Flashcards in Lumbar Spine And Back Deck (22):
What are the primary curvatures of the spinal column?
The C-shaped curve of the thoracic spine
What are the secondary curvatures of the spinal column?
These are developed after birth. They are the lordotic curves developed in the cervical and lumbar regions of the spine.
What are the three types of abnormal curvatures?
Kyphosis: Abnormal thoracic curvature
Lordosis: Abnormal curvature of the lumber curvature
Scoliosis: Abnormal lateral curvature of the spine
Where is the line of gravity in relation to the spinal column?
The line of gravity commonly passes adjacent (anteriorly) to the spinal column - reduces the amount of load applied to it.
How is the back arranged?
It is arranged into the vertebral column and 2 muscle compartments.
The vertebral column includes the intervertebral joints and discs and the vertebral canal and intervertebral foraminae.
The muscles compartments include superficial (extrinsic) and deep (intrinsic) muscles.
At what level does the spinal cord terminate?
This may terminate higher or lower depending on the age of the patient. Clinicians must provide adequate leway when performing LPs.
What is the structure of a typical lumbar vertebra?
- Body: Weight bearing
- Vertebral Arch
- Vertebral canal
- Spinous process
- Transverse process
- Articular processes
- Hyaline cartilage within the joints, thus they are synovial.
What is the main difference between a thoracic vertebra and a lumbar vertebra?
Thoracic vertebrae have costal facets for the attachment of ribs.
What is the structure of the sacrum and coccyx?
- Sacrum is made of 5 fused vertebrae in the coronal plane
- If present, observation of the extent of fusion can help determine age of specimen
- Foraminae at the front and back are equivalent to the intervertebral foraminae: Anterior for anterior rami, posterior for porterior rami, vessels = lateral, sacral veins.
- There is no spinal cord at this level
- Will find nerve roots here
- Spina bifida - open/splitting of the vertebra
- Variable number of coccygeal vertebrae
Describe the blood supply of the vertebral column.
- It has right blood supply
- Supplied by the thoracic and lumbar aorta and its branches
- Veins within the canal drain to the internal vertebral venous plexus, which drain to the EVVP
What are the centres of ossification in the vertebrae?
- 3 primary centres in body and each neural arch
- 5 secondary centres at puberty at the tips of spinous and transverse processes and upper and lower margins of the body (annular epiphysis)
- Epiphyses at SCO can be mistaken for fractures.
Describe intervertebral discs.
- Annulus fibrosus: Attaches to vertebral body and keeps vertebrae together
- Nucleus pulposus: Highly hydrated structure, keeps vertebrae apart.
Loss of water from both structures:
- Annulus: May become damaged and fissue
- Nucleus: Decrease in height with age as less water is taken up.
What ligaments support the spine?
- Interspinous ligament
- Posterior longitudinal ligaments - narrows and fans out between ligaments
- Intertransverse ligaments
- Supraspinouse ligaments
- Anterior Longitudinal Ligament
- Ligamentum flavum - Elastic tissue that allows for flexion/extension.
What is the function of intervertebral discs?
- They are weight bearing.
- Weight bearing forces cause the nucleus to bulge but is resisted by the annular fibres
- Some loads also supported by cartilage end-plate
Why are twisting movements while lifting hazardous?
Annulus layers are perpendicular to each other - Twisting is hazardous as only ~50% of fibres are position to resist the load
What is the nerve and blood supply to the disc?
- Innervated by the recurrent meningeal nerve which contains sensory and sympathetic fibres
- Vessels and nerves only supply the outer third of the discs.
What are the joints of the vertebral arches?
- Facet, synovial joints
- Fibrous capsule, which is lax to permit movement
- Capsule supplied by branches of posterior rami
- They limit the range of movement:
In the thoracic region, they allow rotation. In the lumber region, they allow flexion and extension.
Describe the lumbosacral joint.
The L5 vertebra is oriented differently to the other lumber vertebrae as it has to articulate with the S1 vertebra. The lumbar vertebrae are in the sagittal plane, whereas the sacral vertebrae are in the coronal plane. L5 must be oriented approximately mid-way between these two planes to prevent it slipping anteriorly off the S1 vertebra into the pelvic cavity.
What is housed within the vertebral canal?
The spinal cord, dura mater and the internal vertebral venous plexus.
What can be found within the intervertebral foraminae?
- Nerve roots can be found in the upper part
- Blood vessels and arteries
- Dorsal root ganglion are always situated here
- Both the anterior and posterior rami are made of mixed fibres.
What are the superficial muscles of the back?
- Latissimus dorsi
- Rhomboid major/minor
- Levator scapulae
- The are extrinsic as they all attach to and act upon the upper limb
- They are innervated by anterior rami, except trapezius