Osteology & Articulations of the Spine

Vocabulary flashcards reviewing major bones, special vertebrae, joints, ligaments, curvatures, blood supply, and clinical concepts of the spine.

Vertebral Column

The axial skeletal structure composed of 33 vertebrae that provides stability, mobility, rib/limb articulation, spinal cord protection, nerve exit points, head movement, and center-of-gravity maintenance.

Typical Vertebra

A vertebra possessing a body (weight-bearing), vertebral arch (spinal cord protection), pedicles, laminae, transverse processes, spinous process, and superior/inferior articular processes.

Cervical Vertebrae

Seven superior vertebrae characterized by small concave bodies, bifid spinous processes, horizontal articular facets, and a foramen transversarium for the vertebral artery/vein.

Atlas (C1)

First cervical vertebra lacking a body, featuring anterior & posterior arches, peanut-shaped superior articular facets for the skull, and round inferior facets for C2.

Axis (C2)

Second cervical vertebra distinguished by the dens (odontoid process) that acts as a pivot for skull-atlas rotation.

C7 (Vertebra Prominens)

Most inferior cervical vertebra with the longest, usually non-bifid spinous process palpable at the base of the neck.

Foramen Transversarium

Opening in cervical transverse processes transmitting vertebral artery (C1–C6) and vein (C1–C7).

Bifid Spinous Process

Y-shaped cervical spinous tip providing increased surface area for nuchal-ligament and muscle attachment.

Thoracic Vertebrae

Twelve mid-spine vertebrae with heart-shaped bodies, costal facets for ribs, long inferiorly sloping spinous processes, and coronal-plane articular facets.

Costal Facet

Synovial articular surface on thoracic vertebral bodies or transverse processes that receives a rib head or tubercle.

Demifacet

Half costal facet on superior or inferior edge of most T2–T9 bodies allowing a rib to articulate between adjacent vertebrae.

T1 Vertebra

Atypical thoracic vertebra bearing a full costal facet for rib 1 instead of a superior demifacet.

T11 & T12 Vertebrae

Atypical thoracic vertebrae each with a single full costal facet and lacking costotransverse facets.

Lumbar Vertebrae

Five lower-back vertebrae with large oval bodies, sagittally oriented facets, mamillary processes, and short sturdy spinous processes.

Mamillary Process

Small projection on lumbar superior articular process serving as muscle attachment for multifidus and intertransversarii.

Sacrum

Wedge-shaped bone of five fused vertebrae possessing ventral & dorsal sacral foramina, sacral canal, sacral hiatus, and articular auricular surfaces.

Coccyx

Terminal tailbone of typically four fused coccygeal vertebrae; provides ligamentous and muscular attachment, may fuse with sacrum in age.

Sacral Canal

Continuation of vertebral canal within sacrum transmitting dural sac and cauda equina.

Ventral Sacral Foramina

Anterior openings in sacrum allowing ventral rami of sacral spinal nerves to exit.

Dorsal Sacral Foramina

Posterior sacral openings transmitting dorsal rami of sacral spinal nerves.

Sacral Hiatus

Inferior opening of sacral canal permitting exit of coccygeal nerves and access for caudal epidural anesthesia.

Spinal Curvatures

Alternating lordoses (cervical, lumbar) and kyphoses (thoracic, sacral) that align body mass over the center of gravity.

Lordosis

Anteriorly convex spinal curve; physiological in cervical & lumbar regions but excessive in hyperlordosis.

Kyphosis

Posteriorly convex spinal curve; physiological in thoracic & sacral regions but excessive in Dowager’s hump.

Scoliosis

Abnormal lateral curvature of the vertebral column.

Primary Curve

Kyphotic spinal curve present in fetus (thoracic & sacral regions).

Secondary Curve

Lordotic curve developing postnatally in cervical (head control) and lumbar (standing) regions.

Intervertebral Disc (IVD)

Symphysis between vertebral bodies composed of anulus fibrosus (outer fibrocartilage) and nucleus pulposus (gelatinous core).

Anulus Fibrosus

Concentric lamellae of fibrocartilage forming the tough outer ring of an intervertebral disc.

Nucleus Pulposus

Gelatinous center of an intervertebral disc that shifts with movement to absorb shock.

Uncovertebral Joint (Joint of Luschka)

Small articulations between hook-shaped uncinate processes of cervical bodies; may be synovial and guide cervical motion.

Zygapophyseal (Facet) Joint

Synovial joint between superior and inferior articular processes; orientation dictates regional spinal movements.

Facet Orientation – Cervical

Oblique coronal plane; favors flexion, extension, and lateral flexion.

Facet Orientation – Thoracic

Vertical coronal plane; favors lateral flexion and limits flexion/extension.

Facet Orientation – Lumbar

Vertical sagittal plane; favors flexion and extension, limits rotation.

Atlanto-Occipital Joint

Synovial articulation between atlas superior facets and occipital condyles enabling “yes” (nodding) motion.

Atlanto-Axial Joint

Median (dens) and lateral facet joints between atlas & axis enabling “no” (rotation) motion.

Dens (Odontoid Process)

Upward projection of C2 acting as pivot for atlas and skull rotation.

Transverse Ligament of Atlas

Strong band holding dens against anterior arch of C1, preventing posterior displacement.

Cruciate Ligament

Cross-shaped ligament of atlas consisting of transverse and longitudinal fibers stabilizing C1–C2 complex.

Alar Ligament

Paired ligaments connecting dens to occipital condyles, limiting excessive rotation.

Apical Ligament

Midline ligament from dens apex to foramen magnum; minor stabilizer.

Anterior Longitudinal Ligament (ALL)

Paravertebral ligament running along anterior vertebral bodies; limits hyperextension.

Posterior Longitudinal Ligament (PLL)

Ligament on posterior vertebral bodies inside canal; limits hyperflexion and supports discs.

Ligamentum Flavum

Elastic ligament connecting laminae; resists separation during flexion, aids extension recoil.

Supraspinous Ligament

Fibrous cord linking spinous tips from C7 to sacrum; continuous with nuchal ligament superiorly.

Interspinous Ligament

Thin membranes connecting adjacent spinous processes, limiting flexion.

Nuchal Ligament

Broad median ligament from occipital protuberance to C7 spinous process forming neck muscle septum and head stabilizer.

Anterior Atlanto-Occipital Membrane

Superior continuation of ALL between atlas and occiput.

Posterior Atlanto-Occipital Membrane

Superior extension of ligamentum flavum between atlas posterior arch and occiput.

Costotransverse Ligament

Band attaching rib neck to corresponding transverse process, stabilizing costotransverse joint.

Radiate Ligament

Ligament fanning from rib head to vertebral body and disc, strengthening costovertebral joint.

Costal Process

Embryonic rib element present in all vertebrae; enlarges into ribs in thoracic region, remains vestigial elsewhere.

Intervertebral Foramen

Opening formed by pedicles of adjacent vertebrae allowing passage of spinal nerve and dorsal root ganglion.

Spinal Nerve Exit Rule

C1–C7 nerves exit above corresponding vertebrae; C8 exits below C7; all thoracic and lower nerves exit below their vertebra.

Anterior Radicular Artery

Branch supplying ventral roots, anterior medullary arteries, and anterior spinal artery.

Posterior Radicular Artery

Branch supplying dorsal roots and posterior spinal arteries.

Vertebral Venous Plexus

Valve-less internal and external venous networks along the spine providing bidirectional flow and potential cancer metastasis route.

Basivertebral Veins

Veins traversing vertebral bodies to connect internal and external vertebral venous plexuses and drain bone marrow.