Vertebral Column

(# and types)

7 Cervical

12 Thoracic

5 Lumbar

5 Sacrum (segments)

4 Coccyx (segments)

Scoliosis- abnormal lateral curvature

Kyphosis - exaggerated

thoracic curvature

Lordosis- exaggerated lumbar curvature

Body, pedicles, lamina, spinous process, transverse

processes, articular facets and vertebral notches

Transverse foramina; Atlas (C1): no body or

spinous process, condylar facets; Axis (C2): dens

Trapezius, latissimus dorsi, rhomboids, and levator scapulae

Attached to vertebral column, act on the scapula or shoulder joint

Innervated by ventral rami of

cervical spinal nerves and cranial nerve XI

Accessory respiratory muscles

Support and move the vertebral column

Erector Spinae: Control flexion and extend

vertebral column

Splenius: Bilateral contraction extends the head and neck. Unilateral contraction rotates head to

same side

[image]

1: Spinous Process; Muscle attach/Movement

2: Articular Process; Restrict Movement

3: Vertebral Arch; Protects Spinal Cord

4: Vertebral Body; Supports Body Weight

5: Transverse Process; Muscle attach/Movement

Consist of neuronal cell bodies, nerve

fibers and connective tissues of the brain and spinal cord

CNS initiates, regulates and

coordinates body functions. The CNS

communicates with other functional components

of the body via the peripheral nervous system.

Neuronal cell bodies, nerve fibers and connective

tissues outside the CNS.

Connect the CNS and peripheral structures; relay information between the two.

Collections of neuronal cell bodies

outside the CNS are referred to as ganglia.

Transfers signals between skeletal muscles, tendons, joints and skin.

Conveys general sensations of pain,

temperature, touch and proprioception from the PNS to the CNS.

Signals to and from the viscera. Conveys viscera sensations such as distension.

The sympathetic component

elicits “fight or flight” response

 The parasympathetic component controls

digestive functions, slows the heart rate and constricts the pupils.

Anatomic unit of the

nervous system. Consists of a cell

body, dendrite(s) and an axon.

Functionally, neurons

are classified as being either motor

(efferent) or sensory (afferent).

Multipolar and carry information away from the CNS

The cell bodies of somatic motor neurons are located in nuclei within the ventral horn of the spinal cord.

Somatic motor neurons stimulate contraction of skeletal muscle

Unipolar and carry information towards the CNS.

The cell bodies of sensory neurons are clustered in ganglia located outside the CNS.

Ganglia associated with spinal nerves are called dorsal root ganglia (spinal ganglia).

Lies within the vertebral canal extending from the foramen magnum to the level of the intervertebral disc between L1/L2 vertebra.

The spinal cord is surrounded by three meningeal layers 

Spinal nerves (31 pairs) attach to the spinal cord via ventral (motor) and dorsal (sensory) roots and functionally divide it into 31 spinal cord segments.

 Dura mater (outermost), arachnoid mater (intermediate), and pia mater (innermost) and bathed in cerebrospinal fluid (CSF) that fills the subarachnoid space.

Sonsists of white matter (bundles of myelinated axons arranged in discreet fiber tracts) and gray matter (arranged into three major horns: ventral (motor), dorsal (sensory) and lateral (autonomic motor)).

The skin is divided up into segments or slices called

dermatomes

Each dermatome is innervated by the ventral or dorsal rami of spinal nerves

1: Spinous Process

2: Articular Process

3: Transverse Process

4: Vertebral Arch 

5: Nucleous Pulpous

6: Annulus Fibrosus

7: Vertebral Canal

Support and provide mobility to the vertebral column.

The discs are reinforced anteriorly by a broad, thick ligament called the anterior longitudinal ligament that resists hyperextension of the vertebral column and posteriorly by a narrow, thin ligament called the  posterior longitudinal ligament that resists hyperflexion of the vertebral column.

Hyperflexion of the vertebral column compresses the off-center nucleus pulposus forcing it posteriorly.

Nucleus ruptures the anulus fibrosus

posterolaterally due to thinner & weaker ligaments

Commonly performed in diagnosing meningitis.

Access subarachnoid space 

With the spinal cord ending at the level of the L1/L2 IV disc and the dural sac ending at S2, a

needle can be safely inserted through the L3/L4 or L4/L5 interspinous space.

There are 31 pairs of spinal nerves: 8 cervical,

12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

Spinal nerves C1-C7 exit above corresponding vertebral level (i.e., C3 nerve exits through intervertebral

foramen between vertebra C2 and C3). Spinal nerve C8 emerges below C7 vertebra.

The thoracic, lumbar and sacral nerves exit below vertebral level . (i.e., T5 nerve exits through

intervertebral foramen between vertebra T5 and T6).

Attached via a ventral (motor) root and a dorsal

(sensory) root. The ventral root carries only motor nerve fibers and the dorsal root carries only sensory nerve fibers.

These roots merge to form the mixed (motor and sensory fibers) spinal nerve. The spinal nerve divides into two forming a ventral ramus and a dorsal ramus

which are also mixed nerves. 

Dorsal rami innervate three things: skin of the back, true back muscles and zygapophyseal joints.

Ventral rami innervate the remainder of the skin and

skeletal muscles of the neck, trunk and limbs.

Cell bodies (Dendrites) mostly found in the gray matter

Axons are mostly found in white matter

More cell bodies in cervical and lumbar due to innervating nerves for muscles in limbs