Cardiac Anatomy

Question 1

What structure occupies the central portion of the heart and is wedged between all 3 other valves?

Answer 1

Aortic valve

Question 2

Which AV cusp has fibrous continuity with the anterior leaflet of the mitral valve

Answer 2

Non-coronary cusp

Question 3

Anatomic orientation of the AV groove

Answer 3

Obliquely oriented closer to vertical than horizontal

Question 4

Two pericardial recesses

Answer 4

1. Transverse sinus
   
   1. Anterior boarder: posterior surface of aorta/PA
   2. Posterior boarder: interatrial groove
2. Oblique sinus
   
   1. Behind LA (between IVC and Pulmonary veins)

Question 5

Location of phrenic nerve in mediastinum

Answer 5

• Descends anterior to the anterior scalene muscle (posterior to IMA)
• Passes anterior to the pulmonary hilum
• Left phrenic: attached to the lateral aspect of persistent Left SVC
• Right phrneic: attached to the lateral aspect of SVC

Question 6

Anatomy of vagus nerve in mediastinum

Answer 6

• Courses along carotid arteries and enters thorax posterior to phrenic.
• Descends posterior to pulmonary hilum (phrenic is anterior)
• Left vagus: descends btw LCCA and LSCA (posterior to Ao Arch), left RLN hooks anterior around ligamentum arteriosum and ascends in TE groove.
• Right vagus: right RLN hooks under RSCA artery anteriorly and ascends in the TE groove

Question 7

Coronary arteries arise from what structures

Answer 7

Sinuses of Valsalva

Question 8

Coronary artery dominance defined by what?

Answer 8

Supply of PDA

(RCA 85% of cases)

Question 9

Anatomy of Left Main Coronary Artery (LMCA)

Answer 9

• Arises from left Sinus of Valsalva
• Courses behind PA and anterior to LA appendage
• Bifurcates into: LAD and LCx
  
  • Trifurcates: LAD, Ramus and OM

Question 10

Anatomy of LAD

Answer 10

• Courses along interventricular groove towards cardiac apex
• Branches:
  
  • Septal perforators (dive perpendicularly into septum)
  • Diagonals (course over LV anterior wall)
  • RV branches (course to the RV anterior wall)

Question 11

Anatomy of Circumflex Coronary Artery

Answer 11

• Travels in left AV groove (ends near obtuse margin of LV)
• In Left Dominant circulation, continues in AV groove to supply PDA (10-15%)
• Branches:
  
  • Obtuse marginals (OM): supply lateral wall of LV and posteromedial PM
  • Sinoatrial (SA) node branch: 50% of population

Question 12

Anatomy of RCA

Answer 12

• Arises from right Sinus of Valsalva
• Course: anterior to Ao and descends in right AV groove
• Branches:
  
  • Conal branch: 1st branch, courses left of infundibulum
  • Acute marginals: supply anterior RV free wall
    
    • May continue across diaphragmatic surface to supply distal interventricular septum (10-15% pop)
  • Bifucates:
    
    • Posterior Descending Artery (PDA)
    • Right posterolateral artery (a.k.a. posterolateral ventricular branch [PLVB])

Question 13

Anatomy of PDA

Answer 13

• Courses along interventricular groove towards apex
• Septal perforators (posteror 1/3 of septum)

Question 14

Anatomy of PLVB

Answer 14

Provides branches to posterior wall of LV

Question 15

Venous drainage of heart

Answer 15

• Coronary sinus: 85% of coronary blood flow
• Thebesian veins: 15% of coronary blood flow (directly into RA/RV)
• Anterior interventricular vein: analog to LAD
• Great cardiac vein: travels in AV groove and turns into coronary sinus
• Posterior interventricular vein: analog to PDA
  
  • Last tributary and drains near the coronary sinus orifice
    
    • Explains why RV protection from retrograde cardioplegia can be marginal as cannula is usually inserted beyond entry point of vein.
• Anterior RV veins: form small cardiac vein (right AV groove); drain into CS or RA

Question 16

Anatomy of Persistent Left SVC

Answer 16

• Usually drains into coronary sinus
• Ineffective to adminster retrograde cardioplegia unless LSVC is occluded and flow diverted.

Question 17

Anatomy of SA Node

Answer 17

• Junction of RA and SVC (between RA appendage and SVC)
• Horeshoe SA node: draped along SVC/RA junction (10% of patients)

Question 18

Anatomy of fossa ovalis

Answer 18

• True intra-atrial septum
• Location where LA should be entered for transseptal approach
• Location of PFO

Question 19

Thebesian valve

Answer 19

Valve of coronary sinus

Question 20

Eustachian valve

Answer 20

Valve of IVC

Question 21

Tendon of Todaro

Answer 21

Continuation of Thebesian valve to the Eustacian valve

Question 22

Important structure lying within Triangle of Koch

Answer 22

AV node

Question 23

Boundaries of Triangle Koch

Answer 23

1. Tendon of Todaro
2. Orifice of Coronary Sinus
3. Septal leaflet of TV

Question 24

Anatomic structure located at apex of Triangle of Koch

Answer 24

Bundle of His (prior to branching on the interventricular septum)

Question 25

Crista terminalis

Answer 25

Confluence of trabeculated RA muscle into a well defined muscle band.

Question 26

Anatomy of Tricuspid Valve

Answer 26

* Leaflets: * Anterior * Septal * Inferior * Continutiy with fibrous skelaton of heart * Does not have true fibrous annulus circumferentially

Question 27

Important anatomic relationships with Tricuspid Valve

Answer 27

* AV node located at base of septal leaflet * Aortic valve near junction of septal and anterior leaflets

Question 28

Surgical access to Left Atrium

Answer 28

* Anterior to right pulmonary veins (Sondargaard's groove) * An incision in LA dome * Often involves transecting the SVC * Transseptal approach via RA (fossa ovalis)

Question 29

Anatomy of Mitral Valve

Answer 29

* Leaflets: * Anterior (A1, A2, A3) * Fibrous continuity with non-coronary cusp of AV * Anterior in surgeons view * Covers 1/2 of annular circumference * Longer leaflet * Posterior (P1, P2, P3) * Covers 2/3 of annulus but is short with respect to dept of orifice coverage * Carpentier segments: * A1 and P1 most medial (to left in surgeons view)

Question 30

Important anatomic relationships to the mitral annulus/valve

Answer 30

* Left side of posterior annulus (P1): circumflex artery * Right side of posterior annulus (P2/P3): coronary sinus * A3 segment: AV node

Question 31

Anatomy of right and left fibrous trigones

Answer 31

* Dense collagenous tissue * Locations: 10 o-clock and 2 o-clock positions on the annulus * Anteror to the valve commisures

Question 32

Anatomy of RVOT

Answer 32

* Infundibulum * Pulmonic valve (tricuspid) * No fibrous annulus (suspended in muscle) * Only valve **not connected to fibrous skelaton** of heart

Question 33

RV papillary muscle anatomy

Answer 33

* Anteror PPM * Medial PPM * Suspend the Tricuspid Valve

Question 34

Anatomy of LV

Answer 34

* Inflow: Mitral valve and subvalvular apparatus * LVOT: * Mitral-Aortic curtain: * fibrous sheet extending from the anterior leaflet of MV to mitral-aortic continutiy supporting the left and non-coronary leaflets of the AV * Left bundle branch: * enters LVOT posterior to membranous septum (**between right and non-coronary AV cusps**)

Question 35

Anatomy of Aortic Valve

Answer 35

* Sinuses of Valsalva/AV Leaflets: * Right * Left * Non-coronary * Nodule of Arantius: thickened nodule, centrally located on each leaflet at point of coaptation.

Question 36

Definition of Aortic Root

Answer 36

* Aortic annulus * AV leaflets * Sinus of Valsalva * Sinotubular junction * Junction at top of commissures * Point where the sinuses neck down to form the tubular Asc Ao.

Question 37

Posteromedial papillary muscle blood supply

Answer 37

RCA (90%)

Question 38

Anterolateral papillary muscle blood supply

Answer 38

LAD and Cx

Question 39

Average distance from the tips of each papillary muscle to the nearest trigone

Answer 39

~ 23 mm