Session 2: Vertebral Column and Spinal Cord Flashcards
Which part is the lamina of the vertebra?
Between the spinous process + transverse process
What are the 3 main features of a typical vertebrae? What are the functions of each?
Vertebral body (weight bearing)
Vertebral arch ("roof" of vertebral canal, projections for attachment of muscles + ligaments, has sites of articulation for adjacent vertebrae)
Pedicles (anchor vertebral arch to vertebral body)Describe 5 distinctive features of cervical vertebrae.
Triangular vertebral foramen
Rectangular vertebral body
Transverse foramina in the transverse processes
Bifid spine (except C1 + C7)
Atlas + axis (C1 + C2) are specialized for movement
Describe 5 distinctive features of thoracic vertebrae.
Bigger than cervical vertebrae
Circular vertebral foramen
Heart shaped vertebral body
Spinous process pointing sharply downwards
Transverse costal facets (for rib articulation)
Describe 5 distinctive features of lumbar vertebrae.
LARGE
Articular facets are angled to limit movement
Thin, long transverse processes (except L5)
Triangular vertebral foramen
“Kidney shaped” vertebral body
How many bones fuse to form the sacrum?
5
Describe the structure of the sacrum.
Concave anterior surface
Triangular in shape
L shaped articular facets (for articulation with pelvic bones)
How many bones fuse to form the coccyx?
3-4
Vertebral arches + canal are absent
Between which vertebrae do you find intervertebral discs?
C2-S1
What are the 2 parts of the intervertebral disc?
Nucleus pulposus
Anulus fibrosus
Describe how problems with the intervertebral disc can lead to potential clinical problems.
Degenerative changes in the anulus fibrosus can lead to herniation of the nucleus pulposus, which can then impinge on spinal nerves or the spinal cord (causing pain, weakness + changes in sensation)
Name the 2 ligaments that rung along the length of the vertebral bodies from the skull to the sacrum.
Anterior + Posterior Longitudinal Ligaments
Which ligament is typically damaged in whiplash?
Anterior Longitudinal Ligament
What is the name given to the upper part of the posterior longitudinal ligament going from C2 to the skull?
Tectorial Membrane
Which ligament is found between the laminae of adjacent vertebrae? When is this pierced?
Ligamentum flavum
Pierced in a lumbar puncture
Which ligament runs all the way down the back of the spinous processes, connecting them
Supraspinous ligament
Which ligament lies between adjacent spinous processes?
Interspinous ligament
What determines the degree of movement in each spinal cord segment?
Angles of articular facets
Presence of ribs
Presence of muscles
What is the purpose of spinous ligaments?
Provide stability
Allow movement, but limit excessive movement
Describe the shape of the atlas (C1).
NO vertebral body
Consists of 2 lateral masses with an anterior + posterior arch
Describe the articulations of the atlas.
The 2 lateral masses articulate superiorly with the occipital condyles + inferiorly with the superior articular surfaces of C2
Describe the structure of the axis (C2).
A typical cervical vertebra with the body extended upwards to form the dens (odontoid process)
Which ligaments are attached to the dens?
Alar ligaments are attached to the superiolateral surfaces of the dens + the medial occipital condyles. Prevent excessive rotation of head.
Longitudinal fascicles of the cruciform ligament (crosses over the transverse ligament of the atlas to form the cruciate ligament)
How many vertebrae are there in total?
30-33 depending on number of coccygeal vertebrae
Which layer of cranial dura mater is the spinal dura mater continuous with?
Meningeal layer of the cranial dura
At what vertebral level does the spinal cord (+ Pia) end?
L2
What space is present in the vertebral column that you don’t find in the skull?
Epidural space
What does the epidural space contain?
Connective tissue
Fat
Internal vertebral venous plexus
At what vertebral level do the dura + arachnoid layers end?
S2
What is the significance of the subarachnoid space between L2 and S2?
A needle can be inserted here to remove CSF or insert anaesthetic
What is the difference between an epidural and a spinal block?
Epidural: Around dura (large volume can be infused over many hours)
Spinal: In sub-arachnoid space (particular volume, lasts for a particular duration)
How is the sacral hiatus formed? What is the significance of this space?
No lamina/ spinous process on last few sacral vertebrae
Can insert needle into sacral hiatus- possible to infiltrate very low region of epidural space with anaesthetic
Where do the denticulate ligaments attach medially and laterally?
Medially – spinal cord
Laterally – form a series of triangular extensions that anchor through the arachnoid membrane to the dura mater
Why would you perform a lumbar puncture?
To obtain CSF (e.g. to test for meningitis)
To inject spinal anaesthesia (into the subarachnoid space)
At which level would you perform a lumbar puncture?
L3/L4 in an adult
1 or 2 vertebral spaces lower in a child
Which ligament is pierced in lumbar puncture?
Ligamentum flavum
Why would you never do a lumbar puncture in the case of raised intracranial pressure?
It will cause a sudden relieving of pressure, which could cause brainstem herniation and death.
List 6 common spinal pathologies
Low back pain
Prolapsed intervertebral disc (Sciatica)
Spondolysis (degeneration)
Spondololysis (stress fracture of pars interrticularis)
Spondylolistesis (forward displacement of vertebra)
Spondylitis (inflammation of vertebrae)
What are 2 common spinal injuries seen in car crashes?
Ligaments snap
Small parts of bone break off
State 3 common deviations in spinal curvature.
Scoliosis = abnormal lateral curvatures Kyphosis = excessive thoracic curvature Lordosis = excessive lumbar curvature
Name 7 functions of the vertebral column
Hold body weight
Transmit forces
Support the head
Support the upper limbs
Protect the spinal cord
Movement of upper limbs + ribs (extrinsic muscles)
Postural control + movement (intrinsic muscles)
What characterises primary curvatures? Which curvatures in an adult are primary?
They are in the direction that you would expect to see in the foetal position (concave side facing anteriorly)
Thoracic
Sacral
What characterises secondary curvatures? Which curvatures in an adult are secondary?
Concave surface faces posteriorly
Cervical
Lumbar
List 2 functions of intervertebral discs
Help with transmitting forces
Allow flexibility between vertebrae
What is the name of the joint between the skull and C1? What does this allow?
Atlanto-occipital joint
Facets allow skull to rock back + forth (flexion + extension)
“Yes joint”
What is the name of the joint between the C1 and C2? What does this allow?
Atlanto-axial joint
Allows rotation
“No joint”
Where do the spinal nerves emerge?
C1-C7 nerves emerge from above their respective vertebrae
C8- Coccygeal nerves emerge below their respective vertebrae
What is the result of the vertebral column developing at a greater rate than the spinal cord?
The point at which nerves emerge from the spine get progressively further away from where they emerge from the spinal cord
Where is disc herniation more likely to occur? Why?
Lower spine
More weight is being transmitted by the discs (forces get greater)
What are the 3 categories of muscles in the back and which muscles fall into each of these categories?
Superficial: Trapezius, Latissimus dorsi, Levator scapulae, Rhomboid minor, Rhomboid major
Intermediate: Serratus posterior superior + inferior
Deep: Spinotransversales, Erector spinae, Transversospinales, Interspinales, Intertransversarii
State the origin, insertion and function of:
a. Trapezius
b. Latissimus Dorsi
c. Levator Scapulae
d. Rhomboid Minor
e. Rhomboid Major
Trapezius O: external occipital protuberance, cervical + thoracic spine I: clavicle + scapula F: elevate + rotate scapula when humerus is abducted b. Latissimus Dorsi O: T7 to sacrum + thoracolumbar fasica + posterior 1/3 of iliac crest I: intertubercular sulcus of the humerus F: extends, adducts + medially rotates humerus c. Levator Scapulae O: transverse processes of C1-C4 I: upper medial scapula F: elevates the scapula Rhomboid Minor O: spinous processes of C7-T1 I: medial border of scapula F: adduct + elevate scapula e. Rhomboid Major O: spinous processes of T2-T5 I: medial border of scapula F: adduct + elevate scapula
State the origin, insertion and function of:
a. Serratus Posterior Superior
b. Serratus Posterior Inferior
Serratus Posterior Superior O: C7-T3 I: upper border of ribs 2-5 F: elevates ribs 2-5 Serratus Posterior Inferior O: T11-L3 I: lateral inferior margins of ribs 9-12 F: depresses ribs 9-12 + prevents lower limbs from elevating when diaphragm contracts
State the location and function of:
a. Spinotransversales
b. Erector Spinae and Transversospinales
c. Interspinales and Intertransversarii
Spinotransversales
Extensors + rotators of head + neck
The 2 spinotransversales muscles run from the spinous processes up to T6 + ligamentum nuchae, running superiorly + laterally
Erector Spinae + Transversospinales
Extensors + rotators of vertebral column
Erector spinae lie posterolaterally to the vertebral column between the spinous processes medially + the angles of the ribs laterally
Transversospinales run obliquely upward + medially from the transverse process to the spinous process
Interspinales + Intertransversarii
Short segmental muscles, stabilisers of the vertebral column
Interspinales: pass between adjacent spinous processes
Intertransversarii: pass between adjacent transverse processes
Describe the flexibility of the cervical spine in terms of flexion/extension, lateral flexion and rotation.
Can comfortably flex, extend, laterally flex + rotate.
Articular surfaces between vertebrae are almost horizontal, so all these movements are possible.
Neck has less surrounding tissue than other parts of spine
Describe the flexibility of the upper thoracic spine (T1-T6).
NO flexion/extension
Some lateral flexion
Some rotation
Articular surfaces are almost vertical, which doesn’t allow for flexion/extension.
Describe the flexibility of the lower thoracic spine (T7-T12).
Some flexion/extension
Good lateral flexion
Good rotation
Describe the flexibility of the lumbar spine (L1-sacrum).
NO rotation
Good flexion/extension
Good lateral flexion
Articular surfaces curled around articular surfaces of the adjacent superior vertebrae, ensuring no rotation.
