1. The vertebral column: gross anatomy, syndesmology and X-ray anatomy Flashcards
Gross Anatomy
vertebral column is composed of 33 vertebrae:
7 cervical vertebrae (C1–C7)
12 thoracic vertebrae (T1–T12)
5 lumbar vertebrae (L1–L5)
5 sacral vertebrae (S1–S5), which fuse to form the sacrum
4 coccygeal vertebrae (Co1–Co4), which fuse to form the coccyx
Gross anatomy: curvatures
Cervical lordosis (curves forward)
Thoracic kyphosis (curves backward)
Lumbar lordosis (curves forward)
Sacral kyphosis (curves backward)
Gross anatomy: components of each vertebrae
- Vertebral Body (Centrum)
The anterior, weight-bearing portion of the vertebra.
Supports the body’s weight and is larger in vertebrae lower in the spine.
n.b: not found in C1 - Vertebral Arch
Encircles the spinal cord and protects it. The arch is composed of:
Pedicles: Short, thick processes projecting posteriorly from the vertebral body.
Laminae: Flat plates that extend posteriorly from the pedicles to meet at the midline. - Vertebral Foramen
The opening formed by the vertebral arch and the vertebral body.
Collectively, the foramina of all vertebrae form the spinal canal, which houses the spinal cord. - Processes
Spinous Process: Projects posteriorly from the junction of the laminae.
Transverse Processes: Extend laterally from the junction of the pedicles and laminae.
Articular Processes: Two superior and two inferior processes, which form joints with adjacent vertebrae. - Intervertebral Notches
Indentations on the pedicles.
When two vertebrae are stacked, these notches form the intervertebral foramen, through which spinal nerves exit the spinal canal. - Intervertebral Discs (Associated Component)
Present between adjacent vertebral bodies (except between certain fused vertebrae, like in the sacrum).
Function to absorb shock and provide flexibility to the spine.
Gross anatomy: components specific to C1 and C2
C1 (Atlas):
No vertebral body or spinous process.
Anterior and posterior arches with lateral masses.
Articulates with occipital condyles for nodding “yes.”
C2 (Axis):
Has the dens (odontoid process) projecting superiorly, acting as a pivot for the atlas (rotation for “no”).
Gross anatomy: components specific C3-C7
C3–C7:
Small body, triangular vertebral foramen.
Bifid spinous process (except C7).
Transverse foramina in transverse processes for vertebral artery passage.
Components specific to thoracic
Thoracic Vertebrae (T1–T12)
Heart-shaped body.
Circular vertebral foramen.
Long, downward-sloping spinous process.
Costal facets (on body and transverse processes) for rib articulation.
Components specific for lumbar
Lumbar Vertebrae (L1–L5)
Large, kidney-shaped body.
Triangular vertebral foramen.
Short, thick spinous process (hatchet-shaped).
Robust transverse processes with no costal facets.
Components specific for sacral
Sacral Vertebrae (S1–S5, fused)
Forms a single triangular bone (sacrum).
Articulates with ilium via sacroiliac joints.
Sacral canal (continuation of vertebral canal).
Prominent anterior sacral promontory.
Large articular surface
on the lateral part for
articulation with the hip
bone
(os ilium).
components specific to coccygeal
Coccygeal Vertebrae (Co1–Co4/Co5, fused)
JOINS TO THE APEX OF THE SACRUM IN A SMALL SYMPHYSIS
Small, rudimentary bones forming the coccyx (tailbone).
No vertebral foramen.
Co1 may have small transverse processes.
Syndesmology; name of the joint types first
- Intervertebral Joints (Symphysis Joints)
- Facet (Zygapophysial) Joints
- Atlanto-Occipital Joint (C0-C1)
- Atlanto-Axial Joint (C1-C2) : medial and lateral
- Sacroiliac
- Lumbosacral Joint (L5-S1)
- Saccrocoxygeal
- Intervertebral Joints (Symphysis Joints)
Name of joint: Intervertebral disc joint
Type of joint: Cartilaginous (symphysis)
Facets: Located between the vertebral bodies (the anterior part), these joints are formed by the intervertebral discs.
Ligaments:
Anterior Longitudinal Ligament (ALL): Runs along the front of the vertebral bodies.
Posterior Longitudinal Ligament (PLL): Runs along the back of the vertebral bodies, within the vertebral canal.
Ligamenta Flava: Connects the laminae of adjacent vertebrae.
Movement: Limited, provides stability while allowing slight movements (flexion, extension, lateral flexion).
Related Muscles: Muscles of the back (erector spinae, multifidus) assist with movement and stabilization.
- Facet (Zygapophysial) Joints (Synovial Joints)
Name of joint: Facet joints (Zygapophysial joints)
Type of joint: plane/gliding synovial j
Facets: The superior and inferior articular processes of adjacent vertebrae form these joints. The facets allow limited gliding movements.
Ligaments:
Capsular Ligament: Surrounds the joint.
Interspinous Ligaments: Between the spinous processes.
Supraspinous Ligament: Runs along the tips of the spinous processes.
Movement: Gliding motion; allows for extension, flexion, lateral bending, and rotation depending on the region of the spine (cervical, thoracic, lumbar).
Related Muscles: Small intrinsic muscles of the back, such as multifidus, rotatores, and interspinales, which help with stability and fine movements.
- Atlanto-Occipital Joint (C0-C1)
Name of joint: Atlanto-occipital joint
Type of joint: Synovial condyloid
Facets: Between the occipital condyles of the skull and the superior articular facets of the atlas (C1).
Ligaments:
Anterior Atlanto-occipital Membrane: Extends from the anterior margin of the foramen magnum to the anterior arch of C1.
Posterior Atlanto-occipital Membrane: Extends from the posterior margin of the foramen magnum to the posterior arch of C1.
Movement: Primarily allows for nodding of the head (flexion and extension).
Related Muscles: Rectus capitis anterior, longus capitis, and sternocleidomastoid muscles contribute to flexion.
- Atlanto-Axial Joint (C1-C2)
Medial Atlanto-Axial Joint
Location: Between the dens (odontoid process) of the axis (C2) and the anterior arch of the atlas (C1).
Type: Pivot joint.
Function: Allows rotational movement of the head, such as shaking your head “no.”
Support: Stabilized by ligaments like:
Transverse ligament of the atlas
Alar ligaments
Apical ligament of the dens
Tectorial membrane
Lateral Atlanto-Axial Joints
Location: Between the superior articular facets of the axis (C2) and the inferior articular facets of the atlas (C1) on each side.
Type: Plane (gliding) synovial joints.
Function: Permits small gliding movements and helps stabilize rotation provided by the medial joint.
Support: Reinforced by the capsule of the synovial joint and surrounding ligaments like: Capsular ligaments
Accessory atlanto-axial ligament
Ligamentum flavum
Related Muscles: Muscles like sternocleidomastoid, splenius capitis, and semispinalis capitis assist with rotation.
Sacroiliac joints
Sacroiliac joint:
plane joint
between the auricular
surfaces of the ilium and sacrum
(fibrocartilage). Anterior-, posterior- and
interosseous sacroiliac ligaments. Very
strong joint without movements.
