The document discusses the significance of dermatomes and myotomes, detailing the specific areas of skin and muscles innervated by spinal nerve roots. It outlines the various dermatomes associated with different spinal levels and provides clinical insights into muscle weaknesses related to specific nerve root lesions. Additionally, it includes assessment techniques for evaluating nerve root injuries in the upper and lower extremities.

1. DERMATUMES
DERMATUMES
MYOTOMES
MYOTOMES
VS
Niloofar barzegari Medical sudent
Significance of dermatome & myotome

2. Background
Area of skin innervated
by specific nerve root
30 total
Pathologies
Radiculopaties
Shingles
Commonly due to disc
From advanced age or trauma
Reactivation of varicella zoster virus
Assessment
Neurological exam
Pinprick test
1.
Light touch test
2.
Dermatome
This pattern?!

3. Levels of principal
dermatomes:
Dermatomes
Map
T4
T7
T10
S2, S3,S4
Nipple
Xiphoid process
Umbilicus
Perineom
The anal region of the body liesin
the dermatome of the most
distal cord segment. (S5)
In the embryo, this is the tail
region and the most distal
portion of the body. The legs
originate embryologically from
the lumbar and upper sacral
segments (L2 to S3).
Emberyology

4. C2 and C3 dermatomes supply the crown and
posterior scalp, anterior neck, the base of the
skull, and the ear lobes.
C4 spinal nerve supplies the skin over parts
of the neck, the tips of the shoulders, and
upper arms.
C5 covers the lateral upper arm to the elbow.
C6 covers the thumb of the hand and lateral
forearm.
C7 covers the shoulders, posterior arms, and
the middle finger.
C8 covers the pinky of the hand and the
medial forearm.
The L1 innervates the groin, upper
trochanter (or outer hips), and lower back.
L2 innervates the back, hips, and anterior
thighs.
L3 innervates the back, upper buttock, and
the medial thigh and legs to the knees.
L4 innervates the back, the anterior thigh
and calf, posterior knees, medial ankle, and
the heels.
L5 innervates the back; anterior and lateral
calf; and the feet, including the first four
toes
Thoracic
Cervical
Sacral
Lumbar
T1 supplies the upper chest and back, axilla,
and medial aspect of the upper arm.
T2 and T3 cover the upper chest and back.
T4 innervates the area approximately at
the level of the nipples and the back.
The rest of the thoracic dermatomes cover
the abdomen and mid-back, traveling
inferiorly/caudally with T10 notably
innervating the area of the umbilicus
S1 mainly supplies the buttocks and
posterolateral aspect of the leg.
S2 supplies the buttock and
posteromedial aspect of the leg.
S3 supplies the buttock and genitals.
Lastly,
S4 and S5 supply the perineal area,
which include the genitals.

5. Myotome
Info about level in
the spine where
the lesion maybe
present
a group of muscles which is innervated by single
spinal nerve root
Muscle
weakness
IV disc
herniation
Clinical significance

6. Myotome
Wich spinal root?
Which mucle?

7. Upper cervical flexion
Upper cervical extension/neck
rotation
cervical lateral flexion
Shoulder shrung(upper terapezios)
Shoulder abbduction and external
rotation(infraspinatus)
Elbow flexion and wrist extension
Elbow extension and wrist flexion
Thumb extension and ulnar
deviation
Finger adduction and abduction
Myotome and
diffrentiating nerve lesion
C1
C2
C3
C4
C5
C6
C7
C8
T1

8. Myotome and
diffrentiating nerve lesion
Hip flexion
Hip flexion(and also adduction and
medial rotasion)
Leg and knee extension
Dorsiflexion
Great/big toe extension
Ankle plantar flexion and
eversion/knee flexion
Ankle plantar flexion and knee
flexion
None
Bladder and rectome
L1
L2
L3
L4
L5
S1
S2
S3
S4

9. UPPER EXTIMITY NERVE ROUTS LOWER EXTRIMITY NERVE TOUTS
C4
C5
C6
C7
C8
T1
L1_L2
L3
L4
l5
S1_s2
Tested with resisted shoulder
shrung/elevation
Tested with resisted shoulder
abduction
Tested with resisted elbow
flexion/wrist extension
Tested with resisted wrist flexion
Tested with resisted thumb extension
fingers
abbduction and adduction
Tested with resisted hip flexion
Tested with resisted knee extesion
Tested with resisted foot dorsi
flexion
Tested with resisted great toe
extension
Tested with plantar flexion
The quik test for lower extermity to
rule out a nerve root injury is to have
the athlete do a squat

10. THANKS
FOR YOUR
ATTENTION!
THANKS
FOR YOUR
ATTENTION!