Rectus sheath

Question 1

Rectus sheath

Answer 1

• Fromed by aponeurosis of lateral abdominal muscles
• Rectus abdominis muscle is integrated inside of it

Question 2

Main part of the RS (upper 3/4)

Answer 2

• Formed by aponeurosis of internal oblique abdominal muscle and it forms two layers:

1. Ventral layer
2. Dorsal layer

Question 3

Reinforcement of ventral layer

Answer 3

• By aponeurosis of the external oblique abdominal muscle

Question 4

Reinforcement of dorsal layer

Answer 4

• By aponeurosis of the transverse abdominal muscle

Question 5

Lower 1/4 of the RS

Answer 5

• All aponeurosis are located in front of the rectus abdominis muscle
• The dorsal layer is missing here, it is only covered by the transverse fascia and parietal peritoneum

Question 6

Arcuate line (linea semicircularis)

Answer 6

• Demarcates the lower limit of the dorsal layer of the RS
• The inferior epigastric vessels perforate the rectus abdominis muscle here

Question 7

Linea alba

Answer 7

• Medial line where the rectus sheaths meet
• Runs from the xiphoid process to the pubic symphysis
• Approximately half way down the linea alba is an umbilical scar - umbilicus

Question 8

Linea semilunaris

Answer 8

• Between muscular and aponeurotic parts of the lateral abdominal wall
• Used by surgeons for pararectal section in order to access the abdominal cavity