Medical Gross Anatomy: Back
Terms in this set (95)
there are approx. ____ vertebrae.
the weightbearing part of the vertebra and is linked to adjacent vertebral bodies by intervertebral discs and ligaments.
the size increases inferiorly as the amount of weight supported increases.
forms the lateral and posterior parts of the vertebral foramen.
formed by the vertebral foramina of all the vertebrae together.
contains and protects the spinal cord.
superiorly, it is continuous, through the foramen magnum of the skull, with the cranial cavity of the head.
the vertebral arch of each vertebra consists of:
bony pillars that attach the vertebral arch to the vertebral body
flat sheets of bone that extend from each pedicle to meet in the midline and form the roof of the vertebral arch
projects posteriorly and inferiorly from the junction of the 2 laminae and is a site for muscle and ligament attachment.
extends posterolaterally from the junction of the pedicle and lamina on each side and is a site for muscle and ligament attachment and articulation with ribs in the thoracic region
superior and inferior articular processes
projecting from the region where the pedicles join the laminae.
articulate with the inferior and superior processes, respectively, of adjacent vertebrae.
superior and inferior vertebral notches
between the vertebral body and the origin of the articular processes, each pedicle is notched on its superior and inferior surfaces.
these participate in forming intervertebral foramina.
each transverse process of cervical vertebrae is trough-shaped and perforated by this round structure.
articulates with the head.
its major distinguishing features is that it lacks a vertebral body.
ring-shaped and composed of 2
interconnected by an
the atlas' lateral mass articulates below with the superior articular process of this structure.
characterized by the large toothlike dens, which extends superiorly from the vertebral body.
superior articular facets
of cervical vertebrae, they are bean-shaped and concave
inferior articular facets
of cervical vertebrae, they are almost circular and flat.
projects superiorly from the vertebral body of the axis.
acts as a pivot that allows the atlas and attached head to rotate on the axis, side to side.
the anterior surface has an oval facet for articulation with the anterior arch of the atlas.
transverse ligament of atlas
holds the dens in the position. it is posterior to the dens and it spans the distance between the oval attachment facets on the medial surfaces of the lateral masses of the atlas.
the transverse processes of the atlas act as levers for muscle action, particularly for muscles that move the head at this joint.
the 2 superolateral surfaces of the dens possess circular impressions that serve as attachment sites for these strong ligaments, one on each side, which connect the dens to the medial surfaces of the occipital condyles.
check excessive rotation of the head and atlas relative to the axis.
each lateral mass of the atlas articulates above with this structure
the transverse processes of lumbar vertebrae are generally thin and long, with the exception of those on vertebra LV, which are massive and somewhat cone-shaped for the attachment of these ligaments to connect the transverse processes to the pelvic bones.
formed on each side between adjacent parts of vertebrae and associated intervertebral discs.
allow structures (spinal nerves and BVs) to pass in and out of the vertebral canal.
formed by the inferior vertebral notch on the pedicle of the vertebra above and the superior vertebral notch on the pedicle of the vertebra below.
is bordered: posteriorly by the zygapophysial joint btw the articular processes of the 2 vertebrae, and anteriorly by the intervertebral disc and adjacent vertebral bodies.
a disorder in which the 2 sides of vertebral arches, usually in lower vertebrae, fail to fuse during development, resulting in an "open" vertebral canal
a new technique in which the body of a vertebrae can be filled with bone cement (typically methyl methacrylate).
commonly performed for osteoporotic wedge fractures
an abnormal lateral curvature of the vertebral column
abnormal curvature (exaggerated anterior concavity) of the vertebral column in the thoracic region, producing a "hunchback" deformity.
abnormal curvature (exaggerated posterior concavity) of the vertebral column in the lumbar region, producing a swayback deformity.
a pathophysiological condition in which bone quality is normal, but the quantity of bone is deficient. it is a metabolic bone disorder that commonly occurs in women in their 50s-60s and men in their 70s. typical complications of osteoporosis include "crush" vertebral body fractures, distal radial fractures, and hip fractures.
(1) symphyses between vertebral bodies
(2) synovial joints between articular processes
the 2 major types of joints between vertebral bodies
A typical vertebra has a total of ___ joints with adjacent vertebrae.
the symphysis between adjacent vertebral bodies is formed by:
consists of an outer anulus fibrosus which surrounds a central nucleus pulposus.
part of the symphysis between adjacent vertebral bodies.
consists of an outer ring of collagen surrounding a wider zone of fibrocartilage arranged in a lamellar configuration. this arrangement of fibers limits rotation between vertebrae.
fills the center of the intervertebral disc, is gelatinous, and absorbs compression forces between vertebrae.
the synovial joints between superior and inferior articular processes on adjacent vertebrae
the lateral margins of the upper surfaces of typical cervical vertebrae are elevated into crests or lips
"uncovertebral" synovial joints
uncinate processes may articulate with the body of the vertebra to form these small joints
anterior longitudinal ligament
attached superiorly to the base of the skull and extends inferiorly to attach to the anterior surface of the sacrum. along its length, it is attached to the vertebral bodies and intervertebral discs.
posterior longitudinal ligament
on the posterior surfaces of the vertebral bodies and lines the anterior surface of the vertebral canal. it is attached along its length to the vertebral bodies and intervertebral discs.
the upper part of the posterior longitudinal ligament that connects CII to the intracranial aspect of the base of the skull.
on each side, pass between the laminae of adjacent vertebrae. these thin, broad ligaments consist predominantly of elastic tissue and form part of the posterior surface of the vertebral canal.
each one runs between the posterior surface of the lamina on the vertebra below to the anterior surface of the lamina of the vertebra above.
resist separation of the laminae in flexion and assist in extension back to the anatomical position.
a triangular, sheetlike structure in the median sagittal plane.
from CVII to the skull, the ligament becomes structurally distinct from more caudal parts of the ligament.
supports the head. resists flexion and facilitates returning the head to the anatomical position. the broad lateral surfaces and the posterior edge of the ligament provide attachment for adjacent muscles.
connects and passes along the tips of the vertebral spinous processes from vertebra CVII to the sacrum.
pass between adjacent vertebral spinous processes. they attach from the base to the apex of each spinous process and blend with the supraspinous ligament posteriorly and the ligamenta flava anteriorly on each side.
vertebral column stability that consists of the vertebral bodies and the anterior longitudinal ligament
vertebral column stability that comprises the vertebral body and the posterior longitudinal ligament
vertebral column stability that is made up of the ligamenta flava, interspinous ligaments, supraspinous ligaments, and the ligamentum nuchae in the cervical vertebral column.
pars interarticularis fractures
describe the specific region of a vertebra between the superior and inferior facet (zygapophysial) joints. this region is susceptible to trauma, especially in athletes.
if fracture occurs here, the vertebral body may slip anteriorly and compress the vertebral canal. the common sites are the LIV and LV levels.
disorder in which a vertebra slips anteriorly on its inferior counterpart and it is related to abnormal anatomy of the facet joints - facet joint degenerative change
surgical removal of an intervertebral disc, usually due to disc herniation
performed when it is necessary to fuse one vertebra with the corresponding superior or inferior vertebra.
indications are varied, although they include stabilization after fracture, stabilization related to tumor infiltration, and stabilization when mechanical pain is produced either from the disc or from the posterior elements.
assists in rotating the scapula during abduction of humerus above horizontal; upper fibers elevate, middle fibers adduct, and lower fibers depress scapula.
extends, adducts, and medially rotates humerus
retracts (adducts) and elevates the scapula
retracts (adducts) and elevates the scapula
serratus posterior superior
elevates ribs II to V
serratus posterior inferior
depresses ribs IX to XII and may prevent lower ribs form being elevated when the diaphragm contracts
together - draw head backward, extending neck; individually - draw and rotate head to same side
together - extend neck
individually - rotate head to same side
primary extensors of the vertebral column & head
bilaterally, they straighten the back, returning it to the upright position from the flexed position, and pull the head posteriorly.
The spinal cord extends from the _____ to approx. the level of disc between vertebrae _______ in adults.
In neonates, the spinal cord extends approx. to vertebra ___.
the distal end of the spinal cord that is cone-shaped.
a fine filament of connective tissue that is a pial part continues inferiorly from the apex of the conus medullaris;
thin strand of pia mater that anchors conus medullaris to coccyx
A cervical enlargement occurs in the regions associated with the origins of spinal nerves ____, which innervate the upper limbs.
A lumbosacral enlargement occurs in the region associated with the origins of spinal nerves ____, which innervate the lower limbs.
rich in nerve cell bodies, which form longitudinal columns along the cord, and in cross-section these columns for a characteristic H-shaped appearance in the central regions of the cord.
surrounds gray matter and is rich in nerve cell processes, which form large bundles or tracts that ascend and descend in the cord to other spinal cord levels or carry information to and from the brain
segmental spinal arteries
the arterial supply to the spinal cord comes from 2 sources:
segmental spinal arteries
feeder arteries that enter the vertebral canal through the intervertebral foramina at every level. they arise predominantly from the vertebral and deep cervical arteries in the neck, the posterior intercostal arteries in the thorax, and the lumbar arteries in the abdomen.
anterior and posterior radicular arteries
after entering an intervertebral foramen, the segmental spinal arteries give rise to these arteries. this occurs at every vertebral level. these arteries follow, and supply, the anterior and posterior roots.
segmental medullary arteries
at various vertebral levels, the segmental spinal arteries also give off these arteries.
the anterior and posterior spinal arteries are reinforced along their length by 8-10 of these arteries.
anterior spinal artery
a single longitudinal vessel which originates within the cranial cavity as the union of 2 vessels that arise from the vertebral arteries - the resulting single artery passes inferiorly, approx. parallel to the anterior median fissure, along the surface of the spinal cord.
posterior spinal arteries
2 longitudinal vessels which also originate in the cranial cavity, usually arising directly from a terminal branch of each vertebral artery (the posterior inferior cerebellar artery) - the right and left arteries descend along the spinal cord, each as 2 branches that bracket the posterolateral sulcus sulcus and the connection of posterior roots with the spinal cord.
arteria radicularis magna
artery of Adamkiewicz
the largest of the 8-10 segmental medullary arteries. this vessel arises in the lower thoracic or upper lumbar region, usually on the left side, and reinforces the arterial supply to the lower portion of the spinal cord, including the lumbar enlargement.
spinal dura mater
the outermost meningeal membrane and is separated from the bones forming the vertebral canal by an epidural space. it dramatically narrows at the level of the lower border of vertebra SII and forms an investing sheath for the pial part of the filum terminale of the spinal cord.
a thin, delicate membrane against, but not adherent to, the deep surface of the dura mater. it is separated from the pia mater by the subarachnoid space. it ends at the level of vertebra SII.
space between the arachnoid and pia mater contains CSF. it is continuous at the foramen magnum with the same space surrounding the brain. it terminates at approx. the level of the lower border of the vertebra SII.
delicate strands of tissue that are continuous with the arachnoid mater on one side and the pia mater on the other, span the subarachnoid space, and interconnect the 2 adjacent membranes.
the largest in the region inferior to the terminal end of the spinal cord where it surrounds the cauda equina.
a vascular membrane that firmly adheres to the surface of the spinal cord. it extends into the anterior median fissure and reflects as sleevelike coatings onto posterior and anterior rootlets and roots as they cross the subarachnoid space. as the roots exit the space, the sleevelike coatings reflect onto the arachnoid mater.
on each side of the spinal cord, this longitudinally oriented sheet of pia mater extends laterally from the cord toward the arachnoid and dura mater.
generally occur between the exit points of adjacent posterior and anterior rootlets and position the spinal cord in the center of the subarachnoid space.
contains the processes of sensory neurons carrying info to the CNS.
the cell bodies of sensory neurons, which are derived embryologically from neural crest cells, are clustered in these which are at the distal end of the posterior root, usually in the intervertebral foramen.
contains motor nerve fibers, which carry signals away from the CNS. the cell bodies of the primary motor neurons are in anterior regions of the spinal cord.
the area of the spinal cord that gives rise to the
, which will form a single pair of spinal nerves.
innervate only intrinsic back muscles (epaxial muscles) and an associated narrow strip of skin on teh back.
innervate most other skeletal mm (hypaxial mm) of the body, including those of the limbs and trunk, and most remaining areas of the skin, except for certain regions of the head.
recurrent meningeal nerves
near heh point of division into anterior and posterior rami, each spinal nerve gives rise to 2-4 small nerves that reenter the intervertebral foramen to supply dura, ligaments, intervertebral discs, and BVs.
terminal cluster of roots. below the end of the spinal cord, the posterior and anterior roots of the lumbar, sacral, and coccygeal nerves pass inferiorly to reach their exit points from the vertebral canal.
there are approx. ___ pairs of spinal nerves.
the first cervical nerve (C1) emerges from the vertebral canal between the skull and vertebra CI.
cervical nerves C2-C7 emerge from the vertebral canal ____ their respective vertebrae.
because there are only 7 cervical vertebrae, C8 emerges between CVII and TI. As a consequence, all remaining spinal nerves, beginning with T1, emerge from the vertebral canal ____ their respective vertebrae.
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