4 research outputs found
The prevalence of accessory heads of the flexor pollicis longus and the flexor digitorum profundus muscles in Egyptians and their relations to median and anterior interosseous nerves
Entrapment neuropathy in the forearm is not uncommon. Surgical interference
for nerve decompression should be preceded by accurate diagnosis of the exact
cause and site of the nerve entrapment. The aim of the present study was to
investigate the prevalence of accessory heads of the flexor pollicis longus and
flexor digitorum profundus muscles (FPLah) and (FDPah) in Egyptians and their
topographical relationship with both the median nerve and its anterior interosseous
branch.
A total of 42 upper limbs of embalmed cadavers, 36 from males and 6 from
females, were examined to elucidate the prevalence of both the FPLah and the
FDPah muscles, their origin, insertion, nerve supply and morphology. The distribution
of these two muscles in the right and left male and female upper limbs
and their relationship to the anterior interosseous and median nerves were
recorded. The total lengths of both accessory muscles and the lengths of their
fleshy bellies and tendons were also measured.
The FPLah was found to be present more frequently (61.9%) than it was absent,
whereas the FDPah was observed in only 14.24% of the specimens examined.
The combination of the accessory muscles in the same forearm was noticed in
9.52% of cases. As regards side, the FPLah appeared in 77.7% of the right
forearms and in 50% of the left, while the FDPah was found in only 25% of the
left forearms. The accessory muscles showed no single morphology, as the
FPLah appeared fusiform in 53.8%, slender in 30.8% and voluminous fusiform
in 15.4%, while the FDPah was slender in 66.6% and triangular in 33.3% of
specimens. The FPLah arose mainly from the under surface of flexor digitorum
superficialis, while the FDPah took its origin from the under surface of flexor
digitorum superficialis or from the medial epicondyle. The insertion of the FPLah
was mainly into the upper third of the FPL tendon, while the FDPah tendon
joined the tendons of the flexor digitorum profundus muscle to the index or
middle and ring fingers. The FPLah was found between the median nerve anteriorly
and the anterior interosseous nerve posteriorly. Both FPLah and FDPah
took their nerve supply mainly from the anterior interosseous nerve and, less frequently, from the median nerve. The mean values of the total lengths of
FPLah and FDPah were 74.66 mm and 208.33 mm, respectively.
Cadaveric dissection in this study confirmed the prevalence of the FPLah and
FDPah in Egyptians and demonstrated the relationship of the FPLah to the median
nerve and its anterior interosseous branch. These findings may provide the
surgeon with information for the differential diagnosis of the causes and sites
of anterior interosseous nerve syndrome and entrapment neuropathy of the
median nerve in the forearm (Folia Morphol 2008; 67: 63-71)