Lumbo sacral,coccyx sacrum anatomy and positioning

Radiological anatomy and positioning

1. Lumbo-sacral; sacrum ;coccyx anatomy and positioning Dr.Pradeep patil

2. Lumbo-sacral junction

3. Lateral Position of patient and image receptor The patient lies on either side on the Bucky table, with the arms raised and the hands resting on the pillow. The knees and hips are flexed slightly for stability. The dorsal aspect of the trunk should be at right-angles to the image receptor. This can be assessed by palpating the iliac crests or the posterior superior iliac spines. The coronal plane running through the centre of the spine should coincide with, and be perpendicular to, the midline of the Bucky. The image receptor is centred at the level of the 5th lumbar spinous process

4. Direction and location of the X-ray beam The collimated vertical beam is centred at right-angles to the lumbo-sacral region and towards a point 7.5 cm anterior to the 5th lumbar spinous process. This is found at the level of the tubercle of the iliac crest or midway between the level of the upper border of the iliac crest and the anterior supe rior iliac spine. If the patient has particularly large hips and the spine is not parallel with the tabletop, then a 5° caudal angulation may be required to clear the joint space.

5. Antero-posterior Position of patient and image receptor •The patient lies supine on the Bucky table, with the median sagittal plane coincident with, and perpendicular to, the midline of the Bucky. The anterior superior iliac spines should be equidistant from the tabletop. The knees can be flexed over a foam pad for comfort and to reduce the lumbar lordosis. The image receptor is displaced cranially so that its centre coincides with the central ray .

6. Direction and location of the X-ray beam The collimated central beam is directed 10–20° cranially from the vertical and towards the midline at the level of the anterior superior iliac spines. The degree of angulation of the central ray is normally greater for females than for males and will be less for a greater degree of flexion at the hips and knees.

7. Right or left posterior oblique Position of patient and image receptor The patient is positioned supine on the Bucky table and is then rotated to the right and left sides in turn so that the median sagittal plane is at an angle of approximately 45° to the tabletop. The hips and knees are flexed and the patient is supported with 45° foam pads placed under the trunk on the raised side. The image receptor is displaced cranially at a level to coincide with the central ray .

8. Essential image characteristics The posterior elements of L5 should appear in the ‘Scottie dog’ configuration

9. Sacrum

10. Antero-posterior / postero-anterior Position of patient and image receptor The patient lies supine or prone on the Bucky table, with the median sagittal plane coincident with, and at right-angles to, the midline of the Bucky. The anterior superior iliac spines should be equidistant from the tabletop. If the patient is examined supine (AP), the knees can be flexed over a foam pad for comfort. This will also reduce the pelvic tilt. The image receptor is displaced cranially for AP projection, or caudally for PA projections, such that its centre coincides with the angled central ray .

11. Direction and location of the X-ray beam • Antero-posterior : the collimated central beam is directed 10–25° cranially from the vertical and towards a point mid- way between the level of the anterior superior iliac spines and the superior border of the symphysis pubis The degree of angulation of the central ray is normally greater for females than for males and will be reduced for a greater degree of flexion at the hips and knees

12. Postero –anterior : palpate the position of the sacrum by locating the posterior superior iliac spine and coccyx. Centre to the middle of the sacrum in the midline The degree of beam angulation will depend on the pelvic tilt. Palpate the sacrum and then simply apply a caudal angulation, such that the central ray is perpendicular to the long axis of the sacrum

13. Lateral Position of patient and image receptor The patient lies on either side on the Bucky table with the arms raised and the hands resting on the pillow. The knees and hips are flexed slightly for stability. The dorsal aspect of the trunk should be at right-angles to the image receptor. This can be assessed by palpating the iliac crests or the posterior superior iliac spines. The coronal plane running through the centre of the spine should coin cide with, and be perpendicular to, the midline of the Bucky. The image receptor is centered to coincide with the central ray at the level of the midpoint of the sacrum.

14. Direction and location of the X-ray beam The collimated vertical beam is directed at right-angles to the long axis of the sacrum and towards a point in the mid- line of the table at a level midway between the posterior superior iliac spines and the sacro-coccygeal junction .

15. Coccyx

16. Antero-posterior Position of patient and image receptor :- The patient lies supine on the Bucky table, with the median sagittal plane coincident with, and at right-angles to, the midline of the Bucky. The anterior superior iliac spines should be equidistant from the tabletop. The knees can be flexed over a foam pad for comfort and to reduce the pelvic tilt. The image receptor is displaced caudally so that its centre coincides with the central ray .

17. Direction and location of the X-ray beam • The collimated beam is directed 15° caudally towards a point in the midline 2.5 cm superior to the symphysis pubis . Radiological considerations • Anatomy of the coccyx is very variable (number of seg ments , angle of inclination, etc.).

18. Lateral Position of patient and image receptor The patient lies on either side on the Bucky table, with the palpable coccyx in the midline of the Bucky. The arms are raised, with the hands resting on the pillow. The knees and hips are flexed slightly for stability. The dorsal aspect of the trunk should be at right-angles to the image receptor. This can be assessed by palpating the iliac crests or the posterior superior iliac spines. The median sagittal plane should be parallel with the Bucky. The image receptor is centred to coincide with the central ray at the level of the coccyx

19. Direction and location of the X-ray beam The collimated vertical beam is directed at right-angles to the long axis of the sacrum and towards the palpable coccyx .

20. Thank you