You don't "get" it.
"Near" not accurate and is vague. "In" is more correct but does not tell you a location because the armpit is a large area. I wanted to be precise so I provided Dr. Shaw's statement.
Shaw also said (7 HSCA 330): "Lateral to the scapula on the right posterior thoracic wall was a small wound".
My understanding is that the lateral edge of the scapula is the axillary border. The axillary fold is the muscular, fatty surface of the lower armpit behind it.
But the wound was not a single point. It had dimensions. It was about 1.5 cm by .8 cm with the long dimension in the long axis of the body (Shaw 7 HSCA 331). So it appears to have been located in the right armpit extending .8 cm from the posterior border of the right armpit.
As far as the orientation of the bullet is concerned, since the bullet was exactly 3 cm in length I agree that this is not a sideways strike. Shaw said: "The wound in the back was shaped as if the bullet had entered at a slight declination" (Shaw 7 HSCA 331).