Dermatomes Flashcards
What is a dermatome?
A dermatome is an area of skin innervated by a specific spinal nerve root.
How many cervical dermatomes are there, and what areas do they cover?
There are 8 cervical dermatomes (C1–C8). They cover the scalp, neck, shoulders, arms, and hands.
Which areas are innervated by the C2 and C3 dermatomes?
C2: Crown and posterior scalp.
C3: Anterior neck, base of the skull, and ear lobes
Which areas are innervated by the C4, C5, and C6 dermatomes?
C4: Skin over the neck, tips of shoulders, and upper arms.
C5: Lateral upper arm to the elbow.
C6: Thumb and lateral forearm.
Which areas are innervated by the C7 and C8 dermatomes?
C7: Posterior arms, shoulders, and middle finger.
C8: Pinky finger and medial forearm.
Question: How many thoracic dermatomes are there, and what areas do they cover?
There are 12 thoracic dermatomes (T1–T12). They cover the chest, abdomen, arms, and mid-back.
What areas do T1, T4, and T10 specifically innervate?
T1: Upper chest, back, axilla, and medial upper arm.
T4: Around the nipple line.
T10: Around the umbilicus.
How many lumbar dermatomes are there, and what areas do they cover?
There are 5 lumbar dermatomes (L1–L5). They cover the lower back, hips, anterior and lateral thighs, calves, and feet.
What areas are innervated by L1, L3, and L5?
L1: Groin, upper trochanter, and lower back.
L3: Back, upper buttock, and medial thigh.
L5: Back, anterior/lateral calf, and first four toes.
How many sacral dermatomes are there, and what areas do they cover?
There are 5 sacral dermatomes (S1–S5). They cover the buttocks, genitals, posterior legs, and perineal area.
What areas are innervated by S1, S3, and S4/S5?
S1: Buttocks and posterolateral leg.
S3: Buttocks and genitals.
S4/S5: Perineal area, including genitals.
What area does the coccygeal dermatome innervate?
The skin overlying the tailbone (coccyx).
Name two conditions that commonly affect dermatomes.
Radiculopathy (nerve root compression, e.g., from a herniated disc).
Shingles (reactivation of the varicella zoster virus)
What is radiculopathy, and what causes it?
Radiculopathy is nerve root irritation or compression, often caused by disc herniation, trauma, or aging.
What is Pinprick test
A pinprick test is a simple medical test used to assess a person’s sensation, particularly their ability to feel pain. It’s often used to check for nerve damage or other neurological issues.
