abdominal muscles

Question 1

how many abdominal muscles are there and what are they called?

Answer 1

There are 4.
Rectus abdominus, transverse abdominus, external obliques, internal obliques.

Question 2

external abdominal obliques

Answer 2

Outermost muscle on the side. (Russian twists)
Fibers of this muscle run obliquely an an anterior direction (inferomedial). Same direction as putting hands in pocket.
O: Inferior border of ribs 5-12 and interdigitating with the serratus anterior and latissimus dorsi muscles.
I: anterior 1/2 of iliac crest, linea alba, abdominal aponeurosis
A: trunk flexion, lateral flexion, contralateral rotation of the trunk.

Question 3

Internal abdominal oblique

Answer 3

Fibers pf the muscle run obliquely in an inferolateral (posterior) direction.
O: thoracolumbar fascia; anterior 1/3 of the iliac crest and lateral inguinal ligament.
I: abdominal aponeurosis and linea alba; internal surfaces of ribs 10-12, pectineal line of the pubis.
A: trunk flexion, lateral flexion and ipsilateral rotation of the trunk.

Question 4

rectus abdominus

Answer 4

Big 6 pack muscles.
O: pubic crest and symphysis
I: costal cartilage and ribs 5-7, xiphoid process of sternum.
A: compression of abdominal viscera and increases intrabdominal pressure.

Question 5

Transverse abdominus

Answer 5

Deep muscle that has fibers running horizontally.
O: Costal cartilage and ribs 7-12, thoracolumbar fascia, iliac crest and lateral inguinal ligament.
I: linea alba, pubic crest and symphysis.
A: compression of abdominal viscera; increases intra-abdominal pressure.