Pelvis and hips Flashcards
What projections for femur?
Antero-posterior Femur Lateral Femur (HBL)
How do you do a AP femur
Patient core position:
Patient lying supine on x-ray table with leg extended.
Positioning criteria:
Posterior aspect of femur in contact with image receptor.
Femoral condyles should be equidistant from the image receptor
Centring:
To the middle of the receptor with a VCR.
Collimation:
Collimate to include knee joint and and much femur as possible and lateral soft tissue margins. Knee up PLUS overlapping Hip down projections may be required.
Other info:
100/115cm SID.
Lateral femur (HBL)
Patient core position:
Patient lying supine on x-ray table with leg extended.
Positioning criteria:
Patient then turns onto affected side so that Lateral aspect of affected femur is in contact with image receptor, with knee flexed and other limb separated.
Femoral condyles should be superimposed with respect to the IR.
Centring:
To the middle of the IR with a VCR.
Collimation:
Collimate to include from knee to hip joint and lateral soft tissue margins. Knee up PLUS overlapping Hip down projections may be required.
Other info:
100/115cm SID.
LMP/ Pregnancy Rule
Women of ‘child-bearing capacity’
When the ‘beam lays in or near the uterus’
Pregnancy status prior to examination
The 28 day rule is normally used.
Could be over-ruled in significant trauma (life-threatening injuries.)
Projections for pelvis?
AP Pelvis
AP Both Hips
AP Single Hip
What makes up the pelvis girdle?
Innominate bones (2).
Sacrum – part of the vertebral column.
Coccyx – part of the vertebral column.
What forms the The Innominate Bone of the pelvis?
Ilium (top bit)
Ischium (lateral)
Pubis (medial)
What is the acetabulum?
The acetabulum is a cup-shaped hollow in the pelvis into which the head of the femur (thigh bone) fits to form a ball and socket joint
Made up from all the bones of the pelvis
What does ASIS mean and where/what is it?
The anterior superior iliac spine
below the iliac crest
What does psis mean and where/what is it?
posterior superior iliac spine
On the posterior side where it joins the spine
Where is the iliac crest?
Top round part of the iliac bone
What does SIJ?
Sacroiliac Joint
What is the Obturator Foramen?
The hole in the pelvis
- superior pubic ramus
- inferior pubic ramus
- superior pubic ramus (above the hole)
- inferior pubic ramus (medial low bit of the bone by the hole)
What is the Symphysis Pubis?
The middle bit between the pubis, cartilaginous joint in the median plane
on the anterior side of the pelvis
Where is the coccyx?
The last bit of the spine
How does the appearance differentiate between male and female pelvis?
Female is wider, Smaller & more triangular obturator foramen
Males have a longer sacrum
What are the joints of the pelvis?
each other at the Symphysis pubis.
the sacrum at the Sacro-iliac joints (SIJ’s).
The femora at the Hip joints
What are the joints of the pelvis?
each other at the Symphysis pubis. (Cartilaginous Symphysis)
the sacrum at the Sacro-iliac joints (SIJ’s). (Synovial plane joint)
The femora at the Hip joints (Synovial ball and socket)
What are Clinical indications for femur?
Trauma
? Fracture (?#).
Unexplained pain
? bone lesion
How would you take an projection of the femur? Does it fit on the IR?
The joint closest to the pathology should be included on the image if both hip and knee joint cannot be demonstrated. Multiple overlapping projections are usually undertaken.
The routine projections undertaken are an Antero-Posterior and a Lateral.
Clinical Indications for pelvis x-ray linked to trauma?
Trauma – Fall generally = NOF High velocity can lead to other pelvic fractures Pubic rami Acetabulum SIJ disruption Iliac wing #s
Clinical Indications for pelvis x-ray linked for children?
pain in hip / on walking SUFE-Slipped Upper femoral Epiphysis DDH-Developmental Dysplasia of the Hip CDH-Congenital Dislocation of the Hip Perthes-osteochondritis dessicans Osteomyelitis.
Clinical indications for pelvis linked to pain in hip but not trauma?
Pain in hip ?
Osteoarthritis (OA),
Avascular Necrosis
or loose prosthesis.
What does SOJ mean and what is it?
Sacroiliac joint,
Where the sacrum and the iliac bone meet
What do you do for Patient Preparation?
Explanation of procedure. Informed consent Change into a gown. Safety checks. LMP check
What projections are there for the pelvis?
AP Pelvis
AP Both Hips
AP Single Hip
Lateral
Turned
Horizontal Beam
“Frog” leg lateral (Lauenstein)
AP SIJ
PA SIJ
Whats the patient position for AP pelvis and both hips?
Patient supine on table.
Criteria:
Median Sagittal Plane (MSP) perpendicular to the table and co-incident with central long axis of the table.
ASIS’s equidistant from table top.
Lower limbs slightly internally rotated (so heels are slightly apart but big toes touching together)
brings necks of femora parallel to the IR & greater + lesser trochanters into profile.
What’s the centering point for AP pelvis? and collimation?
Over the midline, 5cm above the upper border of the symphysis pubis with a vertical central ray (whole Pelvis).
Collimate to include the superior border of Iliac crests and as much as the femora as you can.
What’s the centering point for AP hips? and collimation?
Over Symphysis pubis.
In the Midline
Collimate to include inferior ileum, acetabulum & upper 1/3rd of Femora (or entirety of prosthesis).
What SID and cassette and AED would you pick for Pelvis, Hip x-ray?
35 x 43cm regular cassette placed landscape in the table bucky, 100cms FFD.
100/115 SID
AED- for pelvis any one (or pick all 3)
For hip depends on metal work, one of the sides that doesnt have metal work.
Centering for an AP single hip
Imagine a line between ASIS and the upper border of symphysis pubis (use R&L as appropriate!)
From the mid-point of this line imagine another line at 90° to this
(this is called a perpendicular bi-sector)
Centre 2.5cm distally along this line (Lateral and Inferior).
Collimation for AP single hip?
Hip Joint.
Whole of prosthesis (if present).
Whole of the Symphysis Pubis.
Turned Lateral single Hip.
Patient positioning
From the supine position on table.
Criteria:
Rotate patient onto affected side (raise unaffected side) so that the Median Sagittal Plane (MSP) is at 45’.
Use a large pad to support the patient in this position.
Knee on Affected side is flexed and externally rotated until lateral aspect is in contact with table (cf lateral knee).
VCR at standard SID
Centre as for an AP single hip.
Patient position Frog Laterals of both Hip Joints?
Patient supine.
Criteria:
Median Sagittal Plane (MSP) perpendicular to the table.
Plantar aspect of feet touching.
Both Knees flexed and externally rotated by upto 60°(or symmetrical).
Patient positioning for HBL hip
Patient supine (as for AP pelvis)
Criteria:
Median Sagittal Plane (MSP) perpendicular to the table.
Do not move the affected leg.
Unaffected Hip & Knee flexed & supported out of the way of horizontal superimposition.
Horizontal Beam Lateral Hip image receptor?
Imaging Receptor:
Within grid (stationary box grid or sometimes erect bucky is used with DR).
Supported parallel to the NOF (450 to long axis of patient)
Upper border in contact with Iliac Crest of affected side.
Centering for HBL hip?
Centring:
Midway between the anterior and posterior skin margins
Directed through the hip joint of the affected limb.
Horizontal central ray (HCR)
Perpendicular to IR
(to avoid grid cut off)
Standard SID
Collimation for HBL hip?
Collimate to include:
Acetabulum.
Proximal 1/3rd of Femur.
Ischial Tuberosity.
Clinical indications for SLJ?
Clinical indications
Trauma
Pain / Degenerative change/ Inflammation.
Pre / Post Surgery
How to do AP SIJ?
Patient Supine
MSP perpendicular to central long axis of the Table
ASIS’s equidistant to Table
Table detector
VCR with10-200 Cranial Angle.
Centred along MSP at a level midway between ASIS and Symphysis pubis
How to do PA SIJ?
Patient Prone
MSP perpendicular to central long axis of the Table
PSIS’s equidistant to Table
Table detector
VCR with10-200 Caudal Angle.
Centred along MSP at a level midway between the PSIS’s
