Axial Skeleton

Vertebral Column/ Spinesupports the skull /transfers weight

• Structure:• 26 irregular bones• (33 pre-birth)

• 7 cervical• 12 thoracic• 5 lumbar• 1 sacrum• 1coccyx

• Intervertebral foramen-Between each vertebraeFor spinal nerves

Intervertebral discs-Cushion/absorbs shockProvides flexibilityHardens with age

Herniated Disc

• When the annulus wall weakens, the disc will press against the spinal nerve = PAIN

curvatures• Primary curvature-• What you are born with• Posterior = Convex• Secondary curvature-• What develops• Cervical becomes-

posterior concave when baby lifts head

• Lumbar becomes posterior concave when baby walks

Abnormal Curvatures• Scoliosis- abnormal side

to side• Kyphosis-Exaggerated

posterior curvature of thoracic vertebrae- osteoporosis

• Lordosis-exaggerated posterior curve of lumbar

• Pregnancy, pot belly

Typical Vertebrae

• Body- weight bearing anterior

• Vertebral Arch- join the laminae and pedicles posterior

• Vertebral Foramen- canal that spinal cord passes

• Transverse Process- 2 lateral projections from the arch

Typ ical verteb rae

• Spinal Process- single projection from posterior arch

• Superior and Inferior Articular Processes- paired projections lateral to the foramen allows the vertebrae to join each other

Cervical Vertebrae - neckC1 - ATLAS

• No body • receives the

occipital condyles • Allows the “yes”

nod

Cervical vertebrae

C-2 - AXIS

• Has an upright pivot called dens or odontoid process

• Allows rotation- “no”

Cervical vertebraeC-3 to C- 7

• Small• Short bifid spinous process• Transverse processes contain

foramen for arteries

Thoracic VertebraeT1 – T12

• Larger heart shaped body• Long spinous

process-points downward• 2 costal facets on

either side for ribs

Thoracic Vertebrae

Lumbar vertebraeL1 – L5

•Massive body• Hatchet like

spinous process• Takes most

stress

Sacrum 5 fused vertebrae• Posterior Pelvis• wing like• Lateral

articulation with hip• Medial Sacral

Crest- posterior fused spinous processes

Sacrum

• Sacral foramina- lateral to crest• Sacral Canal-

down the center• Sacral Hiatus-

inferior opening

Coccyx 3-5 fused vertebrae

• tailbone

Bony Thorax

• Ribs• Sternum• Thoracic

vertebrae

Sternum

• Manubrium- jugular notch

• Body- sternal angle (3rd rib)

• Xiphoid Process- small point at bottom

Xiphoid

• The Xiphoid process can cause damage because of the location of the liver

Costal Cartilage

• The costal cartilage attaches the ribs to the sternum-hyaline cartilage

Ribs- 12 pairs• True ribs-are

connected to the sternum- vertebrosternal # 1-7

• Posterior – attached to thoracic vertebrae 1-7

• Anterior- attached to sternum

• False Ribs- are not connected directly to the sternum

• Ribs 8-10 are called false

• Ribs 8-10 are called vertebrochondral

• Posterior- attaches to vertebrae

• Anterior- attaches to cartilage

• Floating Ribs- ribs 11 & 12

• They are not connected in the anterior, only the posterior

• Posterior- vertebrae• Anterior- nothing

Ribs- flat bones

• Head- meets with the body of the thoracic vertebrae

• Neck- meets with the transverse process of the thoracic vertebrae

• Shaft- angles downward