Thorax Muscles

Question 1

External Intercostals Origin & Insertion

Answer 1

Origin:
Lower border of rib

Insertion:
Upper border of rib

Question 2

External Intercostals Function & Innervation

Answer 2

Function:
Elevate ribs during inspiration

Innervation:
Intercostal nn.

Question 3

Internal Intercostals Origin & Insertion

Answer 3

Origin:
Inner surface of rib and costal cartilages

Insertion:
Upper border of adjacent ribs below

Question 4

Internal Intercostals Function & Innervation

Answer 4

Function:
Depress ribs during expiration

Innervation:
Intercostal nn.

Question 5

Transversus Thoracis Origin & Insertion

Answer 5

Origin:
Inner surfaces of lower 1/3 of sternum
Adjacent surfaces of xiphoid processes

Insertion:
Internal surfaces of sternocostal joints of rib 2-6

Question 6

Transversus Thoracis Function & Innervation

Answer 6

Function:
Rib depression

Innervation:
Intercostal nn.

Question 7

Quadratus Lumborum Origin & Insertion

Answer 7

Origin:
Iliolumbar ligg and Ilium crest

Insertion:
Rib 12 and L1-L4 transverse processes tips

Question 8

Quadratus Lumborum Function & Innervation

Answer 8

Function:
Lumbar extension
Lumbar side flexion
Expiration

Innervation:
Ventral ramus of spinal nerve roots T12-L3

Question 9

Psoas Major Origin & Insertion

Answer 9

Origin:
Transverse processes, intervertebral discs and lateral bodies of T12-L5

Insertion:
Femur lesser trochanter

Question 10

Psoas Major Function & Innervation

Answer 10

Function:
Lumbar forward flexion and side flexion
Hip flexion

Innervation:
Ventral rami L1-L3 branches

Question 11

Iliacus Origin & Insertion

Answer 11

Origin:
Iliac fossa superior 2/3
Iliac crest inner lip

Insertion:
Femur lesser trochanter

Question 12

Iliacus Function & Innervation

Answer 12

Function:
Hip flexion

Innervation:
Femoral n.

Question 13

Rectus Abdominis Origin & Insertion

Answer 13

Origin:
Pubic crest
Anterior pubic ligg.

Insertion:
Thorax front wall; near horizontal line passing lateral (5-7 costal cartilages)

Question 14

Rectus Abdominis Function & Innervation

Answer 14

Function:
Spine flexion
Expiration

Innervation:
Lower 6 or 7 thoracic loves

Question 15

External Oblique Origin & Insertion

Answer 15

Origin:
Lateral side of ribs 4-12

Insertion:
Iliac crest; linea alba; contralateral rectus sheaths

Question 16

External Oblique Function & Innervation

Answer 16

Function:
Bilaterally-
Trunk flexion
Posterior pelvic tilt
Unilaterally-

Innervation:
Lower 6 thoracic n.

Question 17

Internal Oblique Origin & Insertion

Answer 17

Origin:
Iliac crest; Inguinal ligg; Thoracolumbar fascia

Insertion:
Ribs 9-12; Linea alba; Contralateral rectus sheaths

Question 18

Internal Oblique Function & Innervation

Answer 18

Function:
Unilaterally-
Trunk lateral flexion
Trunk ipsilateral rotation
Bilaterally-
Trunk flexion
Posterior pelvic tilt

Innervation:
Lower 6 thoracic nn. and first lumbar n.

Question 19

Transversus Abdominis Origin & Insertion

Answer 19

Origin:
Iliac crest; Thoracolumbar fascia; Rib 6-12 inner surface of cartilage; Inguinal ligg

Question 20

Transversus Abdominis Function & Innervation

Answer 20

Function:
Bilateral-
Abdominal mm stabilization attachment sites
Abdominal cavity compression

Innervation:
Lower 6 thoracic nn. and first lumbar n.