Skull Baselines

What are some pathologic Indications?

1. Skull fractures

2. Gunshot wounds

3. Neoplasm (cancerous growth)

4. Multiple myeloma (cancer in bone marrow)

5. Pituitary Adenoma (tumor)

6. Paget’s Disease (fragile, misshapen bones)

What is the degree difference between the glabellomeatal line and the OML

8°

What is the degree difference between the OML and the IOML

7°

MESOCEPHALIC

• Typical shape

• Petrous pyramids are 47° from MSP

• Petrous pyramids are at the base of the cranium

• Optic foramina are 37° open anterior to MSP

BRADYCEPHALIC

• Short front to back

• Broad side to side

• Shallow vertex to base

• Petrous pyramids are 54° from MSP

• Internal structures higher

DOLICEPHALIC

• Long front to back

• Narrow side to side

• Deep vertex to base

• Petrous pyramids 40° from MSP

• Internal structures lower

Why should we consider general body position when we are positioning for skull radiographs?

• The head is attached to the body.

• Poor and uncomfortable body positions causes difficulty in getting the head positioned, resulting in rotation or other motion and repeats.

• Inability to hold position because of muscle strain

Name some key points when positioning the body for skull

• Align patient’s body with table

• Support any elevated part

• Hyposthenic patients may need chest elevated

• Hypersthenic patients may need head elevated

• View patient on most appropriate plane and get an eye level view

What are 5 common positioning errors

1. Rotation

2. Tilt

3. Excessive Flexion

4. Excessive Extension

5. Incorrect CR angle

What are some cleanliness rules

• Clean area with disinfectant before and after positioning 

• Hair & face are naturally oily and leave a residue

  • Which is worse when the pt is sick

• Hair, mouth, nose & eyes come in contact with IR, bucky, and table

• May place a cloth or paper towel between IR and patient

Name some radiation protection rules

• Thyroid, thymus & gonads shielded on infants & children

• Best way to protect is by using proper collimation

• Ensure patient is properly instructed

• Use of immobilization reduces likelihood of having to repeat

What are some patient preparation protocols

• Remove all radiopaque artifacts

  • Eyeglasses

  • Dentures and partial plates

  • Hearing aids

  • Jewelry

  • Wigs/hairpieces

  • Hairpins, barrettes, and pony tail holders

  • False eyes

Rotation of head prevention

• Check MSP to IR 

  • Upright or Recumbent 

  • Perpendicular or parallel

Tilt of head prevention

• Check MSP to IR

  • Upright or Recumbent

  • Perpendicular or parallel

• Align long axis (cervical) with midpoint of the foramen magnum

How to provide support

• Any elevated part (shoulders/hip with pillows)

Recumbent examinations of hyposthenic or asthenic patients

Elevate patient’s chest 

Recumbent examinations of hypersthenic patients

Elevate patient’s head