TOPIC 6: THE VERTEBRAL COLUMN AND THORACIC CAGE

A set of vocabulary flashcards covering key terms related to the vertebral column and thoracic cage.

Vertebral column

The axial skeleton component consisting of 33 vertebral bones and intervertebral discs, organized into cervical, thoracic, lumbar, sacral, and coccygeal regions.

Axial skeleton

The central skeleton including the skull, vertebral column, and thoracic cage.

Cervical spine

Neck region containing 7 cervical vertebrae (C1–C7) with intervertebral discs.

Thoracic spine

Mid-back region with 12 thoracic vertebrae (T1–T12) and their intervertebral discs.

Lumbar spine

Low back region with 5 lumbar vertebrae (L1–L5) and their discs.

Sacral region

Sacrum: 5 fused sacral vertebrae; discs usually absent.

Coccygeal region

Tailbone: 4 fused coccygeal vertebrae; discs usually absent.

Lordosis

Normal inward curvature of the cervical and lumbar spine.

Kyphosis

Normal outward curvature of the thoracic and sacral/coccygeal spine.

Scoliosis

Abnormal lateral curvature of the spine, often with twisting; common in the thoracic region.

Intervertebral disc

Fibrocartilaginous pad between adjacent vertebrae with an outer annulus fibrosus and inner nucleus pulposus.

Annulus fibrosus

Outer fibrous ring of an intervertebral disc.

Nucleus pulposus

Inner gel-like core of an intervertebral disc with high water content.

Herniated disc

Protrusion of the nucleus pulposus through a weakened annulus fibrosus, potentially compressing a spinal nerve.

Jelly donut

Analogy for a herniated disc where the nucleus pulposus bulges through the annulus fibrosus.

Intervertebral foramen

Openings on each side of a vertebral level allowing spinal nerves to exit the spinal canal.

Vertebral foramen

The central hole of a vertebra through which the spinal cord passes.

Vertebral canal

Tunnel formed by stacked vertebral foramina through which the spinal cord travels.

Lamina

Part of the vertebral arch forming the posterior portion of the arch.

Spinous process

Posterior projection of a vertebra for muscle and ligament attachment.

Bifid spinous process

Split spinous process seen in C2–C6 of the cervical spine.

Transverse process

Lateral posterior projection from the vertebral arch; attachment sites for muscles/ligaments; cervical vertebrae have transverse foramina.

Transverse foramina

Openings in cervical vertebrae through which the vertebral arteries pass.

Pedicle

Short bony projection from the body that forms part of the vertebral arch.

Superior articular process

Process bearing a facet that articulates with the inferior articular facet of the vertebra above.

Inferior articular process

Process bearing a facet that articulates with the superior articular facet of the vertebra below.

Articular facet

Flat joint surface at the end of an articular process.

Facet joint

Joints between superior and inferior articular facets of adjacent vertebrae.

Atlas (C1)

First cervical vertebra; no body or spinous process; has anterior and posterior arches and tubercles; supports the skull.

Axis (C2)

Second cervical vertebra; has the dens (odontoid process) that allows rotation of C1 on C2.

Dens (odontoid process)

Peg-like projection on C2 that acts as pivot for C1 rotation (atlanto-axial rotation).

Occipital condyles

Articulate with the atlas; allow nodding motion of the head.

Sacrum

Fused sacral vertebrae (S1–S5) forming part of the pelvis; features include promontory, alae, and auricular surfaces.

Sacral promontory

Anterior, superior lip formed by the body of S1.

Ala (alae) of the sacrum

Wing-like extensions on the anterior sacrum formed by the transverse processes of S1.

Auricular surface

Articular surfaces on the sacrum that articulate with the ilia to form the sacroiliac joints.

Median sacral crest

Posterior midline ridge formed by fused sacral spinous processes.

Lateral sacral crest

Ridges on the posterior sacrum, lateral to the median crest; remnants of transverse processes.

Anterior sacral foramina

Openings on the anterior surface for the passage of spinal nerves.

Posterior sacral foramina

Openings on the posterior surface for exiting spinal nerves.

Sacral canal

Continuation of the vertebral canal through the sacrum; carries spinal nerves.

Sacral hiatus

Distal opening of the sacral canal.

Coccyx

Tailbone composed of 4 fused coccygeal vertebrae.

Intervertebral disc components

Outer annulus fibrosus and inner nucleus pulposus.

Nucleus pulposus (age effect)

Water content declines with age, reducing disc height and flexibility.

Spina bifida

Congenital failure of lamina to fuse; folic acid supplementation reduces risk.

Spinal cord end level

In adults, ends at L1–L2; below this level the canal contains cauda equina rather than spinal cord.

Atlanto-occipital joint

Synovial condyloid between occipital condyles of skull and atlas; flexion/extension and side flexion.

Atlantoaxial joint

Synovial pivot joint between atlas (C1) and axis (C2); allows most head rotation.

Intervertebral joints

Two parts: facet joints (synovial plane) and joints between vertebral bodies with intervertebral discs (cartilaginous/amphiarthrotic).

Costovertebral joint

Vertebrae–rib joints; synovial plane; allows gliding of ribs.

Sternocostal joint

Joints between sternum and costal cartilages; 1st rib is cartilaginous, 2–7 are synovial plane.

Costochondral joint

Cartilaginous joints between costal cartilage and rib; no movement.

Costal cartilage

Cartilage connecting ribs to the sternum.

True ribs

Ribs 1–7; direct attachment of cartilage to the sternum.

False ribs

Ribs 8–12; attach to cartilage of the rib above (11–12 have no anterior attachment).

Floating ribs

Ribs 11–12; false ribs that do not attach to the sternum.

Head of the rib

End of the rib that articulates with the vertebrae; has two demi-facets.

Demi-facet

Partial facet on the rib head that articulates with a vertebral body.

Neck of the rib

Region between the head and the tubercle.

Tubercle of the rib

Bony knob with a facet that articulates with the transverse process of the same-numbered vertebra.

Costal groove

Groove on the inferior border of the rib that houses intercostal vessels and nerves.

Ribs 2–9 articulation (head and tubercle)

Head has superior and inferior demi-facets articulating with adjacent vertebrae; tubercle facet articulates with transverse process.

Ribs 1, 10, 11, 12 articulation

These ribs articulate with their own vertebra via a full facet on the head.

Sternal angle (Angle of Louis)

Landmark where manubrium meets the body; aligns with rib 2.

Jugular notch

Depression at the top of the sternum; palpable.

Clavicular notch

Lateral notch at the manubrium; location of the sternoclavicular joint.

Xiphoid process

Distal end of the sternum; palpable.

Ribs vs sternum attachment summary

Ribs attach to sternum directly (true ribs) or via costal cartilage (false) or not at all anteriorly (floating).

External oblique fiber direction

Fibers run inferiorly and medially.

Internal oblique fiber direction

Fibers run superiorly and medially.

Rectus sheath

Fibrous covering around the rectus abdominis.

Linea alba

Midline connective tissue seam in the anterior abdomen.

Six-pack abs

Tendinous intersections across the rectus abdominis giving a segmented appearance.

Erector spinae

Back extensor muscles: iliocostalis, longissimus, spinalis; extend the trunk.

Quadratus lumborum

Flank muscle; primary lateral flexor of the trunk; attaches to iliac crest and lumbar transverse processes.

Rectus abdominis

Main trunk flexor; located along the midline.

External oblique

Lateral trunk flexor and contralateral rotator.

Internal oblique

Lateral trunk flexor and ipsilateral rotator; supports abdominal wall.

Transversus abdominis

Deep abdominal muscle; stabilizes trunk and compresses abdomen.

Movement types of the vertebral column

Flexion, extension, rotation, and lateral (side) flexion at the intervertebral joints.

Ligaments: ALL

Anterior longitudinal ligament running along the anterior surfaces of vertebral bodies; resists extension.

Ligaments: PLL

Posterior longitudinal ligament along the posterior aspect of vertebral bodies; resists flexion.

Ligaments: Supraspinous

Runs along the tips of spinous processes; resists flexion.

Ligaments: Interspinous

Between adjacent spinous processes; resists flexion.

Ligaments: Ligamentum flavum

Elastic ligament posterior to the spinal canal; resists flexion.

Ligamentum nuchae

Nuchal ligament from external occipital protuberance to C7; resists flexion.

Spina bifida

Lack of lamina fusion in utero; folic acid before pregnancy helps prevent.