Pronation and Supination of the Tibia and Fibula
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Pronation and Supination of the Tibia and Fibula
Replace the word Tibula with Tibia
By leg in this context I mean the part of the body between the knee and the foot, possibly including the knee but not including the thigh above the knee.
By forearm in this context I mean the part of the body between the elbow and the hand, possibly including the elbow but not including the arm above the elbow.
Some anatomists do not consider the forearm to be part of the arm but common people consider the forearm to be part of the arm.
Common people consider the arm to include the forearm and what some anatomists call the arm. What some anatomists call the arm, common people call the upper arm.
Some anatomists do not consider the thighs to be part of the leg but common people consider the thigh to be part of the leg.
The forearm is to the leg as the wrist is to the ankle and as the hand is to the foot
The forearm is similar to the leg
The wrist is similar to the ankle
The hand is similar to the foot
The radius and ulna of the forearm are similar to the tibia and fibula of the leg
Very bad terminology has become popular even among medical doctors and anatomy professors in which foot, ankle or leg pronation and supination have no clear definitions.
One anatomy professor I heard speak but have no citation for since what I verbally heard him say was not a published work, claimed he sent letters to multiple medical doctors asking the definition of pronation and supination of the foot or ankle. I do not remember if he said foot or ankle, although I suspect he unfortunately said foot instead of ankle. He said the replies he got were inconsistent and he found no clear definitions.
This maybe partly because it is very difficult or perhaps anatomically or physiologically impossible to purely pronate or supinate the foot, ankle or leg without also additionally everting, inverting, plantar and or dorsiflexing the foot or ankle.
But instead of inventing new definitions in which pronation and supination movements occur in multiple planes one should simply describe pronation and supination as rotation in a single plane and describe the real movements of people's legs, ankles or feet as occuring as a combination of movements in pronation or supination plus movements in the other two planes.
I will explain what the definition of pronation and supination of the hand, forearm or wrist is and how it is not described as a combination of the other types of wrist movements and then describe how if one is consistent pronation and supination of the leg, ankle or foot would have a specific meaning without the degree of ambiguity these doctors and anatomists are fabricating.
If you flex your elbow to 90 degrees and your forearm is in a supinated position then you can pronate your elbow by rotating the distal end of your radius around your ulna while the proximal end of the radius and the ulna stay mostly still relative to the larger movement of the distal end of the radius "wrapping around" or "crossing over" the ulna.
"Wrapping" might not be the best term because the radius primarily does not deform and change shape to circle around the ulna the way a ribbon would change shape to wrap around a present, but primarily maintains it's shape as a mostly rigid object.
If the radius and ulna were seen from a viewpoint in which they are considered "parrallel" line segments when your forearm is fully supinated then they might be seen as "crossing" line segments that are not parallel when your forearm is fully pronated from that same point of view. They are not exactly shaped like line segments or rectangular solids so I put "parallel" in quotes. By viewpoint or point of view I mean at the correct "camera" angle for an x-ray or machine that could enable someone to see bones in the arrangement described and also mean a perspective of viewing those bones as line segments.
If you flex your elbow to 90 degrees and your forearm is in a pronated position then you can supinate your elbow by rotating the distal end of your radius around your ulna while the proximal end of the radius and the ulna stay mostly still relative to the larger movement of the distal end of the radius which "unwraps around" or "uncrosses over" the ulna.
Or so I have been told. Frankly when I watch myself pronate and supinate my forearm it looks to me like both the distal end of the ulna and the distal end of the radius move while the proximal end of the ulna and the proximal end of the radius do not move much and stay approximately in the same position relative to the much larger movements of the distal ends of those bones. It might be that I am simultaneously internally or externally rotating my humerous and creating the illusion of ulnar rotation when I pronate or supinate my forearm.
The wrist can be viewed as potentially rotating in three perpendicular planes
1 flexion and extension
2 ulnar and radial abduction or deviation or adduction back toward a "neutral" midpoint between the two positions of radial and ulnar deviation
3 pronation and supination
One might argue the pronation and supination does not actually occur at a wrist joint in which the hand intersects with the forearm, but instead occurs at the forearm between the wrist joint and the elbow joint.
One might also argue that ulnar and radial abduction or deviation are not pure rotations but are gliding movements that contain some degree of translation.
But it is clear that radial and ulnar deviation are not parallel to wrist flexion and extension even if they are not viewed as pure rotations. Radial and ulnar deviation are also not parallel to forearm or wrist pronation and supination even if they are not viewed as pure rotations.
Wrist pronation and supination are not flexion and extension
Wrist pronation and supination are not radial and ulnar abduction or deviation
Wrist pronation and supination are not described as a combination of other wrist movements. But some people describe foot or ankle pronation or supination as a combination of movements including dorsiflexion, plantarflexiom, inversion and or eversion. If one is to be consistent in how one treats the ankle with how one treats the wrist then people who say that ankle or foot pronation or supination include plantarflexion, dorsiflexion, inversion or eversion are wrong.
Pronation and supination is best described as a movement of the forearm or radioulnar joint instead of a movement of the wrist. But, I can understand why pronation and supination are described as movements of the wrist because the wrist is between or connects the hand and the forearm or is viewed as the joint between the hand and the forearm and when the forearm pronates or supinates the hand changes position.
Pronation and supination can best be described as a motion occuring in the leg or tibiofibular joint instead of occuring in the ankle if I am to be consistent with pronation and supination being best described as a motion of the forearm instead of a motion of the wrist. But, I can understand why pronation and supination are described as movements of the ankle because the ankle is between or connects the foot and the leg or is viewed as the joint between the foot and the leg and when the leg pronates or supinates the foot changes position. Pronation and supination should not be described as occuring in the foot unless they are also described as occuring in the hand. It is ok to describe pronation and supination as occuring in the ankle if it is ok to describe pronation and supination as occuring in the wrist.
If pronation and supination of the forearm is a rotation involving the radius and the ulna then pronation and supination of the leg is a rotation involving the tibia and fibula
When someone starts standing in the anatomical position pronation of the forearm would result in rotating the hand in the transverse plane as a result of the transverse plane rotation of the distal ends of the radius and or ulna of the forearm around a vertical axis perpendicular to the transverse plane
When someone starts standing in the anatomical position pronation or supination of the leg therefore would result in rotating the foot in the transverse plane as a result of the transverse plane rotation of the distal ends of the tibia and or fibula of the leg around a vertical axis perpendicular to the transverse plane
If someone was in the anatomical position, wrist flexion or extension would consistently be defined as flexion or extension in the sagital plane
If someone was in the anatomical position, Plantar or Dorsiflexion would consistently be defined as flexion or extension in the sagital plane.
If someone was in the anatomical position, wrist radial or ulnar abduction would consistently be defined as abduction in the coronal or frontal plane
If Eversion and Inversion is perpendicular to Pronation and Supination and also perpendicular to Plantar and Dorsiflexion then if someone in the anatomical position inverted or everted their ankle or foot they would rotate their foot in the coronal or frontal plane
If I am wrong and the distal ends of the tibia and or fibula do not rotate in a similar manner to the distal ends of the radius and or ulna rotating during pronation and or supination then I would suggest the terms pronation and supination of the ankle or foot be removed
The terms pronation and supination of the ankle or foot could be replaced with the terms, medially and lateral rotation and or internal and external rotation of the foot or ankle or with the terms little toe or big toe abduction or deviation or with the terms horizontal flexion and extension or horizontal adduction and abduction of the foot or ankle.
Earlier in this article when I described how to understand what pronation and supination of the forearm is I said, "If you flex your elbow to 90 degrees"
There was a reason for that. If you start with a straight unbent elbow when you pronate or supinate your forearm it will result in rotating your hand in the same plane as if you internally or externally rotate or medially or laterally rotate your shoulder or humerus or rotate your humerus along it's long axis.
If you start with a straight unbent knee when you pronate or supinate your leg it will result in rotating your foot in the same plane as if you internally or externally or medially or laterally rotate your hip or femur or rotate your femur along it's long axis.
If you sit in a chair with your knees bent to ninety degrees you can pronate or supinate your leg and see that the rotation of your foot in the transverse plane is not caused by internal or external or medial or lateral rotation of the hip or femur or rotation of the femur along it's long axis.
Some people may find that it is difficult or impossible to rotate their foot in the transverse plane without additionally rotating it in the sagital and or coronal plane but that does not mean supination and pronation should be considered a rotation in two or three perpendicular planes. In such a case they should just say that when they pronate or supinate their leg or ankle in the transverse plane they additionally invert or evert and or plantarflex or dorsiflex their foot or ankle in the sagital and or coronal plane because they are anatomically , physiologically or mentally unable to easily do pure pronation or supination of the leg or ankle but can only easily pronate or supinate the leg or ankle in the transverse plane while simultaneously plantar or dorsiflexing and or inverting or everting the foot or ankle in the sagital and or coronal plane. Maybe most people can easily do pure pronation or supination of the leg or ankle in the transverse plane only or maybe no one or only a small percent can.
It may also be that when people walk when there foot, ankle or leg supinates or pronates they simultaneously also plantar or dorsiflex and or invert or evert their foot or ankle. But one should not say that plantar or dorsiflexion or inversion or eversion are or are part of supination or pronation because of this. Instead one should say that when someone supinates or pronates during walking they also simultaneously plantar or dorsiflex or invert or evert their feet, but pure pronation or supination does not include any plantarflexion, nor dorsiflexion, nor inversion, nor eversion and neither pure pronation nor pure supination occurs during walking. At least if one is to be consistent with pronation and supination in the foot, ankle or leg compared to pronation or supination in the hand, wrist or forearm
"Pronation is a natural movement of the foot that occurs during foot landing while running or walking. Composed of three cardinal plane components: subtalar eversion, ankle dorsiflexion, and forefoot abduction,[1][2] these three distinct motions of the foot occur simultaneously during the pronation phase.[3] Pronation is a normal, desirable, and necessary component of the gait cycle.[4] Pronation is the first half of the stance phase, whereas supination starts the propulsive phase as the heel begins to lift off the ground.[5]"
http://web.archive.org/web/20210620115936/https://en.m.wikipedia.org/wiki/Pronation_of_the_foot
https://duckduckgo.com/?q=supination+leg+wikipedia&ia=about
The following is an example of what I was talking about in regards to people wrongly defining pronation or supination of the foot, ankle or leg as occuring in incorrect additional planes or incorrectly adding plantarflexion, dorsiflexion, inversion or eversion into the definition of pronation or supination when it is factually wrong to do so if you are consistent with how the term pronation and supination are used in regards to the hand, wrist or forearm.
"Inversion occurs when the sole of the foot turns inwards.
Plantar flexion is where the foot and toes point downwards.
Ankle adduction involves the foot pointing inwards, across the body.
Combine all three movements and you have supination."
http://web.archive.org/web/20210505232524/https://www.sportsinjuryclinic.net/treatments-therapies/foot-biomechanics-gait-analysis/over-supination-foot-biomechanics
https://duckduckgo.com/?q=supination+fibula&ia=web
https://duckduckgo.com/?q=supination+tibia&ia=web
https://duckduckgo.com/?q=pronation+fibula&ia=web
https://duckduckgo.com/?q=pronation+tibia&ia=web
https://duckduckgo.com/?q=supination+leg&ia=web
https://duckduckgo.com/?q=pronation+leg&ia=web
The following are quotes or searches involved in trying to confirm or refute that the tibia and fibula rotate in the transverse plane similar to how the radius and ulna behave during pronation and supination
The fibula provides lateral stability for the lower leg and acts as a tie rod to increase the range of motion for the ankle, especially lateral and medial rotation of the foot.
http://web.archive.org/web/20220605233002/https://www.verywellhealth.com/fibula-anatomy-4587597
Four of the flexors (popliteus, gracilis, semi-membranosis and semi-tendinosis) medially (or internally) rotate the tibia on the fixed femur, whereas the biceps femoris is a lateral rotator of the tibia. The semi-tendinosis, semi-membranous and biceps femoris muscles (hamstrings) flex the knee and extend the thigh.
http://web.archive.org/web/20220610084856/https://findanyanswer.com/what-muscle-externally-rotates-the-tibia
https://duckduckgo.com/?q=fibula+rotate&ia=web
https://duckduckgo.com/?q=fibula+rotates&ia=web
https://duckduckgo.com/?q=fibula+rotation&ia=web
https://duckduckgo.com/?q=fibula+rotating&ia=web
https://duckduckgo.com/?q=tibia+rotate&ia=web
https://duckduckgo.com/?q=tibia+rotates&ia=web
https://duckduckgo.com/?q=tibia+rotation&ia=web
https://duckduckgo.com/?q=tibia+rotating&ia=web
https://duckduckgo.com/?q=tie+rod&ia=about
https://en.m.wikipedia.org/wiki/Tie_rod
The popliteus muscle assists in knee flexion and its function is decided according to position of the lower extremity, i.e. weight bearing or non weight bearing, as it is a primary internal rotator of the tibia in a non weight bearing position.[2]
1 In open chain kinematics, it rotates tibia medially
http://web.archive.org/web/20201111235937/physio-pedia.com/Popliteus_Muscle
https://duckduckgo.com/?q=difference+between+straight+and+locked+knees&ia=web
The tibiofibular joints are a set of articulations that unite the tibia and fibula. These two bones of the leg are connected via three junctions;
The superior (proximal) tibiofibular joint - between the superior ends of tibia and fibula
The inferior (distal) tibiofibular joint - between their inferior ends
The interosseous membrane of leg (middle tibiofibular joint) - connects their shafts
The superior tibiofibular joint is a plane synovial joint, while the inferior one is a syndesmosis (fibrous joint). These joints allow no active movements. They do, however, permit a small range of gliding movements that accomodate the movements of the ankle joint.
https://web.archive.org/web/20200812145313/https://www.kenhub.com/en/library/anatomy/tibiofibular-joints
There are no actions of the leg comparable to the supination and pronation of the arm.
http://web.archive.org/web/20220522143836/britannica.com/science/human-skeleton/Long-bones-of-arms-and-legs
https://www.youtube.com/watch?v=Y5fTfDzvMiA
http://web.archive.org/web/20220706163514/https://www.youtube.com/watch?app=desktop&v=Y5fTfDzvMiA
Jonathan Fitzgordon
https://m.youtube.com/user/corewalking
http://web.archive.org/web/20220706164229/https://www.youtube.com/user/corewalking?app=desktop
https://duckduckgo.com/?q=tibia+and+fibula+vs+radius+and+ulna&ia=web
Copyright Carl Janssen 2022
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