Many people find touch pads to be less stressful on their wrists, hands and arms. This is because there is less movement and resistance than a traditional mouse. Touch Pads are also excellent for people with limited upper body mobility – as they might operate the touch pad with their toe using “dwell clicking software” or other switches to simulate mouse clicks. More . . .

Ergo Touchpad

The Ergo Touchpad can be used either as a standalone device or it can be clipped virtually anywhere on the keyboard. Touchpads come in either small or large. More information about the Ergo Touchpad . . .

TouchPad versus Trackpoint (extracted from original article on: Coding Horror)

When it comes to pointing devices on laptops, there are two schools of thought. There's the touchpad...

.. and there's the trackpoint, which was popularized by IBM thinkpads:

The author of this article wrote," The touchpad wins, for me, because it's such a simple input method -- yet it supports some complex, subtle nuances that are surprisingly intuitive:

1. click, double-click, and right-click by tapping the pad. In case you were wondering, on the Mac, a right click is a two-finger tap.
2. scroll horizontally or vertically by dragging your finger along the edges of the pad.
3. press harder to drag items further.
4. slide faster to move faster.

Original article . . .

Another user said of the Trackpoint, " Why a trackpoint, you say? Why do I love those little, rubbery eraser-like protrusions sticking out of the keyboard wedged between the G, H and B keys, when perhaps 99% of the world’s computing population absolutely abhors them? Again, my reason is ergonomics. For one, the distance of a rubbery trackpoint tip is only one inch from where my right forefinger would usually rest–the J key (or to lefties, the F key). This means my right hand does not need to travel more than twelve inches to reach that mouse, or four inches below to reach a touchpad. My hand stays right on the keyboard."

The author went on to say, " . . . With a trackpoint, hand movements are minimal. I just tell my finger to put a little pressure to the left, right, upwards or downwards, and the cursor moves. More pressure, and the cursor moves faster. A softer nudge, and the cursor moves just a tiny bit, one pixel at a time."

Original article . . .

The MacBook Touchpad

Touch Pad Pencil You know how hard it can be to navigate around your Laptop computer using your index finger on the touch pad, well this stubby little ‘pencil’, called the Digital Pencil or the Touch Pad Pencil, makes life a lot easier. Drawing with a pencil is second nature, far quicker, more accurate and controllable than your fingertip. (Supplier).

A useful overview of touch pads on Wikipedia