MASONRY AND ITS SYMBOLS

Harold W. Percival

SPINAL CORD
and
SPINAL NERVES

Fig. VI-A, b

CROSS SECTION of
SPINAL CORD

Fig. VI-A, c

Gray matter Central matter White matter
SPINAL COLUMN
and
SPINAL CORD

Fig. VI-A, d

7th–cervical–1st vertebrae 12th–dorsal vertabrae–1st 5th–lumbar–1st Sacrum Coccyx Terminal filament
THE SPINAL CORD
and its Relation to the Spinal Column

The spinal cord proper reaches from the base of the brain to about the junction of the 12th dorsal and the 1st lumbar vertebrae; its prolongation downward is called the terminal filament, which is anchored below to the coccyx. The spinal cord has a central canal, the prolongation downward of the ventricles of the brain; below, in the embryo, this canal reaches to the end of the terminal filament, but in the adult it usually becomes clogged up within the filament and disappears more or less, in the run of human beings.

The spinal column is divided into five sections: the cervical, dorsal, and lumbar vertebrae, and the sacrum and coccyx. Bony processes and the shape of the vertebrae create openings on both sides through which pass spinal nerves to the neck, trunk, and upper and lower extremities, (Fig. VI-A, b).