The superior processes are connected by the supraspinous ligament and the inter-spinous ligament (fig. 346).

The former runs along the tops of the superior spinous processes, to each of which it becomes attached from the second cervical vertebra to the sacrum. The anterior portion is represented by a broad yellow elastic structure, termed the ligamentum nuchoe (fig. 347), which extends from the head backwards as far as the sixth dorsal spine, where it becomes continuous with the second portion or dorso-lumbar, which is continued to the sacrum or haunch. The ligamentum nuchae consists of a superior rounded (funicular) portion and an inferior broad flat (lamellar) portion.

The former or funicular portion extends from the sixth dorsal spine to the posterior part of the cranium, where it becomes inserted into the tuberosity of the occipital bone. This division of the ligament is very strong, and shows a groove running along its superior surface. It is usually covered with a dense mass of fat and connective tissue, which gives roundness to the superior border of the neck.

The lamellar portion is a broad sheet of yellow elastic tissue attached to the under surface of that last described. It is composed of two layers, one placed closely in apposition with and connected to the other by a loose fibrous substance. The fibres of these layers pass obliquely forward from the spines of the first five or six dorsal vertebrae to those of the six posterior neck-bones. The supra-spinous ligament gives support to the head and neck, and thereby relieves the muscles from the weight which would otherwise be imposed upon them at all times. Moreover, by its clasticity it allows of a certain degree of stretching, and freedom of movement in all directions. Situated in the middle line of the neck it separates the muscles of one side from those of the other.

The dorso-lumbar portion of the supra-spinous ligament is attached to the summits of all the lumbar and the twelve or thirteen posterior dorsal spines. In front it becomes continuous with the cervical division or "ligamentum nuchas", behind with the sacro-iliac ligament.

Fig. 346. - Ligaments of Spine (Side View).

1. Supra-spinous ligament. 2. Inter-spinous ligaments. 3. Bodies of dorsal vertebrae divided longitudinally and vertically. 4. Inferior common ligament. 5. Inter-vertebral discs. 6. Spinal canal.