Lecture 10: Anterior Abdominal Wall & Inguinal Region Flashcards
What are the layers of the antero lateral abdominal wall?
Parietal peritoneum Extraperitoneal fascia Transversalis fascia Transversus abdominis muscle Internal oblique muscle External oblique muscle Scarpa's fascia Camper's fascia Skin
What is the linea alba?
Where the muscles interdigitate along the midline
What is the bony framework (muscle attachments) of the abdomen?
Costal margin
Iliac crest
ASIS
Pubic tubercle
What is the most superficial anterior abdominal wall muscle?
External oblique “front pockets”
Overlaps the costal margin, pec major, serratus anterior and ribs anterolaterally
Has a free inferior edge = inguinal ligament
Extends ASIS to pubic tubercle with an opening (superficial/external inguinal ring)
What is the intermediate anterior abdominal wall muscle?
Internal oblique “back pockets”
Lowermost fibres arise from lateral 2/3 of inguinal ligament
Arch up, over and down to insert into public crest
Attaches:
Costal margin - lateral/above
Thoracolumbar fascia - behind
Linea alba - middle
What is the deepest anterior abdominal wall muscle?
Transversus abdominus
Horizontally orientated fibres
Continuous with the muscular diaphragm, under lapping internal costal margin
Lowermost fibres arise from lateral 1/3 of inguinal ligament, arching to insert into the pubic crest via conjoined tendon with internal oblique
Where does rectus abdominis attach?
5, 6, 7, costal cartilage
Three tendinitis intersections
Gets wider as it goes up and overlaps costal margin
What is the formation of the abdominal muscles in the upper rectus sheath?
External oblique (in front of rectus abdominis)
Internal oblique (splits around rectus abdominis, half in front/half behind)
Transversus abdominis (behind rectus abdominis)
Transversalis fascia
Parietal peritoneum
What is the formation of the abdominal muscles in the lower rectus sheath?
External and internal obliques (in front of rectus abdominis)
Transversus abdominis (behind rectus abdominis)
Transversalis fascia
Parietal peritoneum
What are the arteries of the anterior abdominal wall?
Internal thoracic -> gives off Superior epigastric and musculophrenic artery
External iliac -> gives off Inferior epigastric
Superficial epigastric runs in subcutaneous tissue
Where do the superior and inferior epigastric arteries anastomose?
Both run in the rectus sheath, deep to the rectus abdominis
Anastomose in rectus abdominis
What is the arcuate line?
A horizontal line that demarcates the lower limit of the back layer of the rectus sheath.
Where the inferior epigastric vessels perforate the rectus abdominis.
Occurs about 1/3 of the distance from the umbilicus to the pubic crest (variable)
What layer of muscle are the nerves of the anterior abdominal wall found?
Between the intermediate and deep layers
Between internal oblique and transversus abdominals
What is the venous drainage from the anterior abdominal wall?
Superficial veins in fascia Deep veins follow arteries Dual venous drainage: IVC - systemic Portal Overlap , can go to either
What is the pectineal ligament?
Linear extension along the pectineal
What is the lacunar ligament?
Medial extension of the inguinal ligament
Reflects onto pectineal line of the pubic bone
What is the deep inguinal ring?
Hole/deficiency half way between the ASIS and pubic tubercle
Mid point of the inguinal ligament
What are the boundaries of the inguinal canal?
Floor: inguinal
Roof: arching fibres of internal oblique and transversus abdominus
Anterior wall: external oblique aponeurosis and internal oblique muscle (lat)
Posterior wall: transversalis fascia and conjoint tendon (medial)
What are the 3 layers surrounding the spermatic cord?
Internal spermatic fascia
Cremasteric muscle fibres (fascia) -cold water
External spermatic fascia (external oblique)
What is an abdominal wall hernia?
Protrusion of abdominal contents through abdominal wall
Where are the areas of weakness where an abdominal wall hernia can occur?
Linea alba
Umbilical
Linear semilunaris
What is the inguinal ligament?
Folded inferiori border of external oblique aponeurosis extending between ASIS and pubic tubercle
What is the superficial inguinal ring?
Medial opening in the external oblique aponeurosis
What is a bilateral indirect inguinal hernia?
Protrusion through the deep ring into the inguinal canal
Into scrotum
What does an indirect hernia arise from?
Incomplete closure of the processus vaginalis, weak arching fibres of transversus abdominal & internal oblique, ilioguinal nerve L1, hence the herniated peritoneal contents extend into the scrotum (or labia)
Pulls peritoneum with it
What is a bilateral direct inguinal herniae?
A protrusion forwards into the inguinal canal through an area of weakness in its posterior wall Bulges only, doesn't transverse Exploits inguinal (hesselbach's) triangle
