Clavicle (Collar Bone)

Last updated 20.05.13

Definition

- Bone of upper limb which forms part of pectoral girdle

Clinical Relevance

- Clavicle fracture

Orientation

- 2 bones bilaterally, 1 each side

- Lies anterior to the anterior wall of the thorax on its most superior aspect

- Serves as attachement of upper limb to axial skeleton (sternum to scapula)

- Common site of fracture usually with fall injuries

Anatomical Features

- Most landmarks on inferior surface

- Superior surface is mostly indistinct and quite smooth

- Body curves anterioroly (convex) at its medial 2/3 & posteriorly (concave) at its lateral 1/3

- Sternal Extremity (Medial Extremity)

- Large more bulbous end

- Attachment site of:

- Interclavicular ligament

- Anterior sternoclavicular ligament

- Posterior sternoclavicular ligament

- Clavicular head of sternocleidomastoid muscle

- Articulates medially with the superiolateral surface of the manubrium of the sternum at the sternoclavicular joint

- Is enclosed in joint capsule of the sternoclavicular joint

- Forms the lateral borders of the jugular notch

- Costal Tubercule

- Located at sternal end of inferior surface of clavicle

- Serves as the attachement site for the costoclavicular ligament from the 1st rib and its costal cartilage

- Shaft

- Attachment site of:

- Deltoid muscle attaches to the lateral anterioinferior surface

- Trapezius muscle (upper fibers) attaches to the lateral anteriorsuperior surface

- Pectoralis muscle (clavicular head) attaches to the majority of the anterior surface

- Platysma muscle attaches to the anteriosuperior surface

- Subclavian Groove

- Located on the inferior surface of the clavicle

- Covers the middle third of the inferior surface

- Serves as the elongated attachment site for the subclavius muscle

- Conoid Tubercule

- Located at the posterior inferior surface of the acromial end of the clavicle

- Large rounded elevation

- Serves as the attachment site for the conoid ligament of the coracoclavicular ligament

- Trapezoid Line

- Located immediately lateral to the conoid tubercule on the inferior surface of the acromial end of the clavicle

- Roughened line extending laterally from the conoid tubercule

- Serves as the attachment site for the trapezoid ligament of the coracoclavicular ligament

- Acromial Extremity (Lateral Extremity)

- Flatter more broad extremity

- Attachment site of the acromioclavicular ligament

- Articulates laterally with the medial surface of the acromium of the scapula at the acromioclavicular joint

- Trapezius attaches to superior aspect

References

Moores Clinically Oriented Anatomy

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