1) Prominent overbite of maxillary incisors -overbite means recessed lower mandible, which means less room for tongue = less room for you to see -big incisors/beaver teeth = get in way of your view because you wont be able to line your blade up properly = increased possiblity of broken teeth 2) During voluntary protrusion, patients cannot bring mandibular incisors anterior to maxillary Think about when you lift up and away with your laryngoscope. That action TRANSLATES the jaw forward opening up the posterior pharynx and allowing you to get a better view of the larynx. If you person cant translate their jaw forward = less room for you to manuver with = crappier view 3) High arched palate or narrow High arched, dunno. Unless it is associated with some other sort of anomaly. Narrow = less room. 4) Compliance of mandibular space (what is the mandibular space?) If you grabbed my lower jaw and ripped it out, tongue (the whole thing to the thyroid notch)and all, everything lying inbetween the two halves of the mandible to the thyroid notch is the mandibular space. This is all the soft tissue you must manuver around in order to get your view. 5) Thickness of neck...i can understand short necks..but why thickness? Big thick neck probably correlates with a LOT of soft tissue on the inside. Soft tissue LOVES to collapse when you put the patient to sleep. Grab any anesthesia book and check out the 3 axis of the airway (oral, pharyngeal, laryngeal). That will lead to a nice simple understanding of some of the anatomic barriers you must try and overcome in order to get a view (i.e. the sniffing position and a ramp for phatties in order to get their head higher than their chest.). Some studies suggest that the sniffing position doesn't make all that much difference if an airway is difficult.