Tag Archives: anatomy

Rock on, Dude!

In the rock climbing world, there is not much that people fear more than the sound of a “pop” coming from their fingers. That sound means months of rehab and can keep you off the rock for up to six months [1]. But what exactly is happening when you hear that dreaded sound? The fingers are so small, how can one injury to the fingers be so devastating? Let’s dive in.

As a review of hand anatomy, direct your attention to the graphic on the right. There are two main tendons that run up each finger to allow the fingers to produce the curling motion. In order to keep these tendons close to the bones to provide for maximum torque,

Diagram of the hand showing the tendons and pulleys
Anatomy of the hand [2]
they are held by pulleys. The pulleys are the culprits of the “pop” when grabbing tiny holds. Without these pulleys, the tendons would “bowstring” and pull away from the axis of rotation of the finger and thus decrease the strength of the system [2]. The important pulleys in climbing are the A2 and the A4, as they are fibro-osseous pulleys (connect bone to bone) and are stiffer than the A3 and A5[3].

In climbing, there are two main hand positions when grabbing

The open hand position
The open hand position [2]
holds: Open-hand and crimp. The open-hand grip relies heavily on the forearm muscles, while the crimp puts a significantly higher strain on the skeleton. The crimp is incredibly dangerous, as it puts three times the force being applied to the fingertip on the A2 pulley [4]. A common mistake I have noticed for newer climbers is to crimp everything as the big muscles in the upper arm and back are much stronger than the forearms. Putting all the weight on the skeleton and big muscles allows you to skip over the limiting factor of weaker forearms. This allows climbers to pull on smaller holds and climb harder routes. New climbers are not as aware of the dangers and they get excited

hand in the crimp position
Hand in the crimp position [3]
to send harder and harder routes, but this reinforces the bad habit of crimping which will eventually get you injured. Of course, sometimes crimping is unavoidable when the holds are very small, but it is best to avoid it as much as possible.

 

So how strong are these pulleys? In a study performed with recently deceased cadavers, the A2 pulley resisted up to 408 N, which is 91 pounds [5]. This was determined by removing the bone from the hands and pulling on the pulleys until they broke. Based on another study in live humans, the force applied to the A2 pulley was extrapolated to be around 373 N with 118 N applied to the fingertips [4]. This extrapolation was based on a controlled environment. It is easy to see that a pulley could be loaded with much more force than that if a climber’s foot slips mid- move or if you catch a hold with fewer fingers than you mean to. It was also

Me crimping as hard as I can because I'm weak
Me crimping as hard as I can because I’m weak

found that the bowstringing in the intact A2 increased by 30% throughout a warm-up process [4]. This clearly shows the importance of a good warm-up.

Sources and extra reading:

[1]https://theclimbingdoctor.com/pulley-injuries-explained-part-2/

 

[2]https://theclimbingdoctor.com/pulley-injuries-explained-part-1/

[3]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3371120/

[4]https://www.sciencedirect.com/science/article/pii/S0021929000001846

[5]https://journals-sagepub-com.proxy.library.nd.edu/doi/pdf/10.1016/0266-7681%2890%2990085-I

 

Ankle Sprains: An Epidemic in the World of Athletics

Have you ever been out running on a gorgeous fall day, only to have the run cut short by a painful misstep on a tree root covered by leaves? I have, and let me tell you – it’s awful! And even if you aren’t a runner, according to the Sports Medicine Research Manual, ankle sprains are a common, if not the most common, injury for sports involving lower body movements. Now, the solution to preventing this painful and annoying injury could be as simple as avoiding tree roots and uneven ground, but the real problem behind ankle sprains deals with the anatomy of the ankle.

The ankle is made up of many ligaments, bones, and muscles. However, when sprained, it is the ligaments that are mainly affected. Connecting bone to bone, ligaments are used to support and stabilize joints to prevent overextensions and other injuries. The weaker a ligament is, the easier it is to injure. There are three main lateral (outer) ligaments supporting the ankle joint that can become problematic: the anterior talofibular ligament, the calcaneofibular ligament and the posterior talofibular ligament. According to a study from Physiopedia, these lateral ligaments are weaker than those on the interior (medial) of the ankle, with the anterior talofibular ligament being the weakest.

An image depicting the various ligaments of the ankle, both lateral and medial.
Anatomy of the ankle, highlighting the lateral and medial ligaments

The next question that has to be asked is why are these ligaments so much weaker than other ones? The answer to this question is based on their physical make up. Ligaments are made of soft tissue that has various collagen fibers running parallel to each other throughout it. The more fibers there are, the more structure and rigidity there is. Think of the fibers as a rope: The rope can stretch to a certain point, but once it hits that point it will snap and break. But if you have a thicker rope (such as the medial ligaments), it becomes much harder to break.

The ligaments on the outer part of the ankle have fewer collagen fibers than those on the inside of the ankle. Thus, when the ankle is moved in an awkward position, it is more likely that the lateral ligaments will break.

Once you sprain your ankle, the focus turns to treatment. Treatment will differ slightly for every individual depending on the severity of the ankle sprain. The simplest way to treat a sprained ankle is to follow the RICE (Rest, Ice, Compression, Elevation) method. Other forms of treatment include taping the ankle or using a brace to restrict movement and to add support and extra stability. Wearing proper footwear is another way that one can prevent and help treat a sprained ankle, as certain shoes are specifically designed to help avoid such injuries. To prevent future ankle sprains, exercises are recommended to help strengthen and stabilize the joint and surrounding ligaments and muscles.

For more information on ankle anatomy and sprains, check out these articles on BOFAS and SPORTS-Health.

How much wood can a woodpecker peck? The Science Behind a Woodpecker’s Anatomy

Woodpecker anatomy: showing the location of the tongue
Diagram showing the tongue of a woodpecker, obtained from “BirdWatchingDaily.com”

Have you ever wondered how a woodpecker is capable of banging its head against a tree so furiously without seriously injuring itself? The impact of a woodpecker’s beak with a tree can exceed speeds of up to 6 meters per second and occur over 12,000 times a day.These kinds of numbers are what allow woodpeckers to smash through trees to get to those tasty bugs that live inside.

How is this possible you may ask? Scientists have studied the anatomy of a woodpecker and have come across an extraordinary discovery: the tongue of a woodpecker wraps completely around its neck before exiting the mouth, constricting the blood flow to and from the brain. This increases the amount of blood volume in the skull, making it, and its precious cargo, filled to the brim with fluid. This creates an effect known as “slosh mitigation”, where an object that is completely enclosed by an incompressible fluid becomes protected from an outside force due to the constant stabilization of pressure within the enclosed system. Thus, the harsh vibrations translated throughout the skull of the woodpecker are mitigated by a cushioning effect induced by the increased volume of blood in the brain. Ever notice how a snow globe always has a little pocket of air sitting on top of the water? Without it, there would be no pressure changes, and the flakes of snow would be restrained from ever creating that magical snowy blizzard we all love.

This incredible discovery is not just a fascinating fact you can pull out to impress your friends. In fact, companies have begun applying the science behind a woodpecker’s anatomy to the sports arena. A company by the name of Q30 Innovations has been on a mission to curb the estimated 3.8 million concussion occurrences every year. Their latest product, the Q Collar, features a tightly fitted neck brace that applies a mild compression to the jugular in the neck, thus creating the “slosh mitigation” effect on the brain. The Q-Collar has already been put to the test, showing positive results on football players and hockey players. Their latest test showed the effects of wearing the Q-Collar for a high school girls soccer team, whose total head impacts were collected via an accelerometer throughout the entire season. Half the team was selected to wear the Q-Collar, and at the end of the season, the accelerometers of both groups reported similar levels of head impact, both in quantity and severity. However, it was shown the group wearing the Q-Collar required less brain activity to complete a concussion protocol than those of the control group. This shows that despite any of the girls having a reported concussion, the high impact loads exhibited on the brain during the season were enough to prohibit the brain from performing at its optimal level.

Want to learn more about breakthrough technologies covering the challenges of concussions? Learn more at Q30 Innovations.

 

References:

  1. “Do Woodpeckers Get Concussions?”http://explorecuriocity.org/Explore/ArticleId/6734/do-woodpeckers-get-concussions.aspx
  2. “Response of Woodpecker’s Head during Pecking Process Simulated by Material Point Method” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4406624/
  3. “What is a Concussion?” http://www.protectthebrain.org/Brain-Injury-Research/What-is-a-Concussion-.aspx
  4. “Q-Collar tests produce positive results in protecting girl soccer players from concussions” https://www.news5cleveland.com/news/health/q-collar-tests-produce-positive-results-in-protecting-girl-soccer-players-from-concussions

Female Athletes Compete Against Higher Risk of ACL Injuries Than Males

Female athletes face a greater rate of anterior cruciate ligament (ACL) rupture than males. According to Dr. Karen Sutton and Dr. James Bullock from the Department of Orthopaedics and Rehabilitation at Yale University, female athletes are 2 to 8 times more likely to tear their ACL than male athletes. The majority of these injuries (more than two-thirds) are from non-contact situations. A variety of anatomical, biomechanical, and hormonal factors attempt to explain this difference.

Female soccer player stretching her leg
Photo by rawpixel on Unsplash
Differences between female and male lower-body anatomy show the disparity in Q-Angle that results
Taken from Desrosiers, Soccer Nation 2018

Some anatomical factors that help stabilize the knee joint and may be linked to ACL injuries include: the quadriceps angle (Q angle), tibial slope, and intercondylar notch. The Q angle is the angle formed between the upper leg at the hip joint and the lower leg at the knee joint. This angle tends to be 3.4-4.9 degrees greater in females than males when measured in a standing position. The figure at right shows the Q angle difference between men and women that is caused by anatomical differences including a wider pelvis in females. A greater Q angle causes more strain on the quadriceps muscle away from the centerline of the body, which can affect the position of the ACL to be more prone to rupture.

Tibial slope is a quantity used to describe the position of the tibia relative to the femur. When the tibia is positioned more forward than the femur there is a greater posterior tibial slope and therefore increased ACL strain. On average, females have shown to have a greater tibial slope, which may contribute to the higher incidence of ACL injuries. The figure below illustrates the biomechanics of posterior tibial slope: the effect of the knee joint compressive load (down arrow) and the force of the quadriceps (up arrow) result in an anterior shear force, causing anterior translation of the tibia relative to the femur (right-directional arrow) .

Biomechanical force diagram describing posterior tibial slope
Modified from Sutton and Bullock, JAAOS 2013

In terms of biomechanical differences between men and women, women have greater natural muscle contractions for movement away from the centerline of the body. This translates to a difference in landing positions for women compared to men – females tend to land more straight, creating more force on the knee joint, while males absorb the impact better by naturally flexing their knees upon landing. The hamstring to quadriceps ratio (H:Q ratio) is the functional strength of the hamstring muscles (peak torque) relative to the strength of the quadriceps in motion. Poor muscle strength has been linked to higher risk of lower extremity injury. Males have the ability to increase their H:Q ratio during sport motion, but females fail to do so. Women have also shown greater internal rotation laxity – slackness or lack of tension in a ligament – than men. Generalized laxity was also significantly greater among individuals who suffered a noncontact ACL injury compared to an uninjured control group.

Hormonal factors are an additional consideration that researchers have explored, but the results have been inconclusive in making a direct link between hormone levels and the rate of ACL injury.

Additional reading on this topic can be found at VeryWellHealth and SoccerNation. The following video shows some advice for female ACL injury prevention.