PT 793 Lumbar Muscles

Question 1

Transversospinalis

Answer 1

Multifidus: lumbar- spans 2-4 segments
Rotatores: thoracic- spans 1-2 segments
Semispinalis: cervical- spans 4-6 segments

in the bony gutter bwt transverse and spinous processes deep to spinalis muscle of erector spinae

unilateral action: ipsilateral lateral flexion and contralateral rotation

bilateral action: extension of vertebral column and head

Question 2

Multifidus (transversospinalis) m.

Answer 2

o: post ilium, iliac spine, sacrum, transverse processes of T1-T3

i: spinous processes 2-4 segments superior to proximal attachment thickest in lumbar region

inn: post rami of spinal nerves

a: stabilize spine during local movement of vertebrae and extend spine

Question 3

Rotatores (Transversospinalis) m.

Answer 3

o: transverse processes of vertebrae; best developed in thoracic region

i: superior transverse processes 1-2 segments superior to proximal attachment

inn: post rami of spinal nerves

a: stabilize vertebrae with some proprioceptive function. Assist in spinal extension and contralateral rotation

Question 4

Semispinalis (Transversospinalis) m.

Answer 4

o: C4-T12 transverse processes

i: fibers run superomedially to occipital bone and spinous processes in cervical/throacic region 4-6 segments superior

inn: post rami of spinal nerves

a: extends bilaterally, unilaterally contributes to contralateral rotation of head and cervical/thoracic spine and ipsilateral lateral flexion

*deep to splenius

Question 5

Erector spinae

Answer 5

Iliocostalis
longissimus
spinalis

“I Love Science” Lateral to Medial

action
-bilateral: extends spine and head; eccentrically contracts to control back flexion
-unilaterally: ipsilateral spinal lateral flexion

Question 6

Iliocostalis (Erector spinae) m.

Answer 6

o: post iliac crest; post surface of sacrum; sacral/inf lumbar spinous processes

i: fibers run superiorly to angles of lower ribs and cervical transverse processes

inn: post rami of spinal nerves

a:
-bilaterally: ext spine and head; eccentrically contract to control spinal flexion
-unilaterally: ipsilateral lat spinal flexion

Question 7

Longissimus (Erector spinae) m.

Answer 7

o: iliac crest, sacrum, sacral/inf lumbar spinous processes

i: fibers run superiorly to ribs and angle to throracic and cervical transverse processes

inn: post rami of spinal nerves

a: extends head and neck, rotates to SAME side (capitus)

Question 8

Spinalis (erector spinae) m.

Answer 8

o: post iliact crest, sacrum, sacral/inf lumbar spinous processes

i: fibers run superior to spinous processes in upper thoracic region to cranium

inn: post rami of spinal nerves

a
-bilaterally: ext spine and head; eccentrically contract to control spinal flexion
-unilaterally: ipsilateral lat spinal flexion

Question 9

Abdominals superficial to deep

Answer 9

rectus abdominis is just on the front

1. external oblique
2. internal oblique
3. transverse abdominis

Question 10

Rectus abdominis

Answer 10

o: pubic symphysis and pubic crest

i: xiphoid process and 5th-7th costal cartilages

inn: ant rami of T6-T12 spinal nerves
thoracoabdominal

a: flexes trunk (lumbar vertebrae) and compresses abdominal visceral; stabilizes and controls tilt of pelvis (antilordosis)

Question 11

Abdominal bracing vs hollowing

Answer 11

Hollowing: drawing in ant core activating lateral muscles only: obliques (int and ext) and transverse abdomenis (drawing in belly button towards back)

Bracing: contraction of ALL core muscles forming a brace around entire trunk (inflating like you’re about to get punched in the stomach)

Question 12

Transverse abodminis m.

Answer 12

o: int surfaces of 7th-12th costal cartilages, iliac crest

i: linea alba, pubic crest, and pectin pubis via conjoint tendon

inn: ant rami of T6-T12 spinal nerves and 1st lumbar n

a: compresses and supports abdominal viscera therefore increasing intra abdominal pressure key for spinal stability
one of the main core stabilizing muscles of lumbar spine

Question 13

Internal oblique m.

Answer 13

O: ant 2/3 iliac crest

i: inf borders of 10th-12th ribs, linea alba and pectin pubis

inn: ant rami of T6-T12 spinal nerves and 1st lumbar n.

a: flexion of vertebral column, compression and supports abdominal viscera, ipsilateral lateral spinal flexion and rotation

Question 14

External Oblique m.

Answer 14

o: external surfaces of 5th-12 ribs

i: linea alba, pubic tubercle and ant 1/2 iliac crest

inn: T7-T11 spinal nerves and subcostal n

a: ipsilateral lateral flexion to SAME side, rotation of spine to contralateral side when acting alone; compresses and supports abdominal visceral + flexion

*most superficial

Question 15

Iliacus m.

Answer 15

o: sup 2/3 iliac fossa, ala of sacrum

i: lesser trochanter of femur and shaft

inn: femoral n (L2-L4)

a: flexes hip and stabilizes hip joint; acts with psoas major

Question 16

Psoas major m.

Answer 16

o: transverse processes sides of T12-L5 vertebral bodies

i: lesser trochanter of femur

inn: ant rami of L1-L3 lumbar nerves

a: balances trunk
-inferiorly: with iliacus flexes hip in standing and trunk in sitting
-superiorly: ipsilateral trunk lateral flexion

Question 17

Quadratus lumborum m.

Answer 17

o: 12th rib, lumbar transverse processes

i: internal lip of iliac crest

inn: T12 and L1-L4

a: extends and laterally flexes vertebral column; fixes 12th rib during inspiration

Question 18

Pelvic floor

Answer 18

coccygeus
levator ani (puborectalis, pubococcygeus, iliococcygeus)
piriformis
obturator internus

Question 19

Pelvic floor function

Answer 19

4 S’s:

1. Support the viscera
2. sphincter control
3. sexuality
4. stabilizer of lumbar spine

Question 20

Coccygeus (ischiococcygeus) m.

Answer 20

o: ischial spine

i: sacrum and coccyx

Question 21

Levator ani m.

Answer 21

o: body of pubis, ischial spine

i: coccyx

Question 22

Obturator internus m.

Answer 22

o: pelvic surfaces of the ilium and ischium

i: greater trochanter

inn: nerve to obturator internus

a: rotates thigh laterally

Question 23

Piriformis m.

Answer 23

o: pelvic surface of S2-4 segments, greater sciatic notch

i: greater trochanter

inn: S1-S2

a: rotates thigh laterally