Positioning Ch. 7 Femur & Pelvic Girdle

Question 1

Proximal Femur

Answer 1

4 Major Parts:
Femoral head articulates w/hip bone. Contains depression called Fovea Capitis which the ligament capitis femoris is attached.
Neck of the Femur: process connecting the head of femur to the body.
Greater Trochanter: large prominence located superiorly and laterally to the femoral shaft. *Used as a bony landmark.
Lesser Trochanter: smaller and blunt conical eminence located medially and posteriorly from the junction of the neck and shaft of the femur.

Question 2

Intertrochanteric Crest

Answer 2

both trocanters are joined posteriorly by this thick bony ridge

Question 3

Angles of the femur

Answer 3

angle of the neck to the shaft of the femur is approx. 125 degrees with a 15 degrees variance. Shorter person has less of an angle and taller person has a greater angle.
Longitudinal plane of the femur on an average person is about 10 degrees from vertical. Shorter person with a wider pelvis is closer to 15 degrees and taller person with a narrower perlvis is about 5 degrees.
Angle of the 15-20 degrees in relationship to the shaft of the femur. Femur must e rotated 15-20 degrees internal to place the femoral neck parallel to the IR for a True AP proximal femur.

Question 4

Pelvis

Answer 4

Pelvis means basin. Serves as the base of the trunk. Forms the connection between the vertebral column and the lower limbs.
Consists of 4 bones: 2 hip bones (ossa coxae) or innominate bones, 1 sacrum, 1 coccyx.

Question 5

Hip Bone

Answer 5

3 divisions which fuse at the acetabulum.

Ilium, Ischium, Pubis

Question 6

Ilium

Answer 6

Largest of the 3 hip bones. Composed of the ala and body. Body of ilium is more inferior near acetabulum. Ilium includes the upper 2/5 of the acetabulum. Crest of ilium is upper margin of the ala which extends from ASIS to PSIS. Both ASIS and PSIS are used for positioning landmarks.

Question 7

Ischium

Answer 7

Inferior and posterior to the acetabulum. Didived into the body and ramus. Upper portion of the body of ischium makes up posteriorinferior 2/5 of the acetabulum. Lower portion projects caudally and medially from acetabulum ending at the ischial tuberosity.
Projecting anteriorly from tuberosity is the ramus of the ischium.
Ischial spine is bony projection posterior to the acetabulum.
Directly above this projection is a deep notch called greater sciatic notch below the projection is the lesser sciatic notch.

Question 8

Ischial Tuberosities

Answer 8

bear most of the weight of the body when a person sits.

Question 9

Pubis

Answer 9

Body of the pubis is anterior and inferior to the acetabulum and includes the anteriorinferior 1/5 of the acetabulum.
Superior Ramus- extend anteriorly and medially from the body of each pubis. These two ramus meet in the midline to form a slightly immovable joint called symphysis pubis (pubic symphysis)
Obturator Foramen- largest opening formed by the ramus and the body of each ischium and by the pubis. Largest foramen in the body.

Question 10

False Pelvis (Greater Pelvis)

Answer 10

plane through the brim of the pelvis divides it into 2 cavities. General area above this plane is deemed the false or greater pelvis. Lower abdominal muscles and fetus rest on floor of greater pelvis.

Question 11

True Pelvis (Lesser Pelvis)

Answer 11

area beneath the plane is deemed the lesser or true pelvis. True pelvis is surrounded by bony structures. Size and shape of true pelvis forms the actual birth canal.
Brim of pelvis (superior true pelvis) is the inlet (also called superior aperture)
Outlet (Inferior aperture) is made by the 2 ischial tuberosities and by the tip of the coccyx.

Question 12

Lower Limb Rotation

Answer 12

Anatomic Position: feet straight vertical foreshortens the femoral neck.
Lesser trochanters partially visible.
15-20 degree medial rotation: most desired position for pelvis & hips. Toes pointed in, heels out. True AP projection of proximal femur. lesser trochanters are not visible or just barely.
External Rotation: toes pointed outwards, heels close together. Femoral neck greatly foreshortened. Lesser trochanters visible internally.
Hip Fracture Rotation: fractured leg kept in whatever position it is in. unaffected foot in a neutral position.

Question 13

Shielding

Answer 13

Male can be used to cover the testes but avoid covering essential anatomy.
Female shield for single hips to cover the ovary. Full pelvis cannot use full shielding

Question 14

Exposure Techniques

Answer 14

kVp generally between 77-85 for a normal starting point. Cross-table hip will vary.
Cross table mAs 60-80 300 lb person use weight plus add another 100 mAs
Always use a grid
40 inch SID

Question 15

Locate Femoral head

Answer 15

From ASIS go 1 inch medially and4 inches inferior(towards feet).
or
Use bikini line and center of femur will determine bottom of head of femur.