Cervical Vertebrae

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Structure 

The cervical spine is made up of two anatomically and functionally different segments.  These two segments work together to produce rotation, lateral flexion, flexion and extension of the head and neck.
It is made up of 7 vertebrae. The first 2, C1 and C2, are highly specialized and are given unique names: atlas and axis, respectively. C3-C7 are more classic vertebrae, having a body, pedicles, laminae, spinous processes, and facet joints.
C1 and C2 form a unique set of articulations that provide a great degree of mobility for the skull. C1 serves as a ring or washer that the skull rests upon and articulates in a pivot joint with the dens or odontoid process of C2. Approximately 50% of flexion extension of the neck happens between the occiput and C1; 50% of the rotation of the neck happens between C1 and C2.
The cervical spine is much more mobile than the thoracic or lumbar regions of the spine. Unlike the other parts of the spine, the cervical spine has transverse foramina in each vertebra for the vertebral arteries that supply blood to the brain. 

Typical Cervical Vertebra (C3-C7)

Vertebral body

  • The bodies of these four vertebrae are small, and transverse diameter is greater than anterio-posterior and height dimensions.
  • The anterior and posterior surfaces are flattened and of equal depth; the former is placed on a lower level than the latter, and its inferior border is prolonged downward, so as to overlap the upper and forepart of the vertebra below.
  • The upper surface is concave transversely, and presents a projecting lip posterolaterally on either side .
  • The lower surface is concave from front to back, convex from side to side, and presents laterally shallow concavities which receive the corresponding projecting lips of the underlying vertebra.

Vertebral foramen 

  • Large, triangular in shape.

Bony structures

  • The pedicles are short and project posterolaterally. They are attached to the body midway between its upper and lower borders, so that the superior vertebral notch is as deep as the inferior.
  • The laminae are long, narrow, and thinner above than below.  They curve posteromedially. 
  • The spinous process is short and bifid (to allow ligamentum nuchae to run through). Because the spinous processes are so short, certain superficial muscles (the trapezius and splenius capitis) attach to the nuchal ligament rather than directly to the vertebrae; the nuchal ligament itself attaching to the spinous processes of C2-C7 and to the posterior tubercle of the atlas.
  • The superior and inferior articular processes of cervical vertebrae have fused on either or both sides to form articular pillars, columns of bone that project laterally from the junction of the pedicle and lamina.
  • The articular facets are flat and of an oval form:
    • the superior face backward, upward, and slightly medially.
    • the inferior face forward, downward, and slightly laterally.
  • The transverse processes are short and house the foramen transversarium, which, in the upper six vertebrae, gives passage to the vertebral artery and vein, as well as a plexus of sympathetic nerves. Each process consists of an anterior and a posterior part. These two parts are joined, outside the foramen, by a bar of bone that exhibits a deep sulcus on its upper surface for the passage of the corresponding spinal nerve.
    • The anterior portion is the homologue of the rib in the thoracic region, and is therefore named the costal process or costal element. It arises from the side of the body, is directed laterally in front of the foramen, and ends in a tubercle, the anterior tubercle.
    • The posterior part, the true transverse process, springs from the vertebral arch behind the foramen, and is directed forward and laterally; it ends in a flattened vertical tubercle, the posterior tubercle.

Atypical Cervical Vertebrae (C1-C2) 

C1

The Atlas, C1, is the topmost vertebra, and along with the Axis; forms the joint connecting the skull and spine. Its chief peculiarity is that it has no body, and this is due to the fact that the body of the atlas has fused with that of the Axis.

C2

The Axis, C2, forms the pivot upon which the Atlas rotates. The most distinctive characteristic of this bone is the strong odontoid process (dens) that rises perpendicularly from the upper surface of the body. The body is deeper in front than behind, and prolonged downward anteriorly so as to overlap the upper and front part of the third vertebra. 
Atlas
Axis


Function

The cervical spine functions to provide mobility and stability to the head while connecting it to the relatively immobile thoracic spine.
The movement of nodding the head takes place predominantly through flexion and extension at the joint between the atlas and the occipital bone, the atlanto-occipital joint. However, the cervical spine is comparatively mobile, and some component of this movement is due to flexion and extension of the vertebral column itself.
The movement rotating the head left and right happens almost entirely at the joint between the atlas and the axis, the atlanto-axial joint. A small amount of rotation of the vertebral column itself contributes to the movement.

Pathology

Vertebral Causes of Spinal Pain:
  • Developmental:Scoliosis, Hypermobility, Various uncommon disorders.
  • Degenerative: Disc lesions without root compression, Disc lesions with root compression, Disc lessions with compression of spinal cord or cauda equina, Osteoarthrosis of apophyseal joint, Hyperostosis, .
  • Trauma: Fracture, Stress fracture, Subluxation, Ligamentous injury.
  • Tumour: Secondary carcinoma, Myelomatosis.
  • Infection: Staphylococcal, Tuberculous, E.coli, Brucella melitensis.
  • Inflammatory arthropathy: Rheumatoid arthritis, , Ulcerative colitis, , Psoriasis.
  • Metabolic: Osteoperosis, Osteomalacia.

Cervical Myelopathy: In the late stages of spinal degeneration, bone spurs from the degenerative process can cause a condition known as spinal stenosis. As the bone spurs form, the size of the spinal canal becomes smaller. The bone spurs begin to press on the spinal cord or the nerve roots. Pressure on the nerves in the spinal cord can cause numbness, tingling, or pain in the arms, hands, and legs. This condition is sometimes called cervical myelopathy. It is from the simpler problem where only one nerve root is being pinched by a herniated disc or a bone spur. Cervical myelopathy can affect both the arms and the legs. 

Assessment

Physical examination

Sequence proposed by Matiland for  the physical examination of the intervertebral segment:
    1.Active tests 
    1.1. Active movements: in standing, except for rotation which is best tested in sitting. 
    1.2. Auxiliary tests associated with active movements tests.
 
    2.Passive tests 
    2.1. Movement of the pain-sensitive structures in the vertebral canal and intervertebral foramen. 
    2.2.Palpation: The positions of the vertebrae should be assessed in relation to adjacent vertebrae. Palpation of the spinous process posteriolly and laterally is usefull both in regard to the position of the vertebra and to the state of the interspinous and supraspinous ligaments. No too much importance should be placed on abnormalities found on this assesment, only relevant if they are verified by radiology.

  Treatment

Manual treatment

New Model - Traction

  • Traction    : Traction therapies have been widely adopted in clinics and rehabilitation centers worldwide.Traction therapy, also known as spinal decompression therapy, refers to any medical procedure that applies force along the inferior-superior axis of the spine to extend the cervical and lumbar spine vertebrae. It seems that a inclined position (flexion) not only creates greater intervertebral separations on the posterior sides, it also provides a more accurate and smoother transition when switching between different traction angles. However, the actual efficacy of traction therapy is often questioned by researchers over the years.

  • Manipulation: Spinal manipulation or adjustment is a manual treatment where a vertebral joint is passively moved between the normal range of motion and the limits of its normal integrity. It often involves a high velocity thrust, a technique in which the joints are adjusted rapidly.

  • Two reviews published in 2007 and 2017 points out the lack of knowledge about the incidence of adverse effects of spinal manipulation. there is not an overall conclusion about the safety of this treatment.


  • Mobilization: Mobilization consists of low-velocity rhythmic movements applied in short or large amplitudes.Cervical mobilization has not the risk of rare but serious adverse events which can occur with manipulation, and it produces similar changes than manipulation (improving pain and function) in adults with acute/subacute/chronic neck pain with or without cervicogenic headache or radicular findings. However, it seems that pain reduction due to joint mobilization is not specific to the vertebral level being mobilized.

Posture education

Proper posture reduces the loads placed on the spinal segments at end-ranges and returns the spine to a biomechanically efficient position. Changes in posture can be the cause of neck pain. 

Exercise

Exercise is indicated to improve the stability of the cervical spine, to prevent osteoporosis, and to improve or maintain the range of joint mobility.
Strengthening the stabilizing muscles may enable those muscles to improve the quality and control of movement occurring within the neutral zone.

Invasive treatment

There are several surgical procedures used to treat different pathologies of the cervical spine, as for example, vertebral fracture and cervical spinal stenosis. 

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