Muscles Of Thoracic Wall Flashcards Preview

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Flashcards in Muscles Of Thoracic Wall Deck (15):
0

External intercostal Origin? Insertion? Innervation? Action?

O: Inferior border of ribs

I: Superior border of ribs below

Inner: Intercostal nerve

Action: During forced inspiration elevates ribs

1

Internal intercostal Origin? Insertion? Innervation? Action?

O: Inferior border of ribs

I: Superior border of ribs below

Inner: Intercostal nerve

Action: During forced inspiration: interosseous part depresses ribs; interchondral part elevates ribs

2

Innermost intercostal Origin? Insertion? Innervation? Action?

O: Inferior border of ribs

I: Superior border of ribs below

Inner: Intercostal nerve

Action: During forced inspiration: interosseous part depresses ribs; interchondral part elevates ribs

3

Transversus thoracis Origin? Insertion? Innervation? Action?

O: Posterior surface of lower sternum

I: Internal surface of costal cartilages 2-6

Inner: Intercostal nerve

Action: Weakly depresses ribs

4

External oblique Origin? Insertion? Innervation? Action?

O: External surfaces of 5th-12th ribs

I: Linea alba, pubic tubercle, and anterior half of iliac crest

Innervation: Thoraco-abdominal nerves (anterior rami of T7-T11) and subcostal nerve

Action: Compress and support abdominal viscera; flex and rotate trunk

5

Internal oblique Origin? Insertion? Innervation? Action?

O: Thoracolumbar fascia, anterior 2/3 of iliac crest, and connective tissue deep to inguinal ligament

I: Inferior border of 10-12th ribs, linea alba, and pubis via conjoint tendon

Inner: Thoraco-abdominal nerves (anterior rami of T7-T11) and first lumbar nerve

Action: Compress and support abdominal viscera; flex and rotate trunk

6

Transversus abdominis Origin? Insertion? Innervation? Action?

O: Internal surfaces of 7th-12th costal cartilages, thoracolumbar fascia, iliac crest, and connective tissue deep to inguinal ligament

I: Linea alba with aponeurosis of internal oblique, pubic crest, and pectin pubis via conjoint tendon

Inner: Thoraco-abdominal nerves (anterior rami of T7-T11) and first lumbar nerve

Action: Compresses and supports abdominal viscera

7

Rectus abdominis Origin? Insertion? Innervation? Action?

O: Pubic symphysis and pubic crest

I: Xiphoid process and 5th-7th costal cartilages

Inner: Thoraco-abdominal nerves (anterior rami of inferior 6 thoracic nerves)

Action: Flexes trunk (lumbar vertebrae) and compresses abdominal viscera; stabilizes and controls tilt of pelvis (antilordosis)

8

Psoas major Origin? Insertion? Innervation? Action?

O: Transverse processes of lumbar vertebrae; sides of bodies of T12-S1 vertebrae and intervening IV discs

I: By a strong tendon to lesser trochanter of femur

Inner: Lumbar plexus via anterior branches of nerves L2-L4

Action: Acting inferiorly with iliacus, flexes thigh. Acting superiorly, flexes vertebral column laterally to balance the trunk. When sitting, acts inferiorly with iliacus to flex trunk.

9

Iliacus Origin? Insertion? Innervation? Action?

O: Superior 2/3 of iliac fossa, ala of sacrum, and anterior sacro-iliac ligaments

I: Lesser trochanter of femur and shaft inferior to it, and to psoas major tendon

Inner: Femoral nerve (L2-L4)

Action: Flexes thigh and stabilizes hip joint. Acts with psoas major.

10

Quadratus lumborum Origin? Insertion? Innervation? Action?

O: Medial half of inferior border of 12th rib and tips of lumbar transverse processes

I: Iliolumbar ligament and internal lip of iliac crest

Inner: Anterior branches of T12 and L1-L4 nerves

Action: Extends and laterally flexes vertebral column. Fixes 12th rib during inspiration

11

Levator ani Origin? Insertion? Innervation? Action?

O: Body of pubis, tendinous arch of levator ani, ischial spine

I: Perineal body, coccyx, anacoccygeal ligament, walls of prostate or vagina, rectum anal canal

Inner: Nerve to levator ani (branches of S4), inferior anal (rectal) nerve, coccygeal plexus

Action: Helps support pelic viscera; resists increases in intra-abdominal pressure

12

Coccygeus Origin? Insertion? Innervation? Action?

O: Ischial spine

I: Inferior end of sacrum

Inner: Branches of S4 and S5 nerves

Action: Forms small part of pelvic diaphragm that supports pelvic viscera; flexes coccyx

13

Obturator internus Origin? Insertion? Innervation? Action?

O: Pelvic surface of ilium and ischium; obturator membrane

I: Greater trochanter of femur

Inner: Nerve to obturator internus (L5, S1, and S2)

Action: Rotates thigh laterally; assists in holding head of femur in acetabulum

14

Piriformis Origin? Insertion? Innervation? Action?

O: Pelvic surface of 2nd-4th sacral segments; superior margin of greater sciatic notch and sacrotuberous ligament

I: Greater trochanter of femur

Inner: Anterior rami of S1 and S2

Action: Rotates thigh laterally; abducts thigh; assists in holding head of femur in acetabulum