abdominal muscles Flashcards
pyramidalis
pyramid like, connects to linea alba (connective tissue)
-absent in 20% of people
action : tenses linea alba
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
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
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
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
linea alba
extends from xihpoid process to pubic symphisi
arcuate line
positioned halfway between the umbilicus and the pubis crest