[Verse 1]
Male: Down in the right atrium, hidden in Koch's own triangle,
Female: the AV node waits there quiet, a patient little sentinel.
Male: The bundle of His comes threading through, piercing the septal wall,
Female: hugging the rim, posteroinferior, where the membranous parts grow small.
Both: Then it forks and rides the crest of muscle, splitting left from right,
sending the spark down both bundle branches, out of the surgeon's sight.
[Chorus]
Perimembranous, inlet too — you're living next to the wire,
one restless heartbeat from the axis, close enough to conspire.
Outlet, muscular, most of you — you're far off, out of range,
learn your neighbors' addresses well, they whisper what could change.
[Verse 2]
Female: The membranous septum's got two friends, aortic valve and tricuspid,
Male: the outlet septum courts a pair as well, pulmonary and aortic, half-forbidden.
Female: The inlet septum's greedy, holds both atrioventricular hands,
Male: mitral and tricuspid tangled tight where the inlet border stands.
[Chorus]
Perimembranous, inlet too — you're living next to the wire,
one restless heartbeat from the axis, close enough to conspire.
Outlet, muscular, most of you — you're far off, out of range,
learn your neighbors' addresses well, they whisper what could change.
[Bridge]
Vicinal — that's the word for neighbors standing near,
and vicinal things share their troubles, share the risk, share the fear.
A hole too close to His own bundle drags a heart block in its wake,
a defect nudging the aortic cusp lets the leaflet sag and shake.
Location isn't trivia here, it's prophecy in disguise —
where the opening sits in the septum is where the complication lies.
[Verse 3]
Male: So if the defect's perimembranous, watch the rhythm, watch it close,
Female: inlet holes recruit both valves, that's the risk that nobody knows.
Male: Outlet defects flirt with the aortic cusp, prolapse waiting to begin,
Female: muscular holes, tucked deep and safe, let the conduction axis win.
[Chorus]
Perimembranous, inlet too — you're living next to the wire,
one restless heartbeat from the axis, close enough to conspire.
Outlet, muscular, most of you — you're far off, out of range,
learn your neighbors' addresses well, they whisper what could change.
[Outro]
Both: Two critical neighbors, wire and valve, drawn on the septal map,
learn their names before you touch the wall, or you'll widen the wrong gap.
Vicinal, vicinal, close enough to matter,
know your neighbors well, before the axis starts to shatter.