B • ANATOMY, NEUROPATHOLOGY AND REGENERATION
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Posterior funiculus
Ascending tracts
(fasciculus gracilis and fasciculus cuneatus). These two tracts occupy
practically the whole funiculus posterior and transmit cephalad the proprioceptive
sensibility including sense of position and movement, vibration, two-point discrimina–
tion, appreciation of figure-writing, deep pressure and also touch sensation. The fasci–
culus gracilis (Goll) receives fibres from the posterior roots of the distal parts of the body
(thoracic, lumbar, sacral and coccygeal regions). The fibres coming from the sacral
part are displaced medially by fibres which enter at higher levels. In the upper regions of
the cord the fasciculus gracilis lies in the medial part of the posterior funiculus while the
funiculus cuneatus (Burdach) subserving these modalities of sensibility in the upper part
of the body occupies the lateral part. The fibres of the two fasciculi ascend uncrossed to
the oblongata and after taking part in the decussation of the lemnisci ascend on each side
to the ventral nucleus of the thalamus and from there they are conveyed to areas 1-3 of
the postcentral gyrus of the cortex.
Descending tracts.
There are some descending fibres in the cervical, upper thoracic and
lower thoracic regions in the posterior funiculus which are mainly intersegmental and
represent collectively the septomarginal tract.
Intersegmental tracts.
There are intersegmental fibres in the anterior, lateral and posterior
funiculi which mingle with ascending and descending tracts; some of them cross to the
opposite side.
SOMATOTOPIC ARRANGEMENTS WITHIN THE SPINAL CORD
There exists a somatotopic division of lamellated type representing the various parts of
the body within ascending and descending tracts which is particularly conspicuous in
the cervical region. This has important bearing on the clinical symptomatology following
injuries and other afflictions of the spinal cord (see chapter on Clinical Symptomatology).
There exists also a somatotopic grouping of motoneurones associated anatomically as
well as functionally with particular types of muscles (Gehuchten & de Neef, 1900;
Bikeles & Franke, 1905; Romanes, 1951; Balthaser, 1952) and Fig. 24 shows Glee's
adaptation (1961) from Sharrard's publication (1956).
Vascular supply of the spinal cord
Since Adamkiewicz (1882) described details of the arterial supply of the spinal cord this
problem has been studied by numerous workers in this field (de Kadyi, 1889; Tanon,
1908; Adachi, 1928; Tureen, 1938; Bolton, 1939; Su & Alexander, 1939; Mettler, 1948;
Zulch, 1951; Lazorthes
et
a/., 1957-58; Tonnis, 1963; Romanes, 1965; Tellinger, 1966;
Piscol, 1972; and others). Although there is some disaccord about certain details amongst
authors, there is general agreement that the spinal cord receives its arterial supply from
various sources.
The anterior spinal artery originates on either side from the intracranial end of the
vertebral arteries at the distal part of the oblongata. After forming a solitary trunk this
