abdominal muscles

Question 1

Answer 1

pyramidalis
pyramid like, connects to linea alba (connective tissue)
-absent in 20% of people
action : tenses linea alba

Question 2

Answer 2

external oblique

origin: external surfaces of 5th -12th ribs
insertion: linea alba, pubic tubercle, and anterior half of iliac crest
action: compress and support abdominal viscera; flex and rotate trunk so opposite side as muscle
innervation: thoracic-abdominal and subcostal nerves

fibres run inferiorly

Question 3

Answer 3

internal oblique
Origin: thoracolumbar fascia, anterior two thirds of iliac crest
insertion: inferior borders of 10-12th ribs, line alba and pubis
action: compress and support abdominal viscera; flex and rotate trunk to same side as muscle
innervation: thoracic-abdominal nerves, subcostal and first lumbar nerves

fibres run anterior/posteriorly

Question 4

Answer 4

rectus abdominis
origin: pubic symphysis/ pubic crest
insertion: xiphoid process and 5th-7th costal cartilage
action: flexes trunk (lumbar), compresses abdominal viscera, stabilizes and controls tilt of pelvis.
innervation: thoracic-abdominal and subcostal nerves
8 pack muscle

Question 5

Answer 5

transversus abdominis
innermost muscle

action: compresses and supports abdominal viscera, surrounds guts, help bring spine to neutral
innervation: thoracic-abdominal nerves, subcostal and first lumbar nerve

Question 6

linea alba

Answer 6

extends from xihpoid process to pubic symphisi

Question 7

arcuate line

Answer 7

positioned halfway between the umbilicus and the pubis crest