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Spinal Cord and Spinal Nerves:
The spinal cord and spinal nerves (as well as the cranial nerves) contain neural circuits bringing sensory information up
to the brain (afferent) and motor signals out, away from the brain to the body (efferent).
The CNS is protected by bone (skull and vertebral column); the meninges; and finally it is surrounded and cushioned by
the CSF. You can also imagine that the immune system acts to protect the nervous system.
SPINAL CORD:
The spinal cord is found within the vertebral canal, the hollow tube created by stacking all the vertebral foramen up.
Spinal cord: The major column of nerve tissue that is connected to the brain and lies within the vertebral canal and from
which the spinal nerves emerge. Thirty-one pairs of spinal nerves originate in the spinal cord: 8 cervical, 12 thoracic, 5
lumbar, 5 sacral, and 1 coccygeal. The spinal cord and the brain constitute the central nervous system. The spinal cord
consists of nerve fibers that transmit impulses to and from the brain. Like the brain, the spinal cord is covered by three
connective-tissue envelopes called the meninges. The space between the outer and middle envelopes is filled with
cerebrospinal fluid (CSF), a clear colorless fluid that cushions the spinal cord.
Meninges: The three membranes that cover the brain and spinal cord (singular: meninx).
The outside meninx is called the dura mater, and is the most resilient of the three. The center layer is the arachnoid
membrane and the thin innermost layer is the pia mater.
epidural space the space between the dura mater and the lining of the vertebral canal.
subarachnoid space the space between the arachnoid and the pia mater.
subdural space the space between the dura mater and the arachnoid.
The pia mater and arachnoid considered as one unit enveloping the brain and spinal cord. Also called pia-arachnoid.
denticulate ligament: a serrated, shelflike extension of the spinal pia mater projecting in a frontal plane from either side
of the cervical and thoracic spinal cord; its approximately 21 pointed processes fuse laterally with the arachnoid and
dura mater midway between the exits of the roots of adjacent spinal nerves, with the highest process attaching
immediately superior to foramen magnum.
Spinal Cord Cross Section (Model)
1.
2.
3.
4.
5.
6.
Anterior (Ventral) Median Fissure
White Matter
Ventral Root (Motor)
Gray Matter
Dorsal Root Ganglia
Dorsal Root (Sensory)
7.
8.
9.
10.
11.
12.
Posterior (Dorsal) Median Sulcus
Central Canal
Posterior Gray Horn (Sensory)
Gray Commissure
Anterior Gray Horn (Motor)
Spinal Nerve
Structures:
1. Posterior Median Sulcus
2. Gray Commissure
3. Central Canal
4. Anterior Median Fissure
Gray Matter:
5. Posterior Horn
6. Lateral Horn
7. Anterior Horn
White Matter:
8. Posterior Funiculus
9. Lateral Funiculus
10. Anterior Funiculus
Optional Features (you will not need to find these on the slide):
11. Pia Mater
12. Subarachnoid Space
13. Dura & Arachnoid Maters
1.
2.
3.
4.
Posterolateral sulcus
Dorsal rootlets
Dorsal root (spinal) ganglion
Ventral ramus
1.
2.
3.
4.
5.
6.
Intervertebral disc
Vertebral body
Dura mater
Extradural or epidural space
Spinal cord
Subarachnoid space
1) Dorsal root ganglion
2) Dorsal root
3) Lateral horn
4) Posterior horn
5) Posterior median sulcus
6) Epidural space
7) Central canal
8) Posterior funiculus
9) Lateral funiculus
10) Anterior median fissure
11) Anterior funiculus
12) Anterior horn
13) Ventral root
1:Anterior Median Fissure; 2:Pia Mater; 3:Denticulate Ligaments;
4:Arachnoid and Dura Mater (reflected); 5:Spinal Blood Vessel;
6:Dorsal Root of 6th Cervical Nerve; 7:Ventral Root of 6th Cervical Nerve.
Nerve Plexus
Cervical Plexus
Peripheral Nerves
Phrenic Nerve (diaphragm)
Median nerve
Brachial Plexus
Radial nerve
Musculocutaneous nerve
Lumbar Plexus
Femoral nerve
Sacral plexus
Sciatic nerve