Description

This video covers the anatomy of the lower leg bones – the tibia and fibula.

Each structure is explained with landmarks, joint connections, muscle attachments, and clinical relevance.

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TIBIA (Tibia)

Proximal End

Medial condyle (condylus medialis) – articulates with medial femoral condyle
Lateral condyle (condylus lateralis) – articulates with lateral femoral condyle
Superior articular surfaces – support femoral condyles
Intercondylar eminence (eminentia intercondylaris) – separates intercondylar areas
Anterior intercondylar area (area intercondylaris anterior) – attachment for ACL, anterior horns of menisci
Posterior intercondylar area (area intercondylaris posterior) – attachment for PCL, posterior horns of menisci
Articular facet for fibula – forms proximal tibiofibular joint
Tuberosity for iliotibial tract – insertion for iliotibial band

Shaft

Tibial tuberosity (tuberositas tibiae) – insertion for patellar ligament
Anterior border (margo anterior) – sharp, subcutaneous “shin”
Medial border (margo medialis)
Interosseous border (margo interosseus) – attachment for interosseous membrane
Medial surface (facies medialis) – subcutaneous surface
Lateral surface (facies lateralis) – origin for tibialis anterior
Posterior surface (facies posterior) – origin for flexor muscles
Soleal line (linea musculi solei) – origin of soleus and fascial separation

Distal End

Medial malleolus (malleolus medialis) – supports ankle joint, attachment for deltoid ligament
Articular facet of medial malleolus – articulates with talus
Inferior articular surface (facies articularis inferior) – articulates with talus
Malleolar groove (sulcus malleolaris) – guides flexor tendons
Fibular notch (incisura fibularis) – anchors fibula via tibiofibular syndesmosis

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FIBULA (Fibula)

Proximal End

Apex of head (apex capitis fibulae)
Head of fibula (caput fibulae) – articulates with tibia, muscle and ligament attachment
Articular facet of fibular head – part of superior tibiofibular joint
Neck of fibula (collum fibulae) – common fibular nerve crosses here

Shaft

Anterior border (margo anterior)
Posterior border (margo posterior)
Interosseous crest (crista interossea) – attachment for interosseous membrane
Medial surface (facies medialis) – muscle origin
Lateral surface (facies lateralis) – origin of fibularis muscles
Posterior surface (facies posterior) – origin of tibialis posterior and flexor hallucis longus

Distal End

Lateral malleolus (malleolus lateralis) – lateral support of ankle
Articular facet of lateral malleolus – articulates with talus
Malleolar fossa (fossa malleoli lateralis) – ligament attachment
Malleolar groove – guides tendons of fibularis longus and brevis

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Joints Between Tibia and Fibula

Superior tibiofibular joint (articulatio tibiofibularis) – plane synovial joint, supported by anterior and posterior ligaments of fibular head
Interosseous membrane (membrana interossea cruris) – fibrous sheet between shafts, stabilizes and transmits force
Distal tibiofibular joint (syndesmosis tibiofibularis) – fibrous syndesmosis, reinforced by anterior and posterior tibiofibular ligaments

—

Clinical Relevance

Osgood-Schlatter disease – inflammation at tibial tuberosity due to overuse
Common fibular nerve injury – from trauma to fibular neck, may cause foot drop
Tibiofibular syndesmosis injury – high ankle sprain due to ligament rupture

—

Sources

Kozlowski, T. (2017). Memorix Anatomy, 2nd ed.
Standring, S. (2020). Gray’s Anatomy, 42nd ed.
White TD, Folkens PA. (2005). The Human Bone Manual

Programs used

Complete Anatomy (3D4Medical), PowerPoint, Canva, Camtasia

Transcript

0:00:00.080,0:00:04.880
This is a video about the bones of the lower leg,
more specifically about the tibia and the fibula.

0:00:04.880,0:00:09.840
The tibia is the main weight-bearing bone – it
forms the shin and helps make up the joints at

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both the knee and the ankle. The fibula runs
along the side of the leg and, while it doesn’t

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bear much weight, it provides important muscle
attachments and helps stabilize the ankle.

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So what we’re going to do in this video is go
through the parts of each of these bones, look at

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their surface landmarks, and then talk a little
bit about the joints that hold them together.

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What’s up everyone, my name is Taim. I’m a
medical doctor, and I make animated medical

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lectures to make different topics in medicine
visually easier to understand. If you’d like a

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PDF version or a quiz of this presentation, you
can find it on my website, along with organized

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video lectures to help with your studies.
Alright, let’s get started.

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So let’s start with the tibia, and to keep
things simple, let’s isolate just this bone.

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Like any long bone, we divide it
into three parts: the proximal end,

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the shaft, and the distal end. Let’s look at all
landmarks related to the proximal part first.

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Now, right away, we can see two large expansions
on either side. We’ve got the lateral condyle

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here, and the medial condyle on this side.
If we just tilt it a little bit, we can see that

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both condyles carry superior articular surfaces,
smooth regions where the femoral condyles sit. And

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right above these, we normally find the menisci,
which help absorb shock and together with all

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the ligaments and capsule form the knee joint,
which we covered visually in the last video if

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you wanna learn about it in detail.
Otherwise on the lateral condyle,

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there’s also an important site just off to
the side: the fibular articular facet. This

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is where the fibula locks in and forms the
superior tibiofibular joint. It’s a small

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plane-type synovial joint—doesn’t move much—but
it’s tightly bound and helps stabilize both bones

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together, especially during ankle movement.
Between the condyles, we’ve got this raised

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ridge—the intercondylar eminence. Anterior
to it is the anterior intercondylar area,

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and behind it is the posterior intercondylar area.
Why are these important? Because this is where

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the cruciate ligaments of the knee attach. The
anterior cruciate ligament, or ACL, anchors right

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into the anterior intercondylar area, along with
parts of the medial and lateral menisci. And if

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we look at the back, the posterior intercondylar
area gives attachment to the posterior cruciate

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ligament, or PCL, as well as the menisci
And as you can see from this posterior view, the

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PCL sits deep into that area, anchoring the tibia
to the femur and resisting posterior displacement.

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Lastly, just under the lateral condyle, there’s
a small bump called the tuberosity for the

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iliotibial tract, which provides attachment
of the iliotibial tract, as you see here.

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So that was all the structures I wanted to
highlight for the proximal part of the tibia.

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The view we are looking at right now is the
anterior view of the tibia. If we flip it around,

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here’s the posterior view of the
lower leg, so let’s go ahead and

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isolate the tibia from this side as well.
Since we’re done with the proximal end,

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let’s now go through the landmarks
associated with the shaft of the tibia.

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The first one to notice is this diagonal
line running across the posterior surface,

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called the soleal line. This is where the
soleus muscle originates, and it also serves

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as an attachment for the transverse intermuscular
septum, which separates the superficial and deep

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muscle compartments in the posterior leg.
Look at the front side of the leg now,

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we can find a really important bump here called
the tibial tuberosity. This is the insertion point

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of the quadriceps femoris. The quadriceps tendon
runs over the patella, and then continues as the

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patellar ligament, which inserts directly onto
this tuberosity. So when your quads contract, they

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pull on this spot, which extends your knee. In
adolescents, overuse of this region can actually

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cause a condition called Osgood-Schlatter disease,
where the tuberosity becomes painful and swollen.

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Now, let’s look at the borders of the shaft.
We’ve got three: the anterior border, which

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is this sharp ridge you can feel right down the
front of your shin; the interosseous border, which

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is lateral and faces the fibula. And we can see
the medial border, which runs along the inside.

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These borders divide the shaft into three
surfaces. We’ve got the posterior surface,

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facing backward, this one gives origin to several
deep flexor muscles like tibialis posterior.

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Then we have the lateral surface, which lies
between the anterior and interosseous borders,

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this is where muscles like tibialis anterior
originate. And we got the medial surface,

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which faces inward and is very subcutaneous,
lying just under the skin, so you can easily

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palpate it on yourself along the shin.
Alright, now let’s move down to the

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distal end of the tibia, so let’s zoom in.
The first thing we see here is the medial

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malleolus – this prominent bony projection on
the inside of the ankle. It forms the medial

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side of the ankle joint and provides
attachment for the deltoid ligament,

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also known as the medial collateral ligament. It’s
a strong, fan-shaped ligament that stabilizes the

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ankle and resists eversion.
If we look at it from below,

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we can see the articular facet of the medial
malleolus, which articulates with the talus.

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And next to it is the inferior articular surface
of the tibia, this flat surface bears weight and

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articulates directly with the trochlea of
the talus, forming part of the ankle joint.

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Looking at the posterior side, we can see the
malleolar groove. This shallow depression guides

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the tendons of the tibialis posterior and flexor
digitorum longus muscles as they pass behind the

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medial malleolus. And finally, on the lateral
side of the distal tibia, we’ve got the fibular

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notch. This is the groove where the distal end
of the fibula fits in and gets held tightly by

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the tibiofibular syndesmosis, which helps lock
the tibia and fibula together at the ankle.

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So that’s all the structures I
wanted to mention on the tibia.

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Now let’s go ahead and focus on the
fibula, so let’s isolate the fibula now.

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Just like the tibia, the fibula also
consists of three parts: the proximal end,

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the shaft, and the distal end.
Let’s begin with the proximal end.

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So, looking at the top of the fibula, we can
see a small, pointed projection called the apex

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of the head of the fibula. And if we rotate the
fibula just a little medially, you’ll notice this

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articular facet, right here. This is where the
fibula articulates with the lateral condyle of the

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tibia, forming the proximal tibiofibular joint.
Now, these structures—the apex and the articular

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facet—are both part of the head of the
fibula, which is this expanded upper portion.

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The head of the fibula serves several
important roles. It provides insertion

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for the biceps femoris, origin for the
soleus and fibularis longus muscles,

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and acts as an attachment site for a bunch of
ligaments: the fibular collateral ligament,

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arcuate popliteal ligament, and both the anterior
and posterior ligaments of the fibular head.

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Just below the head, we have this narrower region
called the neck of the fibula, which is clinically

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important because the common fibular nerve wraps
around it. That means trauma or fractures here can

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easily injure the nerve, leading to foot drop.
Alright, so that wraps up the structures of

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the proximal fibula.
If we now look at the

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posterior view of the leg and isolate the fibula
again, we can take a closer look at the shaft.

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Running along the shaft, we can
see several borders and surfaces.

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Starting here, we’ve got the anterior border of
the fibula, which runs vertically along the front.

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Just beside it is the interosseous crest—this
is where the interosseous membrane attaches,

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linking the fibula to the tibia and
helping maintain their alignment.

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On the back side, we’ve got the posterior border
of the fibula, and then surrounding these borders

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are the surfaces of the shaft.
We’ve got the lateral surface,

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which lies between the anterior and posterior
borders—it gives origin to the fibularis muscles,

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like fibularis brevis and longus.
Then we have the posterior surface,

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where deep muscles like tibialis posterior
and flexor hallucis longus arise.

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And finally, the medial surface—this one
faces the tibia and also provides origin

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for parts of extensor digitorum longus.
So that was a quick overview of the shaft

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of the fibula. Now let’s cover the structures
associated with the distal end. So let’s zoom in.

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The first thing we see here is the articular facet
of the lateral malleolus—as you can see, it sits

0:08:02.240,0:08:07.280
tightly against the lateral side of the talus,
forming the lateral part of the ankle joint.

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If we flip it around to the posterior
view, we can see this depression called

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the malleolar fossa. It gives attachment to
ligaments that stabilize the ankle joint.

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And running alongside it is the malleolar
groove—this is where the tendons of the fibularis

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brevis and fibularis longus pass through. These
tendons share a common tendon sheath, and they’re

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held firmly in place by the superior fibular
retinaculum as they curve around the ankle.

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So that’s all the structures I wanted to highlight
on the fibula. And with that we’ve covered the

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Tibia and Fibula of the lower leg.
Now—how are the tibia and

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fibula actually held together?
They’re connected at three levels:

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along the shaft, up here at the proximal
end, and down here at the distal end.

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Let’s start with the proximal tibiofibular
articulation—this is a plane-type synovial

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joint between the lateral condyle of
the tibia and the head of the fibula.

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It’s supported by two ligaments: the
anterior ligament of the fibular head

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and the posterior ligament of the fibular head.
Then, along the shaft, we’ve got the interosseous

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membrane. This fibrous sheet spans between the
interosseous borders of the tibia and fibula.

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It stabilizes the bones, allows for muscle
attachment, and helps transmit forces from

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the fibula to the tibia during movement.
And lastly, at the distal end, we’ve got

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the distal tibiofibular joint, which is a
syndesmosis—a fibrous joint that doesn’t

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move much but provides strong stability.
This joint is reinforced by the anterior

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and posterior tibiofibular ligaments.
So, that was everything I wanted to talk

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about for the tibia and fibula.
I really hope it was helpful!

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The next topic in our lower limb
skeletal series is the bones of the foot.

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So if you’re curious about how the tarsals,
metatarsals, and phalanges come together

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to form the arches and structure of
the foot, click on the next video to

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continue learning, and I’ll see you there.
If you want a handmade PDF version of this

0:09:55.120,0:09:59.120
lecture, take a quiz to test your knowledge,
or access an organized list of all my videos,

0:09:59.120,0:10:02.000
you can find everything on my website.
Thanks for watching! See you in the next one.