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Local muscle transfers usually involve the
temporalis muscle or masseter muscle. The disadvantage of the transfers is
that smiling is not synchronized with the contralateral normal face, but is
produced by effort of clenching the teeth together. This is the case since
the muscles used in local transfers are muscles of mastication, and they fire
when a chewing motion is performed. This can give the odd appearance of
smiling during the chewing process, or an appearance of clenching the jaw during
the smiling process.
Anatomy of Masseter and Temporalis Muscles
The temporalis and masseter muscle are pictured
above. The temporalis muscle inserts onto the coronoid
process of the mandible (hidden here, but seen in this
link). It is a powerful muscle that elevates and
retracts the mandible. The insertion of the muscle can be approached
surgically with
an intra-oral incision for the procedure, more commonly known as the McLaughlin
transfer - also known as a temporalis tendon transfer or temporalis muscle
transfer. The upper fibers are approached separately and are used to power
orbicularis oculi muscle closure. The transfers are pictured below. The
upper fibers are inserted into the upper and lower lid, while the coronoid
process is detached from the mandible and attached to the orbicularis
oris with a
fascial graft for length.
If the main vector to be reproduced to obtain
symmetry with the normal side is a lateral pull, then the masseter muscle can be
used since it is placed more inferiorly on the skull and can produce that
effect. The inferior portion of the muscle is released from the mandible
and brought anteriorly to insert on the upper and lower lips.
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