Clinical Applications of spinal anatomy Flashcards
what is the function of the spine?
multidirectional mobile column linking the locomotion units (legs) and manufacturing appendages (arms) with the central processing unit (head)
what is bone strength of the VC increased by?
Requires adequate calcium intake
Strength ↑ by:
Exercise
Sunshine (vitamin D metabolism)
Moderate alcohol
what is bone strength of the VC decreased by?
Strength ↓ by the 5 T’s:
Time (aging)
Tobacco
Tippling (too much drinking)
Telly (inactivity)
Tablets (e.g. steroids)
what are the 3 different regions within the spinal canal?
Within the spinal cannel there are 3 different regions:
C1-T12 –> Spinal cord
T12-L1 –> Conus Medularis: Most distal end of the spinal cord
Contains cell bodies supplying the lower limb
L2 – Sacrum –> Cauda Equina: Collection of nerves at the end of the spinal cord
Contains nerve roots that supplies the lower limb.
Lesions above the Conus medularis will produce an upper motor neurone picture
Lesions below T12 will produce a lower motor neurone picture
what are the implications of level of neural compression?
The further down the spinal cord the compression –> smaller loss in motor and sensory function.
L5 and below:
Impaired sphincter and sexual function
Foot and ankle weakness
L5 – L2: decreasing leg function - Progressively less likely to walk
L1/2 – T1: can’t walk (paraplegia)
T1 – C5: decreasing arm function - Lower the injury the better the upper limb function
C5 –> quadriplegia
Above C4: Can’t breathe as diaphragm loses innervation
(C3, 4, 5 keeps the diaphragm alive)
what is myelopathy?
where does it usually occur?
Myelopathy: An injury to the spinal cord caused by severe compression.
It may be as a result of spinal stenosis, disc herniation, autoimmune disorders or other trauma (see later on)
Myelopathy usually occurs at the cervical level - weakness and sensory changes usually affecting the upper limb more than the lower limb
what is myelopathy characterised by?
It is characterised by:
development of Broad-based shuffling gait
Upper limb radiculopathy (symptoms due to pinching of nerve root)
E.g. Spastic paresis, increased tone, clonus (involuntary, rhythmic, muscular contractions and relaxations) of upper limb
what does myelopathy cause?
You get Brisk reflexes,
Extensor plantar reflex:
On stoking the sole of foot, the big toe will move up (extension) rather than down.
Myelopathy can rarely be accompanied with urinary symptoms
Retention, overflow and automatic bladder
what is Radiculitis?
Radiculitis: Inflammation of a nerve root
You will get nerve root pain (occurs in sclerotomal pattern) and nerve root tension
what is Radiculopathy?
Radiculopathy: Pinching of the nerve root in the spinal column
You will get nerve root dysfunction
what happens when there is pain and compression of the nerve root?
If there is compression/irritation of nerve root:
Pain will be experienced in sclerotomal distribution
Sensory disturbance occurs in a dermatomal distribution
Muscle weakness occurs in a myotomal distribution.
what happens when the L5 nerve root is irritated?
what would the patient experience?
Patient experiences:
Pain occurs in sclerotomal distribution: The L5 nerve supplies bones, ligaments and joints.
Therefore, patient will feel pain, in lateral aspect of thigh, lateral aspect of calf and dorsum of foot.
Sensory disturbance occurs in a dermatomal distribution:
L5 Dermatome: Lateral aspect of calf and dorsum of foot.
Muscle weakness occurs in a myotomal distribution:
Weakness of dorsi flexion of foot and great toe
May have difficulty in abducting of thigh away from the midline.
explain the vascular Supply of the Spine?
Principal spinal cord blood supply is from:
Anterior spinal artery
2 posterior spinal arteries
Supplemented by segmental vessels
Vulnerable regions (poor supply):
Upper thoracic T1-4
Thoraco-lumbar junction
what are the spinal cord columns?
Dorsal columns: Carry light touch, proprioception and vibration signals
Ventral columns: Carry pain, temperature and motor signals
how does a spinal cord syndrome occur?
Cord stroke: This occurs when the anterior spinal artery is obstructed.
This means there would be loss of pain, temperature and motor.
But preservation of light touch, proprioception and vibration.
Because the dorsal columns have a paired blood supply it is unusual to see an isolated loss of dorsal column function.
what kind of pathology could occur in the spine?
Spinal Deformity
Degenerative conditions
Neoplastic (tumour): primary, secondary
Infection
Inflammatory
what is spinal balance?
When the spine is in balance it is energy neutral –> comfortable
When the spine is imbalanced:
Muscle fatigue in the short term –> Postural Pain
Degenerative change in the long term –> mechanical pain
what are the types of spinal deformity?
Deformity in Sagittal plane
Kyphosis - excessive outward curve
Lordosis - excessive inward curve
Coronal plane deformity:
Left/right - Scoliosis
Deformity in Transverse plane
Rotation, usually associated with scoliosis
what are the physical signs of scoliosis?
Physical signs:
Visible curve (lordosis)
Scapula prominence
Hip prominence
Shoulder asymmetry
Waist asymmetry
Forward bend test: By performing a forward bend test the rib or lumbar hump becomes more prominent
what are the causes of spinal deformity – component abnormality?
Spinal deformity can occur due to abnormalities in the bony components.
Abnormalities arise due to:
Failure vertebral formation
Failure of vertebral segmentation
These both result in bending of the spine.
what are the causes of Spinal deformity - neutrally/muscle mediated?
Spinal deformity can also occur due to abnormalities in innervation or abnormalities in the muscle innervated.
Upper motor neurone abnormalities
When there in too much tone on one side of the body in comparison to the other - spine may be ‘pulled over’
This may occur in:
Cerebral palsy (CPU abnormality)
Cord abnormality
Lower motor neurone disorder
When there is Insufficient tone on one side in comparison to the other- spine may ‘fall over’
This may occur in:
Viral myelitis (polio)
Spinal muscular atrophy
Muscular dystrophies
Trauma
how do you perform a scoliosis surgical correction?
A rod is connected to the spine by wires within the spinal canal.
These wires pull the spine onto the rod and straighten it.
You can also use pedicle screws.
what is ‘Normal’ spinal degeneration?
Affects everyone
Prevalence increases with age
Age of onset determined genetically and by environmental influence
Degeneration can be seen particularly well using MRI
Variably symptomatic (symptoms don’t always occur)
what are the types of normal spinal degeneration?
Disk Degeneration
Disk Protrusion
Facet degeneration
Annular Fissure