Some ideas on larger herbivore types. That cervical curve is really going to dip if we make a character with those distinctive rounded shoulders with a neck in a 'stoop'. The nuchal ligaments are going to have to act like a crane arm to help stop that neck collapsing - it's rather unstable. So I've also highlighted some context as to large stabilising muscle shapes of the neck. I think this would really limit head rotation. Also the cervical vertebra in this configuration would have to be bulkier to take the stress of the lateral rotation.

Great video on cervical spine rotation.

Skull to Neck

As heads get bigger, so does the weight of keeping them upright. Here i'm showing the nuchal ligament as being an important part of keeping a larger head upright.

We need to strike a careful balance with how we expect larger anthro skulls to sit on a biped spine. The cervical vertebrae is the most flexible part of the spine but this comes at a trade-off with strength. Strong yet flexible interspinal ligaments hold the vertebrae from palling apart and in many quadrupeds the nuchal ligament is very important in holding the head and neck from collapsing under it's weight. In humans this tough ligament is less important, our skulls are balanced on the 1st cervical vertebrae, the Atlas, with stability aided by numerous muscles. An anthro skull by contrast would likely be heavier, larger facial features, big jaw. This upsets the balance and we can either reposition the skull on the atlas like a pivot or we recruit ligaments and muscles to help stability. Nuchal ligaments would act like a suspension bridge, pulling from the processes on the thoracic vertebrae to a prominent crest on the part of the Occipital bone of the skull.

What does this mean for character designs: 

consider the weight of your characters heads, this includes big horns and teeth! 

How would the cervical vertebrae curve, is it realistic

Where is the load of the head being distributed

Spinal processes are going to be visible along their backs

How will bigger back muscles such as the trapezius look and how is that head able to flex and move?!