Lecture 4- Vertebral Column & Spinal Cord Flashcards
Vertebral Column Function
- Supports body weight
- Physiologic motion between head, trunka nd pelvis
- Brace for upper limb
- Attachment site for muscles
- Main structural element for body posture
- Protection of spinal cord
Vertebral Column Regions
- Cervical: 7
- Thoracic 12
- Lumbar 5
- Sacrum: 5 fused
- Coccyx: 3-4 fused, sometimes multiple bones
Spinal Curvatures
Primary: Thoracic and Sacral -Concave anteriorly -Maintains original embryonic orientation
Secondary: -Cervical and Lumbar -Convex anteriorly -Establishes center of gravity -Enables minimum energy to maintain posture
Typical Vertebrae Features
- Vertebral body (supports weight)
- Vertebral arch
- Pedicle (means feet)
- Transverse arch
- Lamina
- Spinous process
- Superior articular process (facet)
- Inferior articular process (facet)
- Intervertebral foramen (formed by superior and inferior ventral notches)
Vertebrae Function
- Attachment for muscle, affect movement, support weight
- Has intervertebral foramen to allow spinal nerve to exit vertebral canal
Zygapophysial (facet) Joint
- Formed by superior and inferior articular processes
- Different shapes and orientations in different regions allow for different movements
Movements of the Back
- Extension/flexion
- Lateral flexion
- Rotation
- Range of motion limited by: -Thickness/elasticity/compressibility of discs -Shape/orientation of facet joints =Resistance of back muscles/ligaments
Atlas (Cv1) atypical features
- Holds up head
- Anterior/Posterior tubercles and arches
- Facet for dens
- Tubercle for transverse ligament of atlas
Axis (Cv2) Atypical Features
- Allows rotation of head
- Longer, bifid spinous process
- Dens (articulates w/ atlas for head rotation)
Atlantoaxial Joint
- Dens and articular facets allow rotation
- Transverse ligament is crucial (dislocation of atlantoaxial joint can result in spinal cord damage/death)
- Flexion occurs at atlanto-occipital joint
Cervical Vertebrae
Body: -Small/wider from side to side than anteroposteriorly -Concave superior surface -Convex inferior process
Vertebral foramen: -Large/irregular
TP: -Transverse foramina small/absent in C7 -Make foramina for vertebral arteries/veins/plexuses -Abterior/posterior tubercles
Articular Processes: -Superior facets directed superoposteriorlu, inferior facets oposite
SP: -C3-C5, short/bifid, -C6: long, -C7: longer
Cervical Rib
- AKA vertebra prominens
- C7
- May have enlarged costal process (cervical rib) that stretches/compresses subclavian artery and/or lower part of brachial plexus
Thoracic Vertebrae
Body: -Heart shaped -1-2 facets for articulation w head of rib
Vertebral Foramen: -Circular/smaller than in cervical/lumbar
TP: -Long/strong -extends posterolaterally -Length decreases from T1-T12 -T1-T10 have facets for tubercle of rin
Articular Process: -Superior facets directed posteriorly/slightly laterally -Inferior facets directed anteriorly/slightly medially
SP: -Long -Slopes posteroinferiorly, tip extends to inferior vertebral body
Lumbar Vertebrae
Body: -Massive -Kidney shaped
Vertebral Foramen: -Triangular -Larger than thoracic, smaller than cervical
TP: -Long/slender -Accessory process on posterior surface of base of each process
Articular Process: -Superior facts directed posteromedially -Inferior facets directed anterolaterally -Mamillary process on posterior surface of each articular process
SP: -Short/sturdy -Hatchet shaped
Sacrum
-Triangular/wedge shaped bone made by 5 fused sacral vertebrae
-Pelvic/dorsal surfaces
Dorsal surface has Sacral Hiatus (used in caudal epidural anesthesia, located by palpation of sacral cornua)
Coccyx
- Small triangular bone,, made by 4 fused coccygeal vertebrae (Co1 may separate and the caudal 3 are fused)
- Non weight bearing -Serves for muscle/ligament attachment
Intervertebral Disc
- 2 parts: Anulus (means ring, anillo) fibrosus (multiple fibrous bands) -Nucleus pulposus (gelatin like center)
- Functions as cushion to compressive loading of spine
- Limits motion in flexion
- No discs beteween occipital condyle and atlas, Cv1-Cv2
- Cartilaginous end plate separates disc from vertebral body
Vertebral Ligaments
- Anterior longitudinal -Posterior longitudinal
- Interspinous
- Supraspinous
- Nuchal (expansion of supraspinous ligament)
- Intertransverse
- Ligamenta flava (between lamina, slightly more yellow due to more vasculature)
Spinal Cord Features
31 pairs of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
- Cervical enlargement is related to upper limb function
- Lumbosacral enlargement is related to lower limb function
- Spinal cord of adult extends betwen L1-L2
- Conus Medullaris: tip of spinal cord
- Cauda Equina: -Nerve roots continuing on to intervertebral and sacral foramen and Filum Terminale
- Filum Terminale: Delicate fibrous tissue extending from Conus Medularis to Sacrum, anchors spinal cord (Internal, extension of pia mater, anchors at S2) (External, extension of dura mater, anchors on coccyx)
Spinal Cord
Gray Matter: -predominantly neurons -Posterior horn: primarily sensory -Anterior horn: motor neurons in somatomotor system -Lateral Horn: preganglionic fibers
White Matter: -predominantly axons
-spinal cord segment related to single dermatome
Spinal Nerve: -Gray matter: mostly neurons -White matter: mostly axons -Anterior/posterior roots/rami -Posterior root ganglion
Spinal Meninges: -Dura mater -Pia mater (small, attached directly to spinal cord) -Arachnoid mater
Denticulate Ligament: anchors rootlets to dura mater (teethlike)
