Sternoclavicular joint (ultrasound)

Ultrasound of the sternoclavicular (SC) joint can have a role along with CT and MRI in the assessment of related pathology and for intra-articular injection.

Indications

• sternoclavicular joint arthropathy

• post-trauma, e.g. suspected sternoclavicular joint dislocation

Normal ultrasound anatomy

• anterior sternoclavicular ligament: hypoechoic structure extending between the clavicular notch of the manubrium and first costal cartilage to the anterosuperior clavicular head ⁹

• sternoclavicular capsule: unable to be differentiated from the anterior sternoclavicular ligament forming a capsuloligamentous structure ⁹

• interclavicular ligament: hypoechoic fibrillary structure extending between the sternoclavicular capsule and the jugular notch of the manubrium ⁹

• sternal head of sternocleidomastoid muscle: hypoechoic tendon covering the medial aspect of the SCJ as it attaches to the manubrium, SCJ itself, and the anterior sternoclavicular ligament ⁹

• articular disc: hyperechoic triangular structure with its base on the anterior capsuloligamentous complex ⁹

Technique

Ultrahigh frequency probes can be used - 6-13 MHz linear probe for main assessment with a hockey sick 22 MHz probe for problem solving ^9,10.

Initial probe placement

Start with the transducer placed transversely (horizontally) over the SC joint. This orientation provides a cross-sectional view of the joint.

Identify landmarks

First, identify the medial end of the clavicle and the manubrium as the primary landmarks.

Tranverse scan

The anterior capsuloligamentous complex and articular disc can be identified in an oblique tranverse plan and the interclavicular ligament in a tranverse plane ⁹. Joint effusion can be seen as a bulging fluid reces anterior to the clavicular head ⁹. Assess for synovial thickening and apply color Doppler to assess for hyperemia, which is indicative of synovitis ^8,9. A "step" in alignment between the mandubrium and sternum can indicate dislocation ¹¹.

Longitudinal scan

Rotate the transducer 90 degrees to obtain a longitudinal (sagittal) view of the SCJ. The sternal head of the sternocleidomastoid can be identified in an oblique longitiundal plane ⁹.

Dynamic assessment

Ask the patient to perform specific movements (e.g. shoulder elevation, retraction, or protraction) to evaluate the joint's function and to detect any abnormalities such as dynamic subluxation ^ref.

Comparative examination

Comparison with the contralateral SCJ can be helpful to detect asymmetric change ^ref.