Lecture 8: Anterior Abdominal Wall & Inguinal Region Flashcards
What are the margins of the abdomen?
ASIS, costal margin, iliac crest, pubic tubercle
What are the anterior abdominal wall layers?
Skin Superficial fascia (campers-fatty, scarpals-membranous) External oblique Internal oblique Transversus abdominus Trasversali fascia Exztraperitoneal fat Parietal peritoneum
What is the relationship of the 3 anterior ab wall muscles to the costal margin?
External overlaps, internal edge to edge, transversus underlaps
What are the features of the external oblique?
Free inferior edge is inguinal ligament - asis to pubic tubercle - meets anteriorly at linea alba
What are the features of the internal oblique?
Arches to insert onto pubic crest and lateral 2/3 attaches to inguinal ligament
What are the features of transversus abdominus?
Arches to insert onto pubic crest with internal oblique - CONJOINED TENDON - lateral 1/3 attaches to inguinal ligament
What is the midline muscle and what are its features?
- Rectus abdominus
- Wider as it ascends to attach to pec major
- Tendinous intersections at umbilicus, xiphoid and halfway between these points
- Enclosed within a sheath
What makes up the rectus sheath?
Upper - external and half of internal go anterior, half of internal and transversus go posterior
Lower - all 3 muscles layers are aponeurotic medially so this fascia goes across anteriorly, no posterior sheath
At what point does the lower part of the rectus sheath start?
Halfway between umbilicus and pubic crest
What muscle layers does the neuromuscular bundle run through?
Internal oblique and transversus abdominus
What arteries supply these muscles and what are they branches of?
Superior (internal thoracic), superficial (femoral) and inferior (external iliac) epigastric
What is the venous drainage of the abdomen?
Systemic and hepatic drainage
What are the extensions of the inguinal ligament?
Pectineal - along pectineal line
Lacunar - crescent shaped, inwards to pectineal line
Where do testes develop?
Extraperitoneal fat on posterior abdominal wall
When are testes in pelvis and when are they in the inguinal canal?
Week 12 and week 28
What is the pathway of the testes?
- Deficiency in transversus abdominus: deep inguinal ring
- arching fibres of internal and transversus
- along inguinal ligament
- Triangular opening in external oblique: superficial inguinal ring
- scrotum
What are the boundaries of the inguinal canal?
Floor- inguinal ligament
Roof - arching fibres of internal oblique and transversus abdomens
Anterior - external oblique and internal oblique
Posterior- transversalis fascia, conjoined tendon
What fascia is the spermatic cord encased in?
Internal (transversals fascia), cremasteric (cremaster muscle), external (aponeurosis of external oblique)
What is the function of the cremaster muscle?
Retract testes back into body
What causes a hernia?
Chronic intra-abdominal pressure, weakness in abdominal wall
What is a bilateral indirect inguinal hernia?
Protrusion through inguinal canal due to deficiency in fascia transversalis (congential abnormality - incomplete closure of pocket - processus vaginalis)
What is a bilateral direct inguinal hernia?
Due to weak abdominal wall muscles - pushing forward
