One important factor in acountryâs population density is its area. SouthAmerican countries, with their relatively largeland areas, tend to have low population densities.In Ecuador, the most densely populated country inSouth America, an average of only 118 peopleshare a square mile (46 people per sq. km).
Trochlear nerve: The nerve that controls the superior oblique muscle of the eye, one of the muscles that move the eye (extraocular muscles). Paralysis of the trochlear nerve results in rotation of the eyeball upward and outward (and, therefore, in double vision).The trochlear nerve is the fourth cranial nerve, and it is the only cranial nerve that arises from the back of the brain stem.aralysis of the trochlear nerve results in rotation of the eyeball upward and outward (and, therefore, in double vision). The trochlear nerve is the fourth cranial nerve, and it is the only cranial nerve that arises from the back of the brain stem.
The tendon of the trochlear nerve sits in the trochlea, a saddle or pulley-like cartilaginous structure that is located in the superomedial orbit. Inflammation of the trochlea, trochleitis, produces swelling and tenderness, presenting as a unilateral periorbital pain, a headache referable to the trochlear apparatus. Trochleitis can be idiopathic or secondary to inflammatory or autoimmune connective tissue disorders.