Lecture 4- Vertebral Column & Spinal Cord

Question 1

Vertebral Column Function

Answer 1

• 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

Question 2

Vertebral Column Regions

Answer 2

• Cervical: 7
• Thoracic 12
• Lumbar 5
• Sacrum: 5 fused
• Coccyx: 3-4 fused, sometimes multiple bones

Question 3

Spinal Curvatures

Answer 3

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

Question 4

Typical Vertebrae Features

Answer 4

• 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)

Question 5

Vertebrae Function

Answer 5

• Attachment for muscle, affect movement, support weight

- Has intervertebral foramen to allow spinal nerve to exit vertebral canal

Question 6

Zygapophysial (facet) Joint

Answer 6

• Formed by superior and inferior articular processes

- Different shapes and orientations in different regions allow for different movements

Question 7

Movements of the Back

Answer 7

• 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

Question 8

Atlas (Cv1) atypical features

Answer 8

• Holds up head
• Anterior/Posterior tubercles and arches
• Facet for dens
• Tubercle for transverse ligament of atlas

Question 9

Axis (Cv2) Atypical Features

Answer 9

• Allows rotation of head
• Longer, bifid spinous process
• Dens (articulates w/ atlas for head rotation)

Question 10

Atlantoaxial Joint

Answer 10

• 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

Question 11

Cervical Vertebrae

Answer 11

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

Question 12

Cervical Rib

Answer 12

• AKA vertebra prominens
• C7
• May have enlarged costal process (cervical rib) that stretches/compresses subclavian artery and/or lower part of brachial plexus

Question 13

Thoracic Vertebrae

Answer 13

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

Question 14

Lumbar Vertebrae

Answer 14

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

Question 15

Sacrum

Answer 15

-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)

Question 16

Coccyx

Answer 16

• 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

Question 17

Intervertebral Disc

Answer 17

• 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

Question 18

Vertebral Ligaments

Answer 18

• Anterior longitudinal -Posterior longitudinal
• Interspinous
• Supraspinous
• Nuchal (expansion of supraspinous ligament)
• Intertransverse
• Ligamenta flava (between lamina, slightly more yellow due to more vasculature)

Question 19

Spinal Cord Features

Answer 19

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)

Question 20

Spinal Cord

Answer 20

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)