Manubrium of sternum

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Bony elements of the sternum.

The manubrium is a thick, large trapezoidal shaped bone that lies above the body of the sternum at the vertebral level T3-T4.

The manubrium of sternum forms the superior wall of the anterior mediastinum, with its superior border also contributing to the superior thoracic aperture.

Its concave superior border is known as the jugular or suprasternal notch. The clavicular notches which articulate with the clavicles on each side forming the sternoclavicular joints are projected upward and laterally on both sides of the jugular notch.

Its lateral boders each carry a depression for the first costal cartilage and just below a demi-facet can be found which receives the upper half of the second costal cartilage.

Its narrow and rough lower border articulates with the body of the sternum with a thin layer of cartilage in between. Their articulation forms the sternomanubrial joint, a secondary cartilaginous joint.

The anterior and posterior surfaces of the manubrium functions as an attachment site for several structures which include the following:

• interclavicular ligaments 
• deep cervical fascia
• pectoralis major muscle
• sternocleidomastoid muscle
• sternohyoid muscle
• sternothyroid muscle.