Bony Thorax. Anatomy and Procedures of the Bony Thorax Edited by M. Rhodes

Transcription

1 Bony Thorax Anatomy and Procedures of the Bony Thorax Edited by M. Rhodes

2 Anatomy Review Bony Thorax Formed by Sternum 12 pairs of ribs 12 thoracic vertebrae Conical in shape Narrow at top Posterior longer than anterior Slide 2

3 Protects heart and lungs Supports wall of pleural cavity and diaphragm Made to vary the volume of thoracic cavity during respiration Functions of Bony Thorax Slide 3

4 Anatomy: Ribs Posterior aspect of typical rib Slide 4

5 Anatomy: Ribs 12 pairs, numbered superiorly to inferiorly Number corresponds to thoracic vertebra to which it attaches Ribs are long, narrow, curved bones Anterior ends lie lower than posterior (vertebral) ends Slide 5

6 Anatomy: Ribs Vary in length and breadth First is shortest and broadest Increases in length from 1 to 7, then decreases to twelfth Classified by attachment True ribs are 1 to 7 because they attach directly to sternum False ribs are 8 to 12 because they do not attach directly to the sternum Floating ribs are 11 and 12 because they only attach to the vertebrae Slide 6

7 Anatomy: Ribs Typical rib consists of Head Neck Tubercle Body Heads articulate with vertebral bodies Form costovertebral joints Tubercles articulate with T-spine transverse processes Form costotransverse joints Slide 7

8 Anatomy: Ribs Enlarged image of rib and T-spine articulations Slide 8

9 Anatomy: Sternum Centered on midline of anterior thorax Narrow, flat bone About 6 (15 cm) in length Three parts Manubrium most superior Body Xiphoid process most inferior Slide 9

10 Anatomy: Sternum Supports clavicles at manubrial angles Forms sternoclavicular (SC) joints Provides attachment for costal cartilages of first seven pairs of ribs at lateral borders Slide 10

11 Anatomy: Sternum Manubrium has jugular notch at superior border Palpable landmark Lies at T2-T3 interspace Body is longest portion (about 4 [10.2 cm]) Joined to manubrium at sternal angle Sternal angle is palpable and lies at T4-T5 interspace Xiphoid process is distal, smallest portion Often deviates from midline Useful landmark Lies over T10 Slide 11

12 Joints Name Type Movement Sternoclavicular Joint SC Costovertebral 1 st 12 ribs Costotransverse 1 st 10 th ribs Costochondral 1 st 10 th rib Sternocostal Synovial Joints - Gliding Joints Synovial Gliding Synovial Gliding Cartilaginous, Synchondroses 1 st rib Cartilaginous Synchondroses 2 nd 7 th ribs Synovial Gliding Fibrocartilage in joint space, Articular capsules, freely moveable Freely moveable Freely moveable Immovable Immovable Freely moveable Interchondral 6 th 9 th ribs - Synovial Gliding 9 th & 10 th ribs Fibrous syndesmoses Freely moveable Slightly movable Manubriosternal Cartilaginous symphysis Slightly moveable Xiphisternal Cartilaginous Synchondroses Immovable Slide 12

13 General Procedural Guidelines Bony Thorax Slide 13

14 General Procedural Guidelines Patient preparation General patient position IR size SID ID markers Radiation protection Patient instructions Slide 14

15 Patient Preparation Patient preparation for bony thorax procedures requires removal of artifacts from the anatomy of interest Necklaces Clothing artifacts Secure all patient possessions in designated manner and location Check for pregnancy Accommodate any trauma Slide 15

16 General Patient Position Ambulatory patients Upright or recumbent Nonambulatory patients Alter positioning to maximize patient comfort SID Textbook gives guidelines Use smallest IR that will demonstrate anatomy Collimate field size to anatomy of interest Slide 16

17 SID SID is standardized as a part of procedural protocol 30 (76.2 cm) is recommended SID for PA oblique sternum 72 (183 cm) SID is recommended for lateral sternum to reduce magnification and distortion caused by increased OID When SID is not specified under a projection, Merrill s Atlas recommends 48 (122 cm) Slide 17

18 ID Markers Right or left side markers must be included on each image Other required ID markers must be in the blocker or elsewhere on the final image Radiation Protection Shield patients of reproductive age and pediatrics Other radiation protection measures Close collimation Optimum technique factors Slide 18

19 Patient Instructions Explain and demonstrate positions, when possible Respiration instructions are essential for imaging the bony thorax Give clear explanations to reduce the need to repeat studies Slide 19

20 Radiographic Procedures Essential Projections of the Bony Thorax Slide 20

21 Essential Projections: Sternum PA oblique RAO position Lateral Upright Recumbent Slide 21

22 PA Oblique Sternum Patient position 15- to 20-degree recumbent RAO Part position Ensure shoulders and hips rotated equal amount Long axis aligned to midline Top of IR 1.5 (3.8 cm) above jugular notch Slide 22

23 CR PA Oblique Sternum Perpendicular to IR Enters elevated side of posterior thorax 1 (2.5 cm) lateral to MSP at level of T7 Can use breathing technique to blur lungs Instruct patient to take slow, shallow breaths during exposure If short exposure time used, suspend breathing at end of expiration Slide 23

24 PA Oblique Sternum (RAO) Entire sternum from jugular notch to tip of xiphoid process Sternum well visible through thorax Pulmonary markings blurred if breathing technique used Minimally rotated sternum and thorax shown by Sternum free of superimposition by vertebral column Vertebrae minimally obliqued to prevent excessive rotation of sternum Lateral portion of manubrium and SC joint not overlapped by vertebrae Slide 24

25 RAO Sternum Slide 25

26 Lateral Sternum Note: Draw large breast of females laterally and secure so the soft tissue shadows do not obscure sternum. Patient position Upright, seated or standing Slide 26

27 Part position CR Lateral Sternum Rotate shoulders posteriorly and lock hands behind back Center sternum to midline MSP vertical Top of IR placed so that upper border is 1.5 (3.8 cm) above jugular notch Perpendicular to IR Enters lateral border of sternum at midsternum Use close collimation to improve image quality Suspend respirations after deep inspiration Slide 27

28 Patient position Lateral recumbent Patient position Lateral Sternum True lateral without rotation Flex hips and knee for comfort Extend arms over head Adjust height of IR to place top border 1.5 (3.8 cm) above jugular notch Slide 28

29 Lateral Sternum CR Perpendicular to gridded IR Enters patient at lateral border of midsternum Close collimation will improve image quality Exposure made after patient suspends respiration at end of deep inspiration Slide 29

30 Lateral Sternum Entire sternum Manubrium free of superimposition by soft tissues of shoulders Sternum free of superimposition by ribs Lower portion of sternum not obscured by breast tissue in female patients Second radiograph with increased penetration may be needed Slide 30

31 Essential Projections: SC Joints PA ( Upright or Prone) PA oblique Body rotation method PA oblique CR angulation method Slide 31

32 Patient position PA SC Joints Prone Upright facing vertical Bucky Slide 32

33 PA SC Joints Part position CR MSP aligned to midline of IR IR centered to spinous process of T3 Shoulders in same transverse plane For bilateral examination, rest head on chin and adjust MSP of head to vertical For unilateral projection, turn head toward affected side and rest cheek on table Perpendicular to center of IR Enters patient at MSP and T3 Suspend at end of expiration Slide 33

34 PA SC Joints Both SC joints and medial ends of clavicles SC joints seen through ribs and vertebrae No rotation on bilateral Slight rotation seen on unilateral Slide 34

35 Patient position Recumbent or upright Part position PA Oblique SC Joints Body Rotation Method 10- to 15-degree RAO or LAO position Affected side placed closer to IR SC joint in center Shoulders in same transverse plane Slide 35

36 PA Oblique SC Joints Body Rotation Method CR Perpendicular to SC joint closer to IR Enters at level of T2-T3 (3, or 7.6 cm, distal to C7) and 1 to 2 (2.5 to 5 cm) lateral, or toward the joint of interest, from MSP Respirations suspended at end of expiration Slide 36

37 PA Oblique SC Joints CR Angulation Method Note: This method images SC closer to IR with less distortion than body rotation method. Patient position Prone (may be performed upright) Place grid IR directly under upper chest Center grid IR to SC joints Slide 37

38 Part position PA Oblique SC Joints CR Angulation Method Extends arms along side body with palms facing up Shoulders in same transverse plane Rest head on chin or rotate chin toward joint of interest CR From side opposite joint of interest, angle 15 degrees toward MSP to midpoint of IR Enters at level of T2-T3 (3, or 7.6 cm distal to C7) and 1 to 2 (2.5 to 5 cm) lateral to MSP Respirations suspended at end of expiration Slide 38

39 PA Oblique SC Joints Body Rotation Method SC joint of interest in center of image Manubrium and medial end of clavicle included Open SC joint space SC joint of interest adjacent to vertebral column with minimal obliquity SC joint clearly visible through superimposed rib and lungs Slide 39

40 PA Chest Essential Projections: Ribs AP Uppers & Lowers Posterior ribs AP oblique Uppers & Lowers Axillary portion PA Upper, anterior ribs PA oblique Axillary portion side away from IR Slide 40

41 Patient position Upright or recumbent facing x- ray tube Upright recommended for upper ribs when patient s condition permits to allow diaphragm to drop lower AP Ribs Slide 41

42 AP Ribs Part position for upper ribs MSP centered to midline of grid Top of lengthwise IR 1.5 (3.8 cm) above upper border of shoulders Rest hands, palms out, on hips Or extend arms, flex elbows, and rest hands under head Shoulders in same transverse plane and rotate forward to move out of ribs Slide 42

43 Part position for lower ribs MSP centered to grid Crosswise IR with lower border level with iliac crests Remaining positioning same as for upper ribs AP Ribs Slide 43

44 AP Ribs CR Perpendicular to center to IR Respiration suspended at full inspiration for upper ribs Depresses diaphragm Respiration suspended at end of full expiration for lower ribs Elevates diaphragm Slide 44

45 AP Ribs For ribs above diaphragm, entire first to tenth posterior ribs on both sides For ribs below diaphragm, entire eighth to twelfth posterior ribs on both sides Ribs visible through lungs or abdomen In unilateral examination, opposite ribs not entirely included Slide 45

46 AP Ribs Slide 46

47 AP Ribs Lower Slide 47

48 Patient position Upright or recumbent Upright recommended for ribs above diaphragm Recumbent patients require radiolucent support AP Oblique Ribs Slide 48

49 Part position AP Oblique Ribs 45-degree RPO or LPO Affected side closer to IR Center affected side on a longitudinal plane halfway between MSP and lateral surface of body Abduct and elevate arm of affected side Rest on head Abduct opposite limb and rest hand on hip Slide 49

50 AP Oblique Ribs For upper ribs, place top of lengthwise IR 1.5 (3.8 cm) above shoulders For lower ribs, place lower edge of IR at level of iliac crests Slide 50

51 AP Oblique Ribs CR Perpendicular to center of IR Respirations suspended at end of deep inspiration for upper ribs Respirations suspended at end of full expiration for lower ribs Slide 51

52 AP Oblique Ribs About twice as much distance between vertebral column and lateral border of ribs seen on affected side Axillary portion of ribs free of superimposition For ribs above diaphragm, first to tenth ribs visible above diaphragm For ribs below diaphragm, eighth to twelfth ribs visible below diaphragm Ribs visible through lungs or abdomen Slide 52

53 AP Ribs Oblique Slide 53

54 Patient position PA Ribs Upright (seated or standing) or recumbent Upright allows diaphragm to descend to lowest position and demonstrates air-fluid levels in chest Recommended when patient s condition permits Slide 54

55 Part position MSP centered to grid PA Ribs Top of lengthwise IR 1.5 (3.8 cm) above upper border of shoulders Rest hands, palms out, on hips Shoulders in same transverse plane If patient is prone, rest head on chin and adjust MSP to vertical CR Perpendicular to center of IR Respiration suspended at end of full inspiration Depresses diaphragm Slide 55

56 Patient position Upright or recumbent Upright recommended for ribs above diaphragm when patient condition allows PA Oblique Ribs Slide 56

57 PA Oblique Ribs Part position 45-degree RAO or LAO Affected side away from IR Center affected side on a longitudinal plane halfway between MSP and lateral surface of body Abduct and elevate arm of affected side Rest on head Abduct opposite limb and rest hand on hip For upper ribs, place top of lengthwise IR 1.5 (3.8 cm) above shoulders For lower ribs, place lower edge of IR at level of iliac crests Slide 57

58 PA Oblique Ribs CR Perpendicular to center of IR Respirations suspended at end of deep inspiration for upper ribs Respirations suspended at end of full expiration for lower ribs Slide 58