Introduction to the Abdomen and Inguinal Canal Flashcards
Name the nine abdominal regions
- Epigastric Region
- Right and Left Hyperchondriac Region
- Right and Left Lumbar Region (Right and Left Lateral Regions)
- Right and Left Iliac Region (Right and Left Inguinal Regions)
- Hypogastric Region (Pubic Region)
- Umbilical Region
Organs within the Left Hypochondraic Region
o Spleen, stomach, splenic flexure of the colon, tail of pancreas, may have extension of liver
Organs within the Right Hypochondriac Region
o Liver and Gallbladder
Organs within the Epigastric Region
o Liver, stomach, body of pancreas, oesophagus, abdominal aorta, IVC
Organs within the Right Lumbar Lateral Region
o Right kidney, right suprarenal gland, hepatic flexure of colon, ascending colon
Organs within the Umbilical Region
o Duodenum, jejunum, head of pancreas, abdominal aorta, IVC, Stomach, transverse colon
Organs within the Left Lumbar Region
o Left kidney, Left Suprarenal Gland, descending colon
Organs within the Right Iliac/Inguinal Region
o Caecum, Vermiform appendix, ileum
Organs within the Hypogastric/Pubic Region
o Sigmoid Colon, rectum, urinary bladder (when distended), ileum
Organs within the Left Iliac/Inguinal Region
o Sigmoid Colon
How to Identify the Transpyloric Plane
Find the Superior Landmark
Jugular Notch of the Manubrium
Find the Inferior Landmark
Pubic Symphysis
Midpoint between these two landmarks (approx. L1 vertebrae) is the location of the horizontal plane
What does the Transpyloric Plane pass through
Passes through L1, the pyloris of the stomach, neck of the pancreas, the gall bladder, and the hepatic portal vein
How to Identify the Transtubercular Plane
Estimate position of the tubercle of the right and left iliac crests
Draw a horizontal line between the two points passing through L5
What does the Transtubercular Plane pass through
Passes through L5 and the tubercles of the iliac crest
How to Identify the Midclavicular Plane
Find the Superior Landmark
Midpoint of the Clavicle
Find the Inferior Landmark
Midinguinal Point
Midpoint between the ASIS and the Pubic Symphysis
How to Identify the Subcostal Plane
Palpate and locate the most inferior region of the Right and Left Costal Margins
What are the Quadrants of the Abdominal Regions
- Right and Left Upper Quadrant
* Right and Left Lower Quadrants
What are the Quadrants of the Abdominal Regions separated by?
• Divided by a midsagittal plane and a transumbilical plane passing through the umbilical
What are the lines of division of the abdominal regions?
• Paired vertical right and left midclavicular planes and two horizontal planes
Peritoneal Cavity
- Consists of organs located within the abdomen
- Cavity is lined with parietal peritoneum
- Superficial organ surfaces are lined with visceral peritoneum
Superior and Inferior Border of the Peritoneal Cavity
- Superior Boundary – Thoracic Diaphragm
- Inferior Boundary – Imaginary plane dividing the abdomen from the pelvis through the superior pelvic aperture (at the pelvic brim)
Classification of Abdominopelvic Organs
• Abdominopelvic organs are classified as either extraperitoneal or intraperitoneal
Extraperitoneal Organ
o Located along the walls of the abdomen and pelvis
o Majority are located posteriorly are referred to as retroperitoneal organs
Extraperitoneal Organ Examples
o Urinary Bladder – Located on the anterior pelvic wall
Intraperitoneal Organs
o Suspended inside the peritoneal cavity by peritoneal folds such as the jejunum and liver
Skeletal Structures of the Abdominal Wall
- Inferior Thoracic Cage
- Hip Bones
- Pelvic Brim/Superior Pelvic Aperture (of lesser or true pelvis)
- Lumbar Vertebrae
Due to the lack of skeletal protections in the anterolateral abdominal wall, the anterolateral abdominal muscles from strong expandable support for this region
Boundaries of the Anterolateral Abdominal Wall
- Xiphisternum
- Costal Margins
- Hip Bones
- Inguinal Ligament
What are the Hip Bones and Important Landmarks?
o Iliac Crest, ASIS, Pubic Tubercle, Pubic Crest, Pubic Symphysis
What is the Inguinal Ligament attached to?
o Attaches to the Pubic Tubercle
Rectus Abdominis
o Divided into differing sections
o Surrounded by a CT sheath – Rectus Sheath
Three Muscles Compose the Anterolateral Abdominal Wall
o External Oblique Abdominis, Internal Oblique Abdominis, Transversus Abdominis
External Oblique Abdominis: Direction of Fibres
Fibres run in an inferomedial direction
Internal Oblique Abdominis: Location and Direction of Fibres
Deep to the External Oblique Abdominis
Fibres run in a superomedial direction
Transversus Abdominis: Location and Direction of Fibres
Muscle fibres run horizontally
Deep to the Internal Oblique Abdominus
Linea Alba: Location and what does it form?
o Located between the Rectus Abdominis muscles
o Forms a vertical line which runs down the midline of the abdomen
Tendinous Intersections
o Separate the rectus abdominus muscles
o Seen on the surface of the skin
Supportive Structures of the Abdominal Wall
o Transversalis Fascia
o Parietal Peritoneum
o Extraperitoneal Fat
o Inguinal Ligament
Supportive Structures of the Abdominal Wall: Inguinal Ligament
CT layer which attaches to the anterior superior iliac spine and the pubic tubercle
Forms a surface landmark – inguinal groove
What does the Inguinal Canal Pass Through?
o Passes through the three muscle layers, transversalis fascia, parietal peritoneum and extraperitoneal fat
o Approximately 4cm long
Opening of the Deep Inguinal Ring
Opening in the deep abdominal wall
Superficial Inguinal Ring
Exit from the inguinal canal
Inferomedial opening in aponeurosis of external obliquus abdominis (superolateral to the pubic tubercle)
Triangular shaped
Major Structures in the Male Inguinal Canal
Ductus Deferens, Testicular blood vessels, Spermatic Cord
Male Inguinal Canal from Superficial to Deep
- Superficial inguinal ring with aponeurosis of external obliquus abdominis
- Belly of internal obliquus abdominis
- Belly and aponeurosis of transversus abdominis
- Deep inguinal ring with transversalis fascia
Female Inguinal Canal
Shorter than male inguinal canal
Round ligament of the uterus, fat pad, blood vessels and nerves
Inguinal Hernia
- Protrusion or passage of a peritoneal sac, with or without abdominal contents, through a weakened part of abdominal wall of inguinal region/groin
- More common in males due to the larger size of the inguinal canal
Two Types of Inguinal Hernia
Direct or Indirect
Direct Inguinal Hernia
o Through peritoneum and transversalis fascia in posterior wall of inguinal canal
o Does not use deep inguinal ring
o 25-33% incidence
o Only traverses medial 1/3 of inguinal canal
o Rarely enters scrotum
Indirect Inguinal Hernia
o Through deep inguinal ring
o 66-75% incidence
o Transverses entire inguinal canal
o Exits through superficial inguinal ring inside spermatic cord
o Commonly enters scrotum
Psoas Major
o Attaches to the bodies of vertebrae T12-L5 superior and the lesser trochanter of the femur inferiorly
o In the posterior abdominal wall
Iliacus
o Within the iliac fossa in the posterior abdominal wall
Iliopsoas
o When the iliacus muscle joins the psoas major and passes into the thigh, the combined muscles are referred to as the iliopsoas muscle
o In the posterior abdominal wall
quadratus lumborum
o Square shaped muscle attaching to the 12th rib and the iliac crest
o in the posterior abdominal wall