Bony Thorax

Tanya Nolan

Bony Thorax

Sternum 12 Ribs 12 Thoracic Vertebrae

FunctionSupports walls of pleural cavity & diaphragmVolume of cavity able to change during respirationProtects heart and lungs

Sternum Flat bone 6 in in length Supports

clavicles and provides attachment to 1st seven costal cartilages of ribs

T2-T3

Sternal Angle

T-10

Provides bony landmark for superior liver and inferior heart

12 Rib Pairs True Ribs

1-7 Attached to the

Sternum False Ribs

8-12 Do not attach directly

to the sternum; attach to costal cartilage of 7th rib

Floating Ribs 11 and 12 Attached only to the

vertebrae

Number Variation Cervical Ribs

Articulate with C7 but rarely attach to sternum

Lumbar Ribs Less Common

Ribs Angle Oblique plane

slanting anteriorly and inferiorly Anterior ends lies 3-5

inches below the level of the vertebral end.

Angle increases from the rib 1-9 then decreases 9-12.

Ribs Vary in breadth and length Facet on head articulates with vertebrae

Vertebral End

Sternal End

Costal Groove

Costal arteries, veins, and nerves

Erythropoiesis Production of red blood cells.

Early Fetus Mesodermal cells of yolk sac

3-4 Months to Adolescence Spleen, Liver, and Skeletal involvement

Adulthood Vertebrae, Sternum, Pelvis, and Ribs

Principal means of delivering oxygen to the body

Bony Thorax Articulations

8 Joints Sternoclavicular Costovertebral

(1-12) Costotransverse

(1-10) Costochondral

(1-10) Sternocostal

(1-7) Interchondral

(6-10) Manubriosternal Xiphisternal

Sternoclavicular

Only points of articulation between the upper limbs and the trunk

Gliding Joints Permit free

movement

Manubriosternal

Joint

XiphisternalJoint

Costovertebral and Costotranverse

Costovertebral Synovial Gliding

Rib Head closely bound to the demifacets and 2 adjacent vertebral bodies

Costotransverse Synovial Gliding

Tubercle of rib articulates with transverse process of lower vertebra

Costochondral and Sternocostal

Sternocostal Cartilaginous

Synchondosis No Movement Articulation

between costal cartilages and true ribs

Costochondral 1st Rib: Cartilaginous

Synchondosis No Movement

2-7: Synovial Gliding Freely moveable

Articulation between rib costal cartilages and sternum

Sternocostal

Interchondral

Between 6-9 RibsSynovial Gliding

Freely moveable

Between 9-10 RibsFibrous

Syndesmosis Slightly moveable

Manubriosternal &Xiphersternal Cartilaginous

SynchondrosisLittle

Movement

Manubriosternal Joint

Xiphisternal Joint

Respiratory Movement Quiet Respiration

Olique rib orientation changes little

Deep Inspiration Degree of obliquity

decreases Ribs carried

anteriorly, superiorly, and laterally while necks are rotated inferiorly

Deep Expiration Degree of obliquity

increases Ribs carried inferiorly,

posteriorly, and medially while the necks are rotated superiorly

Diaphram

Ribs below diaphram best imaged through upper abdomen

Ribs above diaphram best imaged through air filled lungs

WHY?

Diaphram Location Changes

with Body Position Upright

Lowest

Supine Highest Anterior ends of ribs less sharply visualized in supine position

Repiratory Movement 1 ½ inches between deep inspiration and deep

expiration Less in hypersthenic More in hyposthenic

Oblique Projection of Sternum

Degree of angulation depends on the depth of the chest Deep Chest

Less angulation

Shallow Chest More angulation

Why must you do an oblique projection of the sternum versus an AP or PA projection?

Which Oblique Position??? RAO or LAO?

Why?

What technique? Why?

PA Oblique Projection (RAO)Sternum Estimate body

rotation by placing one hand on patient’s sternum and the other hand on the thoracic vertebrae to act as a guide

Top of IR 1.5 inches above jugular notchAverage body rotation is 15-20 degrees

PA Oblique Projection (RAO, LPO)Sternum

Minimal rotation Sternum

projected free from superimposition of the spine

Sternum projected over the heart

When would you use an LPO Position?

Lateral Projection (Upright)Sternum

Rotate patients hands posteriorly

Lock hands behind back

Film 24 x 30 cm lengthwise

IR 1.5 inches above jugular notch

Suspend deep inspiration

Lateral Projection (Supine)Sternum

Bring hands above head

Film 24 x 30 cm lengthwise

IR 1.5 inches above jugular notch

Suspend deep inspiration

Lateral ProjectionSternum

Pectus Excavatum

Sunken or “caved in” chest Most common congenital chest wall

abnormality in children. Severity ranges from a moderate

indentation to constriction of the internal organs.

Sunken chest appears to be a problem with the sternum or ribs, but the problem is with the cartilage piece that connects each rib to the sternum. This costal cartilage connector is deformed, pushing the breastbone inward.

PA ProjectionSternoclavicular Articulations

IR @ T3 (just posterior to jugular notch)

Arms rest by side of patient with palms up

Turn head toward affected side Rotates spine slightly

away from side being examined

Better visualization of lateral manubrium

Suspend at end of expiration

Sternoclavicular Articulations

Bilateral Unilateral

No Rotation Slight Rotation

PA Oblique Projection (RAO, LAO)SC Joints

Rotate patient 10-15 degrees

CR perpendicular to SC Joint closest to the IR (T2-T3)

LAO: Left side of interest

RAO: Right side of interestL R15

S

PA Oblique Projection (RAO, LAO)SC Joints

Ribs Localize Point

of InterestAnterior Ribs

PA Projection

Posterior Ribs AP Projection

Axillary Portion of Ribs Best demonstrated in oblique projection

lateral projection results in superimposition of both sides

Respiration

Upper Anterior RibsPA Projection

Do you use the same technique as you would for a chest x-ray?

Posterior Ribs: AP Projection

Ribs above diaphram1.5 inches above

shouldersFull Inspiration

Ribs below diaphramLower edge of IR at

iliac crestFull Expiration

Posterior RibsAP Projection

Axillary RibsAP Oblique Projection (RPO, LPO)

45 degree Oblique Place affected side

closest to the IR Center affected side

midway between midsagittal plane and lateral surface

Abduct arm of affected side and elevate to carry scapula away from rib cage

Axillary RibsAP Oblique Projection (RPO, LPO)

2 x distance between vertebral column and lateral border affected side visualized

Axillary ribs free of superimposition

Axillary RibsPA Oblique Projection (RAO, LAO) 45 degree oblique

45 degree oblique

Which is the side

of interest? Why?

Axillary RibsPA Oblique Projection (RAO, LAO)