Abdominal Wall Flashcards
What makes up the Anterolateral abdominal wall?
Skin
Subcutaneous tissue/ Superficial fascia/ Fat/ Campers fascia
Muscles and their aponeurosis (External oblique, internal oblique and transversus abdominus) , and
Deep fascia
Extraperitoneal fat
Parietal peritoneum
What makes up the Posterior Abdominal Wall?
Five lumbar vertebrae and associated IV discs (centrally).
Posterior abdominal wall muscles, including the psoas, quadratus lumborum, iliacus, transversus abdominis, and oblique muscles (laterally).
Diaphragm, which contributes to the superior part of the posterior wall.
Fascia, including the thoracolumbar fascia.
Lumbar plexus, composed of the anterior rami of lumbar spinal nerves.
Fat, nerves, vessels (e.g., aorta and IVC), and lymph nodes.
Where is the External Oblique Muscle and what is its role?
External surfaces of 5th-12th ribs
Linea alba, pubic tubercle, and anterior half of iliac crest
Thoracoabdominal nerves (T7-T11 spinal nerves) and subcostal nerve
Compresses and supports abdominal viscera, flexes and rotates trunk
What is the insertion and aponeurosis of the External Oblique Muscle?
Insertion - fleshy fibres -outer lip of the iliac crest
Aponeurosis - Medial Part - linea alba from xiphoid process to symphysis pubis
Lateral part - folded upwards and backwards upon itself tp form the inguinal ligament (ASIS to pubic tubercle)
Where is the Internal Oblique and what is its role?
Thoracolumbar fascia, anterior two thirds of iliac crest, and connective tissue deep to lateral third of inguinal ligament
Inferior borders of 10th-12th ribs, linea alba, and pectineal line via conjoint tendon
Thoracoabdominal nerves (anterior rami of T6-T12 spinal nerves) and first lumbar nerves
Compresses and supports abdominal viscera, flexes and rotates trunk
Where is the transversus abdominis and what is its role?
Internal surfaces of 7th-12th costal cartilages, thoracolumbar fascia, iliac crest, and connective tissue deep to lateral third of inguinal ligament
Linea alba with aponeurosis of internal oblique, pubic crest, and pectineal line via conjoint tendon
Thoracoabdominal nerves (anterior rami of T6-T12 spinal nerves) and first lumbar nerves
Compresses and supports abdominal viscera
What are the dermatomes of the abdomen?
T7-T9 supply the skin superior to the umbilicus.
T10 supplies the skin around the umbilicus.
T11, plus the cutaneous branches of the subcostal (T12), iliohypogastric, and ilioinguinal (L1), supply the skin inferior to the umbilicus.
What are the nerves of the abdomen?
Thoracoabdominal nerves: Anterior rami of the inferior six thoracic nerves
Lateral (thoracic) cutaneous branches: Thoracic spinal nerves T7-T9 or T10.
Subcostal nerve: Anterior ramus of spinal nerve T12.
Iliohypogastric and ilioinguinal nerves: Branches of the anterior ramus of spinal nerve L1.
What are the Vessels of anterolateral abdominal wall?
Superior epigastric vessels and branches of the musculophrenic vessels from the internal thoracic vessels.
Inferior epigastric and deep circumflex iliac vessels from the external iliac vessels.
Superficial circumflex iliac and superficial epigastric vessels from the femoral artery and tributaries of greater saphenous vein, respectively.
Posterior intercostal vessels of the 11th intercostal space and the anterior branches of subcostal vessels.
What are the 3 man veins of the abdomen?
Paraumbilical veins
Thoracoepigastric veins
Deep venous anastomoses
What are the superficial and deep lymphatic vessels of the abdominal wall?
Superficial lymphatic vessels
1. With the subcutaneous veins; superior to transumbilical plane drain to the axillary lymph nodes; & parasternal lymph nodes. 2. Lymphatic vessels inferior to the transumbilical plane drain to the superficial inguinal lymph nodes.
Deep lymphatic vessels
with deep veins of the abdominal wall and drain to the external iliac, common iliac, and right and left lumbar (caval and aortic) lymph nodes.
What is the Inguinal Ligament?
The inguinal ligament is a dense band constituting the inferior most part of the external oblique aponeurosis.
Most fibers of the ligament’s medial end insert into the pubic tubercle, some follow other courses:
Deeper fibers pass posteriorly to attach to the superior pubic ramus lateral to the tubercle, forming the arching lacunar ligament (of Gimbernat), which forms the medial boundary of the subinguinal space.
The most lateral of these fibers continue to run along the pecten pubis as the pectineal ligament (of Cooper).
Superior fibers fan upward, bypassing the pubic tubercle and crossing the linea alba to blend with the lower fibers of the contralateral external oblique aponeurosis. These fibers form the reflected inguinal ligament
What is the inguinal canal and what makes it up?
deep (internal) inguinal ring entrance to the inguinal canal. It is located superior to the middle of the inguinal ligament and lateral to the inferior epigastric artery
superficial (external) inguinal ring exit by which the spermatic cord in males, or the round ligament in females, emerges from the inguinal canal
Anterior wall: external oblique aponeurosis throughout the length of the canal; its lateral part is reinforced by muscle fibers of the internal oblique.
Posterior wall: formed by the transversalis fascia; its medial part is reinforced by pubic attachments of the internal oblique and transversus abdominis aponeuroses that frequently merge to variable extents into a common tendon—the inguinal falx (conjoint tendon)—and the reflected inguinal ligament.
Roof: formed laterally by the transversalis fascia, centrally by musculoaponeurotic arches of the internal oblique and transversus abdominis, and medially by the medial crus of the external oblique aponeurosis.
Floor: formed laterally by the iliopubic tract, centrally by gutter formed by the infolded inguinal ligament, and medially by the lacunar ligament.
What are the predisposing factors of inguinal hernias in direct (acquired) and indirect (congenital)?
DIRECT
Weakness of anterior abdominal wall in inguinal triangle (e.g., owing to distended superficial ring, narrow inguinal falx, or attenuation of aponeurosis in males >40 years of age)
INDIRECT
Patency of processus vaginalis (complete or at least superior part) in younger persons, the great majority of which are males
What is the frequency of inguinal hernias in direct (acquired) and indirect (congenital)?
DIRECT
Less common (one third to one quarter of inguinal hernias)
INDIRECT
More common (two thirds to three quarters) of inguinal hernias
Where do inguinal hernias exit from abdominal cavity in direct (acquired) and indirect (congenital)?
DIRECT
Peritoneum plus transversalis fascia (lies outside inner one or two fascial coverings of cord)
INDIRECT
Peritoneum of persistent processus vaginalis plus all three fascial coverings of cord/round ligament
