Abdominal Regions & Anterolateral Abdominal Wall (Sloan)

How is the abdominal cavity divided into four quadrants?

The abdominal cavity is divided using a vertical median plane and a horizontal transumbilical plane.

These planes intersect at the umbilicus.

What organs are found in the Right Upper Quadrant (RUQ)?

The RUQ contains the liver (right lobe), gallbladder, right kidney, portions of the small intestine, and parts of the colon.

What organs are found in the Left Upper Quadrant (LUQ)?

The LUQ contains the left lobe of the liver, stomach, pancreas, left kidney, spleen, parts of the small intestine, and colon.

What organs are found in the Right Lower Quadrant (RLQ)?

The RLQ contains the appendix, cecum, right ovary (in females), right fallopian tube (in females), right ureter, and parts of the small intestine.

What organs are found in the Left Lower Quadrant (LLQ)?

The LLQ contains the left ovary (in females), left fallopian tube (in females), left ureter, parts of the small intestine, and parts of the colon.

What are the nine abdominal regions?

The nine abdominal regions are: Right Hypochondriac, Epigastric, Left Hypochondriac, Right Lumbar, Umbilical, Left Lumbar, Right Iliac, Hypogastric, and Left Iliac.

What organs are found in the Right Hypochondriac region?

The Right Hypochondriac region contains the liver, gallbladder, right kidney, and parts of the small intestine.

What organs are found in the Epigastric region?

The Epigastric region contains the stomach, liver, pancreas, duodenum, and parts of the large intestine.

What organs are found in the Left Hypochondriac region?

The Left Hypochondriac region contains the stomach, spleen, left kidney, pancreas, and parts of the colon.

What organs are found in the Right Lumbar region?

The Right Lumbar region contains the ascending colon, right kidney, and parts of the small intestine.

What organs are found in the Umbilical region?

The Umbilical region contains the small intestine and transverse colon.

What organs are found in the Left Lumbar region?

The Left Lumbar region contains the descending colon, left kidney, and parts of the small intestine.

What organs are found in the Right Iliac region?

The Right Iliac region contains the cecum, appendix, and right ovary (in females).

What organs are found in the Hypogastric region?

The Hypogastric region contains the bladder, parts of the small intestine, and reproductive organs.

What organs are found in the Left Iliac region?

The Left Iliac region contains the left ovary (in females), sigmoid colon, and parts of the small intestine.

What is the superior boundary of the abdominal wall?

The superior boundary of the abdominal wall is the costal

margin.

What is the inferior boundary of the abdominal wall?

The inferior boundary of the abdominal wall is the anterior superior iliac spine (ASIS), inguinal ligament, and pubic symphysis.

What is the lateral boundary of the abdominal wall?

The lateral boundary of the abdominal wall is the vertical line through the anterior superior iliac spine (ASIS).

Where is the xiphoid process located?

The xiphoid process is located at the inferior end of the sternum, around the T9 vertebra.

What is the iliac crest?

The iliac crest is the superior border of the iliac bone and is palpable on the hips.

What is the pubic symphysis?

The pubic symphysis is the joint between the left and right pubic bones in the pelvis.

Where is the anterior superior iliac spine (ASIS) located?

The ASIS is a prominent point on the iliac bone, just above the hip.

What are the major abdominal planes?

The major abdominal planes are: Xiphoid Process (T9), Transpyloric Plane (L1), Subcostal Plane (L3), Supracisternal Plane (L4), Transtubercular Plane (L5), Interspinous Plane (S2), and Midclavicular Line.

What are the functions of the abdominal wall muscles?

The functions of the abdominal wall muscles include supporting abdominal viscera, assisting in breathing, protecting internal organs, and aiding in posture and movement.

What is the role of the external oblique muscle?

The external oblique muscle is responsible for trunk rotation and compressing the abdomen.

What is the role of the internal oblique muscle?

The internal oblique muscle lies underneath the external oblique and assists in trunk rotation and abdominal compression.

What is the role of the transversus abdominis muscle?

The transversus abdominis is the deepest abdominal muscle and functions to compress the abdominal contents.

What is the role of the rectus abdominis muscle?

The rectus abdominis is located along the midline and functions to flex the vertebral column and compress the abdominal cavity.

What nerves innervate the muscles of the anterior abdominal wall?

The muscles are innervated by the lower six thoracoabdominal nerves (T7-T11), the subcostal nerve (T12), and the iliohypogastric and ilioinguinal nerves (L1).

What is the arcuate line?

The arcuate line is located approximately halfway between the umbilicus and the pubic symphysis. Below this line, the rectus sheath is incomplete, leaving the posterior surface of the rectus abdominis muscle in direct contact with the transversalis fascia.

What structures are associated with the arcuate line?

The arcuate line marks the point of transition where the aponeuroses of the abdominal muscles change, affecting the rectus sheath.

What is the function of the linea alba?

The linea alba is a dense band at the midline of the abdomen, acting as the attachment site for muscles.

What is the function of the linea semilunaris?

The linea semilunaris is a curved border along the lateral border of the rectus abdominis muscle.

What is the function of the inguinal ligament?

The inguinal ligament is a folded border of the external oblique muscle aponeurosis, extending between the ASIS and the pubic tubercle.

What is the role of the aponeuroses in the rectus sheath?

The aponeuroses that make up the rectus sheath are bilaminar, meaning each has both a posterior and anterior lamina. These aponeuroses enclose the rectus abdominis muscle.

What is the relationship between the diaphragm and its apertures?

Structures passing through the diaphragmatic apertures include the inferior vena cava (T8), esophagus (T10), aorta (T12), and various nerves. Compression of these structures can lead to problems with blood flow, breathing, and circulation.

What arteries supply blood to the diaphragm?

The diaphragm is supplied by the superior epigastric artery, superior phrenic arteries, musculophrenic and pericardiophrenic arteries, inferior epigastric artery, and inferior phrenic arteries.

What veins drain the diaphragm?

The diaphragm is drained by the phrenic veins, which empty into the inferior vena cava and internal thoracic vein.

What are the segments and ligaments of the diaphragm?

The diaphragm has muscular parts (sternal, costal, lumbar) and ligaments, including the medial and lateral arcuate ligaments.

What is the function of the diaphragm's crural openings?

The crural openings allow passage of the greater and lesser splanchnic nerves through the diaphragm.

What plane divides the abdominal cavity into right and left halves?

The vertical median plane divides the abdominal cavity into right and left halves.

At what vertebral level does the transumbilical plane pass through?

The transumbilical plane passes through the disc between L3 and L4 vertebrae.

What organs are found in the Left Iliac region?

The Left Iliac region contains the left ovary (in females), sigmoid colon, and parts of the small intestine.

What structures pass through the esophageal hiatus?

The esophageal hiatus allows passage of the esophagus, vagal trunks, and left gastric artery branches.

What is the location and function of the medial umbilical fold?

The medial umbilical fold contains the remnant of the umbilical arteries and covers the medial umbilical ligaments.

What is the function of the lateral umbilical fold?

The lateral umbilical fold covers the inferior epigastric vessels.

What structure is associated with the median umbilical fold?

The median umbilical fold contains the remnant of the urachus, which was a part of the prenatal drainage system for the bladder.

What is the function of the Colles' fascia?

Colles' fascia is a continuation of Scarpa’s fascia into the perineum and is associated with the scrotum.

What is the relationship between the arcuate line and the rectus abdominis muscle?

Below the arcuate line, the rectus sheath is incomplete, and the posterior surface of the rectus abdominis muscle is in direct contact with the transversalis fascia.

How do the aponeuroses of the abdominal muscles contribute to the formation of the rectus sheath?

The aponeuroses of the abdominal muscles, including those of the external oblique, internal oblique, and transversus abdominis, create the rectus sheath by encasing the rectus abdominis muscle.

What is the role of the transversalis fascia in the abdominal wall?

The transversalis fascia covers the inner surface of the deepest muscle layer of the abdominal wall, including the rectus abdominis muscle.

What is the purpose of the linea semilunaris?

The linea semilunaris marks the curved lateral border of the rectus abdominis muscle and serves as an attachment point for certain abdominal muscles.

What is the relationship between the right and left crura of the diaphragm?

The right crus of the diaphragm is larger and is pierced by the esophagus, while the left crus arises from the L1-L3 vertebrae and is smaller. The crura are united by the median arcuate ligament.

How does the diaphragm contribute to breathing?

The diaphragm contracts and moves downward during inspiration, increasing the thoracic cavity volume and facilitating air intake.

What muscles form the diaphragm’s costal part?

The diaphragm’s costal part attaches to the 6th costal cartilage and originates from the ribs.

What arteries supply the diaphragm’s peripheral parts?

The diaphragm’s peripheral parts are supplied by the intercostal branches and the inferior phrenic arteries.

How is the inferior epigastric artery related to the abdominal wall?

The inferior epigastric artery originates from the external iliac artery and runs deep to the inguinal ligament, supplying the abdominal wall below the umbilicus.

What is the significance of the phrenic veins in the venous return from the diaphragm?

The phrenic veins drain the diaphragm and empty into the inferior vena cava and the internal thoracic vein, playing a critical role in venous return from the diaphragm.

What structures are associated with the inguinal fossa?

The inguinal fossa is the location where the inguinal canal passes through the abdominal wall, providing a pathway for structures such as the spermatic cord or round ligament.

How does the linea alba contribute to abdominal muscle function?

The linea alba serves as the midline attachment site for abdominal muscles, providing structural integrity and aiding in force transfer during muscle contraction.

What are the structural components of the diaphragm’s lumbar part?

The lumbar (crural) part of the diaphragm attaches to the lumbar vertebral bodies and includes the right and left crura.

What is the function of the lateral arcuate ligament in the diaphragm?

The lateral arcuate ligament forms the passage for the quadratus lumborum fascia from the L1 transverse process to the 12th rib.

How does the superior epigastric artery contribute to the abdominal wall's blood supply?

The superior epigastric artery is a continuation of the internal thoracic artery, running deep to the rectus abdominis muscle and anastomosing with the inferior epigastric artery.

What is the clinical significance of the inguinal ligament?

The inguinal ligament serves as a structural boundary for the inguinal canal and is important in surgeries and conditions such as hernias.

What role does the iliac crest play in abdominal and pelvic anatomy?

The iliac crest is the superior border of the iliac bone, and it serves as a key landmark for locating certain abdominal and pelvic structures.

How does the inferior phrenic artery contribute to the diaphragm’s vascularization?

The inferior phrenic artery originates from the abdominal aorta and supplies blood to the diaphragm, especially to its peripheral regions.

What is the anatomical significance of the supracisternal plane?

The supracisternal plane is located at the L4 level and provides a horizontal reference for the upper abdominal structures, helping to locate certain organs and vascular structures.

What muscles are responsible for the compression of the abdominal contents?

The external oblique, internal oblique, and transversus abdominis muscles are responsible for compressing the abdominal contents.

How does the subcostal plane relate to abdominal organ positioning?

The subcostal plane is a horizontal plane just below the costal margin (L3) and helps in the identification and positioning of the abdominal organs.

What is the significance of the interspinous plane in abdominal anatomy?

The interspinous plane is located at the S2 level and helps in identifying the lower part of the abdomen, providing a reference for structures like the pelvic organs.

What is the function of the superior phrenic arteries?

The superior phrenic arteries branch from the descending aorta and supply blood to the superior portion of the diaphragm.

What is the anatomical importance of the right and left crus of the diaphragm?

The right crus is larger and pierced by the esophagus, while the left crus is smaller and arises from the L1-L3 vertebrae. Both crura contribute to the diaphragm’s function and form part of the diaphragm’s muscular structure.

How is the diaphragm involved in the mechanics of respiration?

During inhalation, the diaphragm contracts and descends, increasing thoracic volume and facilitating the inflow of air. During exhalation, it relaxes and ascends, aiding in expelling air.