Cervical spondylosis
 Dr. Bindu .K   BHMS,MD(Hom)

Introduction
Vertebrae
Vertebral column consists of a number separate irregular bones called ‘ vertebrae’ , forms the central axis of body .

Functions
1, Protects the spinal cord.
2, Supports and transmits body weight.
3, Provides movement of the trunk.

Vertebrae are named according to the region in which they lie . There are thirty three vertebrae but only thirty one spinal nerves .

VERTEBRAE   NUMBER     SPINAL NERVES     NUMBER
Cervica                l 8                   Cervical                  7
Thoracic              12                   Thoracic                12
Lumbar                 5                    Lumbar                  5
Sacral                  5                     Sacral                   5
Coccygeal            4                  Coccygeal                1

In adults , the sacral vertebrae fuse to form sacrum and the four coccygeal vertebrae fuse to form coccyx .

CHARACTERISTICS OF A VERTEBRA
A typical vertebra has 2parts.
1. Body: the anterior or vertebral part.
2. Arch: the posterior or dorsal part.

Verebral foramen:- lies between the body and arch these are placed one above the other with intervertebral discs between them and forms the vertebral canal which lodges the spinal cord with its meninges and blood vessels.

I. Body of vertebra
1. It is nearly cylindrical in shape, the size and shape varying in vertebrae of different regions
2. It posses six surfaces-upper, lower, anterior, posterior and two lateral.
II. Vertebral (neural) arch:- consists of
1. Pair of pedicles
2. Pair of laminae
3. Seven processes
  a. Spinous-1
  b. Articular-4
  c. Transeverse-2
The arch s connected to the body by the pedicles.

1. Pedicles
i. Short, thick processes pass back ward from the junction of lateral and posterior surfaces of the body
ii. posseses two surfaces and four borders
2. Laminae
i. Broad plates of bones lying behind medial to pedicles
ii. They fuse behind in the median plane in to the spinous process
iii. The form posterior boundary of vertebral foramen
3. Processes
A. Spinous processes (spine)
i. Passes back wards and down wards from the jointsof the two laminae
ii. Shape and size varies in vertebrae of different regions
iii. Gives attachment to muscles and ligaments
B. Articular processes
i. Four in number, 2 superior and two inferior
ii. Arise from the junction of pedicles
C. Transeverse processes
i. Two in number
ii. Project laterally from the junction of pedicle and lamina
iii. In thoracic they articulate with ribs. The most important distinguishing feature of vertebrae of different regions is the
Cervical: Presence of a foramen in the transverse process called foramen trasversarium
Thoracic: presence of coastal facet on the body.
Lumbar: no foramen trasversarium and no coastal facet on the body.

CERVICAL VERTEBRAE
Cervical Vertibrae are 7 in number and form the axial skeleton of the neck.
Identification: presence of foramen trasversarium in the transverse process.
Typical cervical vertebrae: 3rd,4th,5th, and 6th present similar features hence called typical.
Atypical cervical vertebrae: 1st, 2nd and 7th cervical vertebrae present special features hence called atypical
1st cervical vertebrae- atlas
2nd cervical vertebrae-axis
7thcervical vertebrae- vertebrae prominence

Vertebral curvatures
The vertebral column is not straight but present four curvatures
1. Cervical
2. Thoracic
3. Lumbar
4. Sacral
Thoracic and sacral curvatures: Concave anteriorly they develop during foetal life because of flexed posture and thus called primary curvatures
Cervical and lumbar convex anteriorly; they after birth and are called ‘secondary curvatures’. Cervical curvature develops when the child sits up (3rd month) and lumbar curvature when the child learns to stand and walk ( 1 year )
Counting of individual vertebra

This is done by palpating the spines which lie in the median plane and become prominent on bending the body forwards.
1. Spine of the seventh cervical vertebra can be felt in the neck because of it prominence and is the most important land mark for counting the spines.
2. Line joining the medial ends of spines of scapulae passes through third thoracic spine
3. Line joining inferior angles of scapulae passes though seventh thoracic spine
4. Line joining highest points of two illiac crest passes between third and fourth lumbar spines. This taken as guide in doing lumbar puncture.
5. Line joining posterior superior iliac spines corresponds to second sacral spinous process.
Clinically three major types of abnormal curvatures of vertebral column are seen
1. Kyphosis:Hunch back (accentuated thoracic curvature )
2. Scoliosis: Abnormal lateral curvatures
3. Lordosis: Hollow back(accentuated lumbar curvature )

Cervical spondylosis
Degenerative changes develop in the vertebral column with advancing age. The nucleus pulposus of the inter vertebral discs undergo degeneration with reduction in their fluid content, and this results in their collapse and narrowing of the intervertebral spaces. The annulus fibrosus also shows degerative changes and protrude backwards behind the vertebral bodies to form ridges. Osteophytes develop from the vertebral bodies and laminae resulting in compression of the nerve roots in the inter vertebral foramina

The cord may be compressed by osteophytic bars formed in the midline behind the vertebral bodies or the roots may be compressed by osteophyte growing into the inter vertebral foramina. Degenerative changes are seen most markedly and symptoms are more frequent in the cervical and lumbar region of the vertebral column. In addition to the higher mobility of the spine in these region which accounts for greater predilection to the degenerative changes, it is also likely that subjects who developed cervical spondylosis have relatively narrower spinal canals.

In addition to the bony changes soft tissue changes develop. The ligamenta flava lose elasticity and tend to buckle forwards when cervical spine is extended. This leads to compression of the posterior aspect of the cord. In the intervertebral foramina fibrosis of the dural sheath contributes the further pressure on the spinal nerves and their roots. Pressure on the spinal arteries and vertebral arteries during their course in the bony structures leads to secondary vascular changes which causes occlusion and ischemic damage to the cord and lower brain stem. The clinical presentation may vary widely from that of a myelopathy, radiculopathy or both. The site of lesion may be at the actual level of compression, or even distant from that, on account of vascular occlusion.

Clinical features
Though the older age groups are more affected by osteoarthritis, many patients even in the fourth and fifth decades of life may suffer from this disease and this fact should be borne mind in all cases presenting with painful symptoms around the pectoral girdle. Initial symptoms consists of parasthesia pain in the distribution of fifth to the eighth cervical dermatoms. Pain being felt most frequently over the shoulder, arm, scapular region, fore arm and hands. Movements of neck travel and adoption of certain postures aggravate the pain, which may be intermittent or even constant. In majority of patients objective sensory loss to pin prick may be demonstrable. Motor phenomena consists of weakness and wasting of deltoid, triceps biceps or forearm muscles. Wasting of small muscles of the hand is rare in pure cervical spondilosis. Involvement of the C5 segment gives rise to inversion of the supinator jerks. Fasciculation may be seen over the affected muscles. Tendon reflexes are diminished. The lesion may be unilateral or asymmetrically bilateral.

Neurological complications
Cervical radiculopathy : this condition develop when the inter verebral foramina are grossly narrowed in the cervical region, maximal degenerative changes are seen between the 5th ,6th and 7th cervical vertebrae and these nerve roots are most frequently affected.

Compressive myelopathy
This develops as a result of compression of the spinal cord osteophytic bars infront and ligmentum flavum behind. Most frequent site of compression is the C5-C6 region. Ischemia further advances the damage.
The clinical picture is one of insidious onset of spastic paraplegia with motor and sensory symptoms. Pressure on the posterior column gives rise to sensory ataxia.

Occlusive vascular disease
The vertebral artery which ascends in the foramina in the transeverse process over the atlas to enter the magnum is kinked,? Compressed and stretched, when the vertebral column loses height and spondylotic changes occur. In addition, atherosclerotic changes develop early. These changes result in vertebro-basilar ischaemia.

Diagnosis
Cervical spondylosis can be suspected in all cases presenting with cervical cord or root symptoms in persons above the age of 40 years.

Differential diagnosis
Other causes of cord compression syphilitic pachymenigitis, arachnoditis, syrigomylia and motor neuron disease, ankylosing spondylosis.
In some cases of cervical spondylosis flexion or extention of cervical spine causes “electric shock like sensation” over the segments affected. This is called Lhermit’s sign this may occur in other causes of cord compression as well. Clinical diagnosis should be confirmed by radiological studies of spine, X-ray taken in the lateral view with the neck in straight, flexed, and extended positions and oblique views reveal the abnormalities well radiological changes include narrowing and irregularity of the inter vertebral spaces, osteophytes and encroachement of the inter vertebral foramina. In young subjects bony out growths may not be evident, but alteration in the alignment of cervical vertebrae, especially loss of the cervical curvature caused by spasm of neck muscles should be taken as a suggestive sign. Myelography reveals the narrowing of the spinal canal and compression of the cord. A-P diameter of the spinal cord in the cervical region is 9-10 mm. If the vertebral canal is less than 10mm cord compression is likely. The CT scan study is helpful in delineating the lesion. MRI clearly brings out the total picture of vertebral changes and compression of the neural structures. Somatosensory evoked potential help to evaluate physiological and anatomical mal functions of the spinal cord.

Treatment
In the early stages, proper positioning of the neck, physiotherapy and use of a cervical collar to restrict neck movements help to relieve root pains. Exercises designed to strengthen shoulder girdle muscles especially elevators of the scapula help to relieve traction on the nerve roots and prevent reoccurrence of symptoms. Persons who have had symptoms should be advised to wear cervical collar during long journeys, so as to prevent recurrence. Graded cervical traction may help to relive pressure on the nerve roots. If definite bony ridges are demonstrable in cases with cord compression surgery to relieve pressure is indicated.

References
1. Textbook of Medicine – K.V. Krishna Das
2. Harrison’s internal Medicine
3. Gray’s anatomy
4. Davidson’s principles and practice of medicine
5. A Handbook of osteology- Poddar