Seven directions of research · All six steps
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Which functions may change Movement, sensation, autonomic function, breathing — and how the level of an injury relates to what changes. Each function here filters real studies.
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Plate 9 Atlas of a spinal cord injury 9 of 19 How a level is found Dermatome Dermatome Myotome Myotome Front Back The ten key muscles C3 C4 C5 C6 C7 C8 T1 T2 T4 T6 T8 T10 T12 L1 L2 L3 L4 L5 S1 C2 C3 C4 T2 T6 T10 L1 S3 S4-5 S2 L5 S1 C5 C6 C7 C8 T1 L2 L3 L4 L5 S1 Elbow flexors · C5 Wrist extensors · C6 Elbow extensors · C7 Finger flexors · C8 Finger abductors · T1 Hip flexors · L2 Knee extensors · L3 Ankle dorsiflexors · L4 Long toe extensors · L5 Ankle plantar flexors · S1 Reflexes Biceps reflex · C5–C6 Biceps reflex · C5–C6 — Three bodies side by side: the front with its strips of skin coloured and named C3 to S1, the back with the sacral strips where they actually are, and a third with the ten key muscles drawn as muscles and labelled by segment. Under them a table of five deep tendon reflexes: a drawing of the hammer on the limb each is tested in, its name, and the segments it answers for. Biceps reflex · C5–C6 C5–C6 Brachioradialis reflex · C6 Brachioradialis reflex · C6 — Three bodies side by side: the front with its strips of skin coloured and named C3 to S1, the back with the sacral strips where they actually are, and a third with the ten key muscles drawn as muscles and labelled by segment. Under them a table of five deep tendon reflexes: a drawing of the hammer on the limb each is tested in, its name, and the segments it answers for. Brachioradialis reflex · C6 C6 Triceps reflex · C7 Triceps reflex · C7 — Three bodies side by side: the front with its strips of skin coloured and named C3 to S1, the back with the sacral strips where they actually are, and a third with the ten key muscles drawn as muscles and labelled by segment. Under them a table of five deep tendon reflexes: a drawing of the hammer on the limb each is tested in, its name, and the segments it answers for. Triceps reflex · C7 C7 Patellar reflex · L3–L4 Patellar reflex · L3–L4 — Three bodies side by side: the front with its strips of skin coloured and named C3 to S1, the back with the sacral strips where they actually are, and a third with the ten key muscles drawn as muscles and labelled by segment. Under them a table of five deep tendon reflexes: a drawing of the hammer on the limb each is tested in, its name, and the segments it answers for. Patellar reflex · L3–L4 L3–L4 Achilles reflex · S1–S2 Achilles reflex · S1–S2 — Three bodies side by side: the front with its strips of skin coloured and named C3 to S1, the back with the sacral strips where they actually are, and a third with the ten key muscles drawn as muscles and labelled by segment. Under them a table of five deep tendon reflexes: a drawing of the hammer on the limb each is tested in, its name, and the segments it answers for. Achilles reflex · S1–S2 S1–S2 Open this plate
Three bodies side by side: the front with its strips of skin coloured and named C3 to S1, the back with the sacral strips where they actually are, and a third with the ten key muscles drawn as muscles and labelled by segment. Under them a table of five deep tendon reflexes: a drawing of the hammer on the limb each is tested in, its name, and the segments it answers for. × Plate 9 Atlas of a spinal cord injury 9 of 19 How a level is found Dermatome Dermatome Myotome Myotome Front Back The ten key muscles C3 C4 C5 C6 C7 C8 T1 T2 T4 T6 T8 T10 T12 L1 L2 L3 L4 L5 S1 C2 C3 C4 T2 T6 T10 L1 S3 S4-5 S2 L5 S1 C5 C6 C7 C8 T1 L2 L3 L4 L5 S1 Elbow flexors · C5 Wrist extensors · C6 Elbow extensors · C7 Finger flexors · C8 Finger abductors · T1 Hip flexors · L2 Knee extensors · L3 Ankle dorsiflexors · L4 Long toe extensors · L5 Ankle plantar flexors · S1 Reflexes Biceps reflex · C5–C6 Biceps reflex · C5–C6 — Three bodies side by side: the front with its strips of skin coloured and named C3 to S1, the back with the sacral strips where they actually are, and a third with the ten key muscles drawn as muscles and labelled by segment. Under them a table of five deep tendon reflexes: a drawing of the hammer on the limb each is tested in, its name, and the segments it answers for. Biceps reflex · C5–C6 C5–C6 Brachioradialis reflex · C6 Brachioradialis reflex · C6 — Three bodies side by side: the front with its strips of skin coloured and named C3 to S1, the back with the sacral strips where they actually are, and a third with the ten key muscles drawn as muscles and labelled by segment. Under them a table of five deep tendon reflexes: a drawing of the hammer on the limb each is tested in, its name, and the segments it answers for. Brachioradialis reflex · C6 C6 Triceps reflex · C7 Triceps reflex · C7 — Three bodies side by side: the front with its strips of skin coloured and named C3 to S1, the back with the sacral strips where they actually are, and a third with the ten key muscles drawn as muscles and labelled by segment. Under them a table of five deep tendon reflexes: a drawing of the hammer on the limb each is tested in, its name, and the segments it answers for. Triceps reflex · C7 C7 Patellar reflex · L3–L4 Patellar reflex · L3–L4 — Three bodies side by side: the front with its strips of skin coloured and named C3 to S1, the back with the sacral strips where they actually are, and a third with the ten key muscles drawn as muscles and labelled by segment. Under them a table of five deep tendon reflexes: a drawing of the hammer on the limb each is tested in, its name, and the segments it answers for. Patellar reflex · L3–L4 L3–L4 Achilles reflex · S1–S2 Achilles reflex · S1–S2 — Three bodies side by side: the front with its strips of skin coloured and named C3 to S1, the back with the sacral strips where they actually are, and a third with the ten key muscles drawn as muscles and labelled by segment. Under them a table of five deep tendon reflexes: a drawing of the hammer on the limb each is tested in, its name, and the segments it answers for. Achilles reflex · S1–S2 S1–S2 1
Dermatome The patch of skin whose sensation travels through one root. Dermatomes run across the body in bands, which is why testing sensation gives a level.
What may change after an injury The line below which sensation has changed is one of the two things a neurological level is worked out from.
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Myotome The muscle group driven by one root. Testing the strength of key muscles gives a motor level the way dermatomes give a sensory one.
What may change after an injury The level on the left and on the right can differ, so they are tested separately.
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Reflexes Automatic responses that close inside the cord without the brain. They report on the state of a pathway, not on effort.
What may change after an injury Immediately after an injury reflexes can disappear and return later. That is a distinct state and it has a name.
Also on this plate
Biceps reflex · C5–C6 A tap on the biceps tendon bends the elbow. It answers for the upper cervical segments and tests whether they conduct.
Brachioradialis reflex · C6 A tap over the radius near the wrist bends the forearm. It answers for the sixth cervical segment.
Triceps reflex · C7 A tap on the triceps tendon straightens the elbow. It answers for the seventh cervical segment.
Patellar reflex · L3–L4 A tap below the kneecap straightens the knee. It answers for the middle lumbar segments.
Achilles reflex · S1–S2 A tap on the Achilles tendon points the foot downwards. It answers for the upper sacral segments.
Where this goes in the corpus Motor function 31 measurements Sensory function 6 measurements Electrophysiology 3 measurements ← Previous plate The cascade, in order All six steps Next plate → The level, and what it decides Plate 10 Atlas of a spinal cord injury 10 of 19 The level, and what it decides The whole column on the left with its bones labelled, and four rows beside it, one per region. Each row carries a small body with everything below that level shaded — and the shading includes the arms only in the neck row, which is the difference the level makes. Injury at a cervical level Injury at a cervical level — The whole column on the left with its bones labelled, and four rows beside it, one per region. Each row carries a small body with everything below that level shaded — and the shading includes the arms only in the neck row, which is the difference the level makes. 1 Injury at a cervical level Movement Both the arms and the legs are affected. The higher the level, the less control remains over shoulder, elbow and hand. Sensation Sensation is altered from the neck downwards, the arms included. Autonomic functions Control of blood pressure and pulse, of body temperature, and of bladder and bowel is disturbed. Breathing Breathing is at risk: the diaphragm is driven by segments C3–C5, and an injury above them requires ventilator support. Injury at a thoracic level Injury at a thoracic level — The whole column on the left with its bones labelled, and four rows beside it, one per region. Each row carries a small body with everything below that level shaded — and the shading includes the arms only in the neck row, which is the difference the level makes. 2 Injury at a thoracic level Movement The arms work. The legs are affected, and with them the muscles of the trunk — the more so the higher the level. Sensation Sensation is altered from the level downwards; on the trunk the boundary runs as a band. Autonomic functions At T6 and above sudden surges of blood pressure are possible — a state that needs urgent help. Bladder and bowel are controlled differently. Breathing The diaphragm works. Coughing and deep breathing are weaker, because the intercostal and abdominal muscles are affected. Injury at a lumbar level Injury at a lumbar level — The whole column on the left with its bones labelled, and four rows beside it, one per region. Each row carries a small body with everything below that level shaded — and the shading includes the arms only in the neck row, which is the difference the level makes. 3 Injury at a lumbar level Movement Arms and trunk work. Muscles of the hip, knee and foot are affected — which ones depends on the level. Sensation Sensation is altered in the leg and the perineum according to the level. Autonomic functions Bladder and bowel are often flaccid rather than spastic: the roots themselves are damaged, not the pathway above them. Breathing Breathing is not affected. Injury at a sacral level Injury at a sacral level — The whole column on the left with its bones labelled, and four rows beside it, one per region. Each row carries a small body with everything below that level shaded — and the shading includes the arms only in the neck row, which is the difference the level makes. 4 Injury at a sacral level Movement Walking is often preserved. The small muscles of the foot and the pelvic floor muscles are affected. Sensation Sensation is altered in the perineum and the back of the leg — the "saddle" area. Autonomic functions This is the level that controls bladder, bowel and sexual function; here they are the most affected. Breathing Breathing is not affected. Open this plate
The whole column on the left with its bones labelled, and four rows beside it, one per region. Each row carries a small body with everything below that level shaded — and the shading includes the arms only in the neck row, which is the difference the level makes. × Plate 10 Atlas of a spinal cord injury 10 of 19 The level, and what it decides The whole column on the left with its bones labelled, and four rows beside it, one per region. Each row carries a small body with everything below that level shaded — and the shading includes the arms only in the neck row, which is the difference the level makes. Injury at a cervical level Injury at a cervical level — The whole column on the left with its bones labelled, and four rows beside it, one per region. Each row carries a small body with everything below that level shaded — and the shading includes the arms only in the neck row, which is the difference the level makes. 1 Injury at a cervical level Movement Both the arms and the legs are affected. The higher the level, the less control remains over shoulder, elbow and hand. Sensation Sensation is altered from the neck downwards, the arms included. Autonomic functions Control of blood pressure and pulse, of body temperature, and of bladder and bowel is disturbed. Breathing Breathing is at risk: the diaphragm is driven by segments C3–C5, and an injury above them requires ventilator support. Injury at a thoracic level Injury at a thoracic level — The whole column on the left with its bones labelled, and four rows beside it, one per region. Each row carries a small body with everything below that level shaded — and the shading includes the arms only in the neck row, which is the difference the level makes. 2 Injury at a thoracic level Movement The arms work. The legs are affected, and with them the muscles of the trunk — the more so the higher the level. Sensation Sensation is altered from the level downwards; on the trunk the boundary runs as a band. Autonomic functions At T6 and above sudden surges of blood pressure are possible — a state that needs urgent help. Bladder and bowel are controlled differently. Breathing The diaphragm works. Coughing and deep breathing are weaker, because the intercostal and abdominal muscles are affected. Injury at a lumbar level Injury at a lumbar level — The whole column on the left with its bones labelled, and four rows beside it, one per region. Each row carries a small body with everything below that level shaded — and the shading includes the arms only in the neck row, which is the difference the level makes. 3 Injury at a lumbar level Movement Arms and trunk work. Muscles of the hip, knee and foot are affected — which ones depends on the level. Sensation Sensation is altered in the leg and the perineum according to the level. Autonomic functions Bladder and bowel are often flaccid rather than spastic: the roots themselves are damaged, not the pathway above them. Breathing Breathing is not affected. Injury at a sacral level Injury at a sacral level — The whole column on the left with its bones labelled, and four rows beside it, one per region. Each row carries a small body with everything below that level shaded — and the shading includes the arms only in the neck row, which is the difference the level makes. 4 Injury at a sacral level Movement Walking is often preserved. The small muscles of the foot and the pelvic floor muscles are affected. Sensation Sensation is altered in the perineum and the back of the leg — the "saddle" area. Autonomic functions This is the level that controls bladder, bowel and sexual function; here they are the most affected. Breathing Breathing is not affected. 1
Injury at a cervical level Affects the arms, the trunk and the legs, and at a high level breathing as well. The higher the level, the more of the body lies below it.
What may change after an injury The hand is what people ask about first. A small change in the hand often matters more to independence than a larger change elsewhere.
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Injury at a thoracic level The arms are usually spared. The trunk and the legs are affected; the level decides seated balance and trunk control.
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Injury at a lumbar level Mostly the legs. Bladder and bowel function can change as well.
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Injury at a sacral level Affects the feet, the bladder, the bowel and sexual function. The lowest sacral segments are what decide whether an injury is called complete.
Where this goes in the corpus Motor function 31 measurements ← Previous plate How a level is found All six steps Next plate → Tetraplegia and paraplegia Plate 11 Atlas of a spinal cord injury 11 of 19 Tetraplegia and paraplegia Tetraplegia Paraplegia Tetraplegia — The same body twice with the level marked across it. On the left the injury is in the neck and all four limbs and the trunk are shaded below it; on the right it is in the chest and the arms are outside the shading. Above each, the range of segments the word covers. Paraplegia — The same body twice with the level marked across it. On the left the injury is in the neck and all four limbs and the trunk are shaded below it; on the right it is in the chest and the arms are outside the shading. Above each, the range of segments the word covers. VS C1–T1 T2–S5 Breathing Breathing Tetraplegia Tetraplegia Paraplegia Paraplegia Open this plate
The same body twice with the level marked across it. On the left the injury is in the neck and all four limbs and the trunk are shaded below it; on the right it is in the chest and the arms are outside the shading. Above each, the range of segments the word covers. × Plate 11 Atlas of a spinal cord injury 11 of 19 Tetraplegia and paraplegia Tetraplegia Paraplegia Tetraplegia — The same body twice with the level marked across it. On the left the injury is in the neck and all four limbs and the trunk are shaded below it; on the right it is in the chest and the arms are outside the shading. Above each, the range of segments the word covers. Paraplegia — The same body twice with the level marked across it. On the left the injury is in the neck and all four limbs and the trunk are shaded below it; on the right it is in the chest and the arms are outside the shading. Above each, the range of segments the word covers. VS C1–T1 T2–S5 Breathing Breathing Tetraplegia Tetraplegia Paraplegia Paraplegia 1
Tetraplegia The word for the consequences of a cervical injury: all four limbs and the trunk are involved. It describes where the injury is, not how much function remains.
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Paraplegia The word for the consequences of a thoracic, lumbar or sacral injury: the arms are spared, the legs and part of the trunk are involved. Again a statement about location, not about amount.
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Breathing The work of the diaphragm and the intercostal muscles, and the strength of a cough. The diaphragm is driven from the cervical segments C3–C5.
What may change after an injury The higher the cervical level, the more this is about breathing. A weak cough is a problem of its own, no smaller than breathing itself.
Where this goes in the corpus Motor function 31 measurements ← Previous plate The level, and what it decides All six steps Next plate → Complete, incomplete, and the five grades What is missing at this step This layer names the axes the corpus is indexed by. Where an axis holds no records, the panel says so and says what would change it — the gap is part of the answer.
What is still missing → · What is covered →
Where to look next The same corpus, entered a different way: by question, by place, by connection, and by what changed recently. Every one of these reads the records this step has been pointing at.
124 medical statements · 6 authorities · 124 stand on an address that answered · 0 have been read against the source by a person
The last of those numbers is nought, and it is printed rather than left to be assumed. These explanations are ordinary anatomy and ordinary clinical vocabulary, written for this product, and each one names the authority it stands on; nobody has yet sat down and compared them, sentence by sentence, with the text at those addresses.