This document summarizes the key steps and techniques for dissecting the heart and spinal cord during an autopsy. It provides details on the recommended methods for removing and examining the heart, including evaluating the coronary arteries and measuring the heart. For the spinal cord, it describes the anterior, posterior and combined approaches for dissection. Recommendations are provided for demonstrating various pathologies.

1. 12-06-2066
Autopsy dissection of
the Heart and the
Spinal cord
Dr. Rijen Shrestha
M.D. Resident
Dept. of Forensic Medicine

2.  references: ludwig for heart
anatomy books by foreign authors(no names included)
spinal and scrotum -gresham and turner +ludwigs dissection
techniques
 recommendations given after presentation:
short pause between change of slides, more details on layers
of scrotum and heading as dissection of spinal cord and not
vertebral column..
 heart dissection can be tried or practiced by u..but sudnt
forget the names..in regular autopsy..
THign learnt: myocardium dissection sud not be done like we
do in there..whole myocardium sud be subjected to rule out
artifects produced by formaldehyde to middle layer of
myocardium.

3. Dissection of heart
 Removal of heart:
-chest plate
Heart -thoracic bloc:
pericardial adhesion, previous h/o open heart
surgery, pericarditis, congenital cardiac disease,
esophageal/pulmonary carcinoma, aortic dissection ,
injuries to heart (tamponade).
Heart- removed separately
acquired diseases , no adhesions or injuries to
heart.

4. Color of myocardium:
Gray : old infarct
Pale : anemic
Mottled/hemorrhagic spots: acute
infarct/rupture
Shape:
Conical : normal
Irregular/globoid : verntricular
aneurysms, ventricular thromboembolism,
1 or more chamber irregular in
shape(DCM)

5. Left ventricular Consistency:
Firm: hypertrophy, fibrosis,
amyloidosis, calcification, rigor mortis.
Soft: Myocardial infarction, myocarditis,
DCM, decomposition

6. Evaluation of coronaries:
-Before any forms of cardiac dissection is
applied, coronaries should be inspected for
calcification and tortuosity.
-Subjects younger than 30yrs or where cause of
death is non cardiac: coronaries may be
opened longitudinally
-Otherwise, transverse section : 3.5-5mm .
-Calcified vessels are stripped off and decalcified.

7. Grading of coronary obstruction:
-Mild :grade I: > 25% narrowing (cut off point)
-severe : to 70%, critical stenosis : >90%
(grade IV)
-Depending on number of vessel involved:
vessel 1,2,3..if LAD is involved..vessel4.
Ex:
grade 4-critical- vessel4 = >90%, critical stenosis
involving all 4 major coronaries.

8. Cardiac dissection methods:
1. Inflow-outflow method
2. Short-axis method Useful for
3. Four chamber method
demonstrating
cardiac pathology
4. Long axis method
Anatomic
5.Base of heart method teaching and
museum
6.Window method specimen
7.Unrolling method demonstrations
Considerabl
e Mutilation
8.Partition method. / preparations.
of the heart

9. 1. Inflow-outflow method:
Right: -Using scissors, initial cut is made from IVC to
right atrial appendage sparing SVC and SA
node.
-Right ventricle opened with knife along 1cm
parallel to the posterior ventricular septum
-Outflow tract :1cm parallel to anterior
ventricular septum
Left: -Left atrium-between R and L pulmonary veins
-Left atrial appendage checked for mural
thrombus.
-Inflow tract: left ventricle opened along its
inferolateral border.
-Outflow tract :to avoid damage to mitral valve,
1cm parallel to anterior ventricular septal groove.

11. 2. Short Axis dissection:
-Method of choice :slices expose largest
surface area of myocardium.
-Diaphragmatic aspect kept over paper towel to
prevent slippage.
- 1.0-1.5cm thick cuts parallel to atrio-
ventricular groove with long knife.
-One firm slice
-Each slice viewed from apex to base.

12. 1-1.5c
cm

13. 3. Four chamber method:
-long knife, begin at apex of the heart.
-cut extended through acute margin of right ventricle,
obtuse margin of left ventricle and ventricular septum.
-cutting extended through mitral and tricuspid valve
through atria.
-divides heart into 2 pieces each having all 4
chambers.
-Upper half can be opened using inflow-outflow
technique.

15. 4. Long axis method:
-3 straight pins are used to demarcate.
-First pin : apex, 2nd pin : right aortic sinus (just
adjacent to right coronary sinus) 3rd pin: near mitral
valve annulus (between 2 pulmonary veins
openings).
-Heart is cut along this plane from apex to base or
vice versa using knife and scissors passing through
both mitral and aortic valves.

17. 5.Base of the heart method:
-Displays all the valves
-Ideal for demonstrating anatomical relations of the
valves and adjacent coronaries.
6. Window method :
-Perfusion fixed, window of various sizes removed
with scalpel and sent for HP study.
-Small windows, enlarged depending on the size of
the lesions.
-Useful for cardiac museum specimen.

18. 7.Unrolling method:
-Causes considerable mutilation of the
heart, only done in research studies.
8. Partition method:
-Coronaries and epicardial fats are stripped off
-Ventricles separated from IV septum, atria
removed.
-All weighed separately.
-Mutilation.

19. Dissection of cardiac conduction system:
-procedure of no practical diagnostic value
- mentioned at instances in literatures but in
practice such examination is not performed.
Quantitative measurements of the heart:
-Weight
-Wall thickness
-Valve size
-Amount of pericardial fluid
Qualitative analysis of the heart:
-Cardiac valve patency
- Embolism

20. Weight of the heart:
“Total heart weight is most reliable single
measurement at autopsy for correlation with cardiac
disease states.”
-Reiner .L., Gross examination of heart, Pathology of heart and great
vessels, 3rdedition, IL, pp1111-1149.
Other described measurements like linear external
dimension, surface area and volume of entire
myocardium are less useful.
-great vessels are trimmed to about 2cms in length.
-PM clots are removed.
-weights recorded (+/- 5gms adult; =/- 0.1gms infants)
-fixation alters the weight by 5-10%
-heart weight proportional to body weight rather than
age, gender and body size.

21. Thickness of walls of heart:
-usually measured at the level of mitral valve; but since
the wall is thin towards apex and thick towards base;
-MOST reliable average measurement is found at level
of papillary muscles.
-ventricular septum and right ventricle should also be
measured at the same level.
-Trabeculations and papillary muscles should be
excluded.
-Fixation increases the size by 10%.
Confusions:
-physiological hypertrophy - 25% in athletes.
-decomposition vs. dilatation
-postmortem > 24hrs, RM passes –natural dilatation vs.

22. Cardiac valve patency/Size:
◦ Regurgitation can be accessed to some extent by
filling chambers with water to check for retrograde
flow through intact valve.
◦ Stenosis and valve size is best evaluated by
measuring effective orifice size by a calibrated
cone (but not annular size).
◦ Thickness and area of valve increase with age and is
higher in females than males of same body size.

23. Air embolism :
-first coronaries, to check for systemic air
embolism.
-all chambers to be perforated, RV-LV-RA-
LA.

24. Dissection of spinal cord
 1.Anterior approach
 2. Posterior approach
 3.Combined approach

25. Anterior Approach:
-first cut is made across uppermost part of
T1 or T2.
-head is dropped back, wooden block under
mid back.
-either side of thoracic spine up to length of
15cms.
-angle of blade changed and adjusted
according to the type of vertebra.
-muscles removed and vertebra(L1-L4) cut in
similar pattern like thoracic vertebra.
Sacrum and L5 is removed together.
-Carotids are pushed sideways and cervical
vertebrae removed till c2 similarly.

27. Advantages:
-prevents leakage after embalming.
-less mutilation visible.
-course of peripheral nerves for any length in
contiguity from spinal cord can be accessed.
Disadvantages:
-difficult approach to proximal cervical
vertebrae
-conditions like myelomeningocele, and occipital
encephalocele cannot be demonstrated.
-Flexion extension injuries to back of the
neck or other injuries along the posterior
vertebral column cannot be demonstrated.

28. Posterior approach:
-Body prone, wooden blocks under both
shoulders.
-Head rotated forward, flexed.
-Midline incision over spinous
processes, muscles are resected.
-Parallel saw-cuts through vertebral laminae
-Cauda equina divided and lifted up by
Spencer Wells forceps.
-Not to twist or bend the spinal cord.

30. Advantages:
-Pathological conditions like
myelomeningocele, occipital encephalocele can
be demonstrated.
- -dissection can be limited up to the desired level
and stopped.
- -both anterior and posterior aspect of vertebra
can be accessed.
Disadvantages:
-course of peripheral nerves cannot be pursued
along its contiguity.
-Embalming leakage
-Cosmetic disadvantage.

31. Combined
approach:
- For complete removal of meningocele,
myelomeningocele or other midline fusion
defect
-Body is turned back and incision is made
around the desired area then continued
anteriorly.

32. Thank you…