Chapter 10: Bony Thorax-Sternum and Ribs
Rib Cage
-1st ribs are short, broad & the most vertical of all ribs -bony thorax is the widest at lateral margins of the 8th or 9th ribs
Evaluation Criteria: Lateral Sternum
-entire sternum with minimal overlap of soft tissues -no rotation
Anterior Oblique Ribs (RAO & LAO) Above Diaphragm 40" SID 14x17 IR portrait Erect for above diaphragm Anterior oblique= affected side AWAY from IR Clinical Indications: Oblique positions will demonstrate axillary portion of ribs not well seen with AP-PA projections
-erect facing the upright bucky for PA -rotate into 45 anterior oblique with affected side away from IR CR perpendicular; level 7 to 8" below vertebra prominens (T7) Expose on inspiration
Posterior Oblique Ribs (RPO & LPO) Above Diaphragm 40" SID 14x17 IR portrait Erect for above diaphragm Posterior oblique= affected side towards IR Clinical Indications: Oblique positions will demonstrate axillary portion of ribs not well seen with AP-PA projections
-erect with back against upright bucky for AP -rotate into 45 anterior oblique with affected toward IR CR perpendicular; level 3 to 4" below jugular notch (T7) Expose on inspiration
Evaluation Criteria: PA Sternoclavicular Joints
-lateral aspect of manubrium & medial portion of clavicles with SC joints visualized -no rotation evident by equal distance of SC joints from vertebral column rotation example: left SC joint closer to midline=LAO
Evaluation Criteria: Anterior Oblique (RAO & LAO) Sternoclavicular Joints
-manubrium & medial clavicle visible -SC joint best demonstrated on the downside -SC joint of upside foreshortened -SC joint open & shifted away from spine
PA Bilateral Anterior Ribs-above diaphragm 40" SID 14x17 IR landscape erect for above diaphragm Clinical Indications: Pathology of the ribs, including fracture and neoplastic processes Injuries to ribs below the diaphragm are generally to posterior ribs; therefore, AP projections are indicated
-patient erect facing upright bucky -Align right or left side of thorax to CR CR perpendicular; centered to T7 (7 to 8" below vertebra prominens as for PA chest) Expose on inspiration
AP Unilateral Rib Study: Posterior Ribs-above diaphragm 40" SID 14x17 IR portrait Erect for above diaphragm Clinical Indications: Projection is taken to demonstrate specific trauma to one side of the thoracic cavity
-patient erect with back against upright bucky -Align right or left side of thorax to CR CR perpendicular; centered midway between MSP & lateral margin of thorax at a level 3 to 4" below jugular notch (level of T7) Expose on inspiration
AP: Bilateral Posterior Ribs- above diaphragm 40" SID 14x17 IR landscape Erect position for above diaphragm Posterior rib pain=AP Clinical Indications: Pathology of the ribs, including fracture and neoplastic processes
-patient erect with back against wall bucky for AP -raise chin to prevent from superimposing upper ribs; look straight ahead CR perpendicular; centered 3 or 4" below jugular notch (level of T7) Expose on inspiration
AP Unilateral Rib Study: Posterior Ribs-below diaphragm 40" SID 14x17 IR portrait recumbent for below diaphragm Clinical Indications: Projection is taken to demonstrate specific trauma to one side of the thoracic cavity
-patient recumbent CR perpendicular; centered midway between MSP & lateral margin of thorax at a level midway between the xiphoid process & lower rib margin bottom of IR at iliac crest Expose on expiration (diaphragm moves up)
AP: Bilateral Posterior Ribs- below diaphragm 40" SID 14x17 IR landscape Recumbent position for below diaphragm Posterior rib pain=AP Clinical Indications: Pathology of the ribs, including fracture and neoplastic processes
-patient recumbent CR perpendicular; centered midway between xiphoid process & lower rib margin Expose on expiration (diaphragm moves up)
Posterior Oblique Ribs (RPO & LPO) Below Diaphragm 40" SID 14x17 IR portrait Recumbent for below diaphragm Posterior oblique= affected side towards IR Clinical Indications: Oblique positions will demonstrate axillary portion of ribs not well seen with AP-PA projections
-patient supine for below diaphragm -rotate into 45 degree RPO or LPO with affected side closest to IR & knee of opposite side flexed CR perpendicular; midway between xiphoid process & lower rib margin (bottom of IR at level of iliac crest) Expose on expiration
Evaluation Criteria: RAO Sternum
-sternum is visualized, superimposed over heart shadow
3 parts of bony thorax
1. Sternum 2. Ribs 3. Thoracic vertebrae
RAO Sternum 40" SID 10x12 IR portrait Erect (preferred) or semiprone with slight rotation Clinical Indications: Pathology of the sternum including fractures and inflammatory processes
15 to 20 oblique toward the right side (RAO) Place top of IR 1.5" superior to the jugular notch CR directed to center of sternum (1" to left of midline & midway between jugular notch & xiphoid process) Orthostatic (shallow breathing) technique large deep chest= less rotation
Fractures
A break in the structure of a bone. Fractures of the bony thorax can be dangerous because of the proximity of the lungs, heart, & great vessels. Areas of common fractures include: -Ribs -Flail chest -Sternum
floating ribs (11-12)
A type of false ribs, that do not possess costocartilage & are not connected anteriorly.
Anterior Articulations of Bony Thorax
A. joint between the costocartilage & sternal end of the 4th rib is called a costochondral union or junction. B. Sternoclavicular joint C. Sternocostal joint of the 1st rib D. 4th sternocostal joint E. Interchondral joints
Evaluation Criteria: PA Bilateral Anterior Ribs-above diaphragm
Above diaphragm: -1st to 10th posterior ribs visualized -no rotation
Evaluation Criteria: AP Bilateral Posterior Ribs above & below diaphragm
Above diaphragm: -1st to 10th posterior ribs visualized -no rotation Below diaphragm: 9th to 12th posterior ribs visualized -no rotation
Evaluation Criteria: AP Unilateral Rib Study: Posterior Ribs above OR below diaphragm
Above diaphragm: -1st to 10th posterior ribs visualized -no rotation Below diaphragm: 9th to 12th posterior ribs visualized -no rotation
Evaluation Criteria: Posterior Oblique Ribs (RPO & LPO) Above Diaphragm
Above diaphragm: -1st to 10th posterior ribs visualized -no rotation -axillary portion of ribs projected without superimposition
sternoclavicular joint
Articulation between the clavicle and the sternum
Evaluation Criteria: Posterior Oblique Ribs (RPO & LPO) Below Diaphragm
Below diaphragm: 9th to 12th posterior ribs visualized below diaphragm -no rotation -axillary portion of ribs projected without superimposition
Posterior Articulations of Bony Thorax
F. costotransverse joints are formed between the facet of the tubercle of the rib & the adjacent transverse process of a thoracic vertebra G. costovertebral joints are joints that connect the ribs to the vertebral column. The head of the rib is connected to bodies of the thoracic vertebrae.
Sternum
Flat bone with three divisions: 1. manubrium (2") 2. Body (4") 3. Xiphoid process= most inferior total length of adult sternum is 7" does not become totally ossified until 40 years old
Fractures: Flail chest
Fracture of adjacent ribs in two or more places caused by blunt trauma and is associated with underlying pulmonary injury. This type of injury can lead to instability of the chest wall. If flail chest injury is suspected, do erect rib studies
Bony Thorax- Sternum, ribs, thoracic vertebrae palpable landmarks
Jugular notch=T2-T3 Sternal Angle= T4-T5 Xiphoid Process= T9-T10 Inferior Rib (costal) Angle= L2-L3
Fractures: Ribs
Most commonly caused by trauma or underlying pathology. Fractures to the first rib are often associated with injury to underlying arteries or veins, whereas fractures to lower ribs (9 to 12) may be associated with injury to adjacent organs such as spleen, liver or kidney. Any rib fracture may cause injury to the lung or cardiovascular structures (pneumothorax, pulmonary or cardiac contusion)
Fractures: Sternum
Typically caused by blunt trauma, fractures of the sternum are associated with underlying cardiac injury
True Ribs (1-7)
first 7 pairs of ribs; attach directly to sternum via costocartilage
PA Sternoclavicular Joints 40" SID 8x10 IR portrait Clinical Indications: Joint subluxation or other pathology of the sternoclavicular joints
patient prone with arms up beside head or down by side Allow no rotation of shoulders CR perpendicular; directed to T2-T3 or 3" distal to vertebra prominens (spinous process of C7) Suspend on expiration for more uniform density
Lateral Sternum (R or L) 72" SID to reduce magnification by increased OID 10x12 IR portrait erect(preferred) or lateral horizontal beam *left lateral unless indicated otherwise Clinical Indications: -Pathology of the sternum including fractures and inflammatory processes - depressed sternal fractures
patient standing with shoulders & arms drawn back Top of IR 1.5" above jugular notch CR directed to center of sternum (midway between jugular notch & xiphoid process) Suspend respiration on inspiration
Anterior Oblique (RAO & LAO) Sternoclavicular Joints 40" SID 8x10 landscape Prone or erect Clinical Indications: -joint separation, subluxation or other pathology of the SC joints -best visualizes SC joint on downside, demonstrated closest to the spine
prone or erect with 10 to 15 degree rotation CR to level of T2 to T3 or 3" distal to vertebra prominens AND 1 to 2" lateral (towards upside) to MSP Suspend respiration 10 to 15 degree rotation in an anterior oblique will rotate the SC joint across the spine to the opposite side RAO= demonstrate right downside SC joint LAO= demonstrate left downside SC joint
false ribs (8-12)
ribs that do not have a direct attachment to the sternum
