Chapter 10 Bony Thorax- Sternum and Ribs

˜True Ribs 1-7

ØConnect directly to sternum with short piece of cartilage, called COSTOCARTILAGE

˜False Ribs 8-12

ØAll false ribs ( except 11-12) have costalcartilage that join together at the costocartilage of rib 7

˜Floating Ribs 11-12

ØDo not have costocartliage and do not connect to sternum

RAO Sternum

˜15°to 20°RAO

˜CR to center of sternum

Ø1 inch to left of midline

ØHalfway between jugular notch and xiphoid process

˜Trauma alternative: 15° to 20°cross angle, grid landscape

Position patient AP and adjust collimation; then position in RAO

Amount of rotation can be determined by placing one hand on sternum and other on spinous process and determining that these 2 points are not superimposed.

LPO may be performed is patients condition doesn't allow RAO

If Patient cannot rotate, oblique CR 15-20˚ across right side of patient to project sternum lateral to the vertebral column onto the heart shadow

Technical Considerations for Sternum

˜Orthostatic (breathing technique) 2-3 sec

˜kVp range:

ØAnalog: 65-75

ØDigital systems: 70-80

˜40 inches SID

˜ (Never use SID less than 38 inches used to be done to magnify, result distorted image and increase patient dose… (old way of doing exam)

Oblique Sternum Considerations

˜RAO

˜Degree of obliquity- Notice difference on degree required to project over heart

Evaluation Criteria: RAO Sternum

˜Entire sternum visualized

˜Superimposed over heart shadow

˜Correct rotation, sternum alongside vertebral column without superimposition

˜Optimal exposure factors

˜No motion

Over Rotation-Sternum

sternum rotated past heart shadow

Under Rotation- Sternum

sternum still superimposed by vertebral column

Lateral Sternum

˜CR to center of sternum

ØMidway between jugular notch and xiphoid process

˜60-72 inches SID recommended; reduce magnification

˜Inspiration

˜Shoulders drawn back, i.e. stick chest out

Evaluation Criteria: Lateral Sternum

˜Entire sternum visualized; minimal soft tissue overlap

˜No superimposition of ribs

˜Lower sternum not obscured by breasts

˜No rotation

˜Optimal exposure factors

˜No motion

Sternum

˜Composed of highly vascular cancellous tissue covered by thin layer of compact bone

Military IO site

˜Common Site for marrow biopsy’s

˜Body of sternum is in 4 segments at birth and completely fuse around age 25

˜Xiphoid Process usually isn’t completed ossified till age 40

˜Pectus Carinatum

Ø“Pigeon breast”, deformity, anterior protrusion of lower sternum and xiphoid process

˜Pectus Excavatum

Ø“Funnel chest”, deformity characterized by depressed sternum, rarely affects respiration, but usually corrected for cosmetic reasons

ØAffects women 5 times more than men

PA Sternoclavicular Joints

˜True PA

˜40” SID

˜Expiration for uniform density

˜CR perpendicular to T2-T3

Ø(3 inches distal to vertebra prominens)

Evaluation Criteria: PA SC Joints

˜Medial portion of clavicles and SC joints visualized

˜No rotation

ØEqual SC to vertebral column space

˜Optimal exposure factors

˜No motion

Anterior Oblique:
RAO & LAO SC joints

˜10° to 15° rotation

˜CR to level of T2-T3

˜CR 1-2” lateral, toward upside from spinous processes

˜SC joint on downside best visualized

ØRAO=right SC; LAO=left SC

˜40” SID

˜Expiration

Evaluation Criteria: SC Obliques

˜Manubrium and medial clavicle visible

˜SC joint open and shifted away from spine

˜Correct rotation no superimposition of vertebral column or manubrium

˜Optimal exposure factors

˜No Motion

Ribs Below Diaphragm

˜Ribs Number 10-12, maybe 9

˜Recumbent

ØAllows diaphragm to rise to highest position and resulting less thick abdomen

˜Expiration

ØAllow diaphragm to move to level rib 7 or 8, providing uniform density below

˜kVp range:

ØAnalog: 70-80

Digital systems: 80-90

Ribs Above Diaphragm

˜Ribs 1-9

˜Erect if possible, standing or sitting, gravity assisting lowering diaphragm

˜Inspiration

ØLowers diaphragm to below 9^th or 10^th rib

˜kVp range:

ØAnalog: 65-75

Digital systems: 75-85

AP Ribs   (posterior ribs)

40” SID Unilateral

72” SID bilateral ribs

Above

˜Erect

˜CR midsagittal (bilat)

˜CR midway between midline & lateral margin (unilat)

˜CR 3-4” below jugular notch (T7)

˜Raise Chin

˜Rotate Shoulders forward

˜Inspiration

Below

˜Supine

˜CR midsagittal (bilat)

˜CR midway between midline & lateral margin (unilat)

˜CR midway between xiphoid process & lower rib margin

˜Expiration

Evaluation Criteria:
AP Ribs Above Diaphragm

˜1st to 9th ribs visualized above diaphragm

˜No motion

˜No rotation

˜Optimal exposure factors

Evaluation Criteria:
AP Ribs Below Diaphragm

˜10th to 12th ribs visualized below diaphragm

˜No motion

˜No rotation

˜Optimal exposure factors

PA Ribs  (anterior ribs)

40” SID Unilateral 

72” SID bilateral ribs

Above

˜Erect

˜CR midsagittal (bilat)

˜CR midway between midline & lateral margin (unilat)

˜CR 7-8” below vertebral prominens (T7)

˜Raise Chin

˜Rotate Shoulders forward

˜Inspiration

Below

˜Injuries to ribs below the diaphragm are generally to posterior ribs; therefore AP projections are indicated

Evaluation Criteria:
PA Ribs Above Diaphragm

˜1st to 9th ribs visualized above diaphragm

˜No motion

˜No rotation

˜Optimal exposure factors

Obliques-Ribs

Posterior Ribs

Axillary Ribs

Affected Side Towards IR

RPO-injury right posterior ribs

Anterior Ribs

Axillary Ribs

˜Affected Side Away from IR

RAO – injury to left anterior ribs

Posterior or Anterior Oblique Ribs

˜40” SID   or    72” SID

˜45°oblique

˜CR to T7 level

˜Raise elevated side arm above head

˜Extend opposite arm down & behind away from thorax

˜Align thorax midway between spine and lateral margin of thorax on side of interest to CR

˜Elongates Axillary Ribs

Oblique AP/PA Ribs

Above

˜Erect

˜CR 3-4” below jugular notch (T7) –POSTERIOR OBLIQUE

˜CR 7-8” below vertebral prominens (T7) – ANTERIOR OBLIQUE

Inspiration

Below

˜Supine

˜CR to level midway between xiphoid process and lower rib margin – POSTERIIOR OBLIQUE

˜ANTERIOR OBLIQUE-Not performed

Expiration

Axillary Ribs

˜Right Axillary

ØRPO

ØLAO

Left Axillary

LPO

RAO

Evaluation Criteria:
Oblique – Axillary Ribs

˜Above Diaphragm Below Diaphragm

ØRibs 1 thru 9 Ribs 10 thru 12

Axillary portion of ribs appears elongated

Accurate 45˚ oblique demonstrate axillary ribs in profile with the spine shifted away from AOI

No motion

Optimal exposure factors

˜Pneumothorax

ØAbnormal collection of air in the PLEURAL SPACE

Ø“collapsed lung”

˜Hemothorax

ØCollection of blood in the PLEURAL SPACE

ØPleural Effusion composed of 51% blood

˜Flail Chest

ØTraumatic injury where 2 or more ribs located next to each other are fractured in 2 or more places making your chest wall unstable