The Spine Flashcards
What are the distinguishing features of thoracic vertebrae?
Facets on side of body (Demi-facets for articulating with head of rib)
Facets on transverse processes (for articulations with tubercle if rib)
Vertebral foramen is small and circular
Name the regions of the spine and how many vertebrae make up each one
Cervical - 7 Thoracic - 12 Lumber - 5 Sacrum - 5 fused Coccyx - 3-5 fused
What are the gross functions of the vertebral column?
Centre of gravity of the body Attachments of bones Attachments of trunk muscles Protection and passage of spinal cord Segmental innervation of the body
What is kyphosis?
Abnormally increased posterior convexity of the thoracic spine
What is lordosis?
Lordosis is an exaggeration of the anterior (lordotic) curvature of the vertebral column in the lumbar region; may be associated with weakened trunk (anterolateral abdominal wall) musculature.
In pregnancy, women develop a temporary lordosis to compensate for alterations to their lines of gravity.
Name some causes of lordosis
Muscle imbalances such as tight low back muscles, weak hamstrings, or tight hip flexors Pregnancy Congenital abnormality Achondroplasia Rickets
Name some causes of kyphosis
Developmental problems e.g. Scheuermann's disease; Congenital abnormality Nutritional eg vit D deficiency Degenerative diseases such as arthritis Osteoporosis with compression fractures
What three processes emerge from the vertebral arch?
two transverse, one spinous
What is the pedicle?
Part of neural arch between body and the transverse process
What is the lamina?
Part of the neural arch between the transverse process and the spinous process
What do the [superior and inferior] articular processes - found at the junction of the lamina and pedicle - allow for?
Allow for synovial joints to be formed between neural arches of adjacent vertebrae. In turn this prevents anterior displacement of the vertebrae
Where are intervertebral discs found?
Between C2/3 successively to L5/S1
What do the intervertebral discs do?
Allow for movement
Act as shock absorbers
What are the two regions of intervertebral discs?
Nucleus pulosus and annulos fibrosus
Describe the make up of the annulus fibrosus
Collagenous outer bands
Firbrocartilagenous inner bands
What is the nucleus pulposus a remnant of?
The notochord
What is a herniated disc and in what direction does it most commonly herniate?
The annulos fibrosus degenerates/weakens and the nucleus pulposus herniates out - most commonly in a posterior lateral direction
What does a herniated disc compress?
Posteriolateral direction - compression of spinal segmental nerves
Posteriorly - compress spinal cord –> paralysis
What two major ligaments run along the longitudinal axis of the spinal column? Which is stronger?
Anterior longitudinal ligament - stronger
Posterior longitudinal ligament
Where are the Ligamentum flava?
Join Lamina of adjacent vertebrae - stretched by Flexion of the spine (high in elastic content)
Where is the supraspinous ligament found and what does it do?
Joins tips of adjacent spinous processes - they are lax in the extended spine and taut during flexion of the spine, mechanically supporting the spinal column
What are the inter spinous ligaments?
Relatively weak sheets of fibrous tissue, uniting spinous processes along their adjacent borders and fuse with supraspinous ligaments.
Only well developed in the lumber region.
What is the nuchal ligament?
The nuchal ligament is a ligament that is continuous with the supraspinous ligament. It attaches to the tips of the spinous processes from C1-7 and provides proximal attachment for rhomboids and trapezius
Describe the atlanto-axial joints
There are two lateral atlanto-axial joints which are formed by the articulation between the inferior facets of the lateral masses of C1 and the superior facets of C2. These are plane type synovial joints.
The medial atlanto-axial joint is formed by the articulation of the dens of C2 with the articular facet of C1. This is a pivot type synovial joint.
What primary movement does the Atlanto-axial joint permit?
Rotation
What joint permits flexion at the head ie nodding?
Atlanto-occipital
What features characterise the axis?
The axis (C2) is easily identifiable due to its dens (odontoid process) which extends superiorly from the anterior portion of the vertebra. The dens articulates with the articular facet of the atlas, in doing so creating the medial atlanto-axial joint.
This allows for rotation of the head independently of the torso and prevent horizontal displacement of atlas
What levels are susceptible to Herniation?
L4/L5
L5/S1
Name two distinguishing features of cervical vertebrae
Bifid process
Oval transverse foramen in transverse process
Large vertebral (or neural) foramen
What is whiplash? Why is the neck susceptible to it? What are the consequences to patients?
Hyperextension injury - the cervical vertebrae are more flexible and the ligaments are relatively weaker.
In minor cases, the anterior longitudinal ligament of the spine is damaged which is acutely painful for the patient.
In more severe cases, fractures can occur to any of the cervical vertebrae as they are suddenly compressed by rapid deceleration. Again, since the vertebral foramen is large there is less chance of spinal cord involvement.
Hangman’s fracture occurs where?
Fracture of both pedicles or the pars interarticularis of C2- which is a bony column between the superior and inferior articular facets of the axis
What are fractures of the dens caused by and what are the associated risks?
Most commonly caused by traffic collisions and falls.
These are often unstable and are at high risk of avascular necrosis, due to the isolation of the distal fragment from any blood supply. As a result, fractures of the dens often take a long time to heal.
As with any fracture of the vertebral column, there is also a slight risk of spinal cord involvement.
What is a Jefferson fracture of the Atlas?
A vertical fall onto an extended neck e.g. diving into excessively shallow water can compress the lateral masses of the atlas between the occupital condyles and the axis. This causes them to be driven apart, fracturing one or both of the anterior/posterior arches.
If the fall occurs with enough force, the transverse ligament of the atlas may also be ruptured.
Since the vertebral foramen is large, it is unlikely that there will be damage to the spinal cord at the C1 level. However, there may be damage further down the vertebral column.
What is scoliosis?
A lateral curvature of the spine, usually of unknown cause.
What is cervical spondylosis?
A decrease in the size of the intervertebral foramina, usually due to degeneration of the joints of the spine. The smaller size of the intervertebral foramina puts pressure on the exiting nerves, causing pain.
Describe the anatomical course of the spinal cord including where it arises and where it finishes.
- The spinal cord arises cranially as a continuation of the medulla oblongata (part of the brainstem).
- It then travels inferiorly within the vertebral canal, surrounded by the spinal meninges containing cerebrospinal fluid.
- At the L2 vertebral level the spinal cord tapers off, forming the conus medullaris
At what level does the conus medullaris form? What happens to the cord after this level?
L1 and L2, after this the spinal nerves continue to branch out diagonally, forming the cauda equina.
Name three features which distinguish cervical vertebrae
- Triangular vertebral foramen.
- Bifid spinous process
- Oval transverse foramina
What runs through the cervical transverse foramina?
They give passage to the vertebral artery, vein and sympathetic nerves.
The vertebral artery passes through the foramen except for C7 – C7 Foramen passes the smaller accessory vertebral veins
What are the distinguishing features of the lumbar vertebrae?
- Largest of the discrete vertebrae
- Lack of foramina on transverse processes
- Lack costal facets on the side of the body
- Vertebral foramina are triangular & small
Describe C1 - Atlas
- Lacks a body
- Lacks spinous process
- Widest cervical vertebra
What is sciatica?
A set of symptoms including pain caused by general compression or irritation of one of five spinal nerve roots of each sciatic nerve—or by compression or irritation of the left or right or both sciatic nerves.
Name some symptoms of sciatica
Lower back pain, buttock pain, paraesthesia and numbness, pain or weakness in various parts of the leg and foot
Describe the pathophysiology of sciatica and list some causes
Sciatica is generally caused by the compression of lumbar nerves L4, or L5 or sacral nerves S1, S2, or S3, or by compression of the sciatic nerve itself.
Spinal disc herniation
Spinal stenosis
Pregnancy
Piriformis syndrome
How is sciatica managed?
Rest (spontaneous recovery in case of disc herniation/ pregnancy)
Medication - pain management
Surgery - discectomy
What are the zygapophysial joints?
Synovial, plane joints between the articular processes of two adjacent vertebrae. There are two facet joints in each spinal motion segment.
