From: grant_jo@ripple.enet.dec.com (Joel Grant)
Newsgroups: alt.conspiracy.jfk
Subject: HSCA vs. Lattimer, part two
Date: 28 Sep 92 22:18:36 GMT
Organization: Digital Equipment Corporation




(continuing HSCA's vs. Lattimer's trajectory analysis)


(148)  Appropriate adjustments were made under the direction
of Dr. Clyde Snow, a forensic anthropologist at the Civil
Aeromedical Institute of the FAA's Aeronautical Center.  It
was determined that returning Kennedy's head to a normal
position relative to his body would, according to laboratory
tests on men of similar build, adjust his neck wound down about
1.0 centimeter toward his breastbone.  Returning Kennedy's
head to the position it was in at the time he was first wounded -
about 60 degrees to the right of straight ahead of his torso - 
caused only a slight change in the position (approximately
0.1 centimter to the right of the observed position in the
autopsy photographs). (54)

(149)  Because the Zapruder film showed that Kennedy had raised
his right shoulder slighly so as to place his elbow on the side
of the limousine, the resulting movement of skin at the inshoot
location was also assessed.  It was found that the wound was
approximately 0.1 centimers higher and 0.2 centimeter closer to
his midplane than the post mortem photographic observations by
themselves indicated. (55)  While only the vertical position
of the neck wound was substantially altered by these changes
in conformation, all the adjustments were included in the
analysis of trajectory.

(150)  Using the average locations and adjustments, the back wound
was located at a point 4.4 centimeters to the right of and 1.1
centimeters above Kennedy's neck wound at the time of the shot.
The bullet was moving from right to left by 18 degrees and
downward by 4.0 degrees relative to Kennedy if he were sitting
erect (not inclined forward or aft).  Since Kennedy was believed
to have been turned about 5 degrees to his right relative to
the fore-and-aft line of the limousine, it is concluded that
the bullet was moving from right to left by 13 degrees relative
to the midline of the limousine.  By a similar analysis, since
Kennedy was inclined slightly forward by approximately 11 degrees
to 18 degrees (from true vertical), the downward slope of the
trajectory, taking into account the 3 degrees slope of the
street, was established at between 18 degrees and 25 degrees 
(4 degrees plus 11 to 18 degrees, plus 3 degrees).  The Panel
decided to use an angle of 21 degrees for its analysis.

(151)  The analysis by the USGS of the limousine's motion through
Dealey Plaza provided both the location and angular orientation of
the limousine at a time corresponding to Zapruder frame 193; (56)
adjustments were then made with reference to Zapruder frame 190.
(See fig. II-10, JFK exhibit F-133)

(152) The direction of the trajectory was then determined by drawing
a line on a scaled diagram of Dealy Plaza at a 13 degrees (that is,
18 degrees, minus 5 degrees) angle relative to the car and
extending it to the rear until it intercepted the first building
that it encountered.  Assuming frame 190 as the moment of impact,
the trajectory line intercepts the Texas School Book Depository
approximately 14 feet west of its southeast corner.  (See
fig. II-16) Using an angle of 21 degrees, the slope of the
trajectory was then drawn onto a similarly scaled diagram and
found to intersect the Texas School Book Depository at a point almost
level with the sixth floor windowsill.  (See fig. II-17)

(153)  A circle with a radius of 13 feet has been drawn about the
intercept pont of the trajectory in figure II-16, reflecting the
margin of error.  It represents the estimated minimum reasonable
margin of error that can be ascribed to this analysis.  

(154)  The same kinds of considerations as were discussed for
the head wounds case were applicable in assessing the accuracy of the
trajectory based on the President's torso wounds.  Here the most
critical issue was Kennedy's upper torso attitude rather than the
orientation of his head.  Consequently, different types of problems
were encountered.

(155)  The Croft photograph, while quite illustrative of Kennedy's
posture, lacked two features noted in Zapruder frame 312.  Since the
torso is flexible, no clear stable relationship could be established
between the photographed exterior and the unseen interior.  Further,
this picture was taken at least 1.5 seconds before Kennedy was
wounded.  During this interval, he had turned his head 60 degrees
to his right and may have shifted his torso slightly.  Thus, errors
of 5 degrees may easily be present in this interpretation.  Finally,
an accurate determination of his back and neck wound locations was
impeded both by the extremely inappropriate lighting and composition
of the autopsy photographs and by the distortions resulting from
the tracheostomy performed at Parkland Memorial Hospital.  These
latter problems probably contributed little to the uncertainty in
trajectory location as compared with the more serious difficulties
arising from the poor photographic definition of his posture
and position. *  [footnote in Donahue: "* The five degree margin
of error resulted in a smaller margin-of-error radius than in
the head wound trajectory because in this case the limousine was
substantially closer to the Texas School Book Depository. (See
fig. II-10, JFK exhibit F-133).]  

I assume the above footnote was in the original.

I conclude from the above that Lattimer's 20 degree downward
back/neck trajectory is outside the reasonable margins of
error established by the HSCA analysis, that the HSCA put more
elbow grease into the study, and that therefore Lattimer is
in error due to the difficulty of determining precise inshoot/outshoot
locations in the position of the body at the time of bullet impact.

Joel Grant (speaking on his own behalf)