STERNUM

THE STERNUM
📌 Also called breastbone, attaches to the clavicle (collarbone) via the sternoclavicular joint, and to the first seven ribs via costal cartilages, forming the front of the rib cage
📌 Protects the heart, lungs, and major blood vessels
STERNUM COMPOSITION
The sternum consists of three parts:
📌 the manubrium (the upper part)
📌 the body (the middle part)
📌 the xiphoid process (the lower, sword-shaped part)
MANUBRIUM ATTACHMENTS
📌 The manubrium articulates with the medial end of the clavicle, forming the sternoclavicular joint
📌 It also articulates with the first rib and the body of the sternum
BODY ATTACHMENTS
📌 The body of the sternum serves as the anterior attachment for ribs 2 through 7 via costal cartilages
📌 The body articulates with the manubrium superiorly (manubriosternal joint) and the xiphoid process inferiorly (xiphisternal joint)
XIPHOID PROCESS
📌 The xiphoid process is the inferior tip of the sternum and serves as a point for muscular attachment, including the diaphragm, rectus abdominis, and transverse abdominis muscles
MUSCULAR ATTACHMENTS
📌 The manubrium provides attachment for several muscles:

sternocleidomastoid

sternohyoid

sternothyroid
📌 The body of the sternum serves as an attachment point for the transversus thoracis muscle

JOINTS
📌 The sternum articulates with the clavicle at the sternoclavicular joint
📌 The sternum articulates with the ribs at the sternocostal joints
📌 The manubrium and body of the sternum articulate at the manubriosternal joint
📌 The body and xiphoid process articulate at the xiphisternal joint
BLOOD SUPPLY
📌 Arterial: internal thoracic artery
📌 Venous: internal thoracic veins
NERVE INNERVATION
📌 Intercostal nerves, which arise from the anterior rami of the thoracic spinal nerves (T2 to T6)
📌 These nerves provide both motor and sensory innervation to the sternum and surrounding structures
APPLIED ANATOMY
📌 Sternal fractures: fractures of the sternum can occur due to trauma, such as car accidents or falls
📌 Sternal angle: the sternal angle, where the manubrium and body meet, is a landmark for identifying the level of the second intercostal space
📌 Palpation: the sternum is easily palpable, and the jugular notch (a depression at the top of the sternum) and sternal angle can be used as landmarks for clinical procedures
📌 Variations: there can be variations in the sternum's shape or ossification patterns, which can be clinically relevant