Surface anatomy – know your landmarks!

Surface anatomy is key to examination, especially when it comes to percussion and auscultation. Here are some of the major landmarks to guide your examinations:

Heart:

• The apex of the heart is in the mid-clavicular line, 5th intercostal space. This is where the tricuspid valve is best auscultated
• The mitral valve should be auscultated at the lower left sternal edge, medial to the apex in the 5th intercostal space
• The pulmonary valve can auscultated just lateral to the sternum in the left 2nd intercostal space
• The aortic valve should be auscultated just lateral to the sternum in the right 2nd intercostal space

Lung borders:

• The apices of the lungs extend 3cm above the mid clavicular point
• In quiet respiration, the inferior margin of the lungs are:
  • T6 (midclavicular)
  • T8 (midaxillary)
  • T10 posteriorly (median plane)
• Pleura surface markings two ribs lower

Lung Fissures: 

• Oblique fissure – T3 to 6th costochondral junction
• Horizontal fissure – from the oblique fissure in the mid-axillary line to the 4th costal cartilage

Spleen:

• Marked on left side of the back, with its long axis corresponding with that of 10th rib
• Upper border corresponds to upper border of 9th rib & lower border to lower border of 11th rib

Liver:

• The upper surface of the liver is percussed at the level of the fifth intercostal space
• Lower border is the costal margin

Kidneys:

• Posteriorly: T11-L3 (Right lower than left)

Why look for JVP in an abdominal exam?

Looking for a raised jugular venous pressure is normally reserved for cardiac and respiratory examinations. A raised JVP is a sign of venous hypertension and most commonly manifests in the context of heart failure when the right side of the heart is unable to cope with venous return from the systemic circulation. The subsequent back-up manifests in a visible internal jugular vein.

However, it is also worth looking for an elevated JVP in an abdominal exam for both common and rare causes:

1. Portopulmonary hypertension. This is the simultaneous co-existance of high blood pressure in both the portal circulation and the pulmonary circulation. It is a complication of liver cirrhosis and occurs in up to 4% of cirrhotic patients.
2. Carcinoid of the gastrointestinal tract. This is caused by neuroendocrine tumours arising from enterochromaffin cells of luminal epithelia throughout the gut
3. Congestive hepatopathy. Also called cardiac cirrhosis, this is deranged liver function in the setting of right heart failure. Increased pressure in the hepatic veins (secondary to right heart failure) causes necrosis of the liver lobules. This post’s image demonstrates the congested and fibrotic change that occurs histologically in congestive hepatopathy.

Quick tip: palpating for a liver edge

The upper surface of the liver is at the level of the fifth intercostal space on the right side and the lower border is at the costal margin. Therefore in healthy adults you often cannot palpate a liver edge.

The liver should always be palpated on inspiration to maximise the potential for a normal or pathological liver edge to be felt. Because the liver is situated just under the diaphragm, the liver will move inferiorly on inspiration as the diaphragm contracts and moves down itself.

Always palpate from the right iliac fossa up to the costal margin. Place your hand lightly on the patient’s abdomen and ask your patient to take deep breaths in and out. Palpate more firmly as your patient breathes in and attempt to feel the liver edge.

What is colic?

Colic is a form of pain, characterised by intense episodes that start and stop abruptly. It occurs when a muscular tube contracts against an obstruction from within the lumen.

The frequency of the fluctuations in pain can help us determine the anatomical location of the obstruction.

• Renal: The smooth-muscle layer in the distal one third of the ureters contracts at a frequency of 3 per minute.
  • Thus, renal colic is characterised by extreme loin pain with frequent fluctuations in intensity.

• Biliary: Neither the cystic duct nor the common bile duct has peristaltic motility however, the post-prandial gall bladder will contract at a frequency of 3 per hour.
  • Thus, biliary colic is characterised by intense, spasmodic pain every 10-20 minutes until a steady state of dull, aching pain in the upper right quadrant after approximately one hour.

• Gastrointestinal: Perstalsis in the gut varies along its length (stomach 3/min, duodenum 12/min, ileum 9/min) but contractions last a few minutes per 10-20cm segment.
  • Thus, bowel colic tends to be cramping in nature and lasts 2-3 minutes. This is a true colic as there is no pain between episodes.