Mandibular Orthognathic Surgery

Question 1

Dingman and Grabb (1961) relationships

Answer 1

In 81% of specimens, marginal mandibular n. (CN VII) nerve ABOVE inferior border before crossing facial a. 98% nerve was SUPERFICAL to the posterior facial v.

Question 2

Al-Kayat (1979) findings

Answer 2

Mean distance between temporal branch and anterior border of bony external auditory canal 0.8 – 3.5cm Temporal branch located beneath superficial muscular aponeurotic system (SMAS) layer/ temporoparietal fascia Becomes superficial to SMAS layer: 1.5-3cm ABOVE zygomatic arch 1.5cm LATERAL to orbital rim

Question 3

Hayes Martin maneuver

Answer 3

facial vein is divided and slung superiorly to protect the marginal mandibular nerve (Hayes Martin maneuver)

Question 4

Distance from inferior border of mandible to IAN canal:

Answer 4

7mm at first molar 7mm at second molar 11mm at base of coronoid notch

Question 5

Where does the IAN enter the mandible?

Answer 5

IAN enters the mandible 8.3 +/- 0.22mm below the tip of the lingula; 4mm above the occlusal plane

Question 6

Buccal and lingual cortex thickness at first molar, second molar, and coronoid?

Answer 6