by Hannah Farrell
Our Expert Witnesses in spinal medicine specialise in the medical management of spinal conditions resulting from trauma or disease.
Our Experts in spinal medicine have a profound knowledge of management degenerative disc disease, chronic back pain, including sciatica and cauda equina syndrome.
With a strong understanding of appropriate standards of care and NICE Guidelines, in addition to a thorough knowledge of treatment pathways, our Expert Witnesses in spinal medicine can advise on causation, breach of duty, current condition, and prognosis in individuals with spinal conditions.
Anatomy
The spine is comprised of 33 individual vertebrae, functioning to support the body and protect the spinal cord and it’s branches. The spine can be divided into:
- Cervical spine, C1 – C7
- Thoracic spine, T1 – T12
- Lumbar spine, L1 – L5
- Sacral spine, S1 – S5
- Sacrum
Along the length of the vertebral column are the longitudinal ligaments. Connecting each vertebra is the ligamentum flavum and interspinous ligament. Between each vertebra lies a cartilaginous vertebral disc.
The spinal cord begins at the base of the brain (medulla oblongata) and runs through the spinal canal of the spine, to approximately L1. The spinal cord is composed of:
- Grey matter – contains neurons receiving information from the organs, skeletal muscle, and somatosensory information;
- White matter – contains neural pathways connecting to the brain:
- Ascending tracts – transmit sensory information from peripheral nerves to the brain;
- Descending tracts – transmit motor signals from the brain to the lower motor neurones.
At each vertebral levels, the spinal cord gives off a root which innervates specific muscles and areas of the skin. The specific muscle that is innervated is referred to as the myotome. The specific area of the skin innervated by the nerve root is called the dermatome. Altered sensations or movements (limb weakness for example) can indicate a problem at the level of the nerve root i.e., a radiculopathy. A common cause of radiculopathy is a herniated intervertebral disc.
At the level of L2 the spinal cord splits into a group of nerve roots, known collectively as the cauda equina, that extends into the coccygeal spine. The cauda equina has control over sensation in the saddle area, bowel and bladder function, lower limb sensation and movement, and sexual function.
Cervical Spine
Lying between the skull and thoracic vertebrae, the cervical spine consists of the atlas (C1), axis (C2), and five further vertebrae. The atlas articulates with the base of the skull and the axis, allowing the head to rotate. The axis has a distinct process, known as the Odontoid peg, which the atlas sits upon. The vertebral artery passes through C1-C7 and around C7.
Cervical spine radiculopathies generally present with head, neck, and upper limb dysfunction and altered sensation.
Injuries to the cervical spine include:
- Jefferson fracture – a vertical fall onto an extended neck leading to compression, ligament damage, and damage along the vertebral column;
- Whiplash – hyperextension of the neck causing trauma to the longitudinal ligaments;
- Hangman’s fracture – an often deadly fracture leading to a ruptured spinal cord; and
- Fracture of dens – fracture of the odontoid process.
Cervical spine diseases include:
- Cervical stenosis
- Herniated (prolapsed) cervical disc
- Cervical spondylosis – spinal osteoarthritis (degenerative disc disease)
- Discitis – inflammation of the intravertebral disc
Thoracic Spine
The thoracic spine is comprised of 12 vertebrae and forms part of the thoracic cage; each rib articulates with the thoracic vertebrae at a costovertebral joint.
Thoracic spine radiculopathies present with altered sensation across the thorax, abdomen, and armpit, and back and abdominal muscular dysfunction.
A common condition of the thoracic spine is a thoracic kyphosis, classically presenting with an excessive curvature of the thoracic spine. Kyphosis can result from poor posture, Scheuermann’s kyphosis, and osteoporosis.
Lumbar Spine
The lumbar spine consists of five vertebrae which are specifically designed to support the total weight of the torso and are therefore large vertebrae. Due to their shape, the lumbar vertebrae allow easier access to the spinal canal and spinal cord, thus a lumbar puncture (spinal tap) can be performed between L3 and L4.
Lumbar spine radiculopathies present with altered sensation in the legs and abnormal movement of the legs.
Lower back pain is a common, debilitating, and often difficult to treat complaint.
Lumbar spine diseases include:
- Lumbar stenosis
- Excessive lumbar lordosis
- Degenerative disc disease
Sacrum
The sacrum is comprised of five fused vertebrae. The sacrum is a relatively thick bone, which forms part of the pelvis, supporting and aiding movement of the body. The sacrum had various lower limb muscles attached to it. The sacral central canal houses the spinal nerve bundle of the cauda equina.
Sacral spine radiculopathies present with altered sensation and function in the genitourinary and rectal area.
The sacral plexus is a bundle of nerve fibres formed from the sacral spinal nerves and L4 and L5. The sacral plexus supplies the skin, pelvic muscles, and lower limb muscles. The sacral plexus has five main branches:
- Superior gluteal nerve – motor innervation of the buttocks;
- Inferior gluteal nerve – motor innervation of buttocks;
- Sciatic nerve – motor and sensory innervation of legs;
- Posterior femoral cutaneous – sensory innervation of posterior leg and perineum; and
- Pudendal nerve – motor innervation of the perineum muscles, urethral sphincter, levator ani, and anal sphincters, and sensory innervation of the penis, clitoris, and perineum.
Coccyx
The coccyx is the final part of the spine, forming the “tailbone, and, similarly to the sacrum, is comprised of four fused vertebrae. The coccyx serves as an attachment point for the gluteus maximus (buttock muscle), levator ani muscles (pelvis floor muscle), and anococcygeal raphe (supports position of anus).