5/24 intrinsic back muscles

Question 1

serratus posterior superior

Answer 1

SA

• nuchal ligament
• C7-T3

IA
-superior border of 2nd-4th ribs

I
-2nd-5th intercostal nerves

A
-elevate ribs

Question 2

serratus posterior inferior

Answer 2

SA
-inferior borders of 8th-12th ribs near angles

IA
-SP of T12-L2

I

• 9th-11th intercostal nerves
• subcostal nerves (T12)

A
-depress ribs

Question 3

erector spinae
(iliocostalis, longissimus, spinalis)
(intermediate layer of IBM)

Answer 3

O

• SP of inf lumbar and sacrum
• broad tendon from posterior iliac crest
• posterior sacrum
• sacro-iliac lig

IS
iliocostalis (lumborum, thoracis, cervicis)
-angles of lower ribs 
-TP cervicle region
longissimus (thoracis, cervicis, capitis)
-ribs btw tubercles and angles
-TP in thoracic, cervical region
-mastoid process 
spinalis (thoracis, cervicis, capitis)
-SP in upper thoraci c region
-to cranium 

I
-posterior rami of spinal nerve

A
bilaterally
-extend vc and head, ao joint
-when back is flex, control mvm by lengthening 
unilerally
-lateral flex vc

Question 4

splenius
(superficial layer of intrinsic muscle)
(capitis, cervicis)

Answer 4

O

• nuchal lig
• SP C7-T6

IS
capitis
-mastoid process
-lateral 3rd superior nuchal line 
cervicis 
-tubercles of TP of C1-C3

I
-posterior rami of spinal nerves

A
alone
-lateral flex neck and rotate at same side 
together 
-extend head and neck

Question 5

Semispinals
(deep layer of intrinsic back muscle)
(thoracic, cervicis, capitis)

Answer 5

O
-TP C4-T10

I

• occipital bone
• SP in upper thoracic and cervicle region
• spaninvg 4-6 segments

I
-pr

A

• extend head and thoracic and cervicle VC
• rotate contralaterally

Question 6

Multifidous

Answer 6

O

• AP C4-C7
• TP thoracic
• mammillary process of lumbar
• posterior sacrum
• PSIS
• sacro-iliac lig
• aponeurosis of erector spinae

IS

• fibers pass obliquely superiomedially to entire length of SP
• 2-4 segs superior ot origin
• thickest in lumbar region

I
-pr

A
unilateral
-rotate to contralateral side 
-stablize v during local mvm of vc 
-

Question 7

rotators

brevis and longus

Answer 7

O

• TP of v
• best in thoracic region

IS
brevis
-superiomedially to attach to junction of lamina and TP/SP of v immedially
longus
-that of 2 segments superior to veterbra of origin

I
- PR

A

• proprioception
• stabilize vertebrae
• assist local extension and rotarion of vc