Articulations of the Upper Extremity

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Anatomy > Gray's Anatomy of the Human Body > III. Syndesmology > 6. Articulations of the Upper Extremity > a. Sternoclavicular joint

Henry Gray (1821–1865). Anatomy of the Human Body. 1918.

Sternoclavicular Articulation

(Articulatio sternoclavicularis)

Anterior view of the sternoclavicular joint.

Shoulder joint showing ligamentous attachments.

Bones of the shoulder girdle (not from Grays)

The sternoclavicular joint is a synovial joint of the double arthrodial type, connecting the upper limb to the axial skeleton. It is the only true joint between the upper limb and the trunk.

This articulation is formed by the junction of three components:

• The sternal end of the clavicle
• The manubrium of the sternum
• The cartilage of the first rib

Despite the disparity in size between the articular surfaces (the clavicle being significantly larger), stability is achieved through a fibrocartilaginous articular disk and a robust set of ligaments.

Joint Structures

Articular Capsule

The capsular ligament completely encloses the joint. It is strong anteriorly and posteriorly, where it blends with the anterior and posterior sternoclavicular ligaments. Superiorly and inferiorly, the capsule is thinner and more areolar in character.

Articular Disk

The articular disk is a fibrocartilaginous structure interposed between the clavicle and the sternum. It is nearly circular in shape and divides the joint into two separate synovial cavities. It is:

• Attached superiorly to the posterior superior aspect of the clavicle’s articular surface
• Attached inferiorly to the cartilage of the first rib
• Circumferentially continuous with the capsule and ligaments

This disk allows for increased range of motion and contributes significantly to joint stability.

Ligaments

Anterior Sternoclavicular Ligament

(Ligamentum sternoclaviculare anterius)

This ligament reinforces the front of the joint capsule. It passes obliquely from the anterosuperior sternal end of the clavicle to the anterior surface of the manubrium. It is crossed superficially by the sternal head of sternocleidomastoid.

Posterior Sternoclavicular Ligament

(Ligamentum sternoclaviculare posterius)

Located posteriorly, this ligament extends from the posterosuperior clavicle to the posterior manubrium. It lies anterior to the sternohyoid and sternothyroid muscles.

Interclavicular Ligament

(Ligamentum interclaviculare)

A transverse band connecting the superior aspects of both clavicles and the superior border of the manubrium. It spans the jugular notch and helps resist downward displacement of the clavicles.

Costoclavicular Ligament

(Ligamentum costoclaviculare; rhomboid ligament)

This short, strong ligament runs obliquely between the costal tuberosity of the clavicle and the superior surface of the first rib’s costal cartilage. It limits elevation of the clavicle and plays a key role in joint stabilization. It lies anterior to the subclavian vein and posterior to the subclavius muscle.

Synovial Membranes

Two distinct synovial membranes are present:

• The lateral synovial membrane — between the clavicle and the articular disk
• The medial synovial membrane — between the sternum and the articular disk

The medial membrane is usually larger.

Movements

The sternoclavicular joint permits motion in multiple directions:

• Elevation and depression – occurs primarily between the clavicle and the articular disk.
• Protraction and retraction – the clavicle and disk glide over the sternum.
• Circumduction – a composite movement involving the above motions.

The joint acts as a pivot point for scapular movement, indirectly enabling shoulder motion.

Muscles Involved

• Elevation: Trapezius (upper fibers), levator scapulae, sternocleidomastoid (clavicular head)
• Depression: Gravity, subclavius, pectoralis minor, lower fibers of trapezius
• Protraction: Serratus anterior, pectoralis minor
• Retraction: Rhomboids, middle fibers of trapezius

Ligamentous Constraints

• Elevation is limited by the costoclavicular ligament
• Depression is limited by the interclavicular ligament and the articular disk
• Protraction and retraction are checked by the anterior and posterior sternoclavicular ligaments

Clinical Relevance

While rare, dislocations of the sternoclavicular joint can occur due to trauma. Posterior dislocations are particularly dangerous due to the proximity of mediastinal structures. Degenerative changes may also affect the joint with age or repetitive stress.

See Also

• Clavicle
• Sternum
• Shoulder girdle
• Pectoral girdle
• Acromioclavicular joint
• Upper limb anatomy

Gray's Anatomy

• Gray's Anatomy Contents
• Gray's Anatomy Subject Index
• About Classic Gray's Anatomy
• Glossary of anatomy terms

Anatomy atlases (external)

[1] - Anatomy Atlases

Adapted from the Classic Grays Anatomy of the Human Body 1918 edition (public domain)