▌ Cardiac Codex
CARDIAC CODEX / GLOSSARY / RCES

Fossa Ovalis

An EP Anatomy & the Conduction System term on the RCES exam blueprint, defined for cath lab and EP clinicians.

The thin, fibrous floor region of the 'true' interatrial septum, formed by fusion of the septum primum and septum secundum, and the target site for transseptal puncture; puncturing outside this true septum risks extracardiac perforation and tamponade.

Right and left atria separated by the interatrial septum with the fossa ovalis marked as the thin fibrous floor formed by fusion of the septum primum and septum secundum — the target site for transseptal puncture.
The true interatrial septum — and why transseptal puncture must land inside it.

Domain: EP Anatomy & the Conduction System · Blueprint: RCES exam guide

Related RCES terms

Kent Bundle (Accessory Pathway) Left Bundle Branch Area Pacing (LBBAP) Membranous Septum Subclavian Crush Syndrome Vein of Marshall (Ligament of Marshall)

Study RCES terms in context

Cardiac Codex turns definitions like this into a full study system: 179 lessons, 2,198 practice questions with explanations, four blueprint-matched full-length mock exams, live and timed, and Cardiac Coach — an AI tutor grounded in this exact glossary you can ask from any lesson.

Start free Back to the glossary →
Written and reviewed by John-Philip (JP) Maarschalk, BSN, RN, CNML — a nurse manager who runs operations for the cardiac cath lab, electrophysiology, and interventional service lines at an academic health system in North Carolina. He hires and develops the staff who sit for these exams. More about JP and how this content is made →
Cardiac Codex is an independent study tool published by MdoubleA LLC, not affiliated with or endorsed by CCI or any certifying body. This glossary entry is exam-preparation information, not medical advice or a substitute for clinical judgment. Always verify current clinical practice against primary sources and institutional protocol.