Allow me to add a few details. The Arkansas regiment that broke at Prairie Grove was shaky from the start. It was composed largely of NW Arkansas conscripts, many of them outright Unionists, and in the weeks and months leading up to the battle Col. Charles W. Adams treated his men more like prisoners than soldiers. They were kept under guard, herded around like cattle, etc. Not exactly the way to build morale and esprit de corps, I would imagine.
The regiment spent the morning of December 7 near Prairie Grove church facing south. About three o'clock in the afternoon it was ordered into the fight. Upon reaching Battle Ridge the regiment was placed in a gap between Fagan's Brigade and Shelby's Brigade behind the south fence of the Borden orchard. The regiment fired a volley from behind the fence toward the right wing of the Twenty-sixth Indiana. When the Hoosiers fell back the regiment climbed over the fence and advanced north through the orchard (which was filled with fearfully mangled Union and Confederate corpses from an earlier clash) directly toward the Borden house. At approximately the place where the modern tour road crosses the orchard the regiment ran into a storm of fire from the left wing of the Thirty-seventh Illinois, including the left flank company which was armed with Colt revolving rifles. That is when the regiment broke. As both Adams and Hindman noted in their reports, many of the officers went with the men.
By the way, Adams' report of the disaster is quite lengthy and detailed and makes fascinating reading. It is in the Supplement to the Official Records, Vol. 4, pp. 79-84.