Cervical region
Cervical
spine due to its position, complex structure and great mobility is vulnerable
to injuries. It is a complex and vital region. Vital knowledge of cervical region
is essential for physician, while dealing with the patients having the problems
of cervical region.
Components
of the structure of cervical spine:
1. Bony Structure
The cervical spine is composed of first seven vertebrae
of the vertebral column. The seven cervical vertebrae are the smallest movable
vertebrae and identifiable by their transverse processes, which are perforated
by a foramen
a. Typical cervical vertebrae- 2nd to 6th cervical vertebrae:
b. The atlas – first cervical vertebra (C1)
c. The axis – Second Cervical Vertebra (C2)
d. The seventh Cervical Vertebra (C7)
e.
2. Musculature
The muscles of the neck are grouped according to their
position. These groups are
as follows
a. Superficial and Lateral cervical muscles
b. Anterior Vertebral muscles
c. Lateral Vertebral muscles
d. Deep muscles of the back of the neck
e. Sub – occipital muscles
3.
Articulations
(A)
Intervertebral articulations – It is divided into two parts.
a. Articulations of vertebral bodies
b. Articulations of vertebral arches.
(B)
Articulation of vertebral column with cranium:
The articulation of vertebral column with cranium
involves the paired atlanto-occipital joints and ligaments connecting the axis
and occipital bone.
4. Neural and Vascular
contents.
Cervical Spondylosis
Definition:
Cervical
spondylosis is a degenerative condition of the cervical spine. There is degeneration
of inter-vertebral disc, with its protrusion and bony overgrowth of adjacent vertebrae
causing compression of roots, cord or both. Occasionally it is associated with non-compressive
myelopathy consequent to vascular degeneration.
Pathogenesis:
This is
compound effect of the following processes:
a. The
initial change is a decrease in the water content of the nucleus pulposus, the
central
portion of the disc. As the disc dehydrates, it decreases in height and has
less ability
to resist loading and stress,
Disc
degeneration leading to its thinning and protrusion of the nucleus
pulposus
posteriorly or herniation through fear in the fibrous annuloses laterally;
posterior
herniation tends to produce compression of the spinal cord and lateral
bulging
produces compression of roots.
b.
Osteophytic spur formation on the posterior aspect of the vertebral body
leading
to the
‘spondylotic bar’, which is the core pathology resulting in a horizontal
compression
of the anterior aspect of the cord. Osteophytic extension of the bar,
laterally
associated with articulatory hypertrophic changes or encroachment of the
intervertebral
neural foramina by osteophytes developing from the rim of the
foramina,
often cause additional entrapment radiculopathy. Anterior ostephytic
spur
formation is usually symptom less but occasionally produces dysphagia.
c. Partical
sublaxation of vertebrae causing impinging of osteophytes on the nerve
roots during
movement of the neck.
d.
Hypertrophy of the dorsal spinal ligament and dorsilateral facet articulation
or
bucking of
the dorsal spinal ligament particularly during extension of the neck.
All these
may cause further narrowing of the sagittal diameter of a spinal canal,
which might
have been congenitally narrow.
e.
Encroachment of the vertebral foramina where the vertebral artery is lodged
producing
compromise of the arterial lumen and significant vetebro – basilar
ischaemia,
leading to brainstem signs like vertigo, tinnitus, intermittent blurring
of vision
and occasionally episodes of retroocular pain. This apart, the
architectural
pattern of the vasculature of the cervical cord may further affect the
cord lesion
significantly.
f. Presence
of congenital spinal canal stenosis; although the radiographic findings of
spondylosis
are fairly common in the elderly, patients develop myelopathy or
radiculopathy
only if spondylotic changes are associated with congenitally narrow
canal or
foramina. If the shortest AP diameter is 13mm or greater, it is unlikely
that
spondylotic changes are the cause of cord compression.
CLINICAL FEATURES:
The symptoms are related to
(a) Spinal
symptoms – Neckpain, medial scapular pain and shoulder pain probably
originate in
the disc and spine.
(b) Root
compression (Radiculopahty) – The range of movement is reduced
particularly
during rotation and lateral movement of the head. Pain starts from the
trapezius
ridge (C4), tips of the shoulder (C5), anterior part of the arm (C6), radial
forearm
(C6), and often the thumb (C8) or all the fingers (C6, C7, C8).
The pain
worsens with movement of the neck, coughing or sneezing or straining.
The clinical
signs are motor weakness and wasting of proximal muscles or small
muscles of
the hand depending on the roots compressed. In addition, there is also
areflexia
and redicular sensory impairment. Sometimes L’hermitt’s sign or
‘barber’s
chair sign’ can be elicited; this consists of tingling in all four limbs or
electric
shock – like feelings down the back on flexing the neck. The roots most
often
affected are, in order, C6, C7, and C5, C6, C8 and D1 are infrequently
affected.
Occasionally, the shoulderhand syndrome or the so – called frozen
shoulder
ensues if symptoms are unattended for some time.
(c)
Compressive cervical myelopathy – This condition occurs less frequently than
root
syndromes. There is some evidence that the patient has to be predisposed to
compression
by a congenitally narrow canal (Cervical canal stenosis) and usually
presents
with a progressive spastic paraparesis; later, bladder and bowel
involvement
is added to sensory inpairment with a level.
(d) Combined
root and cord compression – In a few cases, clinical features of both
radiculopathy
and myelopathy are combined. In such a combined lesion occurring
at C5 level,
the C5 root is compressed by lateral protrusion and the cord below
this level
is compressed by medial lesion. The reflexes are asymmetrical, with
classically
abscent or decreased supinator and exaggerated triceps jerks;
occasionally
an inverted supinator jerk is elecited when on testing for supinator
response,
there is finger flexion in the absence of the normal supinator response,
indicating a
lesion of C5 with myelopathy below.
(e) Vascular
insufficiency – Some times a completely different category of symptoms
may occur,
viz. evidence of vertebro basilar insufficiency, this may be due to
permanent
narrowing or kinking of the vertebral artery due to inter-vertebral
foraminal
encroachment by ingrowing osteophytes from the bony wall of the
vertebral
canal; it may produce intermittent or perpetual vertigo. Neck movement
may initiate
or exacerbate vertigo by temporary compression of the vertebral
artery
leading to further insufficiency.
The other
symptoms like tinnitus, visual blurring, etc. have already been
referred
too. As discussed earlier, there may be a non compressive myelopathy
due to
compromised vasculature. In such cases, pain is usually absent and
myelography
fails to reveal any spinal block; this is sometimes referred to as
cervical
myelopathy (or cervical spondylotic myelopathy).
Nystagmus,
though rare, is sometimes seen and is probably due to
involvement of the posterior
longitudinal bundle in a high cervical lesion.