Disclosure: The authors have no nancial interest to declare
in relation to the content of this article.
From the *Plastic Surgery Department, Hamad General Hospital,
Hamad Medical Corporation, Doha, Qatar; †Ganga Hospital,
Coimbatore, Tamil Nadu, India; ‡DAFPRS, Rotterdam, The
Netherlands; and §Customer of Patient's Experience and Staff
Engagement (CPESE), Hamad Medical Corporation, Doha, Qatar.
Received for publication February 24, 2021; accepted January 6,
Copyright © 2022 The Authors. Published by Wolters Kluwer Health,
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Although it is relatively uncommon in the popula-
tion, muscle anomalies of the forearm may be encoun-
tered by nearly all hand surgeons over the course of their
careers. These anomalies can be symptomatic but gener-
ally speaking‚ most of them are asymptomatic.1 Despite
its rareness, every surgeon should anticipate the aversion
from normal anatomy, as it might have signicant impact
on the patient’s outcome and quality of life. The pal-
maris longus (PL) muscle has the most common anoma-
lies described in the literature. In this article, we present
an incidental nding of an aberrant muscle in one of our
patients that was operated for right distal forearm lacera-
tion. We believe that this muscle could be considered as
one of the PL muscle variations that has not been men-
tioned in the literature reviews.
A 24-year-old man, right-handed, laborer, nonsmoker,
nonalcoholic, with no past medical or surgical history, sus-
tained a deep laceration to his right distal forearm by a
glass during work. He had no hand complaint before the
On examination‚ he had a15-cm deep laceration on
the volar aspect of theright distal forearm more on the
ulnar side, with weak exion at proximal interphalangeal
joints, weak wrist exion, normal sensory examination,
palpable radial artery, and ulnar arteries with capillary
rell less than 2 seconds. After stabilization and initiation
of antibiotics and pain killers, he was admitted for explo-
ration and repair of cut structures.
The patient was operated on the next day under
regional anesthesia and a tourniquet was applied for
60 minutes on pressure of 250 mm Hg. The wound was
extended minimally‚ proximally‚ and distally for explo-
ration, and the ndings were as follows: complete cut of
exor digitorum supercialis (FDS) of the fourth and
fth digits, partial cut FDS (60 %) of third digit, complete
cut exor carpi radialis, andcomplete cut PL, all of them
at zone 5. Along with that, we noticed an aberrant mus-
cle that was cut completely. All other muscles and their
Salim Allahham, MD*†‡
Zaki T. N. Alyazji, MD*
Ghanem Aljassem, MD*
Ruba Sada, MD, PM, CPESE§
Iqbal Rasool Wani, MD*
Summary: Upper limb muscle anomalies and their clinical implications have been
described frequently in the literature reviews. In this article, we are presenting a
case of aberrant forearm muscle that had not been described before, and could
be considered as a palmaris longus muscle variation. A 24-year-old man presented
to the emergency department, Hamad General Hospital, Doha, Qatar, with right
forearm laceration with multiple cutstructures for which he was admitted for explo-
ration and repair. Intraoperatively, exor digitorum supercialis of the third, fourth,
and fth digits, exor carpi radialis, andpalmaris longus were injured‚ and all of
them were repaired. We noticed an aberrant muscle—which was also injured—that
originated from the distal third of the radius on its medial aspect to insert into the
palmar fascia; pulling this muscle’s tendon resulted in tightening of palmar fascia‚
same as thepalmaris longus. Along with the importance of deep knowledge of typi-
cal human anatomy, hand surgeons must be aware that an aberration from normal
anatomy might be anticipated, to provide the best care to our patients.
(Plast Reconstr Surg Glob Open 2022;10:e4240; doi: 10.1097/GOX.0000000000004240;
Published online 29 April 2022.)
A Rare Anatomical Finding of Undescribed
Accessory Palmaris Longus in the Distal
Forearm: A Case Report
PRS Global Open • 2022
tendons, nerves, and arteries were identied and were
intact. The abovementioned aberrant muscle originates
from the distal third of the radius on its medial aspect and
inserts into the palmar fascia separately from PL tendon,
pulling its tendon resulted in tightening of palmar fascia
(Figs. 1–3). All injured structures were repaired using
Ethilon 3-0 by modied Kessler technique (if complete
cut) and epitenon continuous suturing with Ethilon 5-0,
or horizontal mattress with 4-0 Ethilon (if incomplete).
Postoperatively, the patient stayed for 2 days for pain
management, and was referred to the inpatient occupa-
tional therapist to apply the proper splint and start the
rehabilitation program. The patient was discharged on
antibiotics for atotal of 7 days. He continued occupational
therapy for a period of 8 weeks with frequent clinic visits,
andafter 2 months he had full range of motionand com-
pletely healed wounds and resumed his work.
One of the most encountered muscles with aberra-
tions is thePL muscle. The normal PL originates from the
medial epicondyle with a proximal muscle belly and long
distal tendon that inserts into the palmar fascia.
However, a substantial amount of variation has been
noted, with variations reported as duplicate, reversed, cen-
trally located, bid, divided with an ulnar slip, or hypertro-
phic, in addition to variations in the muscle belly representing
50% of the anomalies of the PL reported.2 The PL can origi-
nate from the lacertus brosis, FDS, exor carpi radialis, and
exor carpi ulnaris and may insert into the antebrachial fas-
cia, thenar eminence, exor carpi ulnaris, or into the car-
pal bones. An accessory tendon may also exist at the ulnar
aspect of the main tendon distally.2 Epidemiologically‚ in a
study byReimann et al2, PL in 9% of the study population
exhibited variations with respect to form, origin, or insertion.
Another muscle anomaly is exor carpi radialis brevis
(FCRB), which has been described historically as “short
radiocarpal exor.”3 The FCRB commonly originates from
the volar aspect of the mid to distal third of the radius and
courses supercial to the pronator quadratus outside of
the carpal tunnel.1 The FCRB has been noted to insert
into the second, third, or fourth metacarpals,4,5 the trape-
zium,6 or the capitate.5 The FCRB may travel distally in the
same sheath as the exor carpi radialis.7
One more forearm muscle anomaly is thepalmaris pro-
fundus (PP). Origins and insertions may vary, but the PP is
characterized by its course through the carpal tunnel adjacent
to the median nerve and its insertion into the palmar apo-
neurosis distally. Possible origins include the radial diaphysis,
ulnar diaphysis, FDS fascia, PL, exor pollicis longus, or the
medial epicondyle. Insertion variations can include the third
metacarpal or the radial carpal bones in some instances. It has
also been found as either reversed or bitendinous.8–10
As described above, our patient had a muscle anomaly
originating from the distal third of the radius and inserted
at the palmar fascia, pulling its tendon andresulting in
tightening of palmar fascia. Our thorough search in the
literaturefound no records of such ananomaly consider-
ing the described origin and insertion.
Describing variations of the human anatomy is and
has always been essential for the progress of the surgical
Fig. 1. The cut PL and‚ adjacent to it‚ the aberrant muscle tendon‚
both with complete cuts.
Fig. 2. A complete cut of PL and aberrant muscle belly and tendon,
in addition to acomplete cut of the FCR tendon.
Fig. 3. The proximal and distal ends of the PL and aberrant muscle
Allahham et al. • Undescribed Accessory PL in the Distal Forearm
science. It helps surgeons to anticipate what to face in the
surgical eld and how to deal with it properly to get the
best patient outcomes; this encouraged us to write our
article to add this unique presentation to the spectrum of
hand muscle variations.
Zaki T. N. Alyazji, MD,
Plastic Surgery Department, Hamad General Hospital
Hamad Medical Corporation
We thank the Qatar National Library for funding the open
access publication of this case report. We acknowledge the peer
reviewers for their valuable comments and feedback that led to
signicantly enhancing the manuscript.
Patients provided written consent for the use of their images.
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