The Neck or Cervical Spine
In order to understand whiplash injury it is helpful to have a basic understanding of the neck and spine itself.
Structurally, the spine is a series of stacked bones, or vertebra, separated by flexible discs which act as cushions between them. The vertebrae are held together by an array of soft tissues.
The neck, or cervical spine as it is properly known, is a highly complex and intricate mechanism comprising (at a basic level) a system of bones, muscles, ligaments, tendons and intervertebral discs arranged together in such a way as to connect and support the skull and to allow movement in almost every plane – rotation, flexion (chin to chest), extension (chin away from chest) and lateral (sideways) bending – while protecting the delicate neural elements such as the spinal cord and cervical nerves and nerve roots.
Looking at the diagram to the right, the section we are interested is coloured in orange and is the area labelled C1 to C7 (cervical vertebrae 1 to 7).
The remainder of the diagram is not especially relevant other than to place the cervical vertebrae in context, and concerns the vertebrae making up the remainder of the spine or vertebral column. For the sake of completeness, these elements are:
- Thoracic Vertebrae (T1-T12)
- Lumbar Vertebrae (L1-L5)
- Sacral Vertebrae or Sacrum – which is a further 5 vertebrae fused together
- Coccygeal Vertebrae or Coccyx (tailbone) – which is a further 3-5 fused vertebrae
The latter two sections together form the Pelvic region.
The section of the spine that we are particulrly interested in – the cervical spine – can be easily damaged by whiplash-type motions. These injuries are usually soft-tissue injuries involving the complex array of ligaments, muscles and connective tissues in the neck, which work together to keep the neck stable and protect against extremes of movement that could cause serious injury. When these extremes of movement take place, these soft tissues typically bear the brunt of any trauma.
Looking at the images below it is possible to see the array of ligaments and muscles in the neck and also to see how they can be easily affected by hyperextension and hyperflexion actions present in whiplash injury.
In the first three of these diagrams the ligaments connecting the vertebrae can be seen very clearly. The fourth diagram shows the complex muscular arrangement within the neck. The muscles are arranged so as to co-ordinate movement and support of the neck – there are different types of muscles, some working together in pairs and some working as opposites (antagonists), where one contracts as the other expands in order to perform a given function in a controlled manner. The muscles in the neck are named largely after the function that they perform – extensors, flexors, rotators sub-groups of these, such as forward flexors and lateral (sideways) extensors for example.
The spinal cord is a key part of the Central Nervous System (CNS) and is responsible for the transmission of neural information and signals between the brain and the rest of the body via the Peripheral Nervous System (PNS) – it is for this reason that any neck or back injury affecting the spinal cord can result in anything from pins and needles to partial or even total paralysis in those affected.
The diagram below shows one of the cervical vertebra – in this case, C7, and illustrates the way in which the vertebrae carry and protect the spinal cord in an area of the vertebra called the ‘dura’:
It is possible for vertebrae to be pushed out of alignment so that they can trap and exert pressure on the spinal cord (myelopathy) or nerve root (radiculopathy) and it is also possible for the protective discs between the vertebrae to rupture rupture and exert pressure on the spinal cord and nerve roots. These conditions can cause anything from numbness or tingling, to paralysis or even death depending on the severity.
Individual nerve roots leave the spinal cord at various points along the spine in order to connect up with whichever organ, muscle or body part that they control or monitor and they can become trapped as described above – it is therefore possible for a doctor to be able to pinpoint which vertebra or nerve may be affected based on a patient’s symptoms.
In the case of cervical spine injuries or complaints, the nerve roots likely to be affected are related to upper body functions. The cervical nerves are named in a similar manner to the vertebrae – C1 to C8, their functions being described below:
C1 & C2 – Head and neck
C3 – Diaphragm
C4 – Upper body muscles
C5 & C6 – Wrist extensors
C7 – Triceps
C8 – Hands
Depending on the severity of a cervical spine condition, treatments vary from rest and painkillers, or a neck brace, through to chiropractic treatment and in more acute cases surgery may be required to correct or remove affected portions of disc or vertebrae.