The Opposable, Not Disposable Thumb

Little Jack Horner

Sat in the corner, eating a Christmas pie;
He put in his thumb, and pulled out a plum...

Just to take our minds off the train wreck that the 2010 season has become, I'm going to tangent into just what made Aramis Ramirez so miserable this year. His left thumb injury (diagnosed as a deep bone bruise) may or not have been related to his season long slump or it just may have prevented him from coming out of it as the weather warmed up. He's been 'missing', even when present for most of 2010 which is somewhat different than his absence last season, starting on May 9th, 2009 from what happened at a similar point in the season, when he dislocated his left shoulder diving for a ball on May 8th in Milwaukee.

From a Gordon Wittenmeyer, Sun-Times article:

Ramirez, mired in a two-month slump, first hurt the hand on a swing-and-miss May 9 in Cincinnati. When it got worse two weeks later, the Cubs considered putting him on the DL, ''but I didn't want to do it because I thought I was good enough to play,'' said Ramirez, who got a cortisone shot instead. Manipulating his bat handle to take pressure off the top of the left hand also didn't work because it was uncomfortable, he said.

''This is the right time to do it. This is the right thing to do,'' he said.

He'll be eligible to return June 23 in Seattle, but a return then is anything but certain considering the down time that'll require before he is even allowed to resume normal baseball activities.

Supposedly, his injury was a deep bone bruise. I have not read any reports about an injured ligament. He has tried to play through the soreness but his thumb kept getting re-traumatized from his attempts at hitting. He didn't want to go on the DL until it was clear he couldn't shake the injury.

This does remind me of the way the Cubs handled Soriano's knee problems last year. Supposedly Soriano's knee was injured around April 22nd but he/they kept playing him with an injury that wasn't dramatic enough to take him out of the lineup. It took months of underperformance compared to his career stats (.241/.303/.423/.726 vs. .278/.327/ .511/.838) to  finally acknowledge it was his knee that was the problem. Maybe they learned something, since it took only a month of struggling with this Ramirez injury before he hit the DL vs. Soriano's 4 month struggle. I believe that some of these situations develop because a team can not put a player on the DL unless he agrees or the team gets the medical staff to document that it's not medically advisable for a player to be on the field. Hockey-like warrior mentality doesn't seem to work in modern baseball, at least not as far as the Cubs are concerned.

The opposable thumb may have been, regarding humanity, the single most important evolutionary development.

When the hands developed dexterity advantages, that freed the front limbs from four limb gait. The opposable thumb literally gripped the development of tools, hence civilization and...dare I ultimately conclude, Baseball.

An animal species is said to have opposable thumbs if the thumb is capable of bending in such a way that it can touch all the other digits on the hand. Most species do not have opposable thumbs. Opposable thumbs are a signature feature of the primate family, and played a large role in the ancient humans' invention and use of tools.

Thumb anatomy is unique when using comparative anatomy to the other fingers and certainly the human big toe. The thumb can be rotated (opposed) from around 50 degrees at rest to as much as 110 degrees of rotation when in a position of opposition against the other digits.

There are unique sets of muscles and tendons (abductor, adductor, flexor, opponens and interosseus of the thumb) that accomplish thumb opposition. This is a complex of movements that include what is called pronation, radial deviation and adduction/abduction and specific muscles match the individual movements required. The bones at the base of the thumb (first metacarpal, trapezoid and trapezium and proximal to them, the carpal navicular/scaphoid bone) have developed to accomplish this opposible movement and the type of joint is called a sellar joint.

Thumb functions include pinch and grasp but the rotation that opposition creates makes it possible to make grip have advanced functionality. There are three types of pinch grips, key (digit side by side, as in holding a key), tip (the end of the digit, where opposition is possible) and palmar pinch (thumbless grasp).Two aspects of grip help hold a baseball bat, span grip and power grip.

There are many common injuries around the thumb. A bone bruise is just what the term sounds like, it's not a fracture but the injury to the bone involves damaged bone cells without structural disruption. A fracture implies there is a definable structural crack/disruption that bridges one of the bones of the thumb (first metacarpal, proximal and distal phalanx). There are many fracture patterns and if a fracture involves an adjacent joint (CMC, MCP or IP joints), it usually is a more serious problem. If an X-Ray shows a fracture, an MRI isn't often needed but when the X-Ray is normal an MRI can be very helpful. Nowadays, MRI imaging can see signal changes in a bone and adjacent soft tissues (ligaments, joint capsule and tendons) that indicate there is damage to the bone and/or soft tissues. Even a bone bruise sets off a healing reaction until the bone structure returns to normal, essentially a "fracture-lite", but still painful and can last many weeks. Other significant thumb injuries involve soft tissue damage. One well known injury is called Gamekeepers Thumb. It involves a torn or stretched ulnar collateral ligament of the metacarpal-phalangeal joint or MCP joint (at the base of the web space, the thumb equivalent of the Tommy John elbow injury). This can be treated conservatively unless the ligament is fully torn or significantly stretched so that the thumb pinch activities become painful. There are surgical repair/reconstruction options when that situation is diagnosed (watch out if you are squeemish, this link is a surgical video).

So when one compares small joint/bone injuries to big joints, Aramis Ramirez has got them covered. If his thumb becomes a lingering problem, the sellar joint of his thumb just might be a major cause of the Cubs entering a seller market.