B-ANATOMY, NEUROPATHOLOGY AND REGENERATION
67
Anterior Vertebral
spinal artery artery
Posterior
spinal artery
Aorta
(a)
(b)
(c)
FIG. 26. The arterial supply of the spinal cord.
A
(after Ziilch, 1954) is based on clinical
and pathological studies. The chief sources of blood are through the radicular arteries
of segments C6, Thio, and L2. The postulated direction of blood flow in the arteriae
coronae is indicated. Regions of apposition of arterial beds, namely, segments Th4 and Li
(diagonal-hatch), are said to be weak points in the circulation on the basis (diagram
to extreme left) that arterial pressure is lowest in the terminal vessels of a system. For
the same reason, the central grey matter and the ventral part of the posterior column also
represent weak points (diagonal-hatch) in the circulation (inset).
B
and
C
(after Bolton, 1939) are based on anatomical studies. The sources of arterial
supply of the cord are the same as in
A.
The postulated direction of blood flow is
indicated. The region of poorest circulation (diagonal-hatch) is said to be at upper
thoracic levels. The arterial beds of the anterior and posterior spinal arteries as seen in
cross section are indicated (inset). The stippled areas in the upper part of the cord
in
A
and
B
represent the two views as to the segments supplied from the cervical branches
of the vertebral artery (from Bing's
Local Diagnosis,
14th Edition).
3 the intermediate zone involving the mid-thoracic segments which is relatively poorly
vascularized, especially at the level of the 4th thoracic segment. This area has been
considered particularly vulnerable to vascular conclusion and ischaemia as found by
Bolton (1939) in his injection studies and later by Ziilch (1954). Fig. 25 taken from Bing's
Local Diagnosis in Neurological Diseases
(i4th edition) as revised and enlarged by Webb
Haymaker (1956) demonstrates the arterial beds and cell aggregates of the spinal cord as
seen in cross section and Fig. 26 shows the blood supply of the spinal cord according to
Bolton (1939) and Ziilch (1954) respectively. Romanes (1965) reported about 22 spinal
cords in which he studied the feeding vessels to the anterior spinal arteries. He found
that while the chance of feeding vessels on the right and left side was about equal in
