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Learn the types of movements of the human body.
Hello everyone! This is Joao from Kenhub, and welcome to this anatomy tutorial where we're going to be talking about the body movements. In this tutorial, we'll be learning the different movements that the body is capable of and the terminology we used for those movements. We'll do a brief overview of movement in general to start with and next, we'll run through each of the different types of movement and where they are possible in the body. Then, we can talk about why this knowledge is important clinically and take a brief look at a condition called arthritis. We'll finish off with a summary of what's been covered. So let's start with that overview of body movements.
All movements will be discussed relative to the anatomical position which you see here on the screen. If you need a refresher on this, I'd recommend that you watch the start of the video or even read the first part of the article on directional terms and body planes which you can find here on the Kenhub website. But now you can see here on the screen that in the anatomical position, the arms are relaxed by the side of the body, the legs shoulder-width apart, and the head facing forward.
Movement or motion is the change in position of an object relative to a fixed point – that's essentially the definition that we have for movement. Almost all movement in the joints in your body is in some way rotational meaning that the part that is further away is moving around a pivot point. That point is called the fulcrum. In the body, this is usually a point within the joint. In some cases, an axis may be a more appropriate description than a fulcrum.
While a fulcrum is a point, an axis is a straight line around which rotational movement happens. Each specific movement happens in a particular plane of motion, for example, the sagittal plane or the coronal plane. You can see here a schematic diagram of a ball-and-socket joint. The gray part is the socket and is fixed. The fulcrum is at the base of the socket and the blue part moves around this fulcrum in the sagittal plane, for example. This might sound overly complicated but these terms allow us to describe the motion of the parts of the body accurately. Let's give you an example using the terms we've just described. We'll use the knee as an example.
If you stand on one leg bend just your knee, your lower leg and foot move while your thigh stays stationary. The object – the thing that moves – is the lower leg, the fixed point is the thigh, and the plane through which the movement happens is the sagittal plane. The fulcrum – the point around which the movement happens – is then the knee joint. The blue dot pulsing here is the axis around which the hinged movement of the knee occurs. All kinds of body movement can be described using these principles.
Now that we have an understanding of the underpinning of movement, we can talk about the concept of antagonism. Many of the body's movements are given in pairs. This is because they work in opposite directions to one another like these guys are doing here. We call this then antagonism and describe the movement as antagonistic to one another. So now we can move on to the different kinds of movement.
The body is capable of a lot of complex movements – no wonder you're able to break it down on the dance floor. However, we can describe the individual movements within certain patterns or movement types. We're going to run through these types of movements starting with the major gross movements which are flexion and extension, lateral flexion, abduction and adduction, and rotation – first of the limbs then we're going to look at head and trunk. We'll talk about the less common, more joint-specific movements namely elevation and depression, protrusion and retrusion, circumduction, supination and pronation, deviation, opposition and reposition, plantarflexion or dorsiflexion, and inversion and eversion.
There are a lot of different types of movement but we'll break them down and once we're done, you'll be able to describe any movement the human body can make.
So let's begin with flexion and extension. For this, we'll need a diagram. Here's that drawing of the knee bending again. This is showing knee flexion. The words flexion and extension are separated by a forward slash meaning that they are antagonistic movements. These motions oppose one another. Flexion is the movement of the object in one direction, extension is the movement of the object in the other direction. Both flexion and extension always happen in the sagittal plane. This is the sagittal plane right here. It's the vertical plane running through the body front to back cutting the body right in half which you see here highlighted in green on this image.
So, we're going to go back to the knee to give a proper definition of each term. So, flexion is a movement which decreases the joint angle in the sagittal plane. When the knee here bends, the angle at the knee joint – that's this angle in the back of the knee – reduces from about one hundred and eighty degrees to ninety degrees in this image although it can go further. Then we have extension on the other hand which increases the joint angle in the sagittal plane. That angle behind the knee increases and, in this case, from approximately one hundred and thirty five degrees to one eighty.
Flexion/extension is always in the sagittal plane and we always isolate the movement as if the rest of the body is in the anatomical position. In other words, if we rotate our legs so that our knee points outwards and then bend the knee, we still call this flexion. The joints capable of flexion and extension can be thought as simple or compound. Now, these are not specific terms. They're just being used to refer to joints capable of only one type of movement or joints that are capable of more than one type of movement, respectively.
A hinge joint has very limited movement in any direction other than in the sagittal plane. These hinge joints are then the knees, the elbows, the interphalangeal joints of the fingers and thumbs, and the interphalangeal joints of the toes. The interphalangeal joints are the joints within the fingers, thumbs and toes not including the joints at the bases of each digit. The joints at the bases are capable of an additional movement which we'll cover later. This list is a list of simple joints.
The compound joints by which I mean joints capable of major movements other than flexion and extension are then the intervertebral joints of the neck demonstrating flexion in this image and the joints of the vertebral column which here are showing extension of the spine. In both these spine examples, the angle of the joint is considered to be the anterior or ventral side of the spine.
The shoulder is also capable of flexion, shown here, which is movement anteriorly from base position right up to overhead position. The endpoint of extension of the shoulder is more limited shown here. You can prove this by trying it yourself. It's also a similar story at the hip. Other joints would include then the metacarpophalangeal or MCP joints of the hands highlighted here. They are the joints at the base of each finger. They are more commonly known as then the knuckles. The other joints are the metatarsophalangeal or MTP joints – joints of the foot which are at the base of each toe.
That's all the joints capable of flexion and extension. Now, let's discuss a similar movement which is known as lateral flexion. It's time for an image. Here we have the coronal plane highlighted in green. It's the vertical plane running through the body from side to side and lateral flexion is a decrease in joint angle of a midline structure in the coronal plane. This image shows lateral flexion on the lumbar spine and like flexion and extension where each term gives the direction automatically, we must give a direction to lateral flexion, for example, right lateral flexion. The direction is always from the perspective of the person performing the movement and it is the side on which the joint angle is decreased which is on the side here. We can see that the joint angle along the right-hand side of the spine is reduced to a hundred and eighty degrees or a straight angle to then approximately a hundred degrees.
As well as the lower back otherwise known as the lumbar spine, lateral flexion can also take place in the vertebral column in the cervical spine or your neck. The thoracic spine has very limited, if any, lateral flexion to protect the lungs from being squashed every time we lean over to one side.
Ready to move on to the next set of movements which are abduction and adduction and, again, another image here that you can see here, you see then the coronal plane. Abduction and adduction are antagonistic movements. Like lateral flexion, abduction and adduction take place in the coronal plane. The easiest way to describe abduction and adduction is relative to your midline, and that's how we do for these movements. This diagram is showing abduction of the arm at the shoulder. Abduction sometimes called ab-duction for clarity so AB-duction, which is a movement away from your midline in the coronal plane.
Remember that to abduct something means to take it away. So, in our shoulder example, the arm is moving away from the midline and can continue up to above the head. Then the other one is adduction or AD-duction which is the motion towards the midline. A convenient way of remembering which is which is that adduction, you are adding the body part towards the midline – just a trick here that you can use.
In the diagram, we are seeing the model returning the arm from the AB-ducted or the abducted position to the AD-ducted or adducted position. The end point of adduction or AD-duction is in here. The normal range of motion from anatomical position to the most inner point is around forty five degrees.
There are a few joints in the body where abduction and adduction can take place. Obviously, there is the shoulder like I talked about before but there is also the hip undergoing abduction or AB-duction away from the midline in this image here, and the MCP joints of the fingers which are AD-ducting or adducting together in this image. With the fingers and toes, we take the midline as the midline of the limb which runs through the middle digit instead of the midline of the body. In the thumb, rather than the MCP joint which is here, the carpometacarpal joints of the thumb seen here in green permits abduction and adduction of the thumb.
So that's all that we have for abducting and adducting joints, now we're going on to rotation.
Rotation differs slightly in different areas so we'll split it into rotation in the limbs and rotation in the head and trunk. We'll talk about the limbs first, and highlighted here in green, we see the transverse plane which is the third major body plane. Rotation is a movement around an axis or a fulcrum in the transverse plane. This is the same for limbs and for the head and trunk in the anatomical position.
In the case of the limbs, we can think of it as rotation around the long axis of the limb. That's the axis passing through the limb along its length, for example, from the shoulder down through the center of the straight arm and out through the middle finger. So in the limb as with the other movements, rotation can be described in two directions – external also known as lateral rotation and internal rotation also known as medial rotation. We'll look at each in turn.
This drawing nicely shows our model performing external rotation at his shoulder. External rotation is movement of the limb in a twisting fashion so that the anterior aspect of the joint moves away from the midline or externally. This is best shown when the arm is bent to ninety degrees because the forearm corresponds to the front of the shoulder joint. So, in the diagram, the forearm is pointing out away from the midline – you can see clearly here externally rotated.
Now we're moving on and looking now on the screen, we're seeing internal rotation happening. Internal rotation is rotation of the anterior aspect of the joint then towards the midline. Again, what the model is demonstrating is the elbow bent ninety degrees and we can see that the hand moves back across the body. For comparison, here we have external rotation at the hip. This time, we're keeping the leg straight and the foot points in the direction of rotation. In the case of external rotation, this is away from the midline as shown. And for completeness, here's internal rotation at the hip with the foot pointing in toward the midline.
So remember that rotation occurs in the limbs around the joints of the hip in the lower limb and the shoulder for the upper limb. The shoulder and hip are the fulcrum for each movement as each is the point around which the rotation is occurring. The axis is a straight line through the center of the shoulder joint or hip joint and the plane is then the transverse plane.
Now we're moving away from rotation of the limbs to then rotation of the head and the trunk. Here we are showing rotation of the head. Rotation of the head and trunk are also twisting motions in the transverse plane. These movements occur around a long axis – in this case, that long axis is the vertebral column. As with rotation of the limbs, we need to give a direction. Because the structures rotating here are in the midline, we cannot use terms external and internal so we use left and right instead. We tend to describe these movements more fully giving then the movement that is rotation, the part that we perceive to be moving, and then the direction.
For example, if the model turns her head to the left, we describe this as rotation of the head to the left. The joints capable of rotating the head and the trunk are then found in the cervical spine or neck and the thoracic spine which is shown rotating in this image. The lumbar spine is capable of very little rotation as it is required to take the heavy load of the body above it. The lumbar spine performs the majority of flexion and extension and lateral rotation in the spine so it really can't do everything, and not rotating makes it more stable.
So we've just finished talking about the more common and important movements that we need to know about. Now we come to the more joint-specific movements. These may be less common in the body but their specificity helps them serve vital functions and we're going to start with depression and elevation of the mandible.
This diagram is showing depression of the mandible, otherwise known as the lower jaw. Depression and elevation are a pair of movements possible only at the mandible. They occur at the temporomandibular joint or TMJ which is a joint that happens between the temporal bone and the mandible. The joint is positioned just anterior to the external ear canal.
Here's the skeletal diagram showing the mandible to help us. Depression and elevation are the translation of an object directly inferiorly and superiorly, respectively. Translation means that the movement is performed without rotation. All the movements that we have discussed so far have been rotational movements in different planes but the jaw is different due to the anatomical makeup of the TMJ. Its structure allows the mandible to essentially be pulled out of the socket. In the case of depression of the mandible, the condyle of the mandible is pulled directly down out of the joint. You might be asking, but what's the function of this?
Well, when the TMJ is closed, the power of the muscles and the depth of the socket make it very stable. This will then reduce the chance of injury. And if you badly injure your jaw, you can't eat, which isn't good from an evolutionary perspective. The payoff for having a deep socket though is limited range of movement which we abbreviated to ROM. In fact, with rotation at the TMJ alone, you can only open your mouth about twenty millimeters or so. The ability to translate the mandible allows us to temporarily destabilize our jaw by pulling it out of the deep socket. No longer limited by the boundaries of the socket, the jaw then gains increased range of movement and can open wide to tackle more food.
So our model here is able to tuck into a big meal instead of being restricted to crumbs like a bird. This is performed through a combination of then depression, rotation in the sagittal plane which could be thought as similar to extension but isn't called that, and another movement called protrusion which we'll talk about next. When we close the jaw, the reverse happens and the mandible is pulled by powerful muscles back into a stable position within the TMJ.
And, as promised, protrusion is up next along with its paired movement, retrusion. Here we're looking at our model performing isolated protrusion of the mandible. Protrusion and retrusion are the anterior and posterior translation of an object respectively. In other words, in protrusion, the part being moved is pulled forward without any rotation which we can see here, the arrow indicating the direction of the movement.
Going back to our friendly skull showing the mandible, let's look at how protrusion helps with opening the mouth wide. Protrusion of the mandible refers first and foremost to the condyle of the mandible – this bit right here. To pull the mandible out of its socket, it would require a huge burst of energy to pull it straight down. Instead, protrusion pulls the condyle forward using the front of the socket like a wedge. This is easier. Think of trying to jump a large height compared to walking up a slope of that same height. The condyle ends up anterior from its resting position around about here. Now the jaw is free to hinge and open wider.
We can see now retrusion shown here, the condyle of the mandible is being drawn posteriorly. You may also hear the terms protraction and retraction. These are not the same as protrusion and retrusion but are sometimes and wrongly used interchangeably. Protraction and retraction mean protrusion and retrusion plus lateral movement. A cow chewing cud is a good example of protraction and retraction.
Moving away from the mandible, let's work down the body to the next special movement which is known as circumduction. Here we have circumduction of the upper limb. This is best defined as the upper limb expressing a conical motion from a point in the shoulder with the point of the cone here. It manifests in real time as drawing a circle with the limb. This movement is a compound movement by which I mean it is a complex interaction of other movements. At the shoulder, it is performed by an almost infinite number of minute changes in flexion, extension, abduction and adduction.
The shoulder is not the only joint capable of circumduction. The other joints able to perform this movement are the hips, the fingers and, of course, the thumbs. Why do we need this movement? Well, it allows a huge range of movement and it means that we can interact with the world around us in a much more fluid way. This, in turn, lets us manipulate liquids amongst other things. As a modern-day example, stirring becomes a lot more difficult using only flexion and extension but please do not try this at home, guys.
Down to the forearms now for a pair of movements called supination and pronation, here's a view of the forearm moving in supination. This movement is specific to the forearm. There are two joints involved in this movement – the proximal and distal radioulnar joints. The proximal one being, well, approximately here and the distal one being here at the wrist. Supination and pronation are the act of putting the palm of the hand into a supine or prone position respectively. For this, it is important to remember that in the anatomical position, the palms are facing anteriorly so when the model is lying down in the anatomical position, the palms are facing upwards or, in other words, supine.
Another quick way to remember it using a pun – who doesn’t love puns? Well, is that palms up as if you are holding a soup bowl so your hands are then supinated. As you can see, we are very creative in anatomy.
Let's continue on and here we flip the arrow to demonstrate that pronation is just the reverse. For this movement to occur, the radius is pulled up and over to the medial side of the ulna at the distal end whilst then remaining lateral to the ulnar proximally. The ability to twist the forearm in this way gives us a lot more dexterity at our hands allowing us to then screw a light bulb or then twirl spaghetti round the fork. I think this is good for all the pasta lovers out there.
Now coming down the wrist, we have the special movement known as deviation. We have this skeleton here viewed from the anterior aspect with the ulna highlighted on each arm. The skeleton is in the anatomical position. It is important to remember which side is the ulna and which side is the radius at the wrist. We do that because the hand can be in many different positions when being examined in a clinic. As we can identify here, ulnar is pinky side – this is medial in the anatomical position – and radial is thumb side – that's the first digit – and is lateral in then the anatomical position.
Now we're looking at ulnar deviation, sometimes called ulnar flexion. Deviation is a more accurate term as this movement involves multiple bones therefore multiple joints at the wrist as opposed to flexion of a single joint. The bones involved are the carpal bones, the radius and the ulna. Ulnar deviation is a reduction in angle between a straight line through the hand and the ulnar side of the forearm.
The movement of deviation at the wrist is in the coronal plane towards the midline and so is most similar to adduction, so AD-duction. The opposite direction is then radial flexion demonstrated here. This time, the angle being reduced is that between a straight line through the hand and the radius at the wrist. In the anatomical position, this is away from the midline in the coronal plane so is more like abduction, so AB-duction. Remember that the wrist is the only joint capable of deviation. Deviation can occur in other joints like the knuckles but only when that joint is diseased or, in other words, when something is wrong with it.
The last specific movement related to the upper limb is one that gets talked about a lot in reference to evolution – opposition and reposition. We're talking about that infamous opposable thumb. Here's that movement demonstrated. Opposition of the thumb is a compound movement which brings the thumb round and across the palm to press against the other finger. This allows us to generate a powerful grip whilst also providing dexterity by allowing us to grip very precisely.
Adduction, abduction and flexion of the fingers bring the fingers towards the thumb to create a grip. Throughout evolution, this has allowed us to grab onto trees, grab onto spears and craft tools with delicate but firm precision. The first carpometacarpal joint highlighted on this diagram makes this movement possible. Carpometacarpal refers to the joint between the carpal bone of the wrist and the metacarpal bone of the hand. In this case, the metacarpal is the part of the thumb which we considered to be the first digit so it is the first metacarpal. The joint therefore is named the first carpometacarpal joint.
This joint is described as a saddle joint because of its shape. The metacarpal rides over the end of the carpal bone. The joint shape allows flexion, extension, abduction, adduction, circumduction, and opposition and reposition. The first carpometacarpal joint is the only saddle joint in the body. This now is showing the reversal of opposition of a thumb called reposition. We can see that the thumb's ends are back in its normal resting position alongside the index finger on the radial side of the hand.
That's all of the upper limb movements complete so now we can move on to the lower limbs. Let's make our way down into the lower limb all the way to the ankle, in fact, and talk about plantarflexion and dorsiflexion. At the ankle joints which, like the wrist, has multiple bones and joints within it, we have two unique pairs of movements – plantarflexion/dorsiflexion and inversion/eversion. We'll deal with the former first.
Our model is showing us plantarflexion. Now, they're demonstrating dorsiflexion. These two movements are antagonistic despite both having flexion in their names. The reason for this is that using the terms extension and flexion could be misleading and, on top of that, there are multiple joints involved so the mechanics of it are not as simple as single joint flexion similar to palmar flexion/dorsiflexion at the wrist. Note that the difference is palmar pertaining to the palm of the hand and plantar referring to the plantar surface or sole of the foot. So which way is which?
While the answer is in the name if we know the terminology of the foot, in plantarflexion, plantar refers to the plantar surface of the foot also known as the sole of the foot. So it follows that plantarflexion is a movement down through the plantar surface of the foot. This is shown by the arrow on the diagram. A helpful way to remember this is that with plantarflexion, you are planting the ball of your foot on the ground, pushing away the ground to sprint away.
Now dorsiflexion is a short way for dorsal flexion – dorsal means relating to the back. If you've heard anyone talking about the dorsal fin of a shark or dolphin, dorsal just means that the fin is on the back. So in the case of the foot, dorsal is meaning towards the dorsum, in other words, the back of the foot. That's the side of the fin which is this side. Dorsiflexion is movement of the foot towards the dorsum of the foot.
We promised another unique pair of movements at the ankle and they are then inversion and eversion. The good news is that this is also the final movement to run through before we complete this tutorial. This is inversion of the foot that you see now. In many ways, it is similar to deviation at the wrist. The multiple bones involved in the ankle are the tarsal bones and the tibia. Inversion and eversion are reduction in the joint angle in the coronal plane. This is similar to adduction – AD-duction – in the case of inversion, and abduction – AB-duction – in the case of eversion.
Inversion turns the plantar surface of the foot to face medially, that is, towards the midline. Eversion shown here turns the plantar surface laterally – in other words, outwards or away from the midline. Inversion and eversion allow us to navigate over uneven terrain whilst remaining stable enough that we could rapidly change speed or direction. While this is favorable as it means we don't get chomped by the big cat sneaking up on us or nowadays get hit by a car that we didn't hear coming.
We're there. We've gone through all of the types of movement in the human body. Give yourself a pat on the back and as you do so, work out what movements you're using, just as a quick test.
As we like to do with all our tutorials, let's add a bit of clinical relevance to this newfound knowledge. Today, we'll introduce arthritis which is a group of conditions that involve the joints. As an example of arthritis, here's a patient with rheumatoid arthritis of the hands. Note that the ulnar deviation of the fingers which is one of the many characteristic features of this condition.
Arthritides –plural for arthritis – are a group of conditions. The term arthritis simply means "inflammation of a joint". Arthritis has its own causes which can be infective known as septic arthritis if it's due to bacteria, autoimmune such as rheumatoid arthritis or psoriatic arthritis, due to wear and tear or repetitive microtrauma to put it into more technical terms leading to then osteoarthritis, or congenital, for example, Ehlers-Danlos syndrome. By knowing the movements and by combining that with knowledge of joint anatomy, you can narrow down where the problem is within the joint like here with the ulnar deviation of the fingers.
Tip for examining a joint – if you're not sure what movements are possible at a particular joint, you can test it on yourself by holding the proximal side of the joint and seeing what movements you can still manage. This is isolating the joint. When you want to test a specific joint of a patient, you should do the same so isolate the joint to make sure they cannot compensate the movement with another movement at another joint and to confirm that any abnormality is coming from the joint being examined.
And that, my friends, is all for this lesson but before we finish, I would like to summarize what we covered on this tutorial. First, we introduced the principles of movement and how to describe it. Next, we started to go through the types of movement in the body giving definitions and listing at what joints each movement is possible. We described flexion and extension as rotational movement in the sagittal plane, lateral flexion as rotational movement of a midline structure in the coronal plane, abduction/adduction as rotational movement of a non-midline structure in the coronal plane, rotation of a limb as rotational movement around the long axis of that limb, and rotation of the head and trunk as rotational movement in the coronal plane or, in other words, around the long axis of the vertebral column.
Having covered that, we come on to looking at more specific movements. Starting at the top, we had the mandible performing depression and elevation which we said is translation inferiorly and superiorly, respectively, and protrusion and retrusion which is translation anteriorly and posteriorly, respectively. There was also protraction and retraction meaning protrusion or retrusion with added lateral movement.
Our next image showed us circumduction at the shoulder with the limb drawing the shape of a cone and we found out that the hip and thumb can also perform this motion. Examining the forearm yielded supination and pronation which is a twisting of the radius over the ulna to make the palm of the hand supine or prone respectively. The wrist gave us deviation also known as ulnar and radial flexion depending on the direction. And we discussed that the ulna is on the pinky side of the hand while the radius is on the thumb side. In the hand, we studied opposition and reposition of the thumb and learned its importance.
Once we finished the upper limb, we completed our search for types of movement at the ankle with plantarflexion or dorsiflexion – that is the rotational movement of the ankle in the sagittal plane in a plantar or dorsal direction – and inversion or eversion which is a rotational movement at the ankle in the coronal plane. We mentioned that palmar as opposed to plantarflexion and dorsiflexion can be used to describe flexion at the wrist. Finally, we gave a reason for needing to know about the types of movement by introducing the clinical scenario of rheumatoid arthritis and we snuck in a tip of examining joints.
And that's it for this tutorial. Thank you for watching and I will see you on the next one.