To compare between two different positions (forward head position and neutral position) when using mobile phone by hand using nerve conduction velocity and F-wave of upper limb nerves ( ulnar, median and radial) in 4 different times.

PURPOSE:

• To compare between forward head position and hand use of mobile phone on conduction velocity of upper limb nerves
• To investigate the F responses of upper limbs nerves.
• To investigate the compound muscle action potential (CMAP) amplitudes of median nerves

BACKGROUND:

Forward head position may affect the cervical nerve root so it can also affect nerve conduction velocity due to continues stretch on nerves, also the over use of smart phone by hand may be affected the hand nerves, so this study determine which one of them has more influence than the other.

If the forward head position has the worst effect on the upper limb nerves investigators must avoid the incorrect position of the head to avoid stretch and compression of the nerves.

HYPOTHESES:

There are no statistical difference between forward head position and hand use of mobile phone on conduction velocity of the nerves of upper limb.

SUBJECTS:

Normal one hundred fifty non-athketic adolescents of both genders will participate in this study. Their age ranges from 14-18 years.

METHODS FOR ASSESSMENT

1. Electromyography (EMG) will be used to measure nerve conduction velocity, F-wave, motor action potential
2. Soft collar will used to fixed the craniovertebral angle during used mobile phone Universal goniometer
3. Goniometer pro iPhone application

Inclusion Criteria:

1. Their ages range from 14-18 years.
2. Not rolled on any regular athletic activity

Exclusion Criteria:

1. Individual with neck pain
2. Congenital deformity for upper limb
3. Peripheral neuropathy due to diabetes mellitus type I
4. Rheumatoid arthritis
5. History of surgical intervention at nerves of the upper extremity

normal subjects