Description

Clavicle (Collarbone) Anatomy | Structure, Joints & Clinical Relevance

Structures covered in this video:

Clavicle Anatomy – Parts:
• Sternal end (Extremitas sternalis)
• Acromial end (Extremitas acromialis)
• Body of the clavicle (Corpus claviculae)
• Sternal facet (Facies articularis sternalis)
• Acromial facet (Facies articularis acromialis)
• Subclavian groove (Sulcus musculi subclavii)
• Conoid tubercle (Tuberculum conoideum)
• Trapezoid line (Linea trapezoidea)
• Impression for costoclavicular ligament

Joints Formed by the Clavicle:
• Sternoclavicular joint (Articulatio sternoclavicularis)
 • Clavicular notch of manubrium (Incisura clavicularis)
• Acromioclavicular joint (Articulatio acromioclavicularis)

Ligaments of the Clavicle:
• Costoclavicular ligament (Ligamentum costoclaviculare)
• Interclavicular ligament (Ligamentum interclaviculare)
• Anterior sternoclavicular ligament
• Acromioclavicular ligament
• Coracoclavicular ligament
 • Conoid ligament (Ligamentum conoideum)
 • Trapezoid ligament (Ligamentum trapezoideum)
• Coracoacromial ligament (Ligamentum coracoacromiale)

Associated Muscles:
• Subclavius
• Pectoralis major
• Sternocleidomastoid
• Trapezius
• Deltoid

Neurovascular Structures Protected by the Clavicle:
• Brachial plexus
• Subclavian artery
• Subclavian vein

Functional Anatomy:
• Clavicle as a strut
• Force transmission from upper limb to axial skeleton
• S-shape acting as a shock absorber
• Scapular suspension and positioning

Clinical Anatomy and Conditions Discussed:
• Clavicle fracture (Middle third most common)
• Clavicle dislocation
• Acromioclavicular joint injury
 • AC joint step-off
 • Cross-body adduction test
 • Piano key sign
 • O’Brien’s test
• Sternoclavicular joint dislocation or arthritis
• Distal clavicular osteolysis (Weightlifter’s shoulder)
• Cleidocranial dysplasia (Absence of clavicle)
• Neurovascular injury signs (Pulse, cap refill, sensory loss)

Imaging Techniques Mentioned:
• AP clavicle X-ray
• CT scan for subtle fractures or joint evaluation
• MRI for osteolysis or soft tissue pathology
• Chest X-ray to rule out associated rib fractures or pneumothorax

Treatment Options:
• Conservative management (sling, NSAIDs, physiotherapy)
• Surgical fixation (for displaced or unstable fractures)
• Grading of AC joint injuries (Type I–III)
• Distal clavicle excision (arthroscopic or open)

Sources:
• Kozlowski, T. (2017). Memorix Anatomy, 2nd ed.
• Standring S. (2020). Gray’s Anatomy, 42nd edition
• Tubbs RS, Shoja MM, Loukas M. (2016). Bergman’s Encyclopedia of Human Anatomic Variation
• White TD, Folkens PA. (2005). The Human Bone Manual

Programs used: Complete Anatomy, Biorender, PowerPoint

Transcript

Introduction & Content
0:00
Let’s take a look at this bone. You’ve probably seen it, felt it, maybe even
0:04
fractured it. It’s the clavicle, or collarbone. Now, let’s place it in context. Here it is on
0:10
the human body, running horizontally from the base of the neck to the shoulder. It’s the
0:14
only long bone that lies horizontally, and it sits right under the skin, superficial,
0:20
easy to feel, and yes, easy to injure. Anatomically, it connects the upper
0:25
limb to the axial skeleton. This makes the clavicle an important part of the upper limb,
0:30
alongside the scapula, humerus, radius, ulna, and hand. It gives your arm freedom to move while
0:37
protecting the underlying neurovascular bundle. So in this video, we’re gonna keep it simple.
0:42
We’ll talk about the clavicle’s parts, surface, basically its anatomy, we’re
0:46
gonna cover the joints it forms, and then ask a simple question—why do we even have a clavicle?
0:52
Because what’s fascinating is, some people are actually
0:55
born without one, to which they can do this. And lastly we’ll look at some clinical relevance,
1:01
injuries, signs, and what to look out for when a patient walks in with clavicle pain.
1:06
What’s up everyone, my name is Taim. I’m a medical doctor, and I make animated medical lectures to
1:10
make different topics in medicine visually easier to understand. If you’d like a PDF version or a
1:15
quiz of this presentation, you can find it on my website, along with organized video lectures
1:19
to help with your studies. Alright, let’s get started.
Clavicle Anatomy
1:21
Clavicle Anatomy. It’s so simple. The clavicle has three basic parts. First,
1:27
we have the sternal end. It’s the medial part, thicker and rounded, and it connects
1:32
to the sternum. Then on the lateral side, we’ve got the acromial end. It’s flatter and broader,
1:38
and this is the part that meets the scapula at the acromion. And in between these two, there’s
1:43
the body of the clavicle, long, curved shaft. Now let’s place this clavicle in the body.
1:50
At the acromial end, we can see the scapula, and specifically the acromion of the scapula,
1:55
this is where the clavicle articulates laterally. Then on the other side, we can see the sternal
2:00
end and the sternum, that’s where the clavicle articulates medially. Alright, I assume it makes
2:06
sense at this point. Let’s expand on this. We’ll isolate the clavicle again, and then
2:11
rotate it slightly in this direction. We’ll see this, the inferior surface. On the medial side,
2:18
we can see a smooth surface called the sternal facet, that’s where it meets the manubrium. Just
2:24
below it, this rough patch is the impression for the costoclavicular ligament, which is involved
2:30
in stabilizing the medial joint, I’ll show you in a minute, but as we move across the body,
2:35
this long groove is the subclavian groove, where the subclavius muscle sits and anchors.
2:41
Then as we move on to the lateral third, we can see the acromial facet, which is where the
2:46
clavicle meets the acromion of the scapula. We can see the conoid tubercle and the trapezoid line,
2:52
these are the attachment points for the conoid and trapezoid ligaments, which are
2:56
essentially part of the coracoclavicular ligament. So that’s the general layout of the clavicle,
Joints of the Clavicle
3:02
it’s very simple. Let’s now move on to the joints it forms. There are two joints. On the medial end,
3:08
the clavicle is attached to the sternum through the sternoclavicular joint. On the lateral end,
3:14
it’s attached to the acromion of the scapula, through the acromioclavicular joint.
Sternoclavicular Joint
3:19
Let’s now focus on the sternoclavicular joint for a moment.
3:23
The sternoclavicular joint is a joint where the articulating head is the sternal facet of
3:28
the clavicle, and the articulating fossa is the clavicular notch on the sternum.
3:33
These two together form the articular surfaces of the sternoclavicular joint.
3:38
Now I’ll remove those labels, and let’s look at the supporting ligaments that
3:42
stabilize this joint. Just below, you can see the costoclavicular ligament, connecting the inferior
3:49
surface of the clavicle to the first rib. Above that, running horizontally across the top, is the
3:54
interclavicular ligament, linking both clavicles across the jugular notch. And right here in front,
4:01
attaching the clavicle to the sternum, is the anterior sternoclavicular ligament.
Acromioclavicular Joint
4:06
Now let’s shift over to the acromioclavicular joint, on the lateral end of the clavicle. First,
4:12
we see the acromioclavicular ligament. This ligament spans from the clavicle to the acromion,
4:18
and it plays an important role in stabilizing the joint. It reinforces what we call the
4:24
joint capsule, which is a fibrous envelope that surrounds and seals the joint space.
4:29
Next, we can see the coracoacromial ligament, which goes from the coracoid process to the
4:34
acromion. This doesn’t connect to the clavicle, but it forms a kind of arch above the shoulder
4:40
joint. This arch acts like a roof, preventing the humeral head from moving upward and out of place.
4:46
Then, we look below the clavicle and find two ligaments that suspend it from the coracoid
4:51
process. Together, they form the coracoclavicular ligament, but they have two distinct parts. The
4:58
trapezoid ligament is more lateral, running almost horizontally. The conoid ligament is more medial
5:04
and runs vertically. These two work together to prevent the clavicle from displacing upward,
5:10
keeping the shoulder stable, especially when you lift heavy things or brace during a fall.
5:15
So overall, these structures form the support system for the lateral end of the clavicle,
5:20
they anchor it to the scapula and keep your shoulder suspended in space.
5:25
So, those are the major joints, and the general anatomy of the clavicle.
Why do we have a Clavicle?
5:29
So, why do we have a clavicle? Well, the clavicle is important because
5:33
it serves as a protective barrier for the major neurovascular structures running underneath it,
5:39
like the brachial plexus, subclavian artery, and subclavian vein. It acts like a shield,
5:44
keeping these structures safe while giving them space. Without the clavicle, these structures
5:50
would be more exposed to compression or trauma. Around it, muscles anchor in from every direction,
5:56
anteriorly, like pectoralis major and subclavius; superiorly, like sternocleidomastoid;
6:02
and posteriorly, trapezius. Even deltoid pulls on it from the lateral side. So the
6:08
clavicle also works as a muscular anchor and helps transmit forces between the upper limb and trunk.
6:14
But more than just a shield or anchor, the clavicle gives the upper limb its
6:19
positioning and reach. And for that, we describe it as acting like a strut.
6:24
So, what is a strut? So, a strut is… well,
6:28
imagine this: you’ve got a car wheel and the body of the car. These two things need to stay
6:33
a certain distance apart, and they need to stay stable, even when the weel hits bumps or turns.
6:40
They do that by adding a supportive rod, that’s the strut. It helps keep the wheel
6:45
in position and absorbs the forces from the road so everything doesn’t collapse or shake apart.
6:50
Now replace that car with your sternum. The scapula is like the wheel.
6:55
And the clavicle connects them, holding the scapula, and your entire upper limb,
7:00
out and away from your chest. This isn’t just about distance,
7:03
it’s about protecting your arm while allowing it to move freely. Notice how
7:08
the clavicle is S-shaped, this adds resilience by helping it act like a shock absorber. How?
7:15
Let’s say you’re doing a handstand, or falling onto an outstretched arm.
7:19
This impact travels through the arm, shoulder, scapula, clavicle then the sternum. So the
7:25
clavicle helps distribute and dampen that force. And without the clavicle, you lose that structural
7:31
bridge, and your shoulders may become hypermobile, even unstable. In conditions like cleidocranial
7:37
dysplasia, patient who don’t have collarbone can bring their shoulders together in front
7:42
of the chest. Cool trick, but it shows how vital the clavicle is for shoulder stability.
Clinical Relevance
7:48
Now, we said that this S-shape gives the clavicle its ability to absorb force,
7:54
but it also makes it vulnerable. The curve creates a natural weak point which
7:58
is usually in the middle third where it’s thinnest and not well protected by muscle. That’s why this
8:04
is the most common site of clavicle fractures. Clavicle fractures are very common, especially
8:09
in sports injuries, or traffic accidents. They account for about 5% of all adult fractures,
8:14
and it most commonly happens when a person fall on an outstretched hand or a direct blow to the
8:20
shoulder. That force travels up through the arm, and the clavicle snaps under pressure.
8:24
And when the clavicle breaks, the medial fragment is often pulled upward by the sternocleidomastoid.
8:30
And the lateral fragment drops downward and forward because of the weight of the arm and
8:34
the pull from the deltoid and gravity. And since it’s so close to the surface, you’ll
8:39
often see a clear deformity of the skin as well. So let’s say a patient comes in complaining of
Possible causes of pain in the Clavicle
8:45
pain in the area of the clavicle. What should go through your mind, think differential diagnosis.
8:50
Well, the clavicle is involved in a surprisingly broad range of conditions. First off,
8:55
trauma is a big one. Think clavicle fractures, common in falls, direct hits to the shoulder,
9:00
or sports injuries. Most fractures happen in the middle third of the bone,
9:04
right where it’s structurally weakest due to its S-shape and lack of muscular coverage.
9:09
But pain here isn’t always a break. It could also be acromioclavicular joint injuries, sprains,
9:15
dislocations, or even osteoarthritis from overuse or repetitive motion, especially in manual workers
9:21
or weightlifters. That condition is also known as distal clavicular osteolysis, and it tends
9:27
to creep up with vague pain during shoulder use. Another possibility is a Sternoclavicular joint
9:33
issue, it’s rare, but when they show up, they can be serious. Dislocation, arthritis, or even
9:39
infections in that joint can present as medial clavicle pain. And in young patients, growth
9:45
plate irritation or congenital conditions like cleidocranial dysplasia could be on your radar if
9:50
they’re hypermobile or have unusual anatomy. So what clinical signs do we look for?
Symptoms of Clavicle Injury
9:57
The patient might report a “pop” or crack during the trauma, or they’ll be guarding the arm,
10:02
holding it in place. Look for deformity, tenderness to palpation, or swelling along
10:07
the bone. If it’s a fracture, often the medial end is pulled upward by the sternocleidomastoid,
10:12
while the lateral end drops due to gravity and muscle pull, it’s quite dramatic.
Clinical Tests of Clavicle Injuries
10:17
For AC joint issues, you may see a step-off at the shoulder or pain during horizontal adduction.
10:18
What do you do first with the patient to test for this?
10:18
For AC joint problems, we use the cross-body adduction test,
10:21
pain means positive. If it’s a fracture, palpation alone might tell you everything,
10:26
but always check for neurovascular signs: radial pulse, cap refill, sensory deficits,
10:31
especially if there’s suspicion of a posterior dislocation or severe trauma.
10:35
For imaging, start with a standard AP X-ray of the clavicle. For joint problems or subtle fractures,
10:41
CT can give you more detail. If you’re suspicious of soft tissue or cartilage issues,
10:46
like in osteolysis, MRI helps. And in high-energy trauma, chest imaging might be needed to rule
10:52
out rib fractures or pneumothorax. There are many other tests you can do too, there’s piano key test
10:56
where you just push down the AC joint to confirm dislocation, there’s Obriens test, and so on.
Treatment of Clavicle Injury
11:01
Treatment depends on the cause. Most midshaft clavicle fractures are treated
11:06
conservatively with a sling, rest, and physio. But if it’s displaced, shortened, or tenting the skin,
11:12
you may need surgical fixation, especially in athletes or active patients. AC joint injuries
11:17
are often graded, lower grades (Type I–II) are treated with rest, ice, NSAIDs, while
11:24
higher grades (Type III+) might need surgery, particularly in those with persistent instability.
11:30
For osteoarthritis or osteolysis, it’s usually about activity modification, NSAIDs,
11:35
physiotherapy, and occasionally injections. If those don’t work,
11:39
a distal clavicle excision, either open or arthroscopic can be done to relieve pain.
11:44
So, that was everything I had for the clavicle. It’s a pretty interesting bone,
11:49
and also the most proximal bone of the upper limb. In the next video, we’ll be
11:54
covering the whole anatomy of the scapula, and throw in a few clinical notes as well. Click
11:58
on the next video, and i’ll see you there If you want a handmade PDF version of this
12:02
lecture, take a quiz to test your knowledge, or access an organized list of all my videos,
12:06
you can find everything on my website. Thanks for watching! See you in the next one.