259
The Spinal Cord in Relation to the Vertebral Column Vet1ebral arch cut away a t CS and C6 to show the w rd being compressed by a spondylotic bar
The Iransverse process of C4 is cut away to show the emerging CS rool damaged by the osteophytes in the exit foraminae
~_----::;:--
Ver/ebral artery
Odontoid peg There is nO disc at C1/C2 interspace
Whether the cord is easily compressed depends on the pre-existent canal diameter. Canals of Ie s thall 13 mm. diameter predispose to compression (llorm,,1 is 15-18 mm.)
C5 Nerve root compres ed by lateral di c lesion
Cord being compre sed by osteophytes and dilC fragments (the spondylitic bar)
Articular facet of first rib
15.12
The cervical spine: latera l and left anterior oblique views.
Latera l Vi ew of the Cervica l Spine in Forward Flexion
Latera l View of the Cervical Spine in Hyperextension
In this movement the cord shortens and would appear to be able to 'flop back' from the bars. But it i by f.l r the mostdangerous movement in cervica l spondylosi . The roots (see above), the denticulate ligaments. and the forward bulging of the buckled ligamentum flavum all tend to hold the cord forwards. Which of these faclors is the most significa nt in cau ing damage is much disputed
In this posilion the canal elongates 1 to 2 cm. The cord must stretch and tends to pull forwards. In cervical pondylosis thi is the el ss dangerous movement. Wilh iI fractured odontoid, however, the unchecked forw,1(d riding of C lan C2 may produce fa tal damage to the upper cord and lower medulla
15.13
The cervical spine in flexion and extension.
USA as the 'barber's chair sign'). This consists of tingling in all four limbs or electric shock-like feelings down the back on flexing the neck if the cervical cord is damaged by multiple sclerosis, cervical spondylosis or any other condition that distorts or inflames the cervical spinal cord. In hyperextension of the neck the canal shortens and the cord shortens. In this position the
spinal cord may be squeezed between the spondylotic bar anteriorly and the buckled ligamentum flavum posteriorly (Fig. 15.13). 6. The cord is not completely free to ride these blows as it is held forward by the anterolaterally directed nerve roots and prevented from riding backwards by the ligamentum denticulatum at each side.