Superimpositions

Question 1

What are 2 of the most important structure for cranial base superimpositions?

Answer 1

1. Anterior wall of Sella Turcica

2. The cribiform plate

Question 2

When is the Anterior wall of sella turcica completely stable?

Answer 2

After 5-6 years

Question 3

When is the cribiform plate completely stable?

Answer 3

After 4-5 years

Question 4

What is the Walker point?

Answer 4

The intersection of anterior wall of sella and the clinoid process

Question 5

When is walker point stable?

Answer 5

After 5-6 years of age

Question 6

What is the ceph landmark that extends from walker point to the greater wings of the Sphenoid and anteriorly past the wings?

Answer 6

Planum Sphenoidale

Question 7

The greater wings of the Sphenoid demarcate the separation of what bones?

Answer 7

Sphenoid

Ethmoid

Question 8

What two lines lay anteriorly to the Planum Sphenoidale?

Answer 8

Inferiorly, Cribiform plate

Superiorly, Ethmoidal crest

Question 9

What landmark extends from the anterior aspect of the clinoid process but anteriorly to the greater wings of the sphenoid?

Answer 9

The cerebral surface of the orbital part of the frontal bone

Bilateral and can be uneven

Question 10

What are the primary structures for sagittal orientation?

Answer 10

1. anterior wall of sella

2. greater wings of the sphenoid (If both wings are visible, use the average of the two)

Question 11

What are the primary structures for vertical orientation?

Answer 11

1. Walker point (intersection of anterior wall of sella + inferior aspect of clinoid processes)
2. Cribiform plate
   * If cribiform plate cannot be seen, ethmoidal crest should be used.

Question 12

What are the secondary structures for vertical orientation?

Answer 12

1. Planum Sphenoidale
2. Cerebral surface of the orbital part of the frontal bone
   * *Only used if cribiform plate or ethmoidal crest cannot be visualized.

Question 13

What are the primary structures of the mandible?

Answer 13

1. Contours of the chin, just below pogonion
2. Inner contour of the cortical plate at the lower border of the symphysis
3. Contours of the alveolar canals

Question 14

What is the secondary structure of the mandible

Answer 14

lower contour of the 3rd molar bud

Question 15

What is the most stable area of the maxilla during growth?

Answer 15

The anterior surface of the zygomatic process

Question 16

What structures are traced in the maxilla/

Answer 16

Zygomatic processes (Split the two and average)
Right and Left maxillo-zygomatico temporal sulci
The orbital floors
The nasal floors

Question 17

What is the primary structure for AP superimposition of the maxilla

Answer 17

Anterior surface of the zygomatic process

Question 18

What is the secondary structure for AP superimposition of the maxilla?

Answer 18

The maxillo-zygomatico temporal sulcus

Question 19

What is the primary structure for Vertical superimposition of the maxilla

Answer 19

The orbital floor (shows apposition)
The nasal floor (shows resorption)

Therefore, you slide the superimposition Up and Down along the anterior surface of the zygomatic process so that the orbital floor shows apposition after growth and the nasal floor shows resorption. There should be slightly greater apposition (3/5) than resorption (2/5)