The legend of Achilles has it that he was dipped into the river Styx by his mother Thetis in order to make him invulnerable.
As she immersed him, she held him by one heel and forgot to dip him a second time. The heel she held was never touched by the magic water, and his heel remained mortal, or vulnerable. He was later killed by an arrow shot to that heel.
Eli Manning injured his right heel while dropping back to make a pass in the fourth quarter today with a rapid stop to start, or backward to forward transition, typical of how most Achilles are torn. Most tendon tears occur from a forceful eccentric load (forceful contraction applied to a tendon that is already stretched). See video of Manning now.
Hard to believe we can diagnose an injury without an MRI, but we can easily diagnose a rupture on the sideline. The athlete complains they were shot in the back of the leg and usually would have to be helped off the field. A rupture is a complete tear and would be easily seen, palpated, or diagnosed by simply squeezing one’s calf. A rupture would be a season-ending injury and require surgery.
A strain would be a stretching of the tendon with partial tearing. Less serious than a rupture, no doubt, but a nuisance to heal.
More bad news, there is no quick cortisone cure for the Achilles tendon. The risk: rupture. We don’t inject the Achilles tendon.
I expect Manning to be in a boot tomorrow, get lots of rehab this week, and have the prerequisite MRI (though diagnostic ultrasound would yield more information more quickly and cost less money).
The shot to Achilles probably hit an artery, not his Achilles tendon; though, if you ever rupture your Achilles, it does feel like a shot to the back of the leg.