Muscles of the anterior abdominal wall Flashcards
what is the anterior-lateral abdominal wall made up of?
- 3 flat muscles: internal oblique, external oblique and transverse obliqye
- 2 flat muscles: rectus abdomens and the pyramidalis muscle
What are the actions of the internal and external oblique muscles?
- They flex and rotate the trunk
- They support and compress the abdominal viscera of the abdomen.
What are the actions of the transverse oblique muscle?
The support and compresses the abdominal viscera
What are the actions of the rectus abdominis
- Flexes the trunk
- Compresses the abdominal viscera
- controls the tilt of the pelvis
What is the innervation of the External oblique muscles
T7-T11: thoracic-abdominal nerves
T12: subcostal nerve
What is the innervation of the Internal oblique muscles?
T7-T11: thoraco-abdominal nerves
T12: subcostal nerve
L1
What is the innervation of the transverse oblique muscles
T7-T11
T12
L1
What is the innervation of the rectus abdominis muscle?
T7-T11
What is the rectus sheath?
Aponeurosis of the oblique muscles which encloses the rectus abdominis and the pyramidalis muscle
what is an aponeurosis?
A flat sheet of tendon which connect the muscle to the part of the body it works on
How is the rectus sheath above and below the umbilicus different?
Above the umbilicus: The sheath surround the rectus abdominis anteriorly and posteriorly
Below the umbrellas: the sheath surround the rectus only anteriorly
Vertebral levels of the umbellicus?
L3-L4
Is the umbellicus a good surface landmark
No- may vary depending on layers of subcutaneous fat
Yes-lots of important structures e.g. bifurcation of the aorta
What is the pyramidalis muscle
It is a small triangular muscle, anterior to the rectus abdominis found in the rectus sheath.
It Tenses the linea alba
What is the linea alba?
white fibrous tissue between the Xiphoid process and the pubic symphisis
