Dermatomes, Myotomes, And Associated Paresthesias
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(taken vertbatum from worksheet, whether it makes sense in text or not ---> not included: muscle weakness (myotome) and reflexes affected)
Questions and Answers
- 1.
DERMATOME: Vertex of skull PARESTHESIAS: None
- A.
C1
- B.
C2
- C.
C3
- D.
C4
Correct Answer
A. C1Explanation
The correct answer is C1. C1 is the first cervical dermatome, which is located at the vertex of the skull. Dermatomes are specific areas of the skin that are innervated by a single spinal nerve. In this case, C1 innervates the area at the top of the head, known as the vertex. Paresthesias refer to abnormal sensations like tingling or numbness, and in this case, there are no reported paresthesias associated with C1.Rate this question:
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- 2.
DERMATOME: Temple, Forehead, Occiput PARESTHESIAS: None
- A.
C1
- B.
C2
- C.
C3
- D.
C4
Correct Answer
B. C2Explanation
The correct answer is C2. The distribution of symptoms in the given question suggests involvement of the second cervical dermatome. The symptoms mentioned, such as temple, forehead, and occiput, are all areas innervated by the second cervical nerve. Additionally, the absence of paresthesias further supports the involvement of the C2 dermatome, as paresthesias would typically be present if there was nerve dysfunction in this area.Rate this question:
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- 3.
DERMATOME: Entire neck Posterior cheek Temporal area Prolongation forward under mandible PARESTHESIAS: Cheek Side of neck
- A.
C2
- B.
C3
- C.
C4
- D.
C1
Correct Answer
B. C3Explanation
The correct answer is C3. The explanation for this answer is that the C3 dermatome covers the entire neck, which matches the description given in the first part of the question. Additionally, the C3 dermatome also includes the posterior cheek and temporal area, which aligns with the second part of the question. The other options (C2, C4, and C1) do not cover the entire neck or include the specified areas, making them incorrect choices.Rate this question:
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- 4.
DERMATOME: Shoulder area Clavicular area Upper Scapular area PARESTHESIAS: Horizontal band along clavicle and upper scapula
- A.
C3
- B.
C4
- C.
C5
- D.
C6
Correct Answer
B. C4Explanation
The correct answer is C4. Paresthesias refer to abnormal sensations such as tingling or numbness. The given options represent different dermatomes, which are specific areas of the skin that are innervated by different spinal nerves. The horizontal band along the clavicle and upper scapula corresponds to the C4 dermatome. Therefore, the correct answer is C4.Rate this question:
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- 5.
DERMATOME: Deltoid area Anterior aspect of entire arm to base of thumb PARESTHESIAS: None
- A.
C3
- B.
C4
- C.
C5
- D.
C6
Correct Answer
C. C5Explanation
The correct answer is C5 because the dermatome of C5 covers the anterior aspect of the entire arm to the base of the thumb. Since there are no paresthesias reported, it suggests that there is no abnormal sensation or tingling in this area, further supporting the answer of C5.Rate this question:
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- 6.
DERMATOME: Anterior arm Radial side of hand to thumb and index fingers PARESTHESIAS: Thumb and index finger
- A.
C5
- B.
C6
- C.
C7
- D.
C8
Correct Answer
B. C6Explanation
The correct answer is C6 because the symptoms described in the question, paresthesias in the thumb and index finger, are associated with nerve impingement at the C6 level. The C6 dermatome covers the radial side of the hand to the thumb and index fingers, which matches the distribution of symptoms mentioned.Rate this question:
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- 7.
DERMATOME: Lateral arm and forearm to index, long, and ring fingers PARESTHESIAS: Index, long, and ring fingers
- A.
C6
- B.
C7
- C.
C8
- D.
T1
Correct Answer
B. C7Explanation
The correct answer is C7. C7 refers to the seventh cervical nerve root, which innervates the lateral arm and forearm as well as the index, long, and ring fingers. Paresthesias, or abnormal sensations like tingling or numbness, are specifically experienced in the index, long, and ring fingers. Therefore, C7 is the most appropriate answer that matches the description given.Rate this question:
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- 8.
DERMATOME: Medial arm and forearm to index, long, and ring fingers PARESTHESIAS: Little finger alone or with two adjacent fingers, NOT ring or long fingers, alone or together
- A.
C6
- B.
C7
- C.
C8
- D.
T1
Correct Answer
C. C8Explanation
The correct answer is C8. C8 refers to the eighth cervical nerve root, which innervates the medial arm and forearm as well as the index, long, and ring fingers. Paresthesias, which are abnormal sensations like tingling or numbness, are commonly experienced in the little finger alone or with two adjacent fingers, but not in the ring or long fingers alone or together. Therefore, the symptoms described in the question are consistent with C8 nerve root involvement.Rate this question:
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- 9.
DERMATOME: Medial side of forearm to base of little finger PARESTHESIAS: None
- A.
C8
- B.
T1
- C.
T2
- D.
C7
Correct Answer
B. T1Explanation
The correct answer is T1. The question is asking for the dermatome that corresponds to the medial side of the forearm to the base of the little finger. The dermatome that covers this area is T1. Paresthesias, which refer to abnormal sensations such as tingling or numbness, are not mentioned in the given information.Rate this question:
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- 10.
DERMATOME: Medial side of upper arm to medial elbow Pectoral and midscapular areas PARESTHESIAS: None
- A.
C8
- B.
T1
- C.
T2
- D.
T3
Correct Answer
C. T2Explanation
The correct answer is T2. The given information states that the dermatome extends from the medial side of the upper arm to the medial elbow, as well as covering the pectoral and midscapular areas. The absence of paresthesias suggests that the T2 dermatome is not affected, indicating that the correct answer is T2.Rate this question:
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- 11.
DERMATOMES: Upper thorax PARESTHESIAS: None
- A.
T3-T6
- B.
T5-T7
- C.
T8-T12
- D.
T1-T2
Correct Answer
A. T3-T6Explanation
The correct answer is T3-T6. Dermatomes are specific areas of skin supplied by specific spinal nerves. In this case, the upper thorax is supplied by the spinal nerves T3-T6. Paresthesias refer to abnormal sensations such as tingling or numbness. Since there are no paresthesias mentioned, it indicates that the sensory function in the dermatomes T3-T6 is normal.Rate this question:
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- 12.
DERMATOMES: Costal margin PARESTHESIAS: None
- A.
T3-T6
- B.
T5-T7
- C.
T8-T12
- D.
T1-T2
Correct Answer
B. T5-T7Explanation
The correct answer is T5-T7. Dermatomes are specific areas of the skin that are innervated by a single spinal nerve. T5-T7 refers to the dermatomes that cover the area around the mid-chest and upper abdomen. Paresthesias, which are abnormal sensations such as tingling or numbness, are not reported in this dermatome region.Rate this question:
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- 13.
DERMATOMES: Abdomen and lumbar region PARESTHESIAS: None
- A.
T8-T12
- B.
T1-T2
- C.
T3-T6
- D.
T5-T7
Correct Answer
A. T8-T12Explanation
The correct answer is T8-T12. Dermatomes refer to specific areas of skin that are innervated by a single spinal nerve. In this case, the abdomen and lumbar region are innervated by the thoracic spinal nerves T8-T12. Paresthesias, which are abnormal sensations like tingling or numbness, are not reported in this dermatome region.Rate this question:
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- 14.
DERMATOME: Back, over trochanter and groin PARESTHESIAS: Groin; after holding posture which causes pain
- A.
L1
- B.
L2
- C.
L3
- D.
L4
Correct Answer
A. L1Explanation
The correct answer is L1. This is because the symptoms described, which include paresthesias in the groin after holding a painful posture, are consistent with nerve impingement at the level of the L1 dermatome. The L1 dermatome covers the back, over the trochanter, and the groin, which aligns with the mentioned symptoms.Rate this question:
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- 15.
DERMATOME: Back, front of thigh to knee PARESTHESIAS: Occasionally anterior thigh
- A.
L1
- B.
L2
- C.
L3
- D.
L4
Correct Answer
B. L2Explanation
The correct answer is L2. L2 is the level of the spinal cord responsible for innervating the front of the thigh to the knee. Paresthesias, which are abnormal sensations like tingling or numbness, occasionally occur in the anterior thigh.Rate this question:
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- 16.
DERMATOME: Back Upper buttock Anterior thigh and knee Medial lower leg PARESTHESIAS: Medial knee Anterior lower leg
- A.
L2
- B.
L3
- C.
L4
- D.
L5
Correct Answer
B. L3Explanation
The correct answer is L3. The dermatome for L3 includes the anterior thigh and knee, while the paresthesias associated with L3 are felt in the medial knee. Therefore, L3 is the most appropriate answer as it matches both the dermatome and the paresthesias described.Rate this question:
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- 17.
DERMATOME: Medial buttock Lateral thigh Medial leg Dorsum of foot Big toe PARESTHESIAS: Medial aspect of calf and ankle
- A.
L3
- B.
L4
- C.
L5
- D.
S1
Correct Answer
B. L4Explanation
The correct answer is L4. The distribution of paresthesias in the medial aspect of the calf and ankle corresponds to the L4 dermatome. Dermatomes are specific areas of skin that are innervated by a single spinal nerve. In this case, the paresthesias are occurring in the L4 dermatome, indicating a potential issue with the L4 spinal nerve or its corresponding nerve roots.Rate this question:
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- 18.
DERMATOME: Buttock Posterior and lateral thigh Lateral aspect of leg Dorsum of foot Medial half of sole First, second, and third toes PARESTHESIAS: Lateral aspect of leg Medial three toes
- A.
L4
- B.
L5
- C.
S1
- D.
S2
Correct Answer
B. L5Explanation
The correct answer is L5. L5 dermatome includes the lateral aspect of the leg and the medial three toes. Paresthesias in the L5 dermatome would present as abnormal sensations such as tingling or numbness in these areas.Rate this question:
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- 19.
DERMATOME: Buttock Thigh Posterior leg PARESTHESIAS: Lateral two toes Lateral foot Lateral leg to knee Plantar aspect of foot
- A.
L5
- B.
S1
- C.
S2
- D.
S3
Correct Answer
B. S1Explanation
The given answer, S1, is the correct answer because the symptoms described in the PARESTHESIAS section match the dermatome distribution of S1. The symptoms include paresthesias in the lateral foot and leg to the knee, which correspond to the sensory innervation of the S1 dermatome. Therefore, S1 is the most likely nerve root involved in this case.Rate this question:
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- 20.
DERMATOME: Buttock Thigh Posterior leg PARESTHESIAS: Lateral leg, knee, and heel
- A.
S1
- B.
S2
- C.
S3
- D.
S4
Correct Answer
B. S2Explanation
The correct answer is S2. The question is asking for the dermatome associated with paresthesias in the lateral leg, knee, and heel. Dermatomes are specific areas of skin that are innervated by specific spinal nerves. In this case, paresthesias in the lateral leg, knee, and heel are associated with the S2 dermatome.Rate this question:
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- 21.
DERMATOME: Groin Medial thigh to knee PARESTHESIAS: None
- A.
S1
- B.
S2
- C.
S3
- D.
S4
Correct Answer
C. S3Explanation
The correct answer is S3. The question is asking for the dermatome that corresponds to the groin area. Dermatomes are specific areas of skin that are innervated by a single spinal nerve. The S3 dermatome covers the area of the medial thigh to the knee, which includes the groin region. Paresthesias refers to abnormal sensations like tingling or numbness. The statement "None" indicates that there are no abnormal sensations reported in the S3 dermatome.Rate this question:
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- 22.
DERMATOME: Perineum Genitals Lower sacrum PARESTHESIAS: Saddle area Gentials Anus Impotence Massive posterior herniation
- A.
S5
- B.
S2
- C.
S3
- D.
S4
Correct Answer
D. S4Explanation
The correct answer is S4. The S4 dermatome refers to the area of the skin innervated by the fourth sacral nerve. Paresthesias, or abnormal sensations, in the saddle area, genitals, and anus are commonly associated with S4 dermatome involvement. Impotence and massive posterior herniation are not specific to the S4 dermatome.Rate this question:
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- 23.
Myotome/Muscle Weakness: NONE
- A.
C1, L1, S3
- B.
C1, L2, S3
- C.
C2, L2, S3
- D.
C2, L1, S3
Correct Answer
A. C1, L1, S3Explanation
This answer suggests that the myotome/muscle weakness is present in the C1, L1, and S3 regions. The myotome refers to a group of muscles that are innervated by a specific spinal nerve root. In this case, the weakness is observed in the muscles innervated by the C1, L1, and S3 nerve roots. The specific muscles affected in these regions are not mentioned, but it can be inferred that weakness is present in these areas.Rate this question:
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- 24.
Myotome/Muscle Weakness: Longus Colli, SCM, rectus capitis
- A.
C2
- B.
C3
- C.
C4
- D.
C1
Correct Answer
A. C2Explanation
The correct answer is C2. C2 is the correct answer because the muscles mentioned in the question (Longus Colli, SCM, rectus capitis) are innervated by the C2 spinal nerve. Each spinal nerve innervates specific muscles, and in this case, the muscles mentioned receive their motor innervation from the C2 spinal nerve. Therefore, if there is weakness in these muscles, it suggests a problem with the C2 nerve root.Rate this question:
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- 25.
Myotome/Muscle Weakness: Trapezius, Splenius Capitis
- A.
C2
- B.
C3
- C.
C4
- D.
C5
Correct Answer
C. C4Explanation
The trapezius and splenius capitis muscles are innervated by the spinal accessory nerve (CN XI) and the cervical nerves (C3 and C4). Muscle weakness in these muscles could indicate a problem with the C4 nerve root or the spinal accessory nerve.Rate this question:
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- 26.
Myotome/Muscle Weakness: Trapezius, Levator Scapulae
- A.
C4
- B.
C5
- C.
C3
- D.
T2
Correct Answer
A. C4Explanation
The muscles mentioned in the question, Trapezius and Levator Scapulae, are innervated by the C4 spinal nerve. This means that the motor signals for these muscles originate from the C4 level of the spinal cord. If there is any dysfunction or injury at the C4 level, it can lead to weakness or paralysis of these muscles, resulting in myotome/muscle weakness. Therefore, the correct answer is C4.Rate this question:
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- 27.
Myotome/Muscle Weakness: Supraspinatus, infraspinatus, deltoid, biceps
- A.
C4
- B.
C5
- C.
C6
- D.
T2
Correct Answer
B. C5Explanation
The muscles listed (supraspinatus, infraspinatus, deltoid, biceps) are all innervated by the C5 nerve root. This means that if there is weakness or dysfunction in these muscles, it is likely due to an issue with the C5 nerve.Rate this question:
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- 28.
Myotome/Muscle Weakness: Biceps, supinator, wirst extensors
- A.
C6
- B.
C5
- C.
C7
- D.
C8
Correct Answer
A. C6Explanation
The correct answer is C6. The muscles mentioned, including the biceps, supinator, and wrist extensors, are innervated by the C6 nerve root. Each nerve root corresponds to a specific level of the spinal cord, and damage or compression at the C6 level can result in weakness or paralysis of these muscles. This can lead to difficulty in flexing the elbow, rotating the forearm, and extending the wrist.Rate this question:
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- 29.
Myotome/Muscle Weakness: Triceps, wrist flexors (rarely, wrist extensors)
- A.
C7
- B.
C8
- C.
T1
- D.
C6
Correct Answer
A. C7Explanation
This answer refers to the specific level of spinal nerve involvement in a condition called myotome/muscle weakness. The C7 spinal nerve is responsible for innervating the triceps muscle and the wrist flexors. In some cases, the wrist extensors may also be affected, although this is less common. The other options (C8, T1, and C6) do not correspond to the specific muscles mentioned in the question.Rate this question:
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- 30.
Myotome/Muscle Weakness: Ulnar deviators, thumb extensors, thumb adductors (rarely, triceps)
- A.
C8
- B.
T1
- C.
C7
- D.
C6
Correct Answer
A. C8Explanation
The correct answer is C8. The ulnar deviators, thumb extensors, thumb adductors, and rarely the triceps muscles are innervated by the C8 nerve root. Damage or compression of the C8 nerve root can result in weakness or paralysis of these muscles, leading to a loss of function in ulnar deviation, thumb extension, thumb adduction, and triceps extension.Rate this question:
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- 31.
Myotome/Muscle Weakness: Articular and dural signs and root pain are common. Root signs (cutaneous analgesia) are rare and have such indefinite area that they have little localizing value. Weakness is not detectable.
- A.
T1-T12
- B.
T3-T12
- C.
T3-T11
- D.
T1-T11
Correct Answer
B. T3-T12 -
- 32.
Myotome/Muscle Weakness: Psoas, Hip adductors
- A.
L1
- B.
L2
- C.
L3
- D.
L4
Correct Answer
B. L2Explanation
The correct answer is L2. The psoas and hip adductors are innervated by the L2 spinal nerve. This means that if there is damage or dysfunction at the L2 level, it can result in weakness or impaired function of these muscles. This can manifest as difficulty with hip flexion, hip adduction, and possibly walking or standing. Therefore, L2 is the correct answer for the myotome/muscle weakness associated with the psoas and hip adductors.Rate this question:
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- 33.
Myotome/Muscle Weakness: Psoas, quadriceps, thigh atrophy
- A.
L2
- B.
L3
- C.
L4
- D.
L1
Correct Answer
B. L3Explanation
The correct answer is L3. The muscles mentioned, including the psoas, quadriceps, and thigh, are innervated by the L3 nerve root. Damage or compression of the L3 nerve root can lead to weakness or atrophy in these muscles.Rate this question:
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- 34.
Myotome/Muscle Weakness: Tibialis anterior, extensor hallucis
- A.
L2
- B.
L3
- C.
L4
- D.
L5
Correct Answer
C. L4Explanation
The correct answer is L4. The tibialis anterior and extensor hallucis muscles are innervated by the L4 nerve root. Therefore, weakness in these muscles suggests a problem with the L4 nerve root.Rate this question:
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- 35.
Myotome/Muscle Weakness: Extensor hallucis, peroneals, gluteus medius, dorsiflexors, hamstring and calf atrophy
- A.
L3
- B.
L4
- C.
L5
- D.
S1
Correct Answer
C. L5Explanation
The given answer, L5, refers to the fifth lumbar spinal nerve. The symptoms described, including weakness in the extensor hallucis, peroneals, gluteus medius, dorsiflexors, hamstring, and calf muscles, are consistent with a nerve root compression or injury at the L5 level. This can result in weakness and atrophy of the muscles innervated by the L5 nerve, leading to difficulty with foot and ankle movements, as well as hip stability.Rate this question:
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- 36.
Myotome/Muscle Weakness: Calf and hamstring, wasting of gluteals, peroneals, plantar flexors
- A.
L5
- B.
S1
- C.
S2
- D.
S3
Correct Answer
B. S1Explanation
The given answer, S1, is the correct answer because the symptoms described in the question are consistent with a nerve root compression at the S1 level. This compression can result in weakness and wasting of the calf and hamstring muscles, as well as the gluteals, peroneals, and plantar flexors. Therefore, S1 is the most appropriate answer based on the provided information.Rate this question:
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- 37.
Myotome/Muscle Weakness: Calf and hamstring, wasting of gluteals, plantar flexors
- A.
S1
- B.
S2
- C.
S3
- D.
S4
Correct Answer
B. S2Explanation
The correct answer is S2. The S2 nerve root innervates the calf and hamstring muscles, as well as the gluteal muscles and plantar flexors. Damage or compression of the S2 nerve root can result in weakness or wasting of these muscles.Rate this question:
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- 38.
Myotome/Muscle Weakness: Bladder, rectum
- A.
S4
- B.
S5
- C.
S2
- D.
S1
Correct Answer
A. S4Explanation
The correct answer is S4 because the S4 spinal nerve is responsible for innervating the bladder and rectum. Damage or weakness in this myotome can result in impaired control or function of these organs.Rate this question:
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- 39.
In regards to T1 and T2 myotomes/muscle weakness: Disc lesions at upper two thoracic levels do not appear to give rise to root weakness. Weakness of intrinsic muscles of the hand is due to other pathology (e.g: thoracic outlet pressure, neoplasm of lung, and ulnar nerve lesion). Dural and nerve root stress has T1 elbow flexion with arm horizontal. T1 and T2 scapulae forward and backward on chest wall. Neck flexion at any thoracic level.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The explanation for the correct answer is that disc lesions at the upper two thoracic levels do not cause root weakness. Weakness in the intrinsic muscles of the hand is typically caused by other factors such as thoracic outlet pressure, lung neoplasms, or ulnar nerve lesions. The stress on the dural and nerve roots affects T1 elbow flexion with the arm horizontal, as well as the movement of the scapulae forward and backward on the chest wall. Neck flexion can occur at any thoracic level. Therefore, the statement is true.Rate this question:
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Jan 20, 2025Quiz Edited by
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