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