Axial Skeletal System Anatomy

• Forms the longitudinal axis of the body;
• Supports and protects organ systems;
• Provides surface area for the attachment of muscles

• (SSRS)
• Skull
• Spine
• Ribs
• Sternum

• 29 total bones;
• Cranium bones
• Facial Bones
• Mandible

• jaw bone;
• serves as orienting landmark for palpating the carotid artery to assess pulse

• (VIA)
• Vertebrae
• Intervertebral Disks
• Adult vertebral column

• 33 total vertebrae
• 7 cervical
• 12 thoracic
• 5 lumbar
• 5 sacrum
• 4 coccygeal

4 coccygeal vertebrae fused to form one bone that lies below the sacrum

7 vertebrae of the neck

12 vertebrae of the midback

5 vertebrae of the lower back

5 sacral vertebrae fused to make one bone that acts as trasition pointbetween the spine and pelvis.

• Round, flat, platelike structures composed of fibrocartilaginous tissue
• Disks
• - unite the vertebral bodies
• - serve to absorb shock and bear weight

• (AN)
• Annulus Fibrosus
• Nucleus pulposus

outer, fibrocartilaginous portion of the intervertebral disk

inner gelatinous portion of the intervertebral disk

The 4 major curvatures of the adult spine in the sagittal plane

• (CTLS)
• Cervical curve
• Thoracis curve
• Lumbar curve
• Sacral curve

• Convexity of the curve is posteriorily directed
• - two primary curves of vertebral column (thoracic curve and sacral curve)

• Vertebral column curve that contains the same directional curvature as the spine in the fetus
• - Thoracic curve
• - Sacral curve

• Convexity of the curve is anteriorly directed
• - 2 secondary curves of the vertebral column (cervical and lumbar)

• Curves of vertebral column that develop after birth as infant progresses in weight and bearing
• - Cervical curve
• - Lumbar curve

• - Hyperkyphosis
• - Hyperlordosis

exaggerated posterior thoracic curvature (hunchback)

Exaggerated anterior lumbar curvature

Scoliosis - lateral deviation in the frontal plane

• 12 pairs of ribs.
• - 7 pairs of true ribs
• - 5 pairs of false ribs

7 most superior ribs that attach directly to the sternum with costal cartilage

• 5 inferior pairs of ribs that do not attach directly with the sternum
• - top 3 indirectly attach via costal cartilage of adjacent superior ribs
• - bottom 2 are floating

• Spaces between the ribs
• - Palpation of the intercostal spaces of the true ribs is important for correct ECG electrode placement

• Sternum lies in the midline of the chest
• - Manubrium (superior)
• - Body (middle)
• - Xophoid process (inferior)

Slightly raised surface landmark where manubrium meets of the body of the sternum.

• Surface landmark situated at the bottom of the sternum and in the middle of the inferior border of the rib cage
• - Palpation of the xiphoid is necessary for CPR

Palpation of manubrium helps determine proper paddle placement in defibrillation.