Due to the extremely close proximity of the opposing lines between the two forts, sniper fire was heavy and constant in this area. Potter’s division was located in the ravine a little more than one hundred yards from Elliott’s Salient, which itself was situated at an angle in the Rebel line of works, the closest at any part to the Union lines. Observers at the time felt the Union line had penetrated into the interior of the Confederates’ lines in this area after the last battle and was thus occupying a tenuous position. (2)
The National Park Service identifies Elliott’s Salient as a point where Federals and Confederates had come close together.
One of these locations was in front of Elliott’s Salient, a Confederate strong point near Cemetery Hill and old Blandford Church. Here the Confederate position and the Union picket line were less than 400 feet apart. Because of the proximity of the Union line, Elliott’s Salient was well fortified. Behind earthen embankments was a battery of four guns, and two veteran South Carolina infantry regiments were stationed on either side. Behind these were other defensive works; before them the ground sloped gently downward toward the Union advance line. (3)
Someone has done a nice job exploring the term salient as military term on Wikipedia including a variety of examples of “salients” from the American Civil War as well as other military engagements which you can read here.
From the National Park Service’s virtual tour of the Fredericksburg & Spotsylvania Battlefields: By mid-afternoon on May 12 the fighting at the Muleshoe Salient had reached an impasse. By coincidence, both sides focused attention on another bulge in the Confederate lines known as Heth’s Salient. General Grant ordered General Ambrose Burnside to attack Heth’s Salientat the same time as General Lee ordered General Jubal Early to attack Burnside’s left flank. In doing so, he hoped to relieve pressure on the Confederates at the Bloody Angle.
Muleshoe Salient: Look for reference to Mule Shoe Salient in the Wikipedia post here.
From the National Park Services (see the full story here): The armies flowed onto the battlefield the rest of the day, extending corresponding lines of earthworks east and west of the Brock Road. Ewell’s corps filed in on Anderson’s right and built their entrenchments in the dark to conform with elevated terrain along their front. First light revealed that Ewell’s soldiers had concocted a huge salient, or bulge, in the Confederate line, pointing north in the direction of the Federals. The men called it the “Mule Shoe” because of its shape, but Southern engineers called it trouble. Salient’s could be attacked not only in front but from both sides, and as a rule officers liked to avoid them. Lee, however, opted to retain the position trusting that his cannoneers could keep the “Mule Shoe” safe enough.
From the National Park Service (see the full story here): On May 10, the Union found a weakness in the Confederate defenses. Colonel Emory Upton was ordered with 5,000 men to attack a slight bulge in the Confederate lines known as Doles’s Salient. Upton’s men approached the Confederates on a narrow road (typical of the roads in the area that linked one farm with another) through the woods.
Ypres Salient: Famous for the World War I battle that took place there.