Anterior Abdominal Muscles Flashcards
Which muscles are located in the anterior abdominal wall?
External oblique, internal oblique, transversus abdmoninis and rectus abdominis
How is the EOM characterized?
Runs in downward medial direction and interdigitates with serratus anterior
What is the origin of the external oblique muscle?
Outer surface of lower 7 ribs
What is the insertion for the external oblique?
Aponeurosis and linea alba, anterior iliac crest and pubic tubercle
What innervates the external oblique?
Ventral rami of T7-12 of intercostal nerves (thoraco-abdominal and subcostal)
What is the action of the external oblique?
Compress abdomen and increase intra-abdominal pressure
Move trunk and retain posture
The lower portion of which muscle is rolled under to make the inguinal ligament that is attached to the ASIS and pubic tubercle?
The external oblique
Makes opening of superficial inguinal ring
Some reflexes under to make lacunar ligament
In what direct does the internal oblique muscle run in?
90 degrees from the EOM
What is the origin of the internal oblique?
Iliac crest and some of thoracolumbar fascia
What is the insertion of internal oblique muscle?
Lower 10-12 ribs, aponeurosis, linea alba and pubic crest
What innervates the internal oblique?
T7-12 and L1
Thoraco-abdominal, subcostal, ilioinguinal and Iliohypogastric
What is the action of the internal oblique?
Compresses and supports viscera
Laterally flexes and rotates
What are unique features of the internal oblique?
Lower part makes part of conjoint tendon (inguinal falx)
Some fibers follow spermatic cord to make cremasteric muscle
Aponeurosis part splits to encompass rectus muscle in upper 3/4, otherwise all go in front in lower 1/4
Describe the transversus abdominis muscle
Runs transverso-medially except for some running toward pubic crest (to contribute to conjoint tendon)
Aponeurosis contributes to rectus sheath
What is the origin of transversus abdominis?
Lower 7-12 ribs, thoracolumbar fascia, iliac crest and some off upper inguinal ligament
