Vertebral Column, Spinal Cord and Back Flashcards
The vertebral column is partly ____ and _____ to support posture and locomotion
rigid; flexible
The presacral vertebral column is flexible in part to _____ ____
intervertebral discs
How many vertebrae total?
What are the various sections? How many vertebrae in each?
33 total
7 cervical
12 thoracic
5lumbar
5 sacrum (fused)
4 coccyx (fused)
(Breakfast at 7, lunch at 12, dinner at 5, snack at 9 [sacrum+coccyx])
What are the 4 curvatures of the spine?
What do they provide?
Cervical
Thoracic
Lumbar
Sacral
4 curvatures provide additional flexibility
What is curvature of cervical curvature?
Concave posteriorly (natural lordosis)
What is curvature of thoracic curvature?
anteriorly (natural kyphosis)
What is curvature of lumbar curvature?
concave posteriorly (natural lordosis)
What is direction of curvature of sacral curvature?
concave anteriorly (natural kyphosis)
*not as profound in females so that coccyx protrude less into the pelvic outlet (birth canal)
What are the “high” curves and “low” curves?
High curves C5, L3
Low curves T5, S2
very important for anesthesa- spinal/epidurals
What are some abnormal curvatures?
- Excessive thoracic kyphosis
- erosion and collapse of vertebraie- osteoporosis
- Excessive lumbar lordosis
- weakened trunk musculature
- temporary in late pregnancy
- Scoliosis
- abnormal lateral curvature with rotation of vertebrae
- spinous process turn/rotate
- asymmetric weakness of intrinsic back muscles, failure of half of vertebra to develop or difference in lower limb length
- abnormal lateral curvature with rotation of vertebrae
What is purpose of bertebral body? How does their size change throughout vertebral column?
- Purpose: strengthen vetebral columb
- Increase in size as moving inferiorly
What is the vertebral arch
Formed by pedicles and laminae
What are pedicles?
2 short porcesses that join vertebral arch to vertebral body
What are the laminae?
Join with pedicles and meet midline to complete arch
What is vertebral foramen?
- Formed by arch and body
- Provides passage way for:
- spinal cord
- meinges
- fat
- spinal nerve roots
- vessels
What are the articulating facets?
- 2 superior and 2 inferior
- Form intervertebral foramina with adjacent vertebrae
- gives passage to spinal nerve roots and vessels
- Form intervertebral foramina with adjacent vertebrae
What is the spinous process?
- Projects posteriorly
- Provides attachment for deep back muscles
What are the transverse processes?
- Project posterolateral
- provides attachment for deep back muscles
What are some characteristics of the cervical vertebral bodies?
- 7 total
- Small body
- LARGE vertebral foramn
- allows spinal cord enlargement to pass
- Spinous process of C3-C5 are short and bifid
- allows more muscle attachements
- Spinous process of C7 is long- vertebra prominens
- Transverse process contain foramen (foramina transversarium)
What are the foramina transversairum?
- Foramen in the transverse processes of cervical vertebra
- Allows passage of:
- vertebral arteries
- vertebral veins
- sympathetic plexuses
- ABSENT in C7
What is the atlas vertebrae? Characteristics?
- C1
- Ring-like
- No spinous process or body
- 2 lateral masses connected by anterior and posterior arches
- concave superior articular facets form atlnato-occipital join with occipital condyle
- (where your head rests)
- Articular facet for dens (odontoid process) of C2
- how you’re allowed to turn head
What is the axis?
- C2
- Strongest cervical vertebra
- Dens- projects superiorly form body and provides a pivot for atlas to turn
What are some characteristics of thoracic vertebrae?
- Body contain one or two bilateral costal facets for articulation with head of rib
- Smaller vertebral foramn compared to cervical and lumbar regions
- Transverse processes are long and strong
- length diminishes from T1-T12
- T1-T10 contain costal facets for articulation with tubercle of corresponding rib
- Spinous process slopes significantly postero-inferiorly, overlapping sub adjacent vertebral body
How are ribs named?
- Named based on which transverse process it adheres to
4 facts for lumbar vertebrae?
- 5 Vertebrae
- Massive body
- Vertebral foramn larger than thoracic but smaller than servical
- short and sturdy hartchet-shaped spinous process
What does the sacrum contain?
- 5 fused, orginally seperate vertebrae
- Sacral cornu
- important landmark for identifying sacral hiatus
- Sacral hiatus
- allows filum terminale of spinal cord to pass and attach to coccyx
- Results form absence of laminae and spinous process of S4-S5 vertebrae
- Allows placement of caudal anesthetic into epidural space
Coccyx consists of:
4 fused vertebrae
Which spinous process is vertebra prominens?
C7
What does the scapular spine correspond to?
T3
Inferior angle of scapular corresponds with?
T7 spinous process
Last rib corresponds with ___ spinous process?
T12
Iliac crest is also referred to as ____ ____ and corresponds to ___ spinous process
Tuffier’s line
L4
What is the PSIS? What does it correspond to?
Posterior superior iliac spine
S2 spinous process
end dural sac
What are the 6 ligaments of the spinal column (superficial to deep)
- Nuchal ligament
- Supraspinous ligament
- Interspinous ligament
- Ligamentum flava/flavum
- Posterior longitudinal ligament
- Anterior longitudinal ligament
What is the nuchal ligament?
- Strong, median ligament of neck
- Extends from occipital protuberance and posteiror border of foramen magnum to spinous processes of cervical vertebrae
- Acts as point of muscle attachemtn from C3-C5
What is the supraspinous ligament
- 2nd most layer ligament
- Runs along spinous process form C5 to sacrum after merging superiorly with nuchal ligament
What is the interspinous ligament?
- Stabilizes and unites adjacent spinous processes
- Weak and membranous, runs entire lenght of vertebral column
What is the ligamentum flava/flavum?
- Broad, tough, pale, yellow, wedge shaped elastic fibrous tissue
- Adjoins laminae of adjacent vertebral arches, forming alternating sections of the posterior wall of vertebral canal
- This creates the “pop” you feel. Once you feel this, you need to SLOW DOWN and advance slowly
- Runs C2 to sacrum
- Thickest at midline at L3
What is posterior longitudinal ligament?
- Narrow weaker band
- Runs within vertebral canal along posterior aspect of vertebral bodies from C2 to the sacrum
What is anterior longitudinal ligament?
- Strong broad fibrous band
- Covers vertebral bodies and IV discs (intervertebral)
- Runs from pelvic surface to sacrum to anteiror tubercle of C1 (atlas) and iccipital bone anterior to foramen magnum
What is spinal cord a continuouation of?
Medulla oblongata (caudal part of brainstem)
Where does spinal cord end?
Cous medullaris, in most adults this corresponds to L1 (T12-L3 [kids more L3])
Where is the cervical enlargement?
- C4-T1 anterior rami of spinal nerves form brachial plexus that innervate upper extremity
Where is the lumbosacral enlargmenet?
- L1-S3 segments of spinal cord
- anterior rami of this region provide lumbar and sacral plexuses of nerves for LE
Where are spinals placed?
Below the spinal cord (therefore below level of conus medullaris, which is below T12)
What combines to form dural sac?
Dura and arachnoid meninges
Where does the dural sac end?
Ends at S2, corresponds with PSIS
What is the flium terminale internum?
Continuation of pia mater after conus medularis, inside dural sac
From inferior end of conus medullaris, the ___ ___ ___ descends among the elongated spinal nerve roots of the region and penetrate the end of the dural sac to become the___ ____ ____
filum terminale internum; filum terminale externum
What forms filum terminale externum?
Dura, arachnoid AND pia mater
Passes through sacral hiatus and attaches to coccyx posteriorly to anchor the spinal cord and dural sac
What forms cuada equina?
Nerve roots
How many spinal nerves do we have? How many in each region?
- 31 pairs of spinal nerves
- 8 cervical
- C1 emerges b/w skull and C1 vertebra
- C2-C7 emerge superior to corresponding pedicles
- C8 nad below emerge inferior to corresponding pedicles
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
Which nerve roots are the longest?
Lower lumbar and sacral since spinal cord ends high in vertebral column
Spinal nerves results in a bundle of spinal nerve roots in ___ ____ of subarachnoid space caudal to termination of spinal cord- referred to as ___ ___
Lumbar cistern; cauda equina
Where is gray matter in spinal cord?
- Internally, butterfly shaped
- Consists of unmyelinated interneurons and cell bodies
What is white matter in spinal cord?
- Surrounds gray matter, myelinated nerve cells/axons
What is posterior root of spinal cord?
Dorsal root- afferent sensory information from periphery
- Cell bodies of dorsal root are located outside the spinal cord at dorsal root ganglion
What is the anterior root of spinal cord?
Vental root- carries efferent motor and autonomic signals from CNS to periphery
- Cell bodies of ventral root are located inside the anterior horns of the gray matter
The posterior and anterior roots unite to form___ ___
spinal nerve
Where does the spinal nerve exit the spinal canal?
Through the intervertebral foramen
What does the spinal nerve divide into after intervertebral foramen?
- Dorsal (posterior) primary ramus and ventral (anterior ) primary ramus
What does the dorsal rami supply? Ventral rami?
- Dorsal rami supply deep muscles of back and skin
- Ventral rami supply muscles, joints, and skin of the limbs and remainder of the trunk
The brachial, lumbar and sacaral plexus are from ___ ___?
Anterior rami
What are the spinal meninges?
Dura, arachnoid, pia mater
What is the dura mater in spinal cord?
- Tough, fibrous outermost covering
- Separated from vertebrae by epidural space
- highly vascularized
- Forms spinal dural sac, which ends at S2
The epidural space is a ____ ____
potential space;
We make it exist by placing epidural.
Does not exist in normal anatomy. When we inject anesthetic, it diffuses through dura mater, arachnoid mater, and works at spinal roots
What is the arachnoid mater in spinal cord?
Delicate, avascular membrane
- Lines dural sac, is not attached to dura but pressed against the dura due to CSF
- in our cadavers, arachnoid mater is right against dura mater
- Encloses the subarachnoid space which contains CSF, spinal nerve roots and spinal ganglia
- goal of spinal anesthetic
What is the pia mater (spinal cord)?
- Runs right against the spinal cord. Innervmost covering membrane
- Directly covers the spinal cord, roots of spinal nervesa nd spinal blood vessels
- Denticulate ligament- extensions that help anchor spinal cord centrally
- Continues as flium terminale (internum)
What forms arterial supply to spinal cord?
- 3 longitudinal arteries
- medullar of brainstem to conus medullaris of spinal cord
- One anterior spinal artery
- Two posterior spinal arteries
These three arteries run entire length of spinal cord, but only supply short superior part
Posterior spinal cord as better continuity of blood supply than anterior spinal cord
What is the anterior spinal artery?
- Arises from union of brnaches of vertebral arteries
- Anterior two-thirds of spinal cord
What are the two posterior spinal arteries?
- Arise from branch of either vertebral artieries or posterior inferior cerebellar artery
- Posterior one-third of spinal cord
Where does remainder of spinal cord (beyond superior portion) rely on for arterial supply?
- Branches from
- cervical
- deep cervicla
- vertebral
- posterior intercostal
- lumbar artieres
- Enter vertebral column through the intervertebral foramina
What is the artery of adamkiewicz?
- Most important medullary artery
- helps supply anterior spinal artery
- Comes off left side aorta at T9-T12
- Provides circulation to inferior two thirds of anterior spinal cord
- Plays important role in anesthesia
- Thoracic aneurysm on aorta, going into sx, they clamp aorta to stop bleeding (above and below aneurysm) if bottom clamp is at T7 region, means artery of adamkiewicz no longer supplying anterior spinal artery–> high risk of paraplegia
Venous drainage in spinal cord?
- Veins corresponding names follow arteries
- Epidural space holds internal vertebral venous plexus (Batson plexus)
- provides alternative venous return to heart when IVC is compressed (i.e. tumor)
- Empty into azygos vein or hemiazygos vein located in the abdomen and thorax
- Tends to be engorged in pregnancy
What are intermediate extrinsic muscles of the back?
Serratus posterior superior
Serratus posterior inferior
A/I for serratus posterior superior?
A: Proprioception for respiration
I- 2nd-5th intercostal nerves (anterior rami)
A/I Serratus posterior inferior?
A: proprioception for respiration (Tell you how you are breathing)
I: 9th-11th intercostal nerve (anterior rami)
What are the intrinsic back muscles?
Splenius capitis
Splenius cervicis
- Posture muscles innervated by posterior rami of spinal nerves
- maintain posture
- control movmeent of vertebral column
A/I splenius capitis?
A: Laterally flex neck and rotate head to side of active muscles. Extends head and neck together
I: Posterior rami of spinal nerves
A/I Splenius cervicis?
A: Laterally flex neck and rotate head to side of active muscles. Extends head and neck together
I: Posterior rami of spinal nerves
What are intermediate intrinsic back muscles?
Erector spinae muscles are “sli”
Spinalis
Longissimus
Iliocostalis
A/I spinalis
A: Bilaterally-extends vertebral column.
Unilaterally- flexes vertebral column
I: Posterior rami of spinal cord nerves
A/I Longissimus
A: Bilaterally-extends vertebral column. Unilaterally- flexes vertebral column
I: Posterior rami of spinal nerves
A/I of iliocostalis
A: Bilaterally- extends vertebral column Unilaterally- flexes vertebral column
I: Posterior rami of spinal nervces
What is the posterior ramus of C1?
Suboccipital nerve
Motor innervation
What is posterior ramus of C2?
Greater occipital nerve (lies slightly lateral)
Sensory innervation
What is the posterior ramus of C3?
Third occipital nerve (lies medially)
Sensory innervation
What is anterior ramus of C2-C3?
Lesser occipital nerve (lies laterally)
sensory innervation
lies outside region of suboccipital tirangle, included for completeness
Attachment, innervation, action for rectus capitis posterior major muscle?
Attachement: spinous process C2; occipital bone
Innervation: suboccipital nerve
Action: head posture
Attachement, innervation, action rectus capitis posterior minor
Attachement: posterior tubercle of C1; occipital bone
Innervation: suboccipital nerve
Action: head posture
?Attachment, innervation, action obliquus capitis inferior
Attachment: spinous process C2; transverse process of C1
Innervation: suboccipital nerve
Action: head posture
Attachment, innervation, action obliquus capitis superior?
Attachement: transverse process of C1; occipital bone
Innervation: suboccipital nerve
Action: head posture
What is the sensory innervation of occipital region and head?
- Posterior ramus of C2–> greater occipital nerve (lies lateral)
- sensory innervation- occipital area
- Posterior ramus of C3–> third occipital nerve (lies medially)
- sensory innervation- occipital area
- Anterior ramus of C2-C3–> lesser occipital nerve (lies laterally)
- sensory innervation- posterior to auricle (ear)
What is contained in dorsal root ganglion?
General Somatic afferent, general visceral afferent
What cell bodies are found in anterior horn?
General somatic efferent
What cell bodies are found in lateral horn?
General visceral efferent
