الفهرس 
Anatomy of carpal tunnelOnly 14 pages are availabe for public view
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Abstract
Carpal tunnel syndrome (CTS) is the most common peripheral entrapment disorder, resulting from compression of the median nerve at the wrist where it courses deep to transverse carpal ligament.
CTS is a condition of middle aged people, more common in women than in men. The most cases are idiopathic. overall prevalences of 3.0–5.8% among women and 0.6–2.1% among men have been found in general population samples.
Diagnosis of carpal tunnel syndrome is usually based on a combination of clinical signs and abnormal nerve conduction studies.
Provocative tests (Tinel test, Phalen test and reverse Phalen test) are commonly used to diagnose CTS during the physical examination.
Electrophysiological testing remains an essential technique for quantifying median nerve function in CTS due to its inherent reliability, reproducibility, and objectivity. The majority of electrophysiological tests yield high specificity, but with variable sensitivity.
Numerous studies have previously reported that the comparison of sensory nerve responses is more sensitive than the absolute median latency in documenting the electrodiagnostic abnormalities which indicate CTS.
The aim of this study was to evaluate significance of the Median-Ulnar sensory distal latency difference to the fourth digit in patients suspected of having carpal tunnel syndrome and its comparison with with that to the second and fifth digits and Median-Radial sensory distal latency difference to the first digit.
Patients with a history and symptoms consistent with cervical radiculopathy, brachial plexopathy, polyneuropathy and peripheral nerve trauma were excluded from the study.
The following electrophysiological parameters were done: Median and ulanr distal motor latency, amplitude and conduction velocity, Fwave study to exclude proximal compression, second digit median-fifth digit ulnar antidromic peak latency difference (D2M-D5U), fourth digit median-ulnar sensory peak latency difference (D4M-D4U) , first digit median-radial sensory latency difference(D1M-D1R).
This study included twenty five patients were diagnosed as idiopathic CTS. Twenty one of them were females (84%), four patients were males(16 %) , their ages ranged from 23 to 58 years old with a mean of 38.2 ± 9.6 SD. Ten patients were included as a control, seven of them were females and three of them were males. Their ages ranged from 17 to 50 years with a mean of 36.7 ±9.7SD.
Duration of the disease ranged from 2 to 7 weeks with a mean of 4.16±1.43 weeks.Phalen Test was positive in 14 hands ( 56%) Tinel Test was positive in 14 hands(56 %), Reverse Phalen Test was positive in 12 hands (48 %) and hypothesia was found in 17 hands (68%).No thenar musle weakness or atrophy was found in any hand(0%)
The cutoff value for the fourth digit median-ulnar sensory peak latency difference (D4M-D4U) in our study was set at 0.5 ms, above which was considered abnormal.
It was found that D4M-D4U latency difference was within average values in all controls with no significant difference with D2M-D5U (P>0.05)
A statistically significant difference was found between cases as regards the D4M-D4U latency difference compared with the second digit median-fifth digit ulnar antidromic peak latency difference(D2M-D5U) (P<0.05).
There was highly statistically significant difference regarding fourth digit median-ulnar sensory peak latency difference (D4M-D4U) between patients and control (P<0.01)
A statistically non significant difference between cases as regards the D4M-D4U latency difference compared with the first digit median- radial antidromic peak latency difference(D1M-D1R)(P>0.05).
The sensitivity of the D4M-D4U latency difference was (52%) which was higher than distal motor latency to abductor pollicis brevis(DML)(12%) and second digit median-fifth digit ulnar sensory latency difference (D2M-D5U)(40%) while first digit median-radial sensory latency difference(D1M-D1R)(64%) was the highest sensitivity.