Anatomy study note · Thorax

Sternum

The flat breastbone in the midline of the front of the chest. It has three parts: the manubrium, the body and the xiphoid process.

Key points

• Manubrium (T3–4) + body + xiphoid (xiphisternal joint at T9).
• Sternal angle = 2nd costal cartilage, T4/5 disc, superior/inferior mediastinum boundary.
• Red marrow for life → sternal puncture.
• Costal cartilage 1: cartilaginous joint; cartilages 2–7: synovial joints.
• Develops from 6 parts; middle 4 sternebrae fuse into the body.
• Sternum: fusion of two sternal bars, cranial to caudal.
• Bone: type I collagen + hydroxyapatite.
• Osteoblast builds, osteocyte maintains, osteoclast resorbs.

The full note in the atlas also covers

Features · Articulations · Histology · Development · Clinical notes

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Written from

• Snell’s Clinical Anatomy by Regions, 10th ed., ch. 4, PDF pp. 476–479, 488–489
• Inderbir Singh’s Human Embryology, ch. 10, PDF pp. 139–140
• BRS Cell Biology & Histology, 7th ed., ch. 7, PDF pp. 121–125, 130

More from the thorax

• Superior vena cava
• Sympathetic trunk
• Thymus
• Trachea
• Tricuspid valve
• Vagus nerve
• Aortic valve
• Arch of aorta
• Ascending aorta
• Azygos vein
• Brachiocephalic artery
• Brachiocephalic veins

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