Top NCAA storylines from Ty Lawson's toe to Cinderellas

America's favorite sporting event is also its best. Nothing delivers such an electrifying combination of excitement, unpredictability and competitiveness with such giddy regularity as the NCAA tournament. Below are the five storylines that you'll be hearing about over the next three weeks.

The fate of the free world may not depend on the big toe of North Carolina's star point guard (although given the attention it's getting, you might think so), but the fate of this tournament, and the millions of brackets, surely does. No body part in the big dance will be watched as closely as Lawson's hallux, and with good reason. Since injuring it in practice March 6, Lawson needed an injection to allow him to play in the Tar Heels' home finale against Duke, where he clinched ACC Player of the Year honors with a sterling 13-point, eight rebound, nine assist performance. He then missed the ACC tournament with the greater goal of being fully healed for Carolina's expected run to Detroit.

But the toe isn't healing as quickly as Carolina had hoped and the best cure -- rest -- is a luxury the Tar Heels can't afford. UNC coach Roy Williams has not made a determination on Lawson's status for Thursday's first-round game against No. 16 seed Radford, which means if Lawson can't go, or even if his famous speed is neutralized, the top-seeded Tar Heels' attack will be severely compromised.

Consider the numbers:

In the 30 games with Lawson, UNC shot 48.5 percent from the floor, averaged 91.2 points and had 77.01 possessions per game

In the two games without the star guard, the Tar Heels' field-goal percentage dropped to 41.1, while they averaged 74.5 points and 65.38 possessions.

Lawson's speed makes him a one-man fast break, but it is his ability to penetrate at will -- even in half-court sets to get his teammates open shots -- that makes him especially dangerous. When Carolina's offense is clicking, it can cover for the multitude of sins committed by its famously inconsistent defense. Without Lawson to power its offense to nearly unstoppable levels, the defense must carry an increased burden, and that may crush the Heels' title chances.

If Carolina, the pre-tournament favorite, is knocked out before Lawson can get back to full strength, the South region, and indeed the entire tournament, will suddenly be wide open.

After the brackets were revealed Sunday night, selection committee chairman Mike Slive reiterated that the committee doesn't weigh conferences, but rather individual teams, when making its selections.

Rest assured that once the tournament begins, however, Slive and the rest of the world will be tracking just how well those conferences perform. The Big East got a historic load of three No. 1 seeds -- and five on the top three lines -- but a fairly common overall total of teams in the field: seven. The legitimacy of the league's claim as the best conference ever will be determined by how they perform in the tournament.

The SEC, meanwhile, was lampooned for performing like a mid-major league, a criticism justified by landing just three bids, the fewest ever for a 12-team power conference. Even worse, none were seeded higher than regular-season champion LSU, which got a No. 8 in the South (Tennessee received a No. 9 in the East and conference tournament champion Mississippi State got a No. 13 in the West). The next three weeks will offer those leagues a final chance to live up -- or down -- to their reputations.

The same teams that give the tournament its juice in the early rounds are the ones that give coaches of BCS-conference schools nightmares. But rarely do such underdogs survive long enough to truly challenge for a Final Four berth, let alone a national championship. Those long odds are what made the Cinderella runs of George Mason in 2006 and Davidson in 2008 so special.

The 11th-seeded Patriots were an at-large entry who lived large by knocking out Michigan State, defending-champion North Carolina, Wichita State and top-seeded UConn to reach the Final Four. Davidson was a 10-seed and the Southern Conference champion last season, when the Wildcats and sharpshooting guard Stephen Curry upset established powers Gonzaga, Georgetown and Wisconsin before falling three points short of eventual champion Kansas in the Midwest Regional final.

This season's crop of No. 10 seeds features only teams from power leagues (Minnesota and Michigan from the Big 10, Maryland of the ACC and Pac-10 tournament champion USC), but the 11-seeds feature a couple of schools with the low-conference background and high-impact potential that would make for a perfect fit in a glass slipper. Utah State, the 11th-seed in the West, led the nation in field-goal percentage (49.8) and got a favorable draw. First-round opponent Marquette has lost five of its past six games, and Missouri doesn't have a single player with tournament experience.

VCU, the 11th-seed in the East, slayed Duke two years ago and has a chance to take down another blueblood, UCLA, this year. Led by senior guard EricMaynor, a two-time Colonial Athletic Association Player of the Year whose foul-line jumper beat the Blue Devils in '07, the Rams have the skilled, veteran guard play you need to win in the tournament..

Western Kentucky, the 12-seed in the South, manhandled top-overall seed Louisville on a neutral court back in November in a 68-54 win. The Hilltoppers made the Sweet 16 a year ago and may actually be favored to get there this season. They open with Illinois, who will be without starting point guard ChesterFrazier (broken hand), and will likely take on Gonzaga in the second. Top-seed North Carolina looms as a likely Sweet 16 opponent, but if the Tar Heels don't have Lawson, the South bracket will be there for the taking.

During this decade, Pittsburgh has elbowed its way to the top of the college basketball hierarchy, only to tumble down the mountain -- often earlier than expected -- in the tournament. Since 2002, the Panthers have been seeded third, second, third, ninth, fifth, third and fourth, yet they have never advanced past the Sweet 16. Five times they've been eliminated by a lower-seeded team, most notably in 2006 when 13th-seed Bradley beat No. 4 Pitt in the second round.

This year should be different. The Panthers received a No. 1 seed for the first time, giving them the most favorable draw they've ever had. More significant, the Panthers rank second nationally in rebound differential and 10th in field-goal percentage. Don't expect a Pitt stop anywhere short of the Elite Eight.

Memphis once again steamrolled an overmatched Conference USA for its third-straight undefeated conference season and tournament championship, and nearly snuck onto the top line of the bracket. When the 31-3 Tigers were given a No. 2 seed out West instead, coach John Calipari had an obvious, if tiresome, rallying cry for his team in their quest to make a second-straight Final Four appearance: "No one respects us."

In 2006 (as a No. 1 seed) and '07 (as a No. 2 seed), Memphis reached the Elite Eight. A one-seed again last season, the Tigers advanced to the national-championship game. But unlike those previous teams, this year's Memphis didn't fare nearly as well against competition from the other six top conferences during the regular season. After going 8-1 against such schools (and Gonzaga) in 2008, Memphis was just 4-3 in 2009, with two of the wins (Cincinnati and Seton Hall) and one of the losses (at Georgetown) coming to teams that didn't even make the tournament.

Calipari's club hasn't lost since moving super freshman Tyreke Evans to the point, but it hasn't been tested nearly as often as it will in the weeks ahead either. A potential Sweet 16 matchup with Missouri, an up-tempo squad that favors full-court pressure defense, and an Elite Eight clash with top-seed UConn loom as serious roadblocks in Memphis' path to another Final Four.

The Tigers are bringing in another major recruiting haul next season, meaning the debate about their worthiness as an elite team while playing in such a mediocre conference will continue for years to come.