Elbow Joint – 3D Anatomy Tutorial

Elbow Joint – 3D Anatomy Tutorial


This is a tutorial on the elbow joint. So
at the elbow joint, you’ve got three joints which are involved. You’ve got the humerus,
the radius and the ulna. So there are actually three articulations
involved with the elbow joint. You’ve got an articulation between the humerus and the
ulna, so that’s the humeroulnar joint. You’ve got an articulation between the humerus and
the radius. That’s the humeroradial joint. And you’ve also got an articulation between
the radius and the ulna. This is a proximal radioulnar joint because you’ve also got a
distal radioulnar joint. So there’s three bones involved and you’ve
got three articulations. We’ll just take a quick look at some of the
features of the articulating surfaces of the bones before we move on to things like the
joint capsule and ligaments. So the articulating area of the humerus has
two parts. You’ve got the trochlea and the capitulum. So the trochlea is medial and this
is articulates with the trochlear notch of the ulna. The capitulum is this bit here.
This articulates with the head of the radius and this bit is lateral. So you’ve got the
capitulum and the trochlea articulating with the head of the radius and the trochlear notch
of the ulna respectively. So just a few other points about the distal
humerus which are worth noting. You’ve got three fossae. You’ve got the coronoid fossa
here, the radial fossa here and on the back of the humerus, posteriorly, you’ve got the
olecranon fossa — so three fossae. And you’ve got the epicondyle. So you’ve got the lateral
and the medial epicondyles. So let’s just take a quick look at the ulna
and the radius. So I just switched over to an isolated view
of the ulna. You can see this notch here, this is the trochlear notch and this is what
articulates with the trochlea of the humerus. Just below this notch, you can see this depression
here. This is another notch called the radial notch and this articulates with the head of
the radius. This articulation, you get pronation and supination. This little bit here is called the coronoid
process. If I rotate the ulna posterior, this is the olecranon process. So those are a few
features of the ulna which are worth noting before I go on to talk about other features
of the elbow joint. So I’ve just switched back to this view and
you can see the head of the radius articulating with the ulna at that little notch I showed
you, the radial notch on the ulna. So now you can see the humeroradial articulation
between the capitulum of the humerus and the head of the radius, the trochlea of the humerus
and the trochlear notch of the ulna and the radioulnar articulation, the proximal radioulnar
articulation between the head of the radius and the radial notch of the ulna. So what movements do we get at the elbow joints.
Well, at the humeroulnar and the humeroradial joint, we get flexion and extension — so
flexion up this way and extension back this way. The humeroulnar joint is a hinge joint
and the humeroradial joint is a limited ball-and-socket joint. At this point here, the proximal radioulnar
joint, we get supination. So supination is when the hands are in this position and the
anatomical position of the hand is supinated. If the radius rotates over the ulna to bring
the hands to face toward the body, that’s pronation. So we get pronation and supination
at this joint here, the proximal radioulnar joint. This joint is a pivot joint. So now we’ll just take a look at some of the
other features of the elbow joint. We’ll take a look at the joint capsule and the ligaments. So you’ve got three ligaments basically. You’ve
got the radial collateral ligament, the ulnar collateral ligament and the annular ligament.
And then you’ve got a joint capsule, which can be separated into a fibrous and a synovial
membrane. So we’ll just take a look at the joint capsule first. So I’ve just isolated the joint capsule and
you can look at its attachments. So you can see it attaches to the medial epicondyle.
It runs over the two fossae here, so over the coronoid fossa and the radial fossa. And
then it attaches inferiorly on the neck of the radius and on the coronoid process of
the ulna. So posteriorly, the joint capsules attaches
on the margins of the olecranon. You can see how it overlies the olecranon fossa. Underneath the fibrous membrane, you’ve got
the synovial membrane. The synovial membrane is separated from the fibrous membrane by
fat pads. So if I just remove the fibrous joint capsule, the fibrous membrane of the
joint capsule, you can see the fossae, the coronoid and the radial fossae. So if I drawn on the outline of the synovial
membrane which lies roughly here, you’ve got fat pads which sit on top of it and separate
it from the fibrous membrane. These fat pads, they sit over these two fossae, so they sit
on this region here. And if I rotate the model around, you’ve also got a fat pad which overlies
the olecranon fossa. These fat pads separate the synovial membrane from the fibrous membrane
of the joint capsule. So the fibrous membrane of the joint capsule
actually thickens medially and laterally to form the ligaments of the elbow. So laterally,
which we’re looking at here, you can see the joint capsule thickens and it forms this ligament
called the radial collateral ligament. This ligament attaches on the medial epicondyle
and then it also attaches to the radial notch of the ulna and it also extends inferiorly
and blends with this ligament here, the annular ligament, which I’ll show you in a second.
So that’s the radial collateral ligament. Medially, you’ve got the ulnar collateral
ligament, which is formed by a medial thickening of the fibrous membrane of the joint capsule.
The ulnar collateral ligament attaches on the medial epicondyle and it extends down
and attaches to the coronoid process of the ulna. And if we just rotate the model around, we
can look at the posterior extension of this ligament. So the ulnar collateral ligament
also extends backwardly and attaches onto the olecranon. The last ligament is that one I just mentioned,
the annular ligament. So the word ‘annular’ comes from the Latin ‘annulus’, which means
ring. So this ligament forms a ring around the head of the radius. This ligament, again,
it blends with the radial collateral ligament and it also blends with the joint capsule. This ligament is quite important because it
holds the head of the radius in place and it allows the head of the radius to rotate
on the capitulum of the humerus and also, it allows pronation and supination against
the radial notch of the ulna. So you can see how the head sits in that radial notch. The
head can rotate in this notch and is held in place by the annular ligament. So those are some features of the elbow joint.
So the things to remember are that there are three bones involved (the humerus, the radius
and the ulna) and there are three articulations (a humeroulnar, a humeroradial and a radioulnar
articulation) and you’ve got a joint capsule which consists of fibrous and synovial membrane. The synovial membrane is separated from the
fibrous membrane by fat pads which overlie the radial fossa, the coronoid fossa and the
olecranon fossa. The joint capsule thickens medially and laterally
to form the radial collateral and ulnar collateral ligaments. And you’ve got the annular ligament
which surrounds the head of the radius and allows pronation and supination and rotation
against the humerus. So the movements you get at the elbow are
flexion and extension at the humeroradial and humeroulnar articulations and at the proximal
radioulnar articulation, you’ve got pronation and supination. So that’s the elbow joint.

32 Replies to “Elbow Joint – 3D Anatomy Tutorial”

  1. Excellent video. I rely on these to get a better understanding of anatomy. Thank you for your tutorial. I think one thing you could have mentioned through is that the Ulnar collateral ligament resists valgus or lateral force while the Radial collateral ligament resists medial forces or varus force. Please make more tutorials ๐Ÿ™‚

  2. Atheists are not stupid……but atheism is a stupid belief.ย  This is a design kids and designs require a designer.

  3. thanks, good vid has helped a lot! but if u mention the number of axis (uniaxial,biaxial etc), muscles and freedom of movement (if it relates) it would be even better. not hating just something to help us all. lol

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