Atlas (C1)
Nerve supply: Suboccipital nerve — innervates muscles at the base of the skull.
Why it matters: The atlas supports the skull and allows nodding motion. Misalignment here can restrict blood flow to the brain and affect the entire central nervous system.
Axis (C2)
Nerve supply: Greater occipital nerve — sensory to the scalp.
Why it matters: C2 allows head rotation. Subluxation can contribute to sinus congestion, eye problems, and equilibrium issues.
C3 Vertebra
Nerve supply: Third cervical nerve — feeds the cheeks, outer ear, and facial bones.
Why it matters: Issues here can affect the trigeminal nerve distribution, contributing to facial pain and recurring sinus issues.
C4 Vertebra
Nerve supply: Phrenic nerve originates here (C3–C5) — controls the diaphragm.
Why it matters: C4 subluxation can directly affect breathing mechanics and contribute to chronic neck tension.
C5 Vertebra
Nerve supply: C5 nerve root — contributes to deltoid and biceps function.
Why it matters: Problems here often show as shoulder weakness and pain radiating down the outer arm.
C6 Vertebra
Nerve supply: C6 nerve root — feeds wrist extensors and biceps.
Why it matters: One of the most commonly herniated cervical discs. Can mimic carpal tunnel syndrome with numbness in the thumb and index finger.
C7 Vertebra
Nerve supply: C7 nerve root — the largest cervical nerve, feeds the triceps.
Why it matters: The "vertebra prominens" — the bump you feel at the base of your neck. Issues here affect grip strength and can cause pain radiating down the back of the arm.
C8 Nerve Root
Nerve supply: C8 nerve root (exits below C7) — feeds hand intrinsic muscles.
Why it matters: There is no C8 vertebra — this nerve exits between C7 and T1. Affects fine motor control of the hand and grip.
T1 Vertebra
Nerve supply: T1 nerve — contributes to the brachial plexus for arm/hand function.
Why it matters: Transition from cervical to thoracic — issues here can cause hand weakness and forearm pain.
T2 Vertebra
Nerve supply: T2 intercostal nerve — upper chest and inner arm.
Why it matters: Sympathetic nerve supply to the heart originates in this region.
T3 Vertebra
Nerve supply: T3 intercostal nerve — chest wall and lungs.
Why it matters: Affects bronchial and lung function through sympathetic innervation.
T4 Vertebra
Nerve supply: T4 intercostal nerve — mid-chest, gallbladder reflex area.
Why it matters: Key junction for sympathetic nerve supply to the airways and upper digestive organs.
T5 Vertebra
Nerve supply: T5 intercostal nerve — stomach, liver, solar plexus.
Why it matters: Sympathetic input to the liver and gallbladder.
T6 Vertebra
Nerve supply: T6 intercostal nerve — stomach and upper abdominal organs.
Why it matters: Irritation here can contribute to indigestion, acid reflux, and diaphragm spasms.
T7 Vertebra
Nerve supply: T7 intercostal nerve — pancreas, duodenum.
Why it matters: Midpoint of the thoracic spine — affects both digestive and immune function.
T8 Vertebra
Nerve supply: T8 intercostal nerve — spleen, diaphragm.
Why it matters: The spleen plays a critical role in immune response.
T9 Vertebra
Nerve supply: T9 intercostal nerve — adrenal glands, small intestine.
Why it matters: Adrenal gland innervation means T9 issues can affect stress response and energy levels.
T10 Vertebra
Nerve supply: T10 intercostal nerve — kidneys, ureters.
Why it matters: Directly affects kidney function and fluid regulation.
T11 Vertebra
Nerve supply: T11 intercostal nerve — kidneys, ureters, large intestine.
Why it matters: First "floating rib" vertebra — increased mobility means more vulnerability to misalignment.
T12 Vertebra
Nerve supply: Subcostal nerve (T12) — lower abdomen, reproductive organs.
Why it matters: Thoracolumbar junction — a critical transition point affecting digestion and lymphatic drainage.
L1 Vertebra
Nerve supply: Iliohypogastric and ilioinguinal nerves — lower abdominal wall.
Why it matters: Primary innervation to the large intestine. Subluxation here is strongly associated with bowel irregularity.
L2 Vertebra
Nerve supply: Genitofemoral nerve — thigh, groin, reproductive organs.
Why it matters: Affects circulation to the legs. The spinal cord typically ends near L1-L2.
L3 Vertebra
Nerve supply: Lateral femoral cutaneous nerve — outer thigh.
Why it matters: L3 subluxation can present as anterior knee pain and bladder dysfunction.
L4 Vertebra
Nerve supply: L4 nerve root — quadriceps, inner leg, foot.
Why it matters: One of the most common sites of disc herniation. L4-L5 disc issues are the #1 cause of sciatica.
L5 Vertebra
Nerve supply: L5 nerve root — top of foot, big toe, outer calf.
Why it matters: The largest lumbar vertebra bears the most body weight. L5-S1 is the most commonly affected disc in the entire spine.
Sacrum (S1–S5 Fused)
Nerve supply: Sacral plexus — sciatic nerve, pudendal nerve, gluteal nerves.
Why it matters: Five fused vertebrae forming the base of the spine. The sacroiliac joint is one of the most common sources of lower back pain.
Coccyx (Tailbone)
Nerve supply: Coccygeal nerve — pelvic floor muscles.
Why it matters: Though small, the coccyx anchors important ligaments and pelvic floor muscles.