The Clavicle (or collarbone)

Introduction

In this section, the speaker introduces the topic of the clavicle and explains its importance in the shoulder girdle.

What is the Clavicle?

• The clavicle is an important part of the shoulder girdle that acts as a strut connecting the upper limb to the axial skeleton.

• It has an S-shape and can be palpated along its entire length in most people.

• The clavicle runs from the manubrium of the sternum out to the scapula and then from the scapula we have the glenohumeral joint.

Importance of Clavicle

• The clavicle is crucial in allowing you to do dips, push-ups, and other exercises that require pushing motions.

• It acts as a mechanical strut that pushes away from your axial skeleton and allows muscles to work and give you leverage to move your upper limb.

Anatomy of Clavicle

In this section, we will look at different aspects of clavicular anatomy such as bony bits, joints, ligaments, muscles attached to it.

Bony Bits

• The clavicle has a double curve occurs eight and then curve so it occurs.

• It's got a joint on either end with a whole bunch of ligaments attached to it.

Muscles Attached

• The scapula is covered in muscles which are supporting it and holding it in place because all these bones need support by muscles.

• We'll run through the muscles on this guy here.

Joints

• The clavicle has a joint to either end and moves quite a bit.

• It's got a whole bunch of ligaments, and we'll look at the joints either end.

Injuries to Clavicle

In this section, we will talk about different types of injuries that can occur in the clavicle.

Common Fractures

• A fractured clavicle is a fairly common fracture, especially in cyclists.

• It's most commonly caused by a direct blow to the shoulder.

Symptoms of Fracture

• When you break your clavicle, you can no longer push up because it acts as a strut while most of the shoulder girdle is hanging from the axial skeleton by muscles.

• You sit down and try to push yourself up but can't do it if you have broken your clavicle.

Conclusion

In this section, the speaker concludes by summarizing what was covered in the video.

Summary

• The clavicle is an important part of the shoulder girdle that acts as a strut connecting the upper limb to the axial skeleton.

• It allows for mobility but needs support from muscles since it's not attached to any bone except at its ends.

• The clavicle is crucial in allowing you to do dips, push-ups, and other exercises that require pushing motions.

• A fractured clavicle is a fairly common injury that can occur due to a direct blow to the shoulder.

Anatomy of the Clavicle and Sternoclavicular Joint

In this section, the speaker discusses the anatomy of the clavicle and sternoclavicular joint. The sternoclavicular joint is a synovial joint that has a fibrocartilaginous disc in it. It is reinforced by several ligaments, making it very strong and rarely dislocated.

Anatomy of the Clavicle

• The medial end of the clavicle articulates with the manubrium of the sternum and rib of the first.

• The lateral end of the clavicle articulates with the acromion.

• There are two lumpy bits on the shaft of clavicle: coracoid process and acromion.

• The acromioclavicular joint is another synovial joint that allows for sliding motion between these two bones.

Sternoclavicular Joint

• The sternoclavicular joint is a synovial joint that has a fibrocartilaginous disc in it.

• It has an anterior and posterior sternoclavicular ligament as well as a costo-clavicular ligament running between first rib cartilage and clavicle.

• All these ligaments reinforce this joint, making it very strong and rarely dislocated.

Movements at Sternoclavicular Joint

• As you move your scapula anteriorly or posteriorly, you can feel that your clavicle moves away or towards you respectively.

• You can also move your clavicle anteriorly or posteriorly as you elevate or depress your shoulder.

Acromioclavicular Joint

• The lateral end of the clavicle articulates with acromion at this point.

• This is another synovial joint that allows for sliding motion between these two bones.

• There are tough ligaments reinforcing this joint, making it very strong and rarely dislocated.

Movements at Acromioclavicular Joint

• There is a little bit of movement at this end as the scapula moves around.

• The clavicle acts as one strut in the shoulder girdle, allowing for free arm movements.

Anatomy of the Clavicle

This section discusses the anatomy of the clavicle, including its ligaments and muscles.

Co-Coracoclavicular Ligament

• The co-curricular ligament runs from the coracoid process of the scapula to the clavicle.

• The ligament helps support the weight of the upper limb and ties together the clavicle and scapula.

• There are two parts to this ligament: conoid and trapezoid.

Ligaments

• The conoid ligament is medial and fan-shaped, running from the clavicle to the coracoid process of the scapula.

• The trapezoid ligament is lateral and attaches to both bones as well.

• Together, these two ligaments form a force couple that holds together both bones.

Muscles

• Six muscles attach to or near the clavicle: sternocleidomastoid, subclavius, pectoralis major, deltoid, trapezius, and sternohyoid.

• These muscles help suspend or anchor various parts of the shoulder girdle.

Common Injuries

This section covers common injuries associated with fractures in the clavicle.

Fractures

• A direct blow or fall onto an outstretched hand can cause a fracture in the clavicle.

• Fractures can occur in different locations along its length and may break into one or more pieces.

Shoulder Dislocation and Separation

In this section, the speaker explains the difference between a shoulder dislocation and an acromioclavicular (AC) separation. They also discuss the anatomy of the AC joint and how it can be affected by injury.

Shoulder Dislocation vs AC Separation

• A shoulder dislocation refers to the humerus usually dislocating inferiorly, while an AC separation is when the acromioclavicular joint separates.

• The AC joint has cartilage covering its articular surfaces, and there's often a fibrocartilaginous disc inside.

• On an x-ray, there should be a gap between the acromion and clavicle in a normal situation. However, in a mild separation, that gap might have gotten wider.

Severity of AC Separations

• There are grade 1 to grade 3 AC separations depending on the damage to soft tissues.

• If it's a significant separation, then the clavicle might not be in its right place.

Effects of Clavicle Fracture

• When someone fractures their clavicle, sternocleidomastoid muscle elevates the medial third of the clavicle causing it to go up.

• Fractured ends of bone rubbing against each other can cause extreme pain.

Treatment for Clavicle Fracture

• To let it form a callus on its own and stitch together repair nicely all you need to do is have a sling and take weight off your shoulder so that it can't support any weight anymore.

• Surgery is required to put the two ends back together and nail them together on a plate if the two ends of the clavicle are displaced.

AC Joint Separation

• Repairing bones is easy, but repairing ligaments is very slow as they have a poor blood supply.

• A serious separation can tear Coracoclavicular ligaments, which can be a bigger problem as it's supporting more weight.

Key Takeaways

• The most important part of this region is the ligaments at either end.

• Muscles should be added on to knowledge you have of this region.