L2.1 Back Flashcards
What are the borderes of the back?
- T1 → coccyx
- Medial scapula border
- Pos surfaces ribs
- Iliac crest
What are the different curvatures of the back?
- 1o foetal C-shape
- 2o lordortic curve (due to muscles strengthening)
- Cervical (~6-8months) – to keep head up
- Lumbar (~12-15months) – for walking
What are the vertebral abnormalities?
- Lordosis
- Kyphosis
- Scoliosis
- Cranial shift (features of vert shifted up – ribs on C7)
- Caudal shift (features of vert shifted down)
What is the structure of a lumbar vertebrae?
- (articular surface – sagittal)
- Vertebral arch = pedicle (root) + laminar
- Site of potential injury: pars interarticularis → bilateral fracture → slip disc
What is the structure of a thoracic vertebrae?
- (articular surface – Coronal)
- Essentially the same as lumbar
- Key difference: articular (demi) facets for joint attachment
What is the structure of the sacrum & coccyx?
- (articular surface – Coronal)
- Fusion of vertebra (no discs in between)
- Fuse from below up
- Different articular orientation → stops L5 from slipping forward
- Foraminae → for nerve roots & vessels (esp. sacral veins)
- Canal hiatus → gap between sacrum & coccyx
What veins drain the vertebrae?
- Basivertebral veins: drain vert bodies → internal vertebral venous plexus (outside dura) → external vertebral venous plexus (outside vertebral canal)
What are, and how many centres of ossifications do vertebrae have?
- 3 primary centres
- In body and each vertebral arch (aka neural arch)
- 5 secondary centres
- Tips of spinous and transverse process + upper & lower meninges of body (annular epiphysis)
- Closes during adolescence when vertebral column growth is complete
- There is a growth plate at the tips – may mistake for fractures
What are the vertebral growth anomalies?
- Partial failure of formation – Wedge vertebrae
- Complete failure of formation – Hemi vertebrae
- Unilateral failure of segmentation – Congenital bar
- Bilateral failure of segmentation – Block vertebrae
-
Spina Bifida (~L2-4)
- Occulta (may have no significance)
- Cystica → a sac
- Meningocele (just meninges)
- Meningomyelocele (contains neural tissues)
What is the function of the IV disc?
-
Nucleus pulposus: incompressible but deformable → keeps vertebrae apart
- Made up of water (mucus texture in children)
-
Annulus fibrosus: Attaches below/above vertebral body → keeps vertebrae tgt
- Laid down perpendicular to each other
- Twisting while lifting dangerous → only 50% fibres can resist load
What are the 2 main ligaments of the vertebrae?
-
Posterior longitudinal: Back of vertebral body, within vertebral canal
- Fans out at each IV disc → directs herniation pos-laterally over ligament
- ∴ Herniation → impinges on nerve root below
- E.g. herniation between L4 & 5 → impinge on L5 nerve root
- ∴ Herniation → impinges on nerve root below
- Fans out at each IV disc → directs herniation pos-laterally over ligament
-
Ligamentum flavum: has elastic connective tissues (allows flexion)
- Becomes more fibrous (thickens) with age → encroaches into canal → impinge neural structures in canal
What are the joints of the vertebrae innervated by?
And which structures are aneural/avascular?
- Branches of the POS rami (also supplies overlying skin)
- Synovial joint: capsule has blood & nerve supply
- Hyaline cartilage avascular & aneural
What is the vertebral canal and what does it contain?
- Terminates at L1-2 in adults (Cauda Equina)
- Meninges around the spinal cord
- Contains:
- BV internal venous plexus
- Vertebral column (longer than cord)
- Cord finishes at L1 but dura mater finishes at S3 → leaves space called lumbar cistern → point where needle injected to extract CSF
What does the intervetebral foramen contain?
- Dorsal root ganglion
- Nerve root
- Located in the upper part (inferior vertebral notch) of the foramen
What are the superficial muscles of the back?
- (Innervated by ANT rami)
- Attaches to and act on the UL
-
Trapezius (not innervated by ANT rami)
- innverated by the 11th cranial (Sternocleidomastoid also)
- Lat dorsi
- Rhomboids
- Levator Scapulae