Vertebral Column + CNS

2 Parts of the Skull

1. Neurocranium

2. Viscerocranium

Neurocranium

Protects the brain and brainstem

Viscerocranium

Face of the skull

8 Bones of the Neurocranium

1. Frontal

2. Ethmoid

3. Sphenoid

4. Occipital

5. 2 Parietal

6. 2 Temporal

What type of joints connect the bones of the neurocranium?

Sutures (strong fibrous joints

Coronal Suture

Frontal to parietal bones

Sagittal Suture

Left and right parietal bones

Squamous Suture

Temporal to parietal bones

Lamboid Suture

Occipital to parietal bones

14 Bones of the Viscerocranium

1. Mandible

2. Vomer

3. 2 Maxilla

4. 2 Inferior nasal conchae

5. 2 Zygomatic

6. 2 Palantine

7. 2 Nasal

8. 2 Lacrimal

3 Depressions of the Cranial Cavity

1. Anterior cranial fossa

2. Middle cranial fossa

3. Posterior cranial fossa

Anterior Cranial Fossa

Supports the frontal lobe

Middle Temporal Fossa

Supports the temporal lobe

Posterior Cranial Fossa

Supports cerebellum and brainstem

Primary vs Secondary Vertebral Curvatures

- Lumbar and cervical go from primary to secondary

- Thoracic and sacral stay in primary

Foramen Transversarium

Unique to cervical vertebrae

- Openings in the transverse processes

Where do the vertebral aa. pass through alongside cervical vertebrae?

Foramen transversarium

Bifid

Cervical vertebrae's have 2 clefts of their spinous processes

Why is the vertebral canal bigger in the cervical vertebrae?

To create more space for the cervical enlargement

Another Name for C1

Atlas

Does C1 have a vertebral body?

No

- It has a bigger articulate surface to articulate with the occipital condyle

Why are the C1 facets for the occipital condyle curved anteriorly and posteriorly?

To allow for skull flexion and extension

Another name for C2

Axis

Which vertebrae has the dens?

C2

- Allows for L and R rotation of the skull

Where does the dens of C2 line up with on C1?

Where the vertebral body of C1 would be if C1 had one

Main Cervical Movements (3)

1. Flexion/Extension

2. Lateral flexion

3. Minimal rotation (below C2/rotation mostly occurs between C1/C2)

Which vertebrae are mostly responsible for curvature in scoliosis?

Thoracic

Thoracic vertebrae have 12 ___ for the 12 ___?

Facets, ribs

3 Main Movements of the Thoracic Region

1. Rotation

2. Minimal lateral flexion

3. Minimal flexion/extension

2 Unique Properties of the Lumbar Vertebrae

1. Giant vertebral body for weight bearing

2. Maxillary processes

Main Movements in Lumbar Region

1. Flexion/Extension

2. Lateral flexion

3. Minimal rotation

Do the sacrum and coccyx have intervertebral foramen?

No

Where do ventral rami pass through in the sacrum/coccyx?

Anterior sacral foramina

Where do dorsal rami pass through in the sacrum/coccyx?

Posterior sacral foramina

Between C2-S1 all bodies articulate by ___?

Symphyses (secondary cartilaginous)

- AKA intervertebral discs

Is there an intervertebral disc between C1/C2?

No

2 Components of Intervertebral Discs

1. Anulus fibrosus

2. Nucleus pulposus

Anulus Fibrosus

Outer ring of fibrocartilage arranged in rings

Nucleus Pulposus

Gelatinous core of intervertebral disc

Anterior Longitudinal Ligament

- Runs from occipital bone to sacrum (entire VC length)

- 3x as wide as PPL

What does the Anterior Longitudinal Ligament prevent?

Hyperextension of the spine and anterior herniation of intervertebral discs

Posterior Longitudinal Ligament

- Spans from the sacrum to C2 and then becomes the tectorial membrane

- Thinner and weaker than the ALL

What movement does the Posterior Longitudinal Ligament prevent?

Hyperflexion of the spine

In what direction do most herniated discs occur?

Posteriorly and laterally because the PPL doesn't cover the entire posterior surface of the vertebral column

Zygapophysial Joint (Facet)

Joint between adjacent superior and inferior articular processes

- Each joint is surrounded by a thin capsule

The ___ of articular processes dictates the main movements of the vertebral region?

Orientation

What type of joint is the Zygapophysial?

Synovial, plane

5 Extrinsic Ligaments of the Vertebral Column

1. Ligamenta flava

2. Intertransverse ligament

3. Interspinous ligament

4. Supraspinous ligament

5. Nuchal ligament

Ligamenta Flava

(Yellow)

- Paired ligaments attaching adjacent laminae

What movement does Ligamenta Flava limit?

Flexion of the vertebral column

Intertransverse Ligament

Connects adjacent transverse processes

- Weak

Interspinous Ligaments

Connects adjacent spinous processes

- Weak

Supraspinous Ligament

Connects tips of spinous processes from C7 to sacrum

- Strong

Nuchal Ligament is a continuation of the ___?

Supraspinous ligament

Nuchal Ligament

Spans from C7 to the external occipital protuberance

- Strong

- Site of muscle attachment

What movement does the nuchal ligament limit?

Flexion

Atlanto-Occipital Joint

Between occipital condyles and superior articular facets

Main Movements of the Atlanto-Occipital Joint

- Main are flexion/extension

- Some lateral flexion

What type of joint is the Atlanto-Occipital?

Synovial, condyloid

What 2 membranes reinforce the Atlanto-Occipital Joint?

The anterior and posterior atlanto-occipital membranes

- Attach the occipital bone to C1

- Have holes for the vertebral a. to pass through

3 Articulations of the Atlanto-Occipital Joint

1. Lateral joints (2)

2. Medial joint

Lateral Joints of the Atlanto-Occipital Joint

Between inferior articular surfaces of C1 and superior articular surfaces of C2

Lateral Joints of the Atlanto-Occipital Joint - Type

Synovial, plane

Median Joint of Atlanto-Occipital Joint

Between the dens of C2 and the anterior arch of C1

Median Joint of Atlanto-Occipital Joint - Type

Synovial, plane

Main Movement of All 3 Atlanto-Occipital Joint Articulations

Rotation around the axis

4 Ligaments of the Atlanto-Axial Joint

1. Transverse ligament of atlas

2. Cruciate ligament

3. Alar ligament

4. Tectorial membrane

Transverse Ligament of Atlas

Maintains the position of the dens against C1

Cruciate Ligament

Longitudinal bands + transverse ligament

- Holds C1+C2 and C2 to the skull

Alar Ligaments

Connects the dens to the occipital condyles

Tectorial Membrane

Body of C2 to superior margin of foramen magnum (superior termination of PPL)

3 Parts of the Brain

1. Cerebrum

2. Brainstem

3. Cerebellum

3 Parts of the Brainstem

1. Midbrain

2. Pons

3. Medulla oblongata

4 Lobes of Each Cerebral Hemisphere

1. Frontal

2. Parietal

3. Temporal

4. Occipital

2 Main Sources of Blood Supply to the Brain

1. Vertebral a.

2. Carotid a.

How does the internal carotid a. enter the cranial cavity?

Through the carotid canal

Before supplying the cerebrum, the internal carotid a. gives off the ___, which supplies the eye?

Opthalmic a.

4 Branches of the Internal Carotid a.

1. Anterior cerebral a.

2. Middle cerebral a.

3. Anterior communicating aa.

4. Posterior communicating aa.

Where does the vertebral a. travel in the neck?

Through the transverse foramina of C1-6 vertebrae

How does the vertebral a. enter the skull?

Through the foramen magnum along with the spinal cord

2 Branches off of the Vertebral a.

1. Basilar a.

2. Posterior cerebral a.

5 aa. of the Circle of Willis

1. Anterior communicating a.

2. Anterior cerebral aa.

3. Internal carotid a.

4. Posterior communicating aa.

5. Posterior cerebral aa.

Spinal Cord Length

Spans from the foramen magnum to the L1/2 vertebrae

Where does the spinal cord have enlargements?

Cervical and lumbosacral regions

___ Pairs of Spinal nn.

31

- 8 cervical

- 12 thoracic

- 5 lumbar

- 5 sacral

- 1 coccygeal

Cervical nn. are named for the pedicle of the vertebrae they exit ___?

Above

All other nn. that are not cervical are named for the pedicle of the vertebrae that they exit ___?

Beloww

Is there a C8 spinal n.?

No, but there is a C8 vertebrae

Conus Medullaris

Where the spinal cord tapers between the L1/2 vertebrae

Filum Terminale

Extends from the conus medullaris, formed by the innermost connective tissue (pia mater) and attaches to the coccyx

Cauda Equina

All of the nerve roots for spinal nn. below the end of the spinal cord

3 aa. that supply the spinal cord?

1. Anterior spinal a.

2. 2 Posterior spinal aa.

How far do the anterior and posterior spinal aa. span?

The entire length of the spinal cord

- Branch from the vertebral a. at the medulla

Segmental Medullary aa.

Branch off various branches of the aorta and reinforce the spinal aa. throughout the length of the spinal cord

Radicular aa.

Supply nerve roots

- Anterior aa. supply ventral roots

- Posterior aa. supply dorsal roots

2 Layers of Dura Mater

1. Periosteal (superficial)

2. Meningeal (deep)

Subarachnoid Space

Contains CSF and cerebral av.

Pia Mater

On the surface of the brain

Where does CSF come from?

Blood

How many layers of dura mater are around the spinal cord?

One