Muscles Of Anterolateral Abdominal Wall and rectus sheath

Question 1

What is the origin, insertion, innervation, and action of the external oblique muscle?

Answer 1

O: ribs 5-12
I: Linea Alba, pubic tubercle and anterior 1/2 of iliac crest
N: T7-T11 Thoracoabdominal nn. (From intercostal nn.) And Subcostal n. (12 intercostal n.)
A: compress abdominal viscera, flex and rotate trunk

Question 2

The inguinal ligament extends from the ASIS to the pubic tubercle and is formed by the thickened inferior margin of which muscle? It also serves as the anterosuperior attachment point for Fascia Lata

Answer 2

External oblique muscle

Question 3

What is the origin, insertion, innervation, and action of the internal oblique muscle?

Answer 3

O: thoracolumber fascia, anterior 2/3 of iliac crest and inguinal ligament
I: ribs 10-12, linea alba and pectin pubis
N: T7-11 Thoracoabdominal nn. (From intercostal nn.) and subcostal n. (12th intercostal n.), iliohypogastric n., ilioinguinal n.
A: compress abdominal viscera, flex and rotate trunk

Question 4

The inferomedial fibers of _____ join with the aponeurotic fibers of _____ to form the conjoint tendon. This attached to the pubic crest and pectin pubis

Answer 4

Internal oblique muscle, transversus abdominis muscle

Question 5

What is the origin, insertion, innervation, and action of the transversus abdominis muscle

Answer 5

O: thoracolumbar fascia, costal cartilages 7-12, iliac crest and inguinal ligament
I: linea alba, pubic crest and pectin pubis (via conjoint tendon)
N: T7-T11 Thoracoabdominal nn., subcotal n., iliohypogastric n., ilioinguinal n.
A: compress and support abdominal viscera and trunk

Question 6

What is the origin, insertion, innervation, and action of the reclusive abdominis muscle

Answer 6

O: pubic symphysis and pubic crest
I: xiphoid process and costal cartilages 5-7
N: T7-T11 thoracoabdominal nn. And subcostal n
A: flexes trunk and compresses abdominal viscera

Question 7

The rectus abdominis is _____ and ______ superiorly, and _____ and _____ inferiorly.

Answer 7

Wider and thinner superiorly

Narrower and thicker inferiorly

Question 8

The pyramidalis muscle spans between ____ and ____ overlapping the inferior portion of recurs abdominus. It’s function is to ______. It is absent on one or both side in approx. ______% of people

Answer 8

Spans between pubis and linea alba
Functions to tense linea alba
Absent in ~20% of people

Question 9

Where is the arcuate line located

Answer 9

Located on posterior rectus sheath about 1/4 up from pubic crest

Question 10

What composes the anterior rectus sheath superior to the arcuate line

Answer 10

• aponeurosis of external oblique muscle

- anterior laminae of aponeurosis of internal oblique muscle

Question 11

What composes the posterior rectus sheath superior to the arcuate line

Answer 11

• posterior lamina of aponeurosis of internal oblique muscle
• aponeurosis of transversus abdominis muscle
• endoabdominal (transversalis) fascia

Question 12

What composes the anterior rectus sheath inferior to arcuate line

Answer 12

• aponeurosis of external oblique muscle
• aponeurosis of internal oblique muscle
• aponeurosis of tensversus abdominis muscle

Question 13

What composes the posterior rectus sheath inferior to the arcuate line

Answer 13

• endoabdominal (transversalis) fascia

Question 14

When the anterolateral wall muscles combine to compress the abdominal viscera they assist in what 4 actions

Answer 14

• elevating thoracic diaphragm during forced expiration, coughing, sneezing, etc
• defecation (evacuating fecal material from rectum)
• micturition (urination, evacuating urine from urinary bladder)
• parturition (childbirth, evacuating fetus from uterus)