Tetany and Low Calcium: Cause, Symptoms and NEET Points
Biology · Locomotion and Movement · NEET
Tetany is a muscle disorder that causes rapid spasms, called wild contractions, in the muscles. NCERT says it happens because of LOW calcium (Ca++) in the body fluid, not high calcium. Memory hook: LOW calcium, LOTS of spasms. Calcium normally controls the nerve and muscle, so when it drops, muscles fire and twitch on their own.
Flow of tetany: low calcium in body fluid makes nerves over-excitable, which triggers rapid, wild muscle spasms. The core NEET point is that calcium is LOW, never high.
Your doubts, answered
Is tetany caused by high or low calcium?
LOW calcium. The NCERT line is exact: tetany is rapid spasms (wild contractions) in muscle due to LOW Ca++ in body fluid. NEET writes wrong options saying 'high Ca2+' to trick you. Always pick low calcium.
What exactly is tetany in Class 11 Locomotion and Movement?
Tetany is listed as one of the muscular and skeletal disorders. It is defined as rapid spasms, also called wild contractions, in muscle caused by low calcium in the body fluid. Just remember the phrase 'rapid spasms due to low Ca++'.
What is the difference between tetany and tetanus?
Tetany is a disorder from LOW blood calcium that gives spasms; it is in your NCERT locomotion chapter. Tetanus is a bacterial infection (Clostridium tetani) that causes stiff, locked muscles and is not the same topic. NEET only tests tetany here, so link tetany to calcium.
Why does low calcium make muscles spasm?
Calcium ions help control how nerves and muscles fire. When calcium in the body fluid drops too low, nerves become over-excitable and send extra signals, so muscles contract on their own and twitch fast. This is why low calcium equals wild, rapid contractions.
What are the main symptoms of tetany to remember for NEET?
For NEET, remember one thing: rapid, wild muscle spasms (uncontrolled twitching or cramps) caused by low calcium. You do not need clinical details; just match 'tetany = rapid spasms due to low Ca++' in the disease-symptom matching questions.
⚠️ The NEET trap ✗ Tetany happens because of HIGH calcium (Ca2+) level causing rapid spasms. ✓ Tetany happens because of LOW calcium (Ca++) in body fluid causing rapid, wild spasms. 🧠 NEET flips the word to 'high' in one wrong option. The real NCERT word is LOW. If an option says high calcium for tetany, reject it.
Real NEET questions
NEET 2022
Which of the following is a correct match for disease and its symptoms?
A · Arthritis - Inflamed joints ✓
B · Tetany - high Ca2+ level causing rapid spasms
C · Myasthenia gravis - Genetic disorder resulting in weakening and paralysis of skeletal muscle
D · Muscular dystrophy - An autoimmune disorder causing progressive degeneration of skeletal muscle
Solution: Only 'Arthritis - Inflamed joints' is correct. The tetany option is wrong because tetany is due to LOW Ca2+, not high. Myasthenia gravis is autoimmune (not genetic), and muscular dystrophy is genetic (not autoimmune), so those options are swapped.
NEET 2026
Match List I with List II related to muscular/skeletal system: A. Tetany B. Arthritis C. Myasthenia gravis D. Muscular dystrophy; (I) Inflammation of joints (II) Autoimmune disorder affecting neuromuscular junction (III) Wild contraction in muscle due to low Ca2+ in body fluid (IV) Progressive degeneration of skeletal muscle
A · A-III, B-I, C-II, D-IV ✓
B · A-I, B-II, C-III, D-IV
C · A-IV, B-III, C-II, D-I
D · A-III, B-II, C-I, D-IV
Solution: Tetany matches (III) wild contraction due to low Ca2+. Arthritis matches (I) inflammation of joints. Myasthenia gravis matches (II) autoimmune at the neuromuscular junction. Muscular dystrophy matches (IV) progressive degeneration. So A-III, B-I, C-II, D-IV.
Solved Locomotion and Movement NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Tetany: rapid spasms (wild contractions) in muscle due to low Ca++ in body fluid.
Is tetany a muscle disorder or a bone disorder?
It is a muscular disorder listed under Locomotion and Movement, caused by low calcium affecting muscle contraction.
Which mineral is linked to tetany?
Calcium. Low calcium in the body fluid is the direct cause of the muscle spasms in tetany.
How is tetany different from arthritis in NEET matching questions?
Tetany is rapid muscle spasms from low calcium; arthritis is inflammation of joints. They are different rows in the disease-matching PYQs, so never mix them.
