Part 1: Anterior Abdominal Wall Flashcards
What is the origin and insertion of external oblique muscle?
O: 8 digitations to anterior angles lower 8 ribs. Upper 4 digitate with SAM, lower 4 with LD
I: Outer 1/2 iliac crest. From ASIS forms aponeurosis which inserts to inguinal ligament, pubic tubercle, anterior rectus sheath, linea alba to xiphisternum
What is the action and innervation of external oblique muscle?
A: Supports expiration, raises intrabdominal pressure, abducts and rotates trunk
N: Ant primary rami (T7-T12)
What is the origin and insertion of the internal oblique muscle?
O: Lumbar fascia, anterior 2/3 iliac crest, lat 2/3 inguinal ligament
I: Costal margin, aponeurosis of rectus sheath, conjoint tendon to pubic crest
What is the action and innervation of internal oblique muscle?
A: Supports expiration, raises intraabdominal pressure.
Abducts and rotates trunk
N: Ant primary rami (T7-T12)
Conjoint tendon supplied by ilioinguinal N
What is the origin and insertion of transverse abdominis?
O: Costal margin, lumbar fascia, iliac crest and lateral 1/2 inguinal ligament
I: Aponeurosis of post and anterior rectus sheath, conjoint tendon to pubic crest and pectineal line
What is the action and innervation of transverse abdominis?
A: Support expiration, conjoint tendon supports inguinal canal
N: Ant primary rami (T7-T12), conjoint tendon supplied by ilioinguinal nerve
What is the origin, insertion, action and innervation of rectus abdominis?
O: Pubic crest and pubic symphysis
I: 5-7 costal cartilages, med inferior costal margin and post aspect of xiphoid
A: flexes trunk, aids forced expiration and increases intra-abdominal pressure
N: Ant primary rami (T7-T12)
What is the origin, insertion, action and innervation of pyramidalis muscle?
O: Pubic crest ant to origin of rectus abdominis
I: Lower linea alba
A: Reinforces rectus sheath
N: subcostal nerve (T12)
What are the layers of anterior abdominal wall?
Superficial to deep:
skin, Camper’s fascia, scarpa’s fascia, external oblique, internal oblique, transerve abdominus, transversalis fascia, peritoneum
What forms the rectus sheath?
Aponeurosis of internal + external oblique muscles and transversus abdominis. EOM pass anterior, TAM posterior and IOM splits behind and in front
What forms the arcuate line?
The point at which all layers of rectus sheath become anterior. Occurs a little below umbilicus
What is the semilunar line?
Shallow and bloodless groove from pubic tubercle to costal margin along lateral border of rectus muscle
What is the linea alba?
Strong midline fibrous structure which is firmly attached to xiphoid process and pubic symphysis and which abdominal muscles aponeurosis attach
What nerves supply the anterior abdominal wall?
Lower intercostals and subcostal nerves (T7-T12) supply all abdominal muscles.
In addition lowest fibres of IOM + TAM are supplied by iliohypogastric and ilioinguinal nerves (L1). This is important as these fibres maintain integrity of inguinal canal.
What is the blood supply of anterior abdominal wall?
Superior and inferior epigastric arteries
Deep circumflex iliac artery (branch of ext iliac)
Lumbar arteries
Describe the lymph drainage of abdominal wall
Superficial drainage is in quadrants. To pectoral group above umbilicus either side and superficial inguinal group below umbilicus either side.
Deep lymph drains to mediastinal nodes above and external iliac and para-aortic nodes below