Purpose
Forearm muscles can undergo contracture for a number of reasons, including spasticity.
This deformity is amenable to surgical treatment in select cases. Among the different
techniques available, fractional lengthening of the forearm flexor muscles involves
multiple tenotomies at the musculotendinous junction. We studied the anatomy of the
musculotendinous junction of all forearm flexor muscles to analyze the topography
and extent of muscle-tendon overlapping for each muscle and to determine the area
where fractional lengthening can be performed safely.
Methods
Dissections were performed on 20 fresh cadaveric upper limbs. For each muscle, we
defined and measured the total overlapping zone, “corrected” overlapping zone, and
useful zone (UZ), along with 3-dimensional mapping of the location of each tendon
with respect to the muscles’ fibers.
Results
With regard to the wrist flexors, the average UZ was very short for the flexor carpi
radialis (3.5 cm) and very long for the flexor carpi ulnaris (12.2 cm). With regard
to the finger flexors, the UZ of the superficialis tendons varied greatly (2.7–5.9
cm), whereas it was relatively constant for the profundi (7.6 cm) and flexor pollicis
longus (6.5 cm).
Conclusions
Fractional lengthening is dependent on the anatomy of the musculotendinous junction
of each individual muscle. For muscles with a relatively short and variable UZ (flexor
carpi radialis, flexor digitorum superficialis [FDS] II, and FDS IV), the feasibility
of the procedure must be carefully evaluated intraoperatively. For FDS V, which constantly
displays a very short UZ, with a thin and fragile tendon, the procedure may be risky
and unreliable.
Clinical relevance
When considering fractional lengthening of the forearm muscles, differences between
the tendons should be considered, and surgeons should be prepared for alternative
approaches, especially for FDS V.
Key words
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References
- Flexor-origin release for the pronation-flexion deformity of the forearm and hand in the stroke patient.J Bone Joint Surg Am. 1970; 52: 907-920
- Structural and dynamic bases of hand surgery.Am J Phys Med. 1970; 49: 321
- An operation for the relief of flexion-contracture in the forearm.J Bone Joint Surg Am. 1923; 5: 233-234
- Flexor origin slide for contracture of spastic finger flexor muscles: a retrospective study.J Bone Joint Surg Am. 2013; 95: 446-453
- Preliminary experience with superficialis-to-profundus tendon transfer in the hemiplegic upper extremity.J Bone Joint Surg Am. 1974; 56: 466-472
- Upper extremity surgery in stroke patients.Clin Orthop Relat Res. 1978; 131: 30-37
- Results of fractional lengthening of finger flexors in adults with upper extremity spasticity.J Hand Surg Am. 1987; 12: 575-581
- Die sehnenüberpflanzung und ihre verwertung in der behandlung der lähnungen.Verlag von Veit, Leipzig1902: 68
- Flexor tendon lengthening by tenotomy at the musculotendinous junction.Ann Plast Surg. 1986; 17: 239-246
- Upper extremity dysfunction after stroke or brain injury.in: Wolfe S. Pederson W. Kozin S. Green's Operative Hand Surgery. 6th ed. Churchill Livingstone, 2010: 1-35
- Results and complications of superficialis-to-profundus tendon transfer in brain-damaged patients, a series of 26 patients.Orthop Traumatol Surg Res. 2018; 104: 121-126
- Surgery of the upper limb in cerebral palsy.Orthop Clin N Am. 2010; 41: 519-529
- Surgical management of the hemiplegic spastic hand in cerebral palsy.Surg Clin N Am. 1981; 61: 395-406
- Treatment of the wrist and hand in cerebral palsy.J Hand Surg Am. 2006; 31: 483-490
- Architecture of selected muscles of the arm and forearm: anatomy and applications for tendon transfer.J Hand Surg Am. 1992; 17: 787-798
- Additional observations on muscular anomalies in human anatomy (3rd series), with a catalogue of the principal muscular variations hitherto published.Trans Royal Irish Acad Sci. 1871; 25: 1-134
- Illustrated Encyclopedia of Human Anatomic Variation: Opus I: Muscular System: Alphabetical Listing of Muscles: Flexor Digitorum Superficialis.(Accessed August 6, 2021)
Article info
Publication history
Published online: September 03, 2021
Accepted:
July 14,
2021
Received:
August 10,
2020
Footnotes
No benefits in any form have been received or will be received related directly or indirectly to the subject of this article.
Identification
Copyright
© 2022 by the American Society for Surgery of the Hand. All rights reserved.
