Heart Location: Anatomy and Position in the Human Body

The heart lies in the middle mediastinum, within the thoracic cavity, slightly left of midline.

Anatomical Landmarks

• Borders:
  • Right: Right atrium (3rd–6th costal cartilages).
  • Left: Left ventricle (apex at 5th ICS, midclavicular line).
  • Superior: Great vessels base (2nd intercostal space).
  • Inferior: Diaphragm (RV rests on it).
• Relations:
  • Anterior: Sternum, costal cartilages, thymus (in children).
  • Posterior: Esophagus, descending aorta, thoracic vertebrae.
  • Lateral: Lungs (mediastinal surface), phrenic nerves.
• Orientation: Rotated ~45°; base posterior/superior, apex anterior/inferior/left.

Size & Weight

• Size: ~clenched fist (12×8×6 cm).
• Weight: 250–350 g (men), 200–300 g (women). Athlete's heart: larger.

Clinical Surface Projections

• Apex Beat: 5th ICS, 8–9 cm from midsternal line (midclavicular). Palpable PMI.
• Base: 2nd ICS, parasternal (aortic/pulmonic areas).
• Tricuspid Area: 4th–5th ICS, left sternal border.
• Mitral Area: Apex.

Imaging

CXR: cardiothoracic ratio <0.5. Echo: chamber quantification. CT/MRI: 3D anatomy, great vessels.