Trunk Cavity Muscles

Question 1

Intercostals Action

Answer 1

• external = draw ribs superiorly to assist w/ inhalation
• internal = draw ribs inferiorly to assist w/ exhalation

Question 2

Intercostals Origin

Answer 2

inferior border of rib above

Question 3

Intercostals Insertion

Answer 3

superior border of rib below

Question 4

Intercostals Innervation

Answer 4

thoracic - segmental intercostal nerve

Question 5

Diaphragm Action

Answer 5

draw central tendon down to increase volume of thoracic cavity during inhalation

Question 6

Diaphragm Origin

Answer 6

costal: inner surface of ribs 7-12
lumbar: L1 - L2/L3
sternal: inner xiphoid process

Question 7

Diaphragm Insertion

Answer 7

central tendon

Question 8

Diaphragm Innervation

Answer 8

phrenic nerve (C3, C4, C5)

Question 9

Quadratus Lumborum Action

Answer 9

unilateral: laterally tilt/hike/elevate pelvis; lateral flexion and extension of vertebral column
bilateral: fix rib 12 during forced inspiration

Question 10

Quadratus Lumborum SA

Answer 10

rib 12, tips of TP of L1 - L5

Question 11

Quadratus Lumborum IA

Answer 11

iliolumbar ligament, iliac crest

Question 12

Quadratus Lumborum Innervation

Answer 12

ventral branches T12, L1 - L4

Question 13

Psoas Major Action

Answer 13

• acting inferiorly w/ iliacus = hip flexion
• acting superiorly = lateral flexion of vertebral column
• balance trunk
• acting inferiorly w/ iliacus while sitting = trunk flexion

Question 14

Psoas Major SA

Answer 14

TP of T12 - L5, sides of lumbar vertebrae, discs b/w them

Question 15

Psoas Major IA

Answer 15

lesser trochanter

Question 16

Psoas Major Innervation

Answer 16

ventral rami L1, L2, L3

Question 17

Iliacus Action

Answer 17

hip flexion, stabilize hip joint

Question 18

Iliacus SA

Answer 18

iliac fossa, sacrum, anterior sacroiliac ligaments

Question 19

Iliacus IA

Answer 19

lesser trochanter, psoas tendon

Question 20

Iliacus Innervation

Answer 20

femoral nerve (L2, L3, L4)

Question 21

Rectus Abdominis Action

Answer 21

flexion of vertebral column
compress abdominal viscera
posterior tilt of pelvis

Question 22

Rectus Abdominis Origin

Answer 22

pubic crest, pubic symphysis

Question 23

Rectus Abdominis Insertion

Answer 23

cartilage of 5-7 ribs, xiphoid process

Question 24

Rectus Abdominis Innervation

Answer 24

thoraco-abdominal nerves (anterior rami T6 - T12)

Question 25

External Oblique Action

Answer 25

unilateral: lateral flexion, contralateral rotation of vertebral column
bilateral: flexion of vertebral column, compress abdominal contents

Question 26

External Oblique Origin

Answer 26

external surfaces of ribs 5-12

Question 27

External Oblique Insertion

Answer 27

linea alba, pubic tubercle, anterior half of iliac crest

Question 28

External Oblique Innervation

Answer 28

thoraco-abdominal nerves (T7 - T11), subcostal nerve

Question 29

Internal Oblique Action

Answer 29

unilateral: lateral flexion, ipsilateral rotation of vertebral column
bilateral: flexion of vertebral column, compress abdominal contents

Question 30

Internal Oblique Origin

Answer 30

thoracolumbar fascia, iliac crest, inguinal ligament

Question 31

Internal Oblique Insertion

Answer 31

inferior borders of ribs 10-12, linea alba, pecten pubis via conjoint tendon

Question 32

Internal Oblique Innervation

Answer 32

thoraco-abdominal nerves (anterior rami T6-T12), first lumbar nerve

Question 33

Transversus Abdominis Action

Answer 33

compress and support abdominal viscera
antagonist of diaphragm w/ expiration

Question 34

Transversus Abdominis Origin

Answer 34

internal surfaces of 7-12 costal cartilages, thoracolumbar fascia, iliac crest, connective tissue deep to lateral 1/3 of inguinal ligament

Question 35

Transversus Abdominis Insertion

Answer 35

linea alba w/ aponeurosis of internal oblique, pubic crest, pecten pubis via conjoint tendon

Question 36

Transversus Abdominis Innervation

Answer 36

thoraco-abdominal nerves (anterior rami T6-T12), first lumbar nerve