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
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.
explain what the white, red anf dark disc is showing in this image?
White disc: Hydrated
Dark disc: Not hydrated
Red circle: Disc protrusion
what is spinal stenosis?
(Can be congenital but usually degenerative)
narrowing of the spinal canal. This can put pressure on the nerves that travel through the spine
Those with spinal stenosis have:
‘Simian’ posture: This ↑ effective volume of the spinal canal and takes pressure off the nerves
Bicycle sign: They find it easier to ride a bike
Shoelace sign: They find it hard to walk so have to bend down a lot as this provides relief
what is happening in this MRI scan?
Here the spinal cancel is good dimension at the lumbar-sacral level but it then narrows as you move up which results in compression of nerves.
what is Spondylolysis?
Spondylolysis: a stress fracture through the pars interarticularis of the lumbar vertebrae (uni or bilateral)
Pars Interarticular: the part of a vertebra located between the inferior and superior articular processes of the facet joint.
what is a spinal infection in a child?
Child – Discitis
When a child is growing the intervertebral disc still has a blood supply.
Bacteria in the blood supply may lodge into the intervertebral disc causing discitis
what is a spinal infection in an adult?
Adults – Vertebral osteomyelitis spondylodiscitis
Bacterial inoculation usually occurs beneath vertebral end plate with involvement of disc and adjacent vertebral end plate.
Disc is often involved in pyogenic and TB Infection
In contrast to spinal tumour which spares the disc.
Many patients with spinal infection have other underlying medical condition which compromises their immunity making them susceptible to infection e.g. diabetes.
