Peripheral nerves.
Ganglion or ganglia .
The small groups of nerves outside the brain are called ganglia. Ganglia are clusters of nerve cell bodies (neurons) that are part of the peripheral nervous system and can be found along nerve pathways.
Spinal nerves exit the vertebral column through small openings called intervertebral foramina located between adjacent vertebrae.
Spinal nerves exit the vertebral column through small openings called intervertebral foramina. Once they have exited, these nerves carry sensory information from the body to the spinal cord and transmit motor signals from the spinal cord to the muscles, allowing for movement and sensation.
The dorsal rami are small branches of spinal nerves that emerge from the spinal cord and supply the skin and muscles of the back. They are responsible for providing sensory and motor innervation to the back of the body.
Nerves are pretty small. Consider that the human spinal cord, with its many, many nerve pathways, is under 10 mm in diameter at it widest point. Individual nerves have diameters ranging from perhaps 4 to 100 micrometers, depending on the location.
Not much information here in context to efficiently answer the question but I will try. The spinal cord generally ends (terminates) around the L1 vertebral level in the lumbar spinal column give or take a level or so in normal humans. After this, small spinal nerves continue down in a sac and exit the lumbar and sacral spine to innervate the pelvis and lower extremities.
terminal buttons, the gap between the nerves is the synapse. The small parts at the top of the nerve cell are called dendrites
Anencephaly is when a baby is born with a small or missing brain. Spina Bifida is a birth defect which causes a baby to be born with a hole in the back and/or missing bones (called "spinous processes") in the spine, and the spinal cord and nerves may be seen through a hole in the back or sticking out of the back. It does not cause a small or missing brain.
Vertebra.
Many patients with back pain, leg pain, or weakness of the lower extremity muscles are diagnosed with a herniated disc. When a disc herniation occurs, the cushion that sits between the spinal vertebra is pushed outside its normal position. A herniated disc would not be a problem if it weren't for the spinal nerves that are very close to the edge of these spinal discs.The spinal disc is a soft cushion that sits between each vertabrae of the spine. This spinal disc becomes more rigid with age. In a young individual, the disc is soft and elastic, but like so many other structures in the body, the disc gradually looses its elasticity and is more vulnerable to injury. In fact, even in individuals as young as 30, MRIs show evidence of disc deterioration in about 30% of people.As the spinal disc becomes less elastic, it can rupture. When the disc ruptures, a portion of the spinal disc pushes outside its normal boundary--this is called a herniated disc. When a herniated disc bulges out from between the vertebrae, the spinal nerves and spinal cord can become pinched. There is normally a little extra space around the spinal cord and spinal nerves, but if enough of the herniated disc is pushed out of place, then these structures may be compressed.When the herniated disc ruptures and pushes out, the nerves may become pinched. A herniated disc may occur suddenly in an event such as a fall or an accident, or may occur gradually with repetitive straining of the spine. Often people who experience a herniated disc already have spinal stenosis, a problem that causes narrowing of the space around the spinal cord and spinal nerves. When a herniated disc occurs, the space for the nerves is further diminished, and irritation of the nerve results.SymptomsElectric Shock PainPressure on the nerve can cause abnormal sensations, commonly experienced as electric shock pains. When the compression occurs in the cervical (neck) region, the shocks go down your arms, when the compression is in the lumbar (low back) region, the shocks go down your legs.Tingling & NumbnessPatients often have abnormal sensations such as tingling, numbness, or pins and needles. These symptoms may be experienced in the same region as painful electric shock sensations.Muscle WeaknessBecause of the nerve irritation, signals from the brain may be interrupted causing muscle weakness. Nerve irritation can also be tested by examining reflexes.Bowel or Bladder ProblemsThese symptoms are important because it may be a sign of cauda equina syndrome, a possible condition resulting from a herniated disc. This is a medical emergency, and your should see your doctor immediately if you have problems urinating, having bowel movements, or if you have numbness around your genitals.All of these symptoms are due to the irritation of the nerve from the herniated disc. By interfering with the pathway by which signals are sent from your brain out to your extremities and back to the brain, all of these symptoms can be caused by a herniated disc pressing against the nerves.
From the Related link below:Myelomeningocele - most severe form with spinal cord exposureMeningocele - a severe form with the meninges protruding outside the spine under the skin of the backOccult spina bifida - the mildest form with often a small spinal defect often in the lower back