Bridge

The bridge is found somewhere between the middle and bottom of the body. Depending on the guitar, the strings may originate from the bridge or they might simply be supported by it. Most electric guitars allow the bridge to be raised or lowered, an adjustment necessary in setting up the guitar which may easily and safely be performed by any guitarist. This is typically done by adjusting screws, which are either thumbscrews which can be rotated with the fingers, or traditional screws requiring a screwdriver.

Acoustic guitars usually have a bridge and saddle arrangement. The strings originate at the bridge, usually held in by pegs. The strings then pass over a saddle, a flat piece of material held on its side. The saddle can be made of many materials, but the most common are either plastic or bone. Synthetic bone

Tremolo bar

The tremolo bar, also called the "tremolo arm," "whammy bar," or "vibrato bar," is found on some electric guitars. It was popularized on the Fender Stratocaster, and is now seen on many different models, including some hollow-body electrics. Another popular type of tremolo bar is the Floyd Rose. Its base will be located below the bridge. Pushing down on the bar will lower the pitch of the strings, and pulling it up will raise the pitch. Rapidly pushing and releasing (or pushing and pulling for exaggerated effect) will produce a modulation in pitch, called vibrato. Vibrato is often confused with tremolo (modulation in volume), hence the misnomer tremolo bar.

Neck

The neck of a guitar extends from the body. Some guitars may have it glued on, which is a set neck, and some may have it bolted on. A few guitars are made entirely of one piece of wood, or at the least, one piece of wood comprises the neck and part of the body, up to where the bridge is located, with the sides attached. Set necks are almost universal amongst acoustic guitars. The bolt-on or screw-on neck is similarly common with electric guitars. Both acoustic and electric guitars usually have a steel truss rod going through the neck. It counteracts the pull of the strings on the neck, strenghtening it, and reducing its curvature to an appropriate amount, also allowing for further adjustments if needed. Classical guitars do not require a truss rod, because there is less tension from their strings. Adjusting the truss rod is a step in setting up the guitar, but only an experienced luthier are encouraged to perform this adjustment. There have been several examples of alternative materials for the manufacture of guitar necks, the most noteable being a carbon fibre composite, the neck being the only structural requirement for string tension.