Dermatome & Myotome
By:
Mrs. Nidaa Alanazi
Dermatome:

is an area of skin that is mainly supplied
by a single spinal nerve.
Myotome:

is the group of muscles that a single
spinal nerve root innervates.
Dermatome:
C2
Angle of the jaw ,
Lateral aspect of neck
C3,C4
Shoulder, down to manubrium
C5
Lateral aspect of arm
C6
Lateral aspect of forearm,
Thumb
C7
Middle aspect of forearm,
Middle of the palm ,
Middle 3 fingers
C8
Medial aspect of forearm,
Little finger
T1
Medial aspect of arm
T2-T7
Torax (T4 nipple)
T8-T12
Abdomen ( T8= xiphoid process)
(T10=umbilicus(
(T12=inguinal ligament )
L1
upper1/3 front of thigh
L2
Middle 1/3 front of thigh
L3
Lower 1/3 front of thigh
L4
Antrolateral aspect of the thigh,front of knee
Antromedial aspect of leg
Medical aspect of foot
Big toe
L5
Lateral aspect of thigh
Lateral aspect of leg
Middle 1/3 of dorsum of foot
Middle 3 toes
S1
Postrolateral aspect of thigh and leg
Lateral 1/3 of dorsum of foot
Little toe
S2
posterior aspect of thigh,leg
Sole of foot
S3,4,5
Anal
Perinal
gluteal region
EXAMINATION OF SENSORY
SYSTEM
Sensory Examination:

The Sensory Examination includes testing
for both:
Superficial Sensation
Deep Sensation
Superficial sensation
Pain
Light Touch
Temperature
Indications
Diabetes Mellitus.
 Thiamine Deficiency.
 Neurotoxin Damage.

Contraindications/Precautions:
Dementia.
 Delirium.
 Confusional States.

Rule of sensory Examination:





Demonstration: demonstrate what you are
going to do.
Fatigue: Do Not perform a sensory
examination at the end of lengthy
examination. Why ?
Eyes closed.
Brevity: brief instruction, brief answers, Do
You feel ?(Yes Or No) (Sharp Or Dull) ,
Where?
Suggestion: Do Not interfere with pt’s
decisions by slanting instructions toward the
abnormal.

Sensory Examination should be tested in
all Upper & Lower Extremities.. Why?
Superficial sensory Examination: light Touch
Light Touch Can
be evaluated with
Hand Or wisp of
cotton
Superficial sensory Examination:
Pain for UE.
Pain can be
tested by
Pin.
Superficial sensory Examination:
Pain for LE.
Superficial sensory Examination:
Temperature.
This test can
be done By
two Tube
(hot & cold)
Or by Tuning
Fork
Practical Part