Femur + Pelvis

4 major parts of the proximal femur

1. Head (rounded, articulates with acetabulum, contains fovea capitis for attachment of ligamentum capitis femoris)

2. Neck (triangular, strong, area of intertrochanteric crest)

3. Greater trochanter (superior and lateral to shaft, used as bony landmark)

4. Lesser trochanter (medial and posterior to shaft/neck)

Both the trochanters are joined ________ (anterior or posteriorly) by a thick bony ridge called ________________.

posteriorly; intertrochanteric crest

The angle of the neck to the shaft of the femur is approximately _ degrees, with a variance of about _ degrees

125; 15

The angle of the neck of the shaft to the femur varies based on what two things?

The width of the pelvis and length of lower limbs

The shorter the person, the ____ the angle of the neck-shaft of the femur

greater

The taller the person, the _____ the angle of the neck-shaft of the femur

lesser

The longitudinal plane of the femur on an average person is about __ degrees from vertical.

10

The longitudinal plane of the femur on a short person with a wider pelvis is about __ degrees from vertical.

15

The longitudinal plane of the femur on a tall person with a narrower pelvis is about __ degrees from vertical.

5

The angle of the head and neck of the femur is about ____ degrees anterior in relationship to the shaft of the femur

15-20

The femur must be rotated ____ degrees internal to place the femoral neck parallel to the IR for a true AP proximal femur

15-20

The total pelvis consists of what 4 bones?

1. 2 hip bones

2. 1 sacrum

3. 1 coccyx

Hip bones are also called

Innominate bones

What are the 3 divisions of the hip bone?

1. Ilium (largest, upper 2/5th of acetabulum)

2. Ischium (2/5th of acetabulum)

3. Pubis (anteroinferior 1/5th of acetabulum)

Upper margin of the ala of ilium that extends from ASIS (anterior superior iliac spine) to PSIS

Crest of the ilium

The ilium is composed of what?

Ala, body, and crests

The lower portion of the ischium projects _____ and ______ from the acetabulum, ending at the ischial tuberosity

caudally; medially

Projecting anteriorly from the ischial tuberosity is the ____ of the ischium.

ramus

The ischial _____ is a bony projection posterior to the acetabulum

spine

What bears the most weight when a person sits?

Ischial tuberosities

A large opening formed by the ramus, body of each ischium, and the pubis

Obturator foramen

False pelvis

• Area above the pelvic brim

• Holds abdominal muscles and fetus when pregnant

True pelvis

• Area beneath the pelvic brim

• Surrounded by bony structures

• Forms the birth canal

The inlet is also called?

Superior aperture

The outlet is also called?

Inferior aperture

The pubic outlet is made of what?

By the 2 ischial tuberosities and tip of the coccyx

The female pelvis vs male

Female

• Wider and more flared

• Obtuse angle of pubic arch

• Round and large inlet

Male

• Narrower, deeper, less flared

• Acute angle of pubic arch

• Narrow, heart-shaped inlet

How does the proximal femur look in anatomic position

• Femoral necks partially foreshortened

• Lesser trochanters partially visible

How does the proximal femur look in internal rotation?

• Toes in, heels out

• Lesser trochanters not/barely visible, greater trochanters in profile

How does the proximal femur look in external rotation?

• Femoral neck greatly foreshortened

• Lesser trochanters visible internally

Exposure techniques for hips/pelvis

• kVp - 77 to 85

• Grid needed

• 40” SID

• Cross-table hip varies with kVp
  

How do women vs. men femoral angles differ?

Women - Hips are wider and legs are shorter (more angle)

Men - Hips are not as wide and legs are longer (less angle)

How many vertebrae in a child?

33

• 7 cervical

• 12 thoracic

• 5 lumbar

• 5 sacrum

• 4 coccyx

How many vertebrae in an adult?

26

• 7 cervical

• 12 thoracic

• 5 lumbar

• 1 sacrum

• 1 coccyx

In a LPO, how do the hips and obturator foramen appear?

Left hip elongated, right obturator foramen open (criss-cross)

In a RPO, how do the hips and obturator foramen appear?

Right hip elongated, left obturator foramen open (criss-cross)

What are some ways to find CR for an AP hip?

• Imaginary T between ASIS and pubic symphysis

• Ken doll crease

• Lines up with wrist when arms next to side

Where should the top of the IR be for an AP hip?

ASIS (do not include top of ilium)

If a patient has a suspected hip fracture, what should you do?

Put other leg in desired position so they can be used to compare, leave broken leg in natural position and foot neutral

What are the different views used for the hips and pelvis?

1-view pelvis = full pelvis shot

2-view hip = full pelvis, and single lateral of affected side OR single AP hip with single lateral on affected side

How do you do a lateral hip?

If no fracture suspected and pt able → frog leg hip

If fracture suspected → cross-table hip aka Danelius-Miller method (shoot straight into the crotch)

Collimation for hip x-ray

10×12 normally, but with prosthetic full 14×17

If a patient has a broken hip, what x-rays should you do?

Some kind of AP (single or full pelvis), cross-table hip, and 1V chest

How to differ between a pubic inlet x-ray vs outlet

Inlet - Looks like a balloon (caudal angle)

Outlet - Looks like a butterfly (cephalic angle)

What is a judet view?

X-ray that shows both halves of the acetabulum

How to hang a cross-table hip x-ray?

Entire acetabulum must be visible, lay image so butt is down and pubic symphysis is up

What is a closed reduction?

Popping the head of femur back in place using traction instead of opening patient up

If a frog leg doesn’t look like a beer tap it’s because what 3 things?

1. They’re broken

2. Congenital defect

3. Wrong positioning

Pathologic Fracture

Occurs in bones already weakened by a pre-existing condition.

Comminuted Fracture

The bone is broken into 3 or more fragments - common in long bones such as the femur

Spiral/Torsion Fracture

The break coils around the bone - common in femur fractures

Bone Cyst

Wall of fibrous tissue filled with fluid - they are asymptomatic - appears as a lucent, oval shape with the long axis parallel to the host bone

Inherited generalized disorder of connective tissue characterized by multiple fractures and blue sclera (the white of the eye) - patients suffer repeated fractures caused by the severe osteoporosis and the thin, defective cortices.

Osteogenesis Imperfecta

A hereditary condition in which failure of the resorptive mechanism of calcified cartilage interferes with its normal replacement by mature bone. Results in a symmetric, generalized increase in bone density

Osteopetrosis (Marble Bone)

Impacted Fracture

Bony fragment is wedged into another fragment. Common in hip and shoulder fractures

Results from the loss of blood supply - the femoral head is the most frequent site of it - often necessary to obtain two radiographs in patients with this condition. The first is taken with normal density, whereas the second is made with increased kVp to allow for adequate penetration of the more opaque ischemic bone.

Ischemic Necrosis

Congenital dislocation of hip

Developmental dysplasia (DDH)

Associated with ischemic necrosis of bone. Ischemia results from poor blood supply to the bone. Affects the epiphyses and may be mistaken for tuberculosis of the skeletal system. Tends to occur in males between the ages of 5 to 10 years and often follows injury to the affected hip. Radiographically the bone in the center of the epiphysis is fragmented and the head of the femur is flattened.

Legg-Perthes Disease

Partial dislocation

Subluxation

Full dislocation

Luxation

The most common benign bone tumor - arises from the growth zone between the epiphysis and diaphysis of long bones (Metaphysis). Most commonly involves the lower femur or upper tibia and is capped by growing cartilage. Many time it is asymptomatic unless the affected long bone is traumatized which results in a pathologic fx. of the diseased bone.

Osteochondroma (Exostosis)