Apologies for correcting you but the autopsy report says no such thing, and the entire concept imo is merely a defense red herring. To quote from the autopsy report itself, which does not use the word upward or discuss what angle a knife may have entered the body, anywhere in the report:
"Examination of the torso reveals the following sharp force injuries:
A 1 inch horizontal stab wound of the upper paramidline left chest, which terminates at the level of the sternum
A 1 1/2 inch oblique stab wound of the paramidline right chest, with penetration / perforation of the costochondral junction near the sternum at the level of the 3rd and 4th right ribs; the wound extends to a maximal depth of approximately 3 1/2 inches with penetration of the superior vena cava near the base of the heart, with a small amount of surrounding hemorrhagic in the mediastinal soft tissues and the pericardial sac of the heart; a portion of the costochondral cartilage encompassing the stab wound is excised and retained at the FSC for potential further analysis.
A deep transverse 2 inch incised wound across the lower right chest, belowo the nipple, with penetration of the lower portion of the right pectoralis muscle.
A 1 3/4 inch obliique stab wound of the left upper absominal quadrant, with a near-tangential subcutaneous adipose tissue wound track (5 3/4 inches long), terminating in adipose tissue of the right lower abdominal quadrant; the abdominal cavity is not penetrated.
Two (2) very shallow parallel oblique wounds of the anterior right shoulder, measuring up to 1 3/4 inch."
And to quote from JW's cross-examination of Dr. Horn:
2:24:00 ff in the video below:
JW asks can't you tell the direction of the stab wound?
Dr. Horn says "
It's pretty much straight into his chest."
JW asks, "Doesn't it have an upward trajectory?"
Dr. Horn responds. "
If it is it is very slight."
In fact, the prosecution's theory is that she stabbed him while he was seated. [I concur; it's no accident she got him into a 'sitting duck' position, imo.] JM asks Dr. Horn that very question at 1:11, whether TA could still get up from a seated position after being stabbed and attempt to defend himself. Dr. Horn answers in the affirmative. JM's exchange with Dr. Horn regarding that stab wound begins around the 1:06 mark and lasts for 4-5 minutes.
Jodi Arias Trial Day 3 (Full) - YouTube
TA left this blood streak on his way out of the shower. It could not have reached that point in back of his robe from anywhere in the bathroom itself.
As Dr. Horn testified, if that wound to the superior vena cava nicked the lung, it would cause coughing up of blood. Which we see evidence of on the sink. It is consistent with the first stab occurring in the shower.