How many vertebrae are in the vertebral column and in each region?
5 sacrum (fused)
4 coccyx (1 free, 3 fused)
What is the role of the vertebrae?
1. Protects spinal cord (which resides in the vertebral canal)
2. Transmits all spinal nerves (via the intervertebral foramina)
Where to the spinal nerves exit after leaving the vertebral canal?
-Posterior rami (smaller)-innervates deep back muscles and skin of back, and posterior head and the neck. (sensory info)
-Anterior rami (larger)-innervates all other regions of body, except the head. This means it innervates the extrinsic back (superficial and intermediate) and the Upper & lower limbs (motor info)
What is a dermatome?
The region of skin supplied by 1 spinal nerve
What comprises the axial skeleton?
Vertebral column, cranium, rib cage and sternum.
All other bones are part of the appendicular skeleton
How do the size of vertebrae change from cervical region to the coccyx region?
Vertebrae are small in the upper cervical region-->become progressively larger caudally (towards the tail end) until the 2nd SACRAL vertebra, which then tapers off-->The FIRST coccygeal vertebra flairs outward and then tapers off caudally
Describe the curvatures of the vertebral column
Primary curves-develop BEFORE birth (curved like an embryo)
Primary curves: Thoracic KYPHOSIS and Sacral KYPHOSIS (concave anterior)
Secondary curvatures-develop AFTER birth
cervical LORDOSIS and lumbar LORDOSIS
An increase in thoracic curvature (hunchback) so there is increase in posterior convexity. Contributing factors: Bad posture, aging, compression fracture of thoracic vertebral body due to osteoporsis
-Kyphosis worsens after a patient with osteoporosis suffers compression fracture of vertebral body.
Describe excessive lordosis
An increase in the lumbar curve (sway back) so there is an increase in posterior concavity.
Articular processes-synovial joints limit or guide motion
Clinical: Spina bifida
Disorder where 2 sides of vertebral arches fail to FUSE during development, resulting in an open vertebral canal.
-Spina bifida occulta (hidden) is a defect of bone only. Asymptomatic. Tuft of hair on skin over the defect may be the only sign.
The C7 spinous process, the vertebra prominens
What are the 3 movements of the vertebral column?
Extension (back bending)
Flexion (forward bending)
Lateral flexion (side bending)
What are the joints of vertebral column
Symphysis (secondary cartilaginous) Joints- include the vertebral bodies and fibrocartilage intervertebral disc (the intervertebral disc occupies space between discs and allows MOVEMENT between adjacent vertebral bodies.
Zygapophysial joints-Are synovial joints
Uncovertebral joints-in CERVICAL spine ONLY
Where is the zygapopysial joint?
betwen superior and inferior articular processes. It is surrounded by joint capsule (see image on slide#31)
In this joint, bones are united by a capsule made up of an outer fibrous layer and inner synovial membrane.
-Synovial membrane: a vascular connective tissue that produces synovial fluid which lubricates and nourishes articular cartilage.
-Fibrous capsule has many nerve endings for pain and proprioception
Describe the Intervertebral disc
the SYMPHYSIS between adjacent vertebral bodies is formed by a layer of hyaline cartilage on each body and an intervertebral disc, which lies between the layers.
An outer anulus fibrosus
-Concentric lamellae of fibrocartilage (alternating fiber direction)
An inner nucleus pulposus. * Degenerative change to anulus fibrosus can lead to herniation of nucleus puposus
-Gelatinous; remnant of embryonic notochord
What does the intervertebral disc do?
-Absorbs shock (specifically, the nucleus pulposus absorbs shock during axial compression)
-Allows movement between vertebrae
In what regions of the back is the anterior part of the intervertebral disc thicker than the posterior?
Lumber & Cervical region
What form of imaging reveals good images of soft tissue, such as intervertebral discs?
-Good for viewing disc herniations
Herniated Disc (middle black area)
-Compare herniation to disc above with the defined nucleus puposus and annulus fibrosus
How does a herniated disc affect spinal nerves above and below the vertebrae?
Herniated intervertebral disc compresses the spinal nerve BELOW the named vertebra (Ex: L4/5 disc compresses L5)
-In lumbar region, this occurs because of the oblique (downward) angle of nerves exiting canal
-In cervical region, this is also true, even though nerves enter more horizontally.
There are 8 cervical spinal nerves for only 7 cervical vertebrae. This is because nerves exit ABOVE the vertebrae of the same name (except the C8 spinal nerve)
Uncoverterbral joints (Joints of Luschka) are in:
-C3-C6 Ucinate processes of verterbra below articulates with lateral margins of vertebral bodies above.
-Articular cartilage & fluid filled
-Site of arthritic changes
-Found in CERVICAL vertebrae ONLY
Both ligaments attach to verterbral bodies, intervertebral disc and run the length of verterbral column
Ligamentum flavum is in yellow
It connects adjacent laminae
Consists of Elastic Tissue thus it resists flexion of the vertebral column and aids in extension.
Where is the Interspinous ligament and Supraspinous ligament
Interspinous ligament (between arches)
Supraspinous ligament (outside of arch)
(see page #84 of book!)
What limits full flexion (bending forward) of the vertebral column?
-Posterior longitudinal ligament
-Facet joint capsules
The long ligament in the middle (between the cut pedicles)
-It is more narrow than the anterior longitudinal ligament (over the bodies) thus it provides less support to the intervertebral discs.
*Disc herniation frequently occurs in posterolateral direction (in the space devoid of ligamentous support. THIS IS A VULUNERABLE REGION!
-Ligamentum Nuchae (nuchal ligament)- It is an extension of supraspinous ligament.
*Ligamentum nuchae is visible in mid cervicle region! See slide 51!
(see slide 50)
What limits extension (bending backwards) in vertebral column?
The anterior longitudinal ligament
-Traumatic hyperextension will tear ligament
-anterior body muscle also limits extension
They are PLANE joints between articular processes of adjacent vertebrae
Commonly referred to as "Facet Joints"
What type of joints are zygapopysial joints?
Synovial joints and thus have an articular capsule.
Guide/limit movement between vertebrae
*The angle of the facets varies regionally in vertebral column and is a major factor influencing the degree of motion in each region (See fig. 2.28 in book)
Explain zygapophysial joints in the cervical spine
With what joint does doing (up and down) occur and what cervical vertebrae?
The atlantoccipital joint-Nodding (flexion/extension) occurs between the occipital (skull) and CI. There is also some lateral flex at the atlantooccipital joint.
The occipital condyles (condyles are the round ends of bone, usually part of a joint, or articulation with another bone) articulates with the Superior articular facets of the atlas (C1).
At the Atlantoaxial joint (AA, C1-C2) what type of motion occurs?
At the AA joint, rotation is the ONLY motion.
Rotation here is limited by the Alar Ligaments (alar ligaments attach the dens to the margins of the foramen magnum of the skull)
About 1/2 of available rotation in cervical region occurs at AA joint.
The Alar Ligaments attach the dens to the margins of the foramen magnum of the skull (hole under skull).
The alar ligaments LIMIT rotation of the head
The transverse ligament of the atlas keeps the dens of C2 from moving posterior.
*See page printed from lecture (slide 59)
What can cause spinal cord compression?
-Dislocation secondary to a rupture of the transverse ligament
The tectorial membrane is a superior extension of the posterior longitudinal ligament.
When the tectorial membrane is reflected posteriorly, the cruiciform and alar ligaments are seen
(for bigger pic. see slide 61)
Vertebral Abnormalities: What is Lumbarization
Vertebra normally destined to be the 1st sacral vertebra does not fuse to the rest of the sacrum-so there are 6 lumbar (non fused) and only 4 fused sacral vertebrae.
*If you are given a photo of sacrum and asked if it is normal, COUNT the # of vertebrae and make sure you don't have too few or too many
Vertebral Abnormalities: Sacralization
Vertebra that is normally destined to be L5 fuses to sacrum so there now 6 fused bones of the sacrum and only 4 lumbar vertebrae.
What is the difference between Spondylolysis and Spondylolisthesis?
In Spondylolysis, scottie dog appears to be wearing a collar (at the Isthmus)
In Spondylolisthesis, scottie dog appears decapitated (completely broken at Isthmus)
*The fracture itself is called Spondylolysis, while the actual slippage is called Spondylolisthesis.
It is the forward displacement of 1 vertebrae relative to the one below it.
It occurs because of a defect or bilateral fracture of the pars interarticularis (interarticular parts of the vertebral laminae).
Oblique radiograph reveals Scotty Dog with a collar around it's neck.
This image is a normal radiograph therefore no spondylolisthesis
The Pars Interarticularis (the scotty dog has collar or broken neck) is fractured.
If the facture is bilateral and vertebra slips forward relative to vertebra below, this is called Spondylolisthesis (scotty dog appears decapitated)
1. Have transverse processes with foramina (foramen transversarium) for passage of vertebral artery, EXCEPTION: C7 has foramina, but the vertebral artery does NOT pass through.
2. Large triangular verebral foramina-for passage of the largest part of the spinal cord.
3. C3-C6 bifid spinous processes and uncinate processes.
4. C7 has the longest process in cervical spine. It's called the vertebra prominens.
1. No body, but has lateral masses that have superior articular surfaces for articulation with the occipital condyles of the skull.
2. Has posterior and anterior tubercle but NO spinous process
3. Has a articular facet for the dens of C2
4. Has trasnverse processes with foramina
1. Large, centrally located process (dens, odontoid process) projecting cranially from its body. The dens has a facet that articulates with anterior arch of the atlas at the Atlantoaxial Joint (AA joint)
2. Large bifid spinous process
Use an x-ray beam to check a patient for fracture in dens
-The artery passes through transverse foramina of the upper 6 cervical vertebrae and passes over the posterior arch of atlas
Summary of cervical vertebrae (1)
-All have transverse processes with foramina (for passage of vertebral artery). Remeber verterbral artery does not pass through foramina C7
-Have Large triangular vertebral foramina (for passage of largest region of spinal cord)
Summary of cervical vertebrae (2)
C1 Atlas- No body, has lateral masses, No spinous processes, has tubercles. Supports skull at atlantooccipital joint, has facet for articulation with dens of C2
C2 Axis-Has large centrally located process (dens) that has a facet that articulates with anterior arch of the atlas at atlantoaxial joint (AA)
-C3-C6 have bifid spinous process, uncus (uncinate process) of body
-C7 has longest spinous process in cervical spine, the vertebra prominens
-Superior costal facet articulates with rib of the SAME vertebra level (2nd rib with 2nd vertebra)
-Inferior costal facet articulates with rib 1 level below
-Articular facet on with transverse processes articulates with tubercle of the corresponding rib
Summary of thoracic vertebrae
-It typically articulates with ribs through 2 PARTIAL costal facets (demi facets) on each side of the vertebral body (for head of rib) and a facet on each transverse process (for tubercle of rib)
-Long spinous processes that slope inferiorly
-Vertebral foramina are circular and smaller than cervical vertebrae.
What are the exceptions to the normal thoracic vertebrae?
Atypical ribs 11 and 12 and their corresponding thoracic vertebrae. They articulate only with the heads of their own ribs. They lack transverse costal facets and have one a single complete facet on each side of their bodies.
Describe lumbar vertebrae
-Has largest vertebral body
-Has mammillary bodies and accessory processes
-Short blunt spinous process
-5 fused sacral vertebrae make up sacrum
-the superior articular facets articulate with 5th lumbar vertebra
-sacral hiatus is seen in posterior view of sacrum. It is sometimes used to deliver epidural anesthesia
-Inferolateral angle is palpable and used during OMM
Summary of Sacrum
-composed of 5 fused sacral vertebrae
-median crest (fused spinous processes)
-contains sacral canal (continuation of vertebral canal) where the cauda equina resides
-4 pairs of anterior&posterior sacral foramina (for exit of dorsal and ventral primary rami of 1st-4th sacral spinal nerves
-2, L-shaped facets (auricular surface) for articulation with pelvic bones at sacroiliac joint
-promontory, ala, sacral cornu (horn), sacral hiatus, sacral canal and intervertebral foramen, inferior lateral angl
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