Vertebral Column, Spinal Cord and Back Flashcards
Main Function of the Vertebral column
Protects the spinal cord and spinal nerves
Supports weight of the upper body
Partly rigid and flexible posture and locomotion
Vertebral column is made up of?
Extends from the cranium to the apex of the coccyx
Main part of the axial skeleton
articulated bones of the cranium, vertebral column, ribs and sternum
Presacral vertebral column is flexible in part to intervertebral discs
33 total vertebrae
Name 4 curvatures that provide flexibility to the spine
Cervical curvature concave posteriorly (natural lordosis)
Thoracic curvature concave anteriorly (natural kyphosis)
Lumbar curvature concave posteriorly (natural lordosis)
Sacral curvature concave anteriorly (natural kyphosis)
Not as profound in females so that the coccyx protrudes less into the pelvic outlet (birth canal)
High” Curves C5, L3
“Low” Curves T5, S2
Saddle block is used for what kind of block
Sacral plexus block
What is Excessive thoracic kyphosis
Erosion and collapse of vertebrae- osteoporosis
What is Excessive lumbar lordosis
Weakened trunk musculature
Temporary in late pregnancy
What is Scoliosis
Abnormal lateral curvature with rotation of the vertebrae
Asymmetric weakness of intrinsic back muscles, failure of half of the vertebra to develop or difference in lower limb length(Causes)
Vertebral body:
Strengthen vertebral column
Increases as move inferiorly
Bigger as move down
Vertebral arch components
Formed by the 2pedicles and 2laminae
Pedicles (2):
Short processes that join vertebral arch to vertebral body
Laminae
Join with pedicles and meet in the midline to complete arch
Vertebrae Structure and Function Continued
rtebral foramen the big hole
Formed by the arch and body
Provides passage way for spinal cord, meninges, fat, spinal nerve roots and vessels
Articulating facets (2 superior and 2 inferior):
With adjacent vertebrae form the Intervertebral Foramina which give passage to spinal nerve roots and vessels
Spinous process:
Projects posteriorly
Provides attachment for deep back muscles
Transverse process (2):
Projects posterolateral
Provides attachment for deep back muscles
Vertebral foramen the big hole
Formed by the arch and body
Provides passage way for spinal cord, meninges, fat, spinal nerve roots and vessels
Articulating facets (2 superior and 2 inferior):
With adjacent vertebrae form the Intervertebral Foramina which give passage to spinal nerve roots and vessels
Spinous process:
Projects posteriorly
Provides attachment for deep
Transverse process (2) components and function
Projects posterolateral
Provides attachment for deep back muscles
Atlas (C1)
Ring-like
No spinous process or body
Two lateral masses connected by anterior and posterior arches
Concave superior articular facets form atlanto-occipital joint with occipital condyle
Articular facet for the dens (odontoid process) of C2
Axis (C2)
Strongest cervical vertebra
Dens- projects superiorly from body and provides a pivot for atlas to turn
Cervical Vertebrae (7)
Small body
Large vertebral foramen
Transverse processes contain foramen (foramina transversarium) which allow vertebral arteries, vertebral veins and sympathetic plexuses to pass
Absent in C7
Spinous process of C3-C5 short and bifid(2 points) increases surface area
Spinous process of C7 is long- vertebra prominens,,,,the one that sticks out
Thoracic vertebrae and components
Body contain one or two bilateral costal facets for articulation with head of rib…larger
Smaller vertebral foramen 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
Rib is named in relationship to what?
Spinous process it attaches to.
Lumbar Vertebrae (5)
Massive body
Vertebral foramen larger than thoracic but smaller than cervical
Short and sturdy hatchet-shaped spinous process
Sacrum and Coccyx
Sacrum:
Five fused, originally separate, vertebrae
Sacral cornu
Important landmark for identifying sacral hiatus
Sacral hiatus
Allows filum terminale of the spinal cord to pass and attach to the coccyx
Results from the absence of laminae and spinous process of the S4-S5 vertebrae
Allows for placement of caudal anesthetic into epidural space
Coccyx
Four fused vertebra
C7 spinous process is called?
C7 spinous process is the vertebra prominens..sticks out
Scapular spine correspond to?
Scapular spine corresponds to T3
Inferior angle of scapula corresponds
with T7 spinous process
Last rib corresponds with
T12 spinous process
Iliac crest- Tuffier’s line corresponds with?
L4 spinous process
PSIS corresponds to
S2 spinous process
Ligaments and functions
This is to stabilize the vertebral column
Nuchal ligament
Strong, median ligament of the neck
Extends from the occipital protuberance and posterior border of the foramen magnum to the spinous processes of the cervical vertebrae
Acts as a point of muscle attachment from C3-C5
Supraspinous ligament
Runs along the spinous process from C5 to sacrum after merging superiorly with the nuchal ligament
Interspinous ligaments
Stabilizes and unites adjacent spinous processes
Weak and membranous, runs entire length of vertebral column.
Ligamentum flava/ flavum
Broad, tough, pale, yellow, wedge shaped elastic fibrous tissue…lamina to lamina
Adjoins laminae of adjacent vertebral arches, forming alternating sections of the posterior wall of the vertebral canal. Runs C2 to sacrum. Thickest at the midline at L3
Posterior longitudinal ligament
Narrow, weaker band
Runs within vertebral canal along the posterior aspect of vertebral bodies from C2 to the sacrum
Anterior longitudinal ligament
Strong broad fibrous band
Covers vertebral bodies and IV discs
Runs from pelvic surface of the sacrum to anterior tubercle of C1 (atlas) and occipital bone anterior to foramen magnum
Spinal cord Location anatomically
Major reflex center and conduction pathway between the body and the brain
Begins as a continuation of the medulla oblongata (caudal part of the brainstem)
Ends in the conus medullaris, in most adults this corresponds with L1 (T12-L3)
This is where u place ur spinal below the level of L1
Cervical enlargement of the spinal cord
Cervical enlargement extends from C4-T1, anterior rami of these spinal nerves form the brachial plexus that innervate the upper extremity (see upper extremity lecture)
Lumbosacral enlargement of the spinal cord
Lumbosacral (lumbar) enlargement extends from L1-S3 segments of the spinal cord, anterior rami of this region
provides the lumbar and sacral plexuses of nerves for the lower extremities (see lower extremity lecture)
Dural sac is created by?
the dura and arachnoid meninges (not pia) continue past the spinal cord to create the dural sac
ends at the level of S2, corresponds with PSIS
From the inferior end of the conus medullaris, the filum terminale internum(pia matter) continues to become?
filum terminale externum
Filum terminale internum is the continuation of the PIA mater
Filum terminale externum passes through the sacral hiatus and attaches to the coccyx posteriorly to anchor the spinal cord and dural sac
Filum terminale externum contains dura, arachnoid AND pia mater
Location of the spinal nerves
31 pairs of spinal nerves
8 cervical
C1 emerges between skull and C1 vertebra
C2-C7 emerge superior to corresponding pedicles
C8 and below emerge inferior to corresponding pedicles
12 thoracic
5 lumbar
5 sacral
1 coccygeal
Lower lumbar and sacral nerve roots are the longest since spinal cord ends high in the vertebral column
Results in a bundle of spinal nerve roots in the lumbar cistern of the subarachnoid space caudal to the termination of the spinal cord- referred to as the cauda equina
C1 –c8 comes out of the corresponding main vertebra
What are the components of the spinal nerve
Gray Matter
White Matter
Multiple rootlets attach to the anterior and posterior surfaces of the spinal cord and converge to form the posterior and anterior roots of the spinal nerve
Components of grey matter
Internally it is a butterfly shaped
Unmyelinated Interneurons and cell body
Components of White Matter
Surrounds the Gray matter
Myelinated nerve cells/axons
Posterior root (dorsal root)
carries afferent sensory information from periphery (skin/deep tissues/viscera) to CNS
Cell bodies of the dorsal root are located outside of the spinal cord at the dorsal root ganglion
Anterior root (ventral root)
carries efferent motor and autonomic signals from the CNS to periphery
Cell bodies of the ventral root are located inside the anterior horns of the gray matter
What forms the spinal nerve
The posterior and anterior roots unite to form a spinal nerve,
Spinal nerve exits the exits the spinal canal through
intervertebral foramen
Spinal nerve divides into 2 nerves namely?
The (Dorsal)posterior Primary Rami The Ventral(Anterior) Primary Rami
What is the Function of the dorsal(posterior) Rami
supply the deep muscles of the back and skin
Posture muscle
What is the Function of the Ventral Rami
supply muscles, joints, and skin of the limbs and remainder of the trunk
Where does the Dural Sac end
S2
What is the function of the meninges
Surround, support, and protects the spinal cord and spinal nerve roots
What is the meninges made up of
Dura mater: tough, fibrous outermost covering
Separated from the vertebrae by the epidural space
Highly vascularized
Forms the spinal dural sac, which ends at S2
Arachnoid mater: delicate, avascular membrane
lines the dural sac, is not attached to dura but is pressed against the dura due to cerebral spinal fluid (CSF)
Encloses the subarachnoid space which contains CSF, spinal nerve roots, and spinal ganglia
Pia mater: innermost covering membrane
Directly covers the spinal cord, roots of the spinal nerves and spinal blood vessels
Denticulate ligament- extensions that help anchor spinal cord centrally….no wiggling
Continues as the filum terminale (internum)
Where is the CSF in the spine
Sub arachnoid space is csf……pushes dura against arachnoid
What location does the spinal work in
Spinal Roots
where does the Three longitudinal arteries supply blood to?
medulla of the brainstem to the conus medullaris of the spinal cord
One anterior spinal artery
supplies blood to
Arises from the union of branches of the vertebral arteries
Anterior two-thirds of the spinal cord Blood supply
Two posterior spinal arteries
Arise from a branch of either the vertebral arteries or the posterior inferior cerebellar artery
Posterior one-third of the spinal cord
Posterior spinal cord has better continuity of blood supply than the anterior spinal cord
Both anterior and posterior spinal arteries only supply what location
These three arteries run the entire length of the spinal cord but only supply the short superior part
What arteries supply the spinal cord except the superior part
cervical, deep cervical, vertebral, posterior intercostal and lumbar arteries
Enter the vertebral column through the intervertebral foramina
What does the artery of
ADAMKIEWICZ(Great anterior segmental artery)
supply
Provides circulation to the inferior two thirds of the anterior spinal cord
Generally arises from T9-T12 on the left side of the aorta
Branch from segmental spinal artery
Explain Spinal cord venous Drainage
Veins of corresponding names follow the arteries
Epidural space holds the internal vertebral venous plexus (Batson Plexus)
Provides alternative venous return to the heart when the inferior vena cava is compressed
Empty into the azygos vein or the hemiazygos vein which are located in the abdomen and thorax
Serratus posterior Superior/Innervtion and function
Superficial respiratory muscles
2nd-5th intercostal nerves (anterior rami)
Proprioception for respiration
Serratus posterior inferior
Inn/Function
Superficial respiratory muscles
9th-11th intercostal nerve (anterior rami)
Proprioception for respiration
Splenius Capitis and Splenius Cervicis
INN/ACT
posterior rami of spinal nerves and act to maintain posture and control movements of the vertebral column
Laterally flex neck and rotate head to side of active muscles.
Extends head and neck together
Longissimus
Spinalis
Illiocostalis
Bilaterally- extends vertebral column
Unilaterally- flexes vertebral column
Components of Suboccipital triangle
Region is defined by four postural muscles of the head
Posterior ramus of C1 suboccipital nerve
Motor innervation
Posterior ramus of C2 greater occipital nerve (lies slightly lateral)
Sensory innervation
Posterior ramus of C3 third occipital nerve (lies medially)
Sensory innervation
XXXAnterior ramus of C2-C3 lesser occipital nerve (lies laterally)
Sensory innervation
Lies outside region of suboccipital triangle but included for completeness
Rectus capitis posterior major
Inn/Act
Spinous process C2; occipital bone
Suboccipital nerve
Head posture
Rectus capitis posterior minor
INN/ACT
Posterior tubercle of C1; occipital bone
Suboccipital nerve
Head posture
Obliquus capitis inferior
inn/ACt
Spinous process C2; transverse process of C1
Suboccipital nerve
Head posture
Obliquus capitis superior
Transverse process of C1; occipital bone
Suboccipital nerve
Head posture
Sensory Innervation of the Occipital Region and Head
Posterior ramus of C2 greater occipital nerve (lies slightly 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)
Dermatomes C4-T6
Posterior cutaneous branch of C4-T6
Dermatomes T7-T12
Posterior Cutaneous Branches T7-T12
