Abdominal muscles

Question 1

Abdominal muscles

Answer 1

M. obliquus externus abdominis

M. obliquus internus abdominis

M. transversus abdominis

M. rectus abdominis

Question 2

M. obliquus internus abdominis

Answer 2

Origin: superficial layer of thoracolumbar fascia, tuber coxae, and from ligamentum inguinale

Insertion: fibres run cranioventrally (///) to linea alba. At the preumbilical site it has an outer and an inner layer which envelops m. rectus abdominis.

Action: maintaining abdominal pressure (urination, defecation, parturition), protection

Question 3

M. transversus abdominis

Answer 3

Origin: by means of deep layer of thoracolumbar fascia from transverse processes of lumbar vertebrae, and from medial surface of false ribs; lumbar nerves crossing on its outer surface

Insertion: fibres run transversely (|||) to linea alba

Action: maintaining abdominal pressure (urination, defecation, parturition), protection

Question 4

M. rectus abdominis

Answer 4

Origin: cranially from sternum

Insertion: pecten ossis pubis (on prepubic tendon, together with m. pectineus)

o Action: maintaining abdominal pressure (urination, defecation, parturition), protection

Question 5

Rectus sheet

Answer 5

is formed around m.rectus abdominis, contributed by these muscles:

(external oblique: E, internal oblique: I, transverse: T, rectus: R, fascia transversa abdominis and peritoneum: P).
An outer to inner (or lateromedial) order listed below in the different regions:

thoracic: E — R — thoracic wall
preumbilical: E—I—R—I—T—P
umbilical: E—I—R—T —P
postumbilical: E — I — T — R — P

Question 6

M. obliquus externus abdominis

Answer 6

Origin: superficial layer of fascia thoracolumbalis and lateral aspect of ribs 4-12.

Insertion: fibres run caudoventrally (\) to linea alba, caudally on pelvis it forms the inguinal ligament, and create medial and lateral crus around superficial inguinal ring

Action: maintaining abdominal pressure (urination, defecation, parturition), protection of abdominal organs