Session 6 Flashcards
Describe the number and categories of bones in the vertebral column
33 vertebra - 24 separate vertebra and 9 fused vertebra 7 cervical 12 thoracic 5 lumbar 5 sacral 4 coccygeal
Outline the basic structure of vertebrae
A vertebral body situated anteriorly. A vertebral arch situated Posteriorly. A vertebral foramen that lines up to form th vertebral canal for spinal cord and meninges.
What is the structure and function of the vertebral body?
This is the weight bearing component and its size increases as the vertebral column descends. The superior and inferior aspects are lined with hyaline cartilage.
Describe the bony prominences of the vertebral arch
Spinous process - posterior and inferior projection of bone, a site of attachment for muscles and ligaments
Transverse processes - extend laterally and posteriorly away from the junction of the pedicle and lamina
Articular processes - 2 inferior and 2 superior, arise from the junction between the pedicle and lamina, each bearing an articular facet
Lamina - connects transverse process to spinous process
Pedicle - connects transverse process to the vertebral body (lamina + pedicle = vertebral arch)
What structure do spinal nerves emerge from?
Intervertebral foramina, formed by the superior and inferior intervertebral notch
Outline the structure and function of intervertebral discs
Fibrocartilage cylinder that joins vertebrae. They act as a shock absorber and permit flexibility of the spine. They are wedge shaped in the lumbar and thoracic regions to support the curvature of the spine. There are two regions:
Annulus fibrosus - tough and collagenous, surrounds nucleus pulposus
Nucleus pulposus - jelly like, located Posteriorly in adults
What is a herniated intervertebral disc?
The nucleus pulposus ruptures, breaking through the annulus fibrosus. Most commonly occurs in posterolaterally, causing compression of the spinal nerves
What are the distinguishing features of cervical vertebrae?
There is a bifid spinous process (except C7), longer spinous process).
There are two transverse foramina, one on each transverse process. They conduct the vertebral artery and vein (except C7, which transmits small accessory veins).
Large triangular foramen.
Superior articular facet faces upwards and backwards. Inferior articular facet faces downwards and forward.
Rectangular body
Outline the structure and function of the atlas (C1) and axis (C2) vertebrae
Atlas articulates with occipital bone of skull superiorly (flexion/extension) and atlas inferiorly (lateral rotation). It has no vertebral body. The axis is characterised by the dens, rugged lateral mass and large spinous process. The dens is held into its articular facet by the transverse ligament.
How can the atlas and axis become fractured?
Atlas - Jeffersons fracture resulting from axial load. Fracture of the anterior and posterior arches of atlas
Axis - hangmans fracture resulting from hyperextension. Axis fractures through pedicles.
- peg fracture resulting from blow to Bach of head
What are the distinguishing features of thoracic vertebrae?
Each vertebrae has two Demi facets on each side of the vertebral body for articulation with their respective rib and the rib inferior to it.
There is a costal facet on the transverse processes for the tubercule of the rib (except T11-12)
The spinous processes are slanted inferiorly for increased protection
Circular vertebral foramen
Articular facets directed primarily anteriorly (inferior) and posteriorly (superior).
What are the distinguishing features of lumbar vertebrae?
Large kidney shaped vertebral body
Short, broad and blunt spinous process
Triangular shaped vertebral foramen
Articular processes face medially (superior) and laterally (inferior) to permit flexion
Describe the structure of the sacrum and coccyx
Sacrum is a collection of 5 fused vertebrae. There are facets of the lateral walls for articulation with the ilium.
The coccyx has no vertebral arches, hence no vertebral canal so it does not transmit the spinal cord.
Name the different clinical syndromes resulting from an abnormal curvature of the spine
Kyphosis - excessive thoracic curvature (hunchback). Wedge shaped vertebra
Lordosis - excessive lumbar curvature (swayback)
Scoliosis - lateral curvature of the spine. Idiopathic
Kyphoscoliosis - kyphosis and scoliosis combined. Caused by asymmetric weakening of paraspinal muscles
Outline the development of the spinal curvatures from foetus to young adult
Two lordosis (lumbar and cervical) develop from the primary curvature - single kyphosis - to form the secondary curvature. Thoracic and sacrococcygeal kyphosis remain.
What ligaments strengthen the vertebral body cartilaginous joints?
Anterior and posterior longitudinal ligaments. They prevent hyperextension and hyperflexion respectively. The anterior ligament is stronger.
What ligaments strengthen the vertebral facet joints?
Ligamentum flavum from Lamina to lamina.
Interspinous ligaments unite adjacent spinous processes. Stability in flexion.
Supraspinous ligaments between the tips of adjacent spinous processes. Stability in flexion.
Ligamentum nuchae attached to external occipital protuberance and spinous processes of cervical vertebrae. It maintains the secondary curvature of cervical spine and provides attachment for muscles.
Where is a needle inserted for w lumbar puncture and why?
L3/L4 or L4/L5 - after the conus medullaris, least chance of neurological damage, only spinal nerve roots not cord.
What is cervical spondylosis?
Degenerative osteoarthritis of intervertebral joints in cervical spine. Can put pressure on nerve roots (radiculopathy) or cord (myelopathy).
Where are lumbar nerve roots most vulnerable and why?
Just above their exit foramina as they are the most ventral and lateral root in the vertebral canal (immediately in the path of a lateral disc herniation). Eg a lateral herniation of the L4/5 disc damages the L5 root.
What is the composition of the hip bone?
Made up of the ilium, ischium and pubis that are separated by the triradiate cartilage up to the age 15-17, when they fuse.
Outline the structure and bony landmarks of the ilium.
The ilium expands to form the wing above the acetabulum. The inner surface of the wing is concave and is known as the iliac fossa. The external surface is convex and is known as the gluteal fossa.
The thickened superior surface of the wing is called the iliac crest. It extends from the anterior superior iliac spine to the posterior superior iliac spine.
There is also a posterior inferior iliac spine, anterior inferior iliac spine and a greater sciatic notch on the ilium.
What is the clinical relevance of the anterior superior iliac spine?
Important bony landmark where the inguinal ligament originates, before joining the pubic tubercule. The femoral artery can be palpated midway along the ligament, with the femoral vein lying medially.
True leg length =ASIS to medial malleolus
Apparent leg length = umbilicus to medial malleolus
Where is the pubis and what are its bony landmarks?
The most anterior portion of the hip bone.
It consists of a body (located medially articulating at the pubic symphysis, where the pubic tubercule is found), superior rami (extends laterally from the body, forming part of the acetabulum) and inferior rami (joins the ischium). The superior and inferior rami enclose part of the obturator foramen, where the obturator nerve, vein and artery pass through.
Where is the ischium and what are its bony landmarks?
The posterioinferior part of the hip bone.
It consists of a body (where the ischial tuberosity is found, what you sit on), superior ischial ramus and inferior ischial ramus. The inferior ischial and pubic rami combine to form the ischiopubic ramus.
On the posterior aspect there is the lesser sciatic notch with the ischial spine at its most superior edge.
What ligaments form the greater and lesser sciatic foramen?
Sacrospinous ligament runs from the ischial spine to the sacrum, dividing the two foramen.
Sacrotuberous ligament runs from the sacrum to the ischial tuberosity, forming the inferior part of the lesser sciatic foramen.
How can the pelvic bones become fractured, where do the fractures occur and what are possible complications?
Direct trauma or force transmitted from lower limb (eg heavy fall on feet).
Fractures occur at the weaker points eg Pubic rami, acetabulum or in the region of the sacroiliac joint.
Complication could be soft tissue injury eg bladder or urethra
Outline the bony landmarks of the proximal femur
Head - smooth surface with depression on the medial side for attachment with the ligament of the head.
Neck
Greater trochanter - found on the anterior and posterior sides of the femur, lateral to where the neck joins.
Lesser trochanter - smaller and projects from the posteromedial side of the femur, just inferior to the neck shaft junction.
Intertrochanteric line - a ridge running in an inferomedial direction on the anterior surface of the femur, connecting the two trochanters. The iliofemoral ligament attaches here.
Intertrochanteric crest - on the posterior surface. The quadrate tubercule (for quadratus femoris) is found on this crest.
