal scapular

pathology: scapular retraction and downward rotation of the scapula/glenoid cavity

Question 18

what are origin, insertion and pathology due to loss of function (pathology) for the levator scapulae?

Answer 18

origin: C1-T4 transverse process
insertion: superior medial border of the scapula

Action – elevates scapula

innervation - dorsal scapular nerve (C5); the upper part of the muscle receives branches of C3 & C4

Artery - dorsal scapular

pathology: lesion of the dorsal scapular nerve with symptoms being a winging of the scapula; also chronic pain

Question 19

what are origin, insertion and pathology due to loss of function (pathology) for the serratus anterior ?

Answer 19

origin: lateral ribs 1-8
insertion: anterior surface of medial border of the scapula

Action – protracts scapula

innervation - long thoracic nerve (from ventral rami C5-C7)

Artery – lateral thoracic

pathology: damage to the long thoracic nerve leading to functional loss and so you lose function in the axilla symptoms being trouble elevating the arm and unstable shoulder, wing like tilting called scapula alata

Question 20

what are origin, insertion and pathology due to loss of function (pathology) for the trapezius?

Answer 20

origin: midline occipital protuberance inferior to T-12
insertion: scapular spine

Action
upper fibers - elevate shoulder
middle fibers - retract scapula
lower fibers - depress scapula

Artery -transverse cervical

pathology: A lesion of the accessory nerve may lead to paresis and atrophy of the trapezius. A classic symptom is the inability of abducting the shoulder. The elevation (lifting the arm above 90°) is restricted as well. The shoulder of the affected side is lowered and the medial border of the shoulder blade lies slightly laterally (scapula alata). Injuries of the accessory nerve occur frequently during interventions at the cervical region such as lymph node biopsy or neck dissection, rarely after traumas and skull base tumors.

Question 21

what four muscles comprise the rotator cuff?

Answer 21

infraspinatus, supraspinatus, subscapularis, teres minor

Question 22

name the origin, insertion, and major action of the infraspinatus?

Answer 22

origin: infraspinous fossa of scapula
insertion: middle facet of greater tubercle of humerus

major action: laterally rotates the arm

artery: suprascalular nerve

Question 23

name the origin, insertion, and major action of the supraspinatus?

Answer 23

origin: supraspinous fossa of scapula
insertion: superior facet of greater tubercle of humerus

major action: initiates and assists deltoid in abduction of arms and acts with rotator cuff muscles

artery: suprascapular artery

Question 24

name the origin, insertion, and major action of the subscapularis?

Answer 24

origin: sub scapular fossa (most anterior surface of scapula)
distal: lesser tubercle of humerus

major action: medially rotate s arm

artery: sub scapular artery

Question 25

name the origin, insertion, and major action of the teres minor?

Answer 25

origin: middle part of lateral border of the scapula
insertion: inferior facet of greater tubercle of humerus

major action: laterally rotates the arm

artery: subscapular & scapular circumflex

Question 26

Give the origin, insertion of the following superficial extrinsic back mm that act on the humerus but are not a component of the rotator cuff: latissimus dorsi

Answer 26

origin: T7-12 spinous processes, thoracolumbar fascia, iliac crest
insertion: intertubercular groove of humerus

major action: extends, adducts, and medially rotates humerus and raises body toward arms during climbing

artery: thoracodorsal

Question 27

Give the origin, insertion of the following superficial extrinsic back mm that act on the humerus but are not a component of the rotator cuff: deltoid

Answer 27

origin: lateral third of the clavicle; acromion and spine of the scapula
insertion: deltoid tuberosity of the humerus

major action:
clavicular part: flexes and medially rotates arm

acromial part: abducts arm

spinal part: extends and laterally rotates arm

artery: posterior circumflex humeral artery

Question 28

Give the origin, insertion of the following superficial extrinsic back mm that act on the humerus but are not a component of the rotator cuff: teres major

Answer 28

origin: lower 1/3 dorsal surface lateral border of scapula
insertion: medial side of intertubercular groove of humerus

major action:
adducts humerus
internally rotates humerus
extends humerus from flexed position

artery: sub scapular and circumflex scapular

Question 29

are the following muscles intrinsic or extrinsic?
superficial, deep, intermediate?what do these muscles act on?

rhomboids, levator scapulae, serratus anterior, trapezius

Answer 29

extrinsic; superficial; scapula

Question 30

what superficial extrinsic muscles back muscles lay posterior axio appendicular muscles connecting the axial skeleton (vertebral column) with the superior appendicular skeleton (pectoral girdle and humerus) and produce and control limb movements?

Answer 30

trapezius, latissimus dorsi, levator scapulae, rhomboids

Question 31

what superficial extrinsic muscles act on the scapula?

Answer 31

rhomboids, levator scapulae, serratus anterior, trapezius

Question 32

what are the two intermediate extrinsic back muscles?

Answer 32

serratus posterior superior and the serratus posterior inferior

Question 33

what are the four muscles that comprise the rotator cuff? and are they intrinsic or extrinsic muscles?

Answer 33

supraspinatus, infraspinatus, subscapularis, teres minor

Question 34

what are the extrinsic mm? superficial and deep?

Answer 34

superficial: latissimus dorsi, trapezius
deep: levator scapulae, rhomboid major, rhomboid minor

Question 35

what are the intrinsic mm that originate from the scapula and/or clavicle and attach to the humerus?

Answer 35

deltoid, teres major, rotator cuff muscles

Question 36

what are the superficial extrinsic back mm that act on the humerus but are not a component of the rotator cuff?

Answer 36

latissimus dorsi, deltoid and teres major

Question 37

what is the triangle of auscultation?

Answer 37

relative thinning of the musculature of the back that can be utilized to listen to respiratory sounds

Question 38

what are the borders of the triangle of auscultation?

Answer 38

bounded by the trapezius, medial border of scapula and lattisimus dorsi

Question 39

what do the extrinsic muscles of the back do?

Answer 39

move the shoulder and arm

Question 40

what do the intrinsic muscle of the back do?

Answer 40

control spine and some neck movement

Question 41

what does superficial for the back mean?

Answer 41

associated with movements of shoulder

Question 42

what does intermediate for the back mean?

Answer 42

associated with movements of thorax

Question 43

what does deep for the back mean?

Answer 43

associated with movements of the vertebral column