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A week relatively devoid of serious injuries came crashing down, literally, when Green Bay Packers superstar quarterback Aaron Rodgers sustained a fractured left collarbone during a 27-20 loss to the Chicago Bears.

A GIF of the injury, courtesy of ESPN's Monday Night Football via @gifdsports, shows what happened:

CBS Chicago's Adam Hoge reported the news Monday night via sideline reporter Zach Zaidman, and ESPN's Adam Schefter corroborated the news Tuesday morning.

Then, per ESPN Milwaukee's Twitter account, Rodgers himself confirmed the fracture Tuesday afternoon, but he did not offer a return timetable.

Clavicle fractures can carry a wide range of recovery times. Many factors, such as the presence of associated injuries, fracture location and individual player characteristics all come into play.

To understand what's next for the Packers quarterback, let's take a 50,000-foot view of the clavicle and other relevant structures in the area.

What Is the Clavicle?

Known more commonly as the collarbone, the clavicle connects the scapula—the shoulder blade—to the sternum, or breastbone.

By doing so, it supports the arm and its large range of motion. It also protects multiple underlying structures, such as blood vessels and the brachial plexus—a group of nerve roots responsible for controlling the arm's movement and sensation.

More relevant, however, is the clavicle's function as a shock absorber. Unfortunately, when a shock proves too great, fractures can result.

Where Do the AC and SC Joints Come into Play?



As mentioned, the outer portion of the clavicle, called the "lateral" side, ends at the scapula. Specifically, it meets the acromion process—a portion of bone that juts outward from the main body of the scapula—making the acromioclavicular (AC) joint.

The aptly named acromioclavicular ligament complex horizontally connects the end of the clavicle to the acromion, thereby helping stabilize the AC joint.

A second ligament complex connects the bottom of the lateral side of the clavicle to the coracoid process of the scapula. Not surprisingly, doctors refer to it as the coracoclavicular (CC) ligament group.

The CC ligaments keep the clavicle steady in the vertical direction.

On the other end, the sternoclavicular (SC) ligament network supports the inner, "medial" side of the clavicle. As the name suggests, it connects the clavicle to the sternum.

What Are the Different Kinds of Clavicle Fractures, and How Are They Treated?

Clavicle fractures come in many shapes and sizes.

Management depends largely on the location of the fracture, especially in relation to other structures such as the CC ligament network. The degree of fracture displacement—or how much the two ends of the bone separate—also looms large, as does a fracture's stability.

It's easier to conceptualize two broad fracture categories—operative or non-operative—rather than analyze each individual type, as there are many.

The treatment of operative fractures usually involves surgically manipulating a displaced or unstable fracture back into its proper anatomical position and installing metal hardware to fix it in place while it heals.

Non-operative fractures generally require only rest and immobilization—such as an arm sling—while the bone reconnects.

What Happened to Aaron Rodgers?



Rodgers' classic mechanism of injury closely relates to his ultimate diagnosis. A screenshot of the injury shows why:

As clearly seen, Chicago Bears defensive end Shea McClellin tackles Rodgers in such a way that the Packers signal-caller comes down directly on his left shoulder with his clavicle roughly perpendicular to the ground.

As a result, the immovable ground transmits a large upward-directed force to the shock-absorbing clavicle.

Unfortunately, the combined weight of Rodgers and McClellin overwhelmed the clavicle, causing the fracture.

When Will Rodgers Return?



Fortunately, early reports suggest Rodgers avoided serious injury.

For example, Fox Sports reports he will not need surgery—implying a stable, non-displaced fracture. Additionally, Schefter's tweet states the injury could sideline him for approximately three weeks.

Furthermore, Tyler Dunne of the Milwaukee Journal Sentinel tweeted Tuesday that Packers head coach Mike McCarthy is "relieved" about the latest reports from team doctors.

The optimism comes as a welcome twist compared to recent injuries similar to Rodgers'.

Philadelphia Eagles quarterback Matt Barkley suffered a separated shoulder after a comparable tackle ended his college career at USC in 2012. A separated shoulder implies a dislocation of the AC joint.

In 2010, a clavicle fracture cost Dallas Cowboys quarterback Tony Romo the remainder of the season.

For Rodgers, the exact recovery timetable depends largely on the type and severity of the fracture—details which will probably remain unknown to the public.

However, whereas surgical fractures often take a player out for anywhere from six to 10 weeks or more, non-surgical fractures carry the potential of a quicker recovery.

Perhaps Rodgers will need just a few weeks as Schefter reported, though more than likely it will take longer than the proposed three-week timeframe. Four, five or even more is possible, and Fox Sports' Mike Garafolo confirmed early Wednesday that a source expects a four-to-six week recovery.

While some specialized rehab techniques may further stimulate or speed bone healing, nothing replaces time.

Very generally speaking, bones begin the initial stages of reattachment about three weeks after a fracture. A relatively weak, cartilaginous callus forms over the break, and it continues to solidify over the following weeks and months.

That said, the Packers do not yet have an official timetable.

In the coming weeks, pain tolerance, range of motion and arm strength will guide the final steps of Rodgers' recovery. Luckily, the injury involves his non-throwing shoulder. Nevertheless, throwing a football with a painful opposite shoulder is no easy task.

The extent of any additional AC, CC or SC ligament damage also plays a large role, as each can factor into the stability of the shoulder during and after recovery. No reports of such damage yet exist, but more may surface in the coming days and weeks.

Eventually, the outstanding Packers medical staff will work with Rodgers and his coaches to determine the optimal risk-versus-reward scenario about when to return to the field. He will remain at higher risk of re-injury during the entire healing process, and another tackle similar to Monday night could prove disastrous.

If he landed on his left shoulder before his fracture fully healed, it could break again. A second fracture to the already-weak bone could displace much more easily, necessitating surgery. A surgery would likely cost him the entire season.

Bottom Line

If the extent of Rodgers' injury is, in fact, a minimally or non-displaced clavicle fracture, his recovery will be relatively short when compared to some of the alternatives.

On the other hand, significant ligament or other damage could mean the opposite.

The exact number of weeks missed will depend on:

Rodgers' unique, predetermined healing ability.

The existence, or lack thereof, of other associated injuries.

A risk-versus-reward evaluation involving Rodgers, his medical staff and his coaches.

Each of the above criteria will only become clear with time.

With that in mind—and with a wide-open NFC North—Packers nation may need to continue to hold its breath for some time still.

Dr. Dave Siebert is a resident physician at the University of Washington. Find more of his work at the Under the Knife blog.

Follow Dave on Twitter for more sports, medicine and sports medicine:

Follow @DaveMSiebert

