Back Flashcards
vertebral column extends from —- to —-
cranium to apex of coccyx
functions of vertebral column
- protect spinal cord and spinal nerve
- support weight of body superior to level of pelvis
- provide a partly rigid and flexible axis for body and a pivot for head
- involved in posture and locomotion
vertebral column consists of — vertebrae arranged in — regions:
33 vertebrae in 5 regions:
- cervical (7)
- thoracic (12)
- lumbar (5)
- sacral (5 fused -> sacrum)
- coccygeal (4 fused -> coccyx)
(think…breakfast at 7, lunch at 12, dinner at 5)
vertebral column has – curvatures:
4 curvatures:
- primary curvatures (kyphoses - thoracic and sacral/pelvic curvatures) = concave anteriorly
- secondary curvatures (lordoses - cervical and lumar curvatures) = concave posteriorly
primary curvatures of vertebral column
- thoracic and sacral/pelvic curvatures
- kyphoses
- concave anteriorly
- develop during fetal period (spine exhibits one contious C-shaped curve at birth)
secondary curvatures
- cervical and lumbar curvatures
- lordoses
- concave posteriorly
- being to appear during fetal period but do not become obvious until infancy
- extension of vertebral column and in preparation for need to bear weight
- develop with crawling and walking
spine curvature after age of 3 yrs?
column is S-shaped with four normal curvatures
abnormalities in spinal curvatures can result from:
- disease
- paralysis of trunk muscles
- poor posture
- pregnancy
- congenital defects
scoliosis (curved back)
- abnormal lateral curvature that is accompanied by rotation of vertebrae
- body and arch fail to develop on one side of vertebrae
- most common deformity of vertebral column in pubtertal girls (12-15 yrs old)
- usually in thoracic region
Hyperkyphosis/Excessive Thoracic Kyphosis (hunchback)
abnormal increase in thoracic curvature
- usually from osteoporosis but may also be caused by:
- — osteomalacia (softening of your bones)
- — spinal tuberculosis
- — wrestling or weight lifting in young boys
Hyperlordosis/Excessive Lumbar Lordosis (swayback)
anterior rotation of pelvis, producing an abnormal increase in lumbar curvature
— caused by pregnancy or obesity
Vertebral Body
large, kinda oval-shaped anterior portion of vertebra; gives strength to column and supports body weight
- – its posterior side forms the anterior boundary of vertebral foramen
- – vertebral bodies of adjacent vertebrae are joined by intervertebral discs
Pedicles
two short, thick bony processes that project posteriorly from left and right sides of vertebral body
Laminae
two flat plates of bone that project in a posterior and medial direction from posterior side of pedicles; right and left laminae join in midline at base of spinous process
Spinous Process (1)
bony process that projects from posterior side of vertebrae at midline junction of laminae
Transverse Processes (2)
two bony processes that project laterally in a horizontal plane at junction between lamina and pedicle
Articular Processes (4)
bony protrusions projecting superiorly (superior articular processes - 2) or inferiorly (inferior articular processes - 2) from site where pedicles and laminae meet
— superior articular process joins with an inferior articular process from a superior vertebra to form a synovial joint called zygapophyseal (facet) joint
Vertebral Arch
“U” shaped bony structure formed by pedicles and laminae on posterior side of vertebrae
Vertebral Foramen
large hole formed by attachment of vertebral arch to posterior margin of vertebral
– adjacent vertebral foramina form vertebral (spinal) canal which houses spinal cord, nerve roots and cauda equina below L2 vertebral level
features specific to cervical vertebrae
- vertebral foramen are larger and triangular
- superior articular facets face supero-posteriorly and interior articular facets intero-anteriorly
- transverse foramina are holes through transverse process
- – stacked transverse foramina form the transverse foraminal canal which contains the vertebral artery and vein
- spinous processes are short and bifid
- – C6 & C7(vertebral prominens) are longer
- uncinate processes of C3-C6 form the uncovertebral joints/joints of Lushka
- – found only in cervical region
- – increase stability in cervical spine and limit lateral flexion
C1 Atlas
- lacks a vertebral body and instead consists of two lateral masses
- anterior arch is a thin bony arch that connects the anteromedial sides of lateral masses together to form anterior wall of vertebral foramen; at midpoint of arch, longus colli muscle attaches to it at anterior tubercle
- posterior arch is a bony arch that connects together posteromedial portions of lateral masses together to form posterior portion of vertebral foramen
- inferior articular facet articulates with superior articular facets of C2 forming lateral atlanto-axial joint
C2 Axis
- strongest cervical vertebra
- dens or odontoid process is a tooth-like bony protrusion from superior side of vertebral body
- articulates anteriorly with anterior arch of C1 and posteriorly with transverse ligament of C1
Median Atlanto-Axial Joint
formed between dens of axis and anterior arch of atlas; allows atlas to rotate around the dens as a pivot (shaking head “no”)
Atlanto-Occipital Joint
formed between atlas and occipital bone; allows flexion, extension (nodding head “yes”) and lateral flexion of head
Cruicate Ligament
formed by transverse ligament and longitudinal bands
Transverse ligament of atlas
secures dens against anterior arch of C1
Alar ligaments
extend from dens to lateral margins of foramen magnum of skull’s occipital bone; prevents excessive rotation of head
features specific to thoracic vertebrae
- heart shaped body
- circular and smaller vertebral foramen
costal facets on vertebral body (superior and inferior) and transverse processes (transverse costal facet)
— rib heads articulate with vertebral bodies
— rib tubercles articulate with transverse processes
- circular and smaller vertebral foramen
- most have long and pointed spinous process that slope inferiorly
- superior articular facets = posteriorly (slightly laterally)
- inferior articular facets = anteriorly (slightly medially)
features specific to lumbar vertebrae
- largest and heaviest bodies; kidney-shaped
- triangular vertebral foramen (larger than thoracic but smaller than cervical)
- superior articular facets = posteriomedially; mammilary processes on posterior surface
- inferior articular facets = anteriolaterally
- short and sturdy spinous process
sacrum
formed by fusion of five originally separate sacral vertebrae
posterior sacrum
- sacral hiatus = absence of laminae and spinous processes of S4-S5 → leads to sacral canal
- posterior sacral foramina
- median sacral crests (spinous processes)
- intermediate sacral crests (articular processes)
- lateral sacral crests (transverse processes)
- sacral cornua (inferior articular processes S5)
anterior sacrum
- anterior sacral foramina
- sacral alae
- sacral promontory
coccyx
formed by fusion of 3-5 coccygeal vertebrae; coccygeal cornua
Myelomeningocele
baby’s spine does not form normally during pregnancy; born with a gap in bones of the spine and has a sac that contains part of the spinal cord
Meningocele
sac of fluid comes through an opening in the baby’s back but no spinal cord is in the sac
Spina Bifida Occulta
most common type of congenital anomaly of vertebral column
- develops when laminae of L5/S1 do not fully develop and fuse together
- thought to be due to environmental, genetic or nutritional risk factors
- usually no back problems
- its location is found by a “tuft” of hair
Intervertebral Discs (23)
bind vertebrae together, support weight of body, absorb shock
- Pads consist of nucleus pulposus (inner gelatinous mass) and anulus fibrosus (outer ring of fibrocartilage)
- Herniated Disc (“ruptured” or “slipped” disc): puts painful pressure on spinal nerve or cord
Spondylosis
- degeneration or arthritis of the facet joints in vertebral column; fracture in the pars interarticularis of a vertebra
- usually from degenerative osteoarthritis or from a stress fracture that is caused by repetitive trauma done to lumbar spine (gymnastics, football, etc)
- can occurs in any region (but usually lumbar - L4 & L5) and ranges in severity
- mild spondylosis can cause disc space narrowing with small bone spur formation
- severe spondylosis can include extensive disc narrowing, facet joint narrowing, and large bone spur formation
- – puts pressure on nerve roots, causing pain, paresthesia and muscle weakness in the limbs
- bilateral spondylosis can result in spondylolisthesis
Spondylolisthesis
- anterior subluxation (partial dislocation) of a vertebral body, relative to one below it - vertebrae is sliding off other vertebrae
- can occur from bilateral spondylolysis, developmental abnormality of pedicles or from arthritic degenerative changes of the facet joints that no longer prevents anterior displacement
congenital spondylolisthesis
present at birth; result of abnormal bone formation; greater risk for slipping
isthmic spondylolisthesis
results of spondylosis; fracture weakens bone so much that it slips out of place
degenerative spondylolisthesis
most common; with age, discs lose water, becoming less spongy and less able to resist movement by vertebrae
traumatic spondylolisthesis
injury leads to spinal fracture or slippage
pathological spondylolisthesis
spine is weakened by disease such as osteoporosis
post-surgical spondylolisthesis
slippage that occurs or becomes worse after spinal surgery
grades of spondylolisthesis
- grade 1 = <25% slippage
- grade 2 = 25-50% slippage
- grade 3 = 50-75% slippage
- grade 4 = > 75% slippage
Spinal Stenosis
- narrowing of a space in vertebral column
- can occur from spondylosis, spondylolisthesis, congenital malformations, and space-occupying lesions
- can refer to narrowing of vertebral foramen, lateral recess (space lateral to cord where nerve roots pass to the IVF) and intravertebral foramen/IVF (space formed by superior and inferior vertebral notches)
Atlanto-Occuputal Joint
- between occipital condyles and lateral masses of C1
- allow for nodding “yes” - condylar joint
- anterior & posterior membranes that extend from arches of C1 to foramen magnum
Atlanto-Axial Joint
(2 lateral and 1 median joint)
- lateral = between masses of C1 and superior facets of C2
- median = between dens of C2, anterior arch and transverse ligament; allows shaking head “no”
Intervertebral Discs (IVD) / symphysis or cartilaginous joints
- weight bearing and absorbing shock
- made up of annulus fibrosis (outer) & nucleus pulposus (inner)
Uncovertebral Joints/Joints of Luschka
- between uncinate processes of C3-C6 and inferolateral surfaces of bodies superior to them
- planar-synovial joints
- can form bone spurs
Zygapophysial (facet) Joints
- between superior and inferior articular processes of adjacent vertebrae
- planar-synovial joints
- accessory ligaments help stabilize joints
- innervated by articular branches of medial branches of posterior rami
Vertebral Column Movements
- due to extra amount of movement in cervical and lumbar regions, they are more predisposed to disc pathologies over the thoracic region (limited due to attachment of ribs and angle of facets)
- – cervical = very mobile; movements - flexion (greatest), extension, lateral flexion and rotation
- – thoracic = relatively immobile due to articulating rib cage; movement - rotation
- – lumbar = very mobile; movements - flexion, extension (greatest) and lateral bending
Anterior Longitudinal Ligament (ALL)
- wide ligament, running along anterior surfaces of vertebral bodies & intervertebral discs from sacrum to anterior tubercle of C1 and occipital bone (anterior to foramen magnum)
- firmly attached to periosteum of bodies and annulus fibrosus of discs
- prevents hyperextension of vertebral column and anterior dislocation of vertebrae
- can be injured in force hyperextension of neck (like whiplash in an MVC)
Posterior Longitudinal Ligament (PLL)
- runs within vertebral canal along posterior surfaces of vertebral bodies and intervertebral discs from C2 to sacrum
- thinner and weaker than ALL and attaches mainly to IVD
- weakly prevents hyperflexion of vertebral column
- helps prevent posterior herniation of nucleus pulposus
- many nociceptors (pain receptors)
Ligamenta Flava/Ligamentum Flavum “yellow”
- joins the laminae of adjacent vertebrae - entends from vertebrae above and below
- prevents hyperflexion and assist with straightening vertebral column after flexed position; prevents injury to discs
Interspinous Ligament
- connects adjacent spinous processes
- weak and membranous
Supraspinous Ligament
- connects adjacent tips of spinous processes
- (most posterior on the vertebral column)
- merges superiorly with nuchal ligament; strong and fibrous
Ligamentum Nuchae/Nuchal Ligament
- strong, triangular-shaped structure that divides posterior neck at midline
- consider continuation of the supraspinous ligament from spinous process of C7 to external occipital protuberance of skull
- extends deep to connect to spinous processes of C6-C2 and posterior tubercle of C1
- proximal attachment points of trapezius muscle
Transverse Ligament of Atlas
extends between tubercles on medial sides of lateral masses of C1; holds dens in place
Longitudinal Bands
from transverse ligament to occipital bone and body of C2
Cruciate Ligament
formed by transverse ligament and longitudinal bands, forming a cross
Alar Ligaments
extends from sides of dens to lateral parts of foramen magnum; prevent excessive rotation
Tectorial Membrane
superior continuation of PLL across atlanto-axial joint through foramen magnum to floor of cranium; covers alar and transverse ligaments
When evaluating a radiograph of a patient with cervical trauma, evaluating cervical alignment using the important 3 spinal lines is critical. All lines should follow a slightly lordotic curve and be smooth. Any misalignment should be considered evidence of a ligamentous injury or occult fracture, and cervical spine immobilization should be maintained until a definitive diagnosis is made.
- Anterior Vertebral Body Line: anterior margin of vertebral bodies
- Posterior Vertebral Body Line: posterior margin of vertebral bodies
- Spinolaminar Line: posterior margin of vertebral canal
Diffuse Idiopathic Skeletal Hyperostosis (DISH)/”Forestier’s Disease”
- ligaments begin to ossify at their attachments
- can be caused by excess calcium salts in tendons and ligaments
- anterior longitudinal ligament commonly affected
Periosteal Branches
supply the periosteum that surrounds the vertebrae; around the bone
Equatorial Branches
supply the actual vertebral bodies; goes into the bone
Spinal Branches
pass through IVF and branch into
- Anterior Vertebral Canal Arteries → to vertebral body
- Posterior Vertebral Canal Arteries → to vertebral arch
- Segmental Medullary Arteries → to spinal cord
Arteries that give rise to periosteal, equatorial and spinal branches that directly supply to vertebrae
- Vertebral and Ascending Cervical Arteries → cervical spine
- Posterior Intercostal Arteries → thoracic spine
- Subcostal and Lumbar Arteries → lumbar spine
- Iliolumbar, Lateral Sacral and Medial Sacral Arteries → pelvis
spinal veins
- form venous plexuses (epidural) along vertebral column
- internal vertebral venous plexus along inside of vertebral column
- external vertebral venous plexus outside of vertebral column; communicate through IVF
basivertebral veins
- form within vertebral bodies
- drain into internal and external vertebral plexuses
intervertebral veins
- receive blood from spinal cord and vertebral plexuses
- run next to spinal nerves through IVF to drain into vertebral and segmental veins
vertebral column is primarily innervated by…
meningeal branches of spinal nerves
z-joints are innervated by…
articular branches of medial branches of posterior rami
spinal cord
- continuation of brainstem (medulla oblongata) - becomes spinal cord at foramen magnum
- major reflex center and conduction pathway; found between upper two thirds of vertebral canal
- in adults, spinal cord ends between L1-2 vertebrae and the conus medullaris is found between T12-L3, ending the spinal cord
two regions of spinal cord enlargement
- cervical enlargement = from C4-T1; most of spinal nerves form the brachial plexus, giving nerve intervention to upper limbs
- lumbosacral enlargement = from L1-S3; spinal nerves form lumbar and sacral plexus, innervating lower limbs
- — nerves roots from here and conus medullaris form the cauda equina (bundle of nerves that look like horse’s tail) in subarachnoid space
- – fibrous extension of cord is the filum terminale
how many spinal nerves?
31 spinal nerves
- – 8 cervical (extra one! because cervical nerves come out above its vertebrae body while the other region nerves go below - thus, leaving a space between C7 & T1 that is filled by the 8th cervical spinal nerve)
- – 12 thoracic
- – 5 lumbar
- – 5 sacral
- – 1 coccygeal
anterior and posterior spinal nerves
- posterior nerve = contain afferent fibers from skin, deep tissues and sometimes viscera; have spinal ganglia made up of cell bodies of axons
- anterior nerve = contain efferent fibers from skeletal muscle and presynaptic autonomic fibers; cell bodies found in anterior horns of gray matter
The brain and spinal cord are surrounded by tough, fluid-containing membranes called the meninges. There are three layers:
- dura mater
- arachnoid mater
- pia mater
Dura Mater
- tough, fibrous outermost layer that lines the vertebral canal (closest to bone)
- single-layer not attached to bone - separated by epidural space (outside/above dura and between it and bone)
- forms spinal dural sac that attaches to foramen magnum to continue with cranial dura mater
arachnoid mater
- avascular membrane that lines dural sac and sheaths
- not attached to dura but is pushed against it from cerebral spinal fluid (CSF) deep to it
- CSF found in subarachnoid space (below arachnoid)
pia mater
- innermost layer, covering spinal cord, spinal roots and blood vessels
- continues to become filum terminale
- denticulate ligaments = extensions of pia mater that run along side of spinal cord and anchor it
extrinsic back muscles
muscles
- – superficial = trapezius, latissimus dorsi, levator scapulae, rhomboids
- – intermediate = serratus posterior superior and interior
movement
- – superficial = contraction of these muscles results in movement of upper limb
- – intermediate/deep = elevation/depression of ribs during ventilation of the lungs; do not move the back
innervation = branches of ventral primary rami, except trapezius muscle which is innervated by cranial nerve XI (accessory nerve)
intrinsic back muscles
muscles
- superficial = splenius cervicis and splenius capitis
- intermediate = erector spinae muscles - iliocostalis, longissimus, spinalis (think…I Love Spines)
- deep = transversospinalis muscles - semispinalis, multifidus, rotatores (think…Semi Muscles Rock)
movement
- – superficial = neck posture
- – intermediate = extend vertebral column
- – deep = move vertebral column and posture
innervation = dorsal rami
superficial extrinsic back muscles
connect appendicular skeleton to axial skeleton & produce upper limb movement
- trapezius
- latissimus dorsi
- levator scapulae
- rhomboids
trapezius
- large triangular muscle covering posterior aspect of neck and superior half of trunk; attaches pectoral/shoulder girdle to cranium and vertebral column and assists in movement of upper limb
- actions = scapula elevation - squaring shoulders (superior fibers), retraction - pull it posteriorly (middle fibers) & depression - lower shoulders (inferior fibers); pulls scapula posteriorly & superiorly to brace shoulder; rotation glenoid cavity
- innervation = spinal accessory (CN XI)
- — arises from C1-C5 spinal nerves → enters skull via foramen magnum → exits skull via jugular foramen → runs in lateral triangle of neck → trapezius
- blood supply = superficial branch of transverse cervical
attachments = external occipital protuberance, nuchal ligament (occipital bone → C7), lateral clavicle & scapula - weakness of this muscle causes drooping of shoulders
- test trapezius by asking pt to shrug shoulders against resistance (asymmetrical elevation of shoulders? Significant strength deficit & thus, a positive finding)
latissimus dorsi
- large, fan-shaped muscle that covers a wide area of passing from trunk to humerus
- actions = humerus extension, adduction and medial rotation (climbing/rowing) – think… “getting arrested muscles”
- innervation = thoracodorsal nerve
- — surgery in inferior part of axilla puts the thoracodorsal nerve at risk of injury (breast cancer - mastectomies)
- blood supply = thoracodorsal artery
levator scapulae
- strap-like and lies deep to sternocleidomastoid and trapezius
- actions = scapula elevation (with trapezius) and rotation (with rhomboids); neck bilateral extension and ipsilateral flexion
- innervation = dorsal scapular nerve
- blood supply = dorsal scapular
- levator scapulae stretch to relieve neck pain
rhomboids
- lie deep to trapezius and form broad parallel bands that pass inferolaterally from vertenbrae to medial border of the scapula
- rhomboid major is approximately two times wider than the thicker rhomboid minor lying superior to it
- actions = retract scapula; rotate glenoid cavity inferiorly, fix scapula on thoracic wall; assist serratus anterior in holding the scapula against thoracic wall; used when forcibly lowering the raised upper limbs
- innervation = dorsal scapular nerve
- blood supply = dorsal scapular artery
intermediate extrinsic back muscles
serratus posterior superior and interior
- actions = small role in respiration and bigger role in proprioception (body’s awareness of position and movement)
- innervation = intercostal nerve
- serratus posterior superior is a source of chronic pain in myofascial pain syndromes
superficial intrinsic back muscles
splenius cervicis and splenius capitis
- actions = ipsilateral laterally neck flexion; bilateral neck extension; ipsilateral head rotation
- innervation = dorsal rami
intermediate intrinsic back muscles
erector spinae muscles - iliocostalis, longissimus, spinalis (think…I Love Spines)
- actions = ipsilateral laterally flexion; bilateral extension; maintain posture
- innervation = dorsal rami
- each column is divided regionally into three parts based on superior attachments (ex. Iliocostalis lumborum, ilocostalis thoracis and iliocostalis cervicis)
- bilaterally, they extend back from a flexed position and unilaterally, they are involved in lateral flexion
deep intrinsic back muscles
transversospinalis muscles - semispinalis, multifidus, rotatores (think…Semi Muscles Rock)
- actions = rotation locally; extension; vertebral column stabilization
- innervation = dorsal rami
