Abdominal Anatomy

Question 1

What are the layers of the abdominal wall

Answer 1

Skin
Campers Fascia
Scarpa's Fascia
External Oblique
Internal Oblique
Transverse abdominis 
Transversalis Fascia
Parietal peritoneum

Question 2

What is the attachment and origins of the external and internal Oblique muscles

Answer 2

External Oblique-
Origin- Ribs 5-12.
Insertion - iliac crest, pubic tubercle

Internal Oblique
Origin - inguinal ligament, iliac crest, lumbodorsal Fascia

Innervation both muscles are innervated by

• Thoracoabdominal nerves (T7-T11) as per ASIA chart
• Subcostal Nerves

The internal Oblique has some innervation from the lumbar plexus

Question 3

What is the origin, attachment and innervation of the Transversus abdominis

Think 4 of each for origin and insertion

Answer 3

Origin - Iliac crest, Inguinal ligament, costal cartilage (7-12), Thoracolumbar Fascia

Attachment - Xiphoid Process, Public crest, Linea Alba, Conjoint tendon

Innervation - Thoracoabdominal nerves (T7-11), Subcostal nerve and lumbar plexus (same innervation as internal oblique)

Question 4

What is the origin, insertion and innervation of the rectus abdominis?

Answer 4

Origin - Pubic Crest

Insertion - Xiphoid Process, costal cartilage of ribs 5-7

Innervation - Thoracolumbar Nerves (T7-T11)

Question 5

What are the 3 flat muscles of the abdomen

Answer 5

External Oblique
Internal Oblique
Transversus Abdominis

Question 6

What are the 2 vertical muscles of the anterior abdominal wall

Answer 6

Rectus Abdominis

Pyramidalis

Question 7

What is the origin, insertion and innervation of pyramidalis. What is its relation to the Rectus abdominis

Answer 7

Origin- Pubic Crest and pubic symphysis
Insertion - Linea Alba

Innervation- subcostal nerve (T12)

Relation - sits superficial to rectus abdominis at the inferior aspect

Question 8

Describe the anatomy of the Rectus Sheath
Tip:
Include what it is made from and discuss the anterior and posterior walls.

Answer 8

The Rectus Sheath is formed by the aponeuroses of the 3 flat muscles:

The anterior wall is formed by the aponeuroses of the external Oblique and half the internal oblique.

The posterior wall is formed by half the internal Oblique and transversalis abdominis

Halfway between the umbilicus and the public symphysis, the posterior wall passes anteriorly to join the anterior wall so that there is no longer a posterior wall. THIS IS THE ARCUATE LINE