pt 2- transverse sectional of body

Foundational Principles for Sonographic Sectional Anatomy

• Ultrasound cross-sectional imaging demands a dual command of gross anatomy (three-dimensional organ form) and sectional anatomy (appearance in any imaging plane).
  • The sonographer must evaluate relationships (organ–organ, organ–vessel, peritoneal reflections) rather than rely on rote memorisation of “textbook positions.”
  • Anatomical variants (accessory hepatic lobes, aberrant renal arteries, duplicated IVC, wandering spleen, etc.) are common; real-time scanning requires flexible pattern recognition.
  • Orientation pearls:
  • Transverse images are presented as if viewed from the foot-end: patient’s right on the left of the screen, anterior at the top.
  • Vascular flow direction, ligament attachments, and adjacent viscera are the quickest cues for confirming level.

Transverse Plane – Dome of the Liver & Sub-Diaphragmatic Structures

• Key soft-tissue / peritoneal landmarks:
  • Right & left hemidiaphragms hug the hepatic dome; the falciform ligament (FL) passes superiorly into the diaphragm, anchoring the anterior liver surface.
  • Liver parenchyma may extend to the left mammillary line – do not mistake this normal variant for hepatomegaly.
  • Pleural cavity / pleural sacs superior-posterior to liver; simple pleural effusion may mimic sub-phrenic free fluid in FAST scans.
• Splenic hilum:
  • Splenic artery (SA) enters and splenic vein (SV) exits at the same hilum – a classic arterial-venous crossover frequently visible in coronal reconstructions.
• Abdominal oesophagus sits left of midline, terminating at the cardiac orifice of the stomach.

Transverse Plane – Caudate Lobe Level

• Structural relationships
  • Caudate lobe lies anterior to the inferior vena cava (IVC) and is delineated by the ligamentum venosum (LV).
  • Right hepatic vein (RHV) empties into the lateral wall of the IVC – a valuable landmark when sweeping cranio-caudally.
  • Fundus of the stomach visualised; bordered by the hepatogastric and gastrocolic ligaments.
  • The lesser sac / omental bursa always lies posterior to stomach and anterior to pancreas—a potential space for pseudocysts.
  • Body & tail of pancreas approach the splenic hilum; watch for isoechoic pancreatic tail masquerading as splenic tissue.
  • Adrenal glands lateral to the crura of the diaphragm; right adrenal may be obscured by IVC gas artefact.

Transverse Plane – Celiac Axis (CA) Section

• Vascular trifurcation:
  • Celiac axis (CA) branches into left gastric artery (LGA), splenic artery (SA), and common hepatic artery (CHA) almost immediately after arising anteriorly from the aorta (AO).
  • Sonographic signature: "seagull sign"—splenic artery to patient’s right, CHA to patient’s left, CA trunk resembling the bird’s body.
• Surrounding viscera:
  • Body of pancreas sits anterior to splenic vein but posterior to the stomach.
  • Transverse & descending colons rest inferior to the splenic flexure at this slice.
• Retroperitoneal–peritoneal reference points:
  • IVC is anterior to the crus; aorta remains posterior—helpful in differentiating lymphadenopathy from vascular pathology.
  • Kidneys + adrenal glands lie lateral to spine & crura.

Transverse Plane – Superior Mesenteric Artery (SMA) & Pancreas

• Musculoskeletal framing:
  • Psoas major muscles border the lumbar spine laterally.
• Renal / vascular cross-over:
  • Right renal artery (RRA) courses posterior to IVC.
  • Left renal artery (LRA) originates from the left posterolateral aortic wall.
  • Renal veins lie inferior to their corresponding arteries; left renal vein traverses anterior to the aorta.
• Splanchnic convergence:
  • Portal confluence (