URIES OF THE VERTEBRAL COLUMN

_Partial_ lesions include twists or sprains, isolated dislocations of
articular processes, isolated fractures of the arches and spinous
processes, and isolated fractures of the vertebral bodies. The most
important _complete_ lesions are total dislocations and
fracture-dislocations.

In partial lesions, the continuity of the column as a whole is not
broken, and the cord sustains little damage, or may entirely escape;
in complete lesions, on the other hand, the column is broken and the
cord is always severely, and often irreparably, damaged.

Twists and dislocations are most common in the cervical region, that
is, in the part of the spine where the forward range of
movement--flexion--is greatest. Fractures are most common in the
lumbar region, where flexion is most restricted. Fracture-dislocations
usually occur where the range of flexion is intermediate, that is, in
the thoracic region.

In all lesions accompanied by displacement, the upper segment of the
spine is displaced forwards.

#Twists# or #sprains# are produced by movements that suddenly put the
ligamentous and muscular structures of the spine on the stretch--in
other words, by lesser degrees of the same forms of violence as
produce dislocation. When the interspinous and muscular attachments
alone are torn, the effects are confined to the site of these
structures, but when the ligamenta flava are involved, blood may be
extravasated and infiltrate the space between the dura and the bone
and give rise to symptoms of pressure on the cord. The nerve roots
emerging in relation to the affected vertebrae may be stretched or
lacerated, and as a result radiating pains may be felt in the area of
their distribution.

In the _cervical_ region, distortion usually results either from
forcible extension of the neck--for example from a violent blow or
fall on the forehead forcing the head backwards--or from forcible
flexion of the neck. The patient complains of severe pain in the neck,
and inability to move the head, which is often rigidly held in the
position of wry-neck. There is marked tenderness on attempting to
carry out passive movements, and on making pressure over the affected
vertebrae or on the top of the head. The maximum point of tenderness
indicates the vertebra most implicated. In diagnosis, fracture and
dislocation are excluded by the absence of any alteration in the
relative positions of the bony points, and by the fact that