Back FA Notes Flashcards
General Structure, Regions, and Functions of the Vertebral Column
C1 - Atlas
C2 - Axis
C1-C7 - Cervical Vertebrae
T1-T12 - Thoracic Vertebrae (articulate with ribs)
L1-L5 Lumbar Vertebrae
Sacrum (S1-S5) - fused completely
Coccyx (Co1-Co4)
Curvatures
Adult - Cervical (2º)
Thoracic (1º)
Lumbar (2º)
Sacral (1º)
Lordosis - Secondary Degree
Kyphosis - Primary Degree
Purpose of curvature is for shock absorption, and gives us a center of gravity over midfoot
What are the common abnormal curvatures?
Excessive kyphosis (dowagers hump),
Excessive lordosis (pregnancy, obesity) - weak abs, glutes, hamstrings
Scoliosis - congenital, trauma, idiopathic. More common in females
Movements of the vertebral column
The cervical and lumbar are the areas of flexion and extension. Very little movement in the thoracic spine.
Lateral flexion - Fairly uniform
Rotation - Cervical, and a little lumbar
- Which feauteres allow movement
- Which ligaments resist movement
- Which muscles resist movement
What is the normal anatomy of a typical vertebra
Vertebral Body - weight bearing
Vertebral Arch - everything posterior to the vertebral body
Vertebral foramen - Spinal cord runs through here
Transverse process - muscle and ligament attachment
Spinous Process - muscle and ligament attachment
Intervertebral Disc - joint between two vertebrae that allows for movement
Superior and Inferior Articular process - Stabilize location & relationship, and allow certain movements, disallow others
Joints of Vertebral Column
Intervertebral Joint - Between two vertebrae,
Zygapophyseal joint - limits movement between adjacent vertebrae
Intervertebral foramen - hole between superior vertebral notch, and the inferior vertebral notch. They come together to form the intervertebral foramen to where the spinal cord emerges.
Cervical Specializations - Atlas
C1
Articulates with the occipital condyles of the skull
No vertebral Body
Transverse Foramen have the vertebral arteries and veins run through it
No spinous process
Dens - forms the axis to how the head turns. It is the vertebral body of C2, but fused with C1
Cervical Specializations - axis
Has a Dens - rod like structure
Superior articular facet - horizontal, flat for rotation of head
inferior articular facet - slanted
has everything else the same as other cervical vertebrae
Vertebral Specializations - Cervical
Body is oval shaped
Vertebral Foramen is triangular
Spinous process - bifid
Transverse process with groove (cuplike) for spinal nerve
Zygapophyseal joint - relatively horizontal
Vertebral specializations - C7
C7 - vertebra prominens
has a long spinous process
Specialized joints of the cervical spine
Atlantoaxial joints - medial, and two lateral joints
Atlanto-occipital joints - two of them on the axis
Vertebral Specializations - Thoracic
They have costal facets, named for location on vertebral body. Superior/Interior facets form the zygapophyseal joint)
Body is heart shaped
Long and sloping spinous process (limits extension)
Circular and round vertebral foramen
Zygapophyseal joint is vertical (limits all rotation and flexion/extension, but allows lateral movements)
facets face anterior / posterior
Relatively stable - to protect vital organs
Vertebral body becomes larger as it moves inferior
Vertebral Specializations - Lumbar
Spinous Process - blunt and strong
Vertebral Body - large, kidney shaped
Vertebral Foramen - small and triangular
Costal Process - transverse process & rib fusion
Articular Facets - large, strong, forms zygapophyseal joint
Zygapophyseal Joint - Vertical, and facets face medially / laterally for flexion and extension, and rotate more than thoracic region.
Vertebral Specialization - Sacrum
- Fusion of vertebrae, forms the sacrium
- lateral parts make robust transverse process
- little nubs are the spinous process
- superior articular facet helps maintain stability
- wing of sacrum (ala), sacral tuberosity and auricular surface is on the posterior side, and its part of the sacroiliac joint
- sacral foramina (sacral spinal nerves come out of here)
- sacral promontory sticks out
- big hole runing through called the sacral canal
- sacral hiatus
- sacrococcygeal joint
- coccyx
How does intervertebral disc structure contribute to their function
- Intervertebral disc are there for shock absorption
- Reduces friction
- limits excessive movement
- more inferior -> thicker and bigger
- Nucleus pulposus (gel like, absorbs H2O) - main job is for shock absorption and friction reduction
- Anulus fibrosus made up of collagen fiber rings, every fiber layer has slightly different orientation to strengthen it. Main job is to limit excessive movement and bring back to neutral.
What happens during a intervertebral disc herniation
- Happens when annulus fibrosis to rupture, and ooze out
- Happens during excessive lifting
- Symptoms are pain, numbness
- The fluid pushes on the nerve (compression), which activates sensory pain neurons.
- Happens primarily in the cervical and lumbar regions due to the excessive mobility of those vertebrae
Ligaments that stabilize the atlanto-occipital and atlantoaxial joints
- atlanto-occipital joint being held together by the atlanto occipital membrane, and tectorial membrane.
- They are to resist excessive movement
- atlantoaxial joints are. being held together by the transverse ligament of the atlas.
- transverse ligament of atlas and longitudinal fascicles together are called the cruciform ligament. It holds the dens up to the
- Alar ligaments are limiting excessive movement
What ligaments stabilize the vertebral column?
Anterior longitudinal ligament - limits/resists extension
Posterior longitudinal ligament - limits/resists flexion
Ligamenta flava - run between the lamena of one vertebra to the lamena of the next verebtra. This resists/limits flexion. It also is the posterior lateral wall of the vertebral canal.
Interspinous ligaments - resists/limits flexion
Supraspinous ligaments - runs continuously on the posterior edge of the spinous processes and resists flexion. Becomes the nuchal ligament in the posterior neck region.
Anatomy of the spinal nerves
Anterior
-motor commands
- Anterior Median fissure, deep and broad
Posterior
- Sensory
- Posteriorolateral Sulci is where the posterior roots come from
- Posterior Median fissure, shallow
Spinal nerve
- mixed, gets input from both posterior and anterior roots
Anterior Ramus
- comes from the Spinal Nerve, splits off into Anterior AND Posterior Ramus
- More dominant, supports the Cervical Plexus, Brachial Plexus (upper limb), Intercostal Nerves (Thorax and Abdomen), Lumbar Plexus (lower limb, abdomen and pelvis), Sacral Plexus (pelvic lower limb).
Spinal Cord Segments and Spinal Nerve Classification
-Nerve C1 emerges between the skull and C1 vertebra
-C2 to C7 emerge superior to pedicles
- Nerve C8 emerges inferior to pedicle of CVII vertebra
- Nerves T1 to Co emerge inferior to pedicles of their respective vertebrae
What does each spinal nerve innervate (somatic)
Dermatomes - Region of skin each spinal nerve intervates
Autonomous Zone 0 region of dermatome with no overlap with neighboring dermatome
Vertebral Column Vasculature (arteries)
Thoracic Aorta -> Posterior Intercostal Arteries -> Segmental Arteries
Abdominal Aorta -> Subcostal & Lumbar Arteries -> Segmental Arteries
Aortic Arch -> Subclavian Artery -> Vertebral Arteries -> Segmental Arteries
Vertebral Vasculature (Veins)
- Around vertebral body is external vertebral plexus
- around vertebral canal is internal vertebral plexus -> Internal Jugular Vein
Suboccipital Triangle
Rectus Capitis Posterior Minor
