Sphenoid bone - internal view There are four main parts to the sphenoid bone: the body (corpus), the lesser and greater wings (alae minores et majores) and the pterygoid processes. The body is the most centrally positioned portion. Anteriorly it contributes to the nasal cavity, laterally it builds the medial wall of the optic canal.
The anchor you chose will depend on the type of anchoring you do. Cruising anchors are larger plow or claw anchors capable of holding boats to various bottoms. Kedging, Forfjord and Workboat anchors are used on commercial vessels.
Anchor size recommendations are for boats of average windage and proportions in 30 knots of wind, average bottom conditions, and moderate protection from open seas. Remember that the loads in 42 knots of wind are twice as much as in 30 knots.