| | Conditions Treatments | Broken Bone Is the sternocleidmastoid bone your collar bone? No, sternocleidmastoid is a skeletal muscle that connects the sternum and clavicle to the mastoid process in the temporal bone within the skull. Broken Bone - Related Articles Vein Injuries Congestion in the Sternum & Sinusitis Herbal Cure for Capillary Fragility Tennis Elbow Treatment Exercises What Are the Zetia Medication Side Effects? Hazards of Using Filing Cabinets My knees pop almost every time I bend them up with that?