Flashcards in MSK - Lumbar Spine Structure Deck (62)
How many vertebrae are there, and what groups are they divided into?
There are 33, and they are divided into cervical (7), thoracic (12), lumbar (5), sacral (5) and coccygeal (4)
How many of the vertebrae are discrete and capable of individual movement?
What are the functions of the vertebral column?
- Provides central bony pillar of the body, supporting skull, pelvis, upper limbs and thoracic cage
- protects spinal cord and cauda equina (acts as a conduit which cord can pass through, while still allowing nerve roots to leave)
- allows movement
- haemopoiesis takes place in the red marrow
Why do vertebral bodies increase in size inferiorly?
Due to increase in compression forces
What are the three movements of the lumbar spine?
- lateral flexion
What are the seven 'processes' found on the vertebral arch?
- 1 spinous process
- 2 transverse processes
- 2 superior articular processes
- 2 inferior articular processes
True or false - the vertebral body is made entirely of cortical bone?
False - it's 10% cortical bone, 90% cancellous bone
What are the articular surfaces of the vertebral body covered with?
What is the gap created by the vertebral arch called?
What connects the transverse process to the spinous process?
What connects the transverse process to the body?
What sort of joint is found at the articulation of the superior and inferior articular processes?
Synovial (facet) joint
What is the function of the 'facet' joints of the articular processes?
- prevents anterior displacement of vertebrae
- orientation determines amount of flexion and rotation permitted (moves easily in flexion, less easily in rotation)
What are the intervertebral discs composed of?
70% water, 20% collagen, 10% proteoglycans
How much of the length of the vertebral column is made up of intervertebral discs?
What are the two regions of the intervertebral disc?
Nucleus pulposus and annulus fibrosus
What is the annulus fibrosus composed of?
Lamellae of annular bands in varying orientations. The outer lamellae are type 1 collagen, and the inner lamellae are fibro-cartilaginous. Avascular and anneural
What is the function of the annulus fibrosus?
Surrounds nucleus pulposus and acts as a shock absorber. It is highly resilient under compression
What is the nucleus pulposus derived from embryologically?
What is the nucleus pulposus composed of?
Gelatinous, type 2 collagen with a high water content and high osmotic pressure.
True or false - the size of the nucleus pulposus is constant?
False - it changes in size throughout the day, and with age.
What are the five ligaments/ligament groups in the vertebral column?
- anterior longitudinal ligament
- posterior longitudinal ligament
- ligamentum flavum
- suprasponous ligament
- interspinous ligament
Where is the anterior longitudinal ligament found?
- Anterior tubercle of atlas to sacrum
- united with periosteum of vertebral bodies
- mobile over intervertebral discs
Where is the posterior longitudinal ligament found?
- body of axis to sacral canal
- continues superior to axis as 'tectorial membrane'
How are the functions of the anterior longitudinal ligament and the posterior longitudinal ligament different?
Anterior LL - prevents hyperextension
Posterior LL - prevents hyperflexion
What is the ligamentum flavum?
Ligament which is found between laminae of adjacent vertebrae. Yellow in colour due to elastic fibres. Stretched during flexion of the spine
What are the interspinous ligaments?
Relatively weak sheets of fibrous connective tissue which unite spinous processes along adjacent borders. Only well developed in the lumbar region. Fuses with supraspinous ligaments
What are the supraspinous ligaments?
Strong bands of white fibrous tissue which connect the tips of adjacent spinous processes. They are tight in flexion and lax in extension.
What does the sacrum articulate with?
L5 superiorly, ilium laterally and coccyx inferiorly