Together the flexor pollicis longus, pronator quadratus, and flexor digitorum profundus form the deep layer of ventral forearm muscles.[1] The muscle is named from Latin 'deep bender of the fingers'.
Structureedit
Flexor digitorum profundus originates in the upper 3/4 of the anterior and medial surfaces of the ulna, interosseous membrane and deep fascia of the forearm. The muscle fans out into four tendons (one to each of the second to fifth fingers) to the palmar base of the distal phalanx.[citation needed]
Flexor digitorum profundus lies deep to the superficialis, but it attaches more distally. Therefore, profundus's tendons go through the tendons of superficialis, and end up attaching to the distal phalanx. For this reason profundus is also called the perforating muscle.[1]
It is one of two flexor muscles that is not exclusively supplied by the median nerve (the other is flexor carpi ulnaris). In the forearm, the median nerve travels distally between the flexor digitorum superficialis and the flexor digitorum profundus.[6][7]
Variationedit
The tendon of the index finger often has a separate muscle belly.[1]
Functionedit
Flexor digitorum profundus is a flexor of the wrist (midcarpal), metacarpophalangeal and interphalangeal joints.[1] The lumbricals, intrinsic muscles of the hand, attach to the tendon of flexor digitorum profundus. Thus, the flexor muscle is used to aid the lumbrical muscles in their role as extensors of the interphalangeal joints. As the lumbrical muscles originate on the palmar side of the hand and attach on the dorsal aponeurosis, power is transferred from the flexor digitorum profundus muscle to fully extend the fingers as well as flex the metacarpophalangeal joints.[citation needed]
The tension generated by flexor digitorum profundus at the more distal joints is determined by wrist position. Flexion of the wrist causes muscle shortening at that point, reducing tension that can be generated more distally. Fingers cannot be fully flexed if the wrist is fully flexed.[8]
Other animalsedit
In many primates, the FDP is fused with the flexor pollicis longus (FPL). In great apes the belly of the FDP has a separate tendon for the FDP. In lesser apes, both muscles have separate bellies in the forearm, but in Old World monkeys they separate in the carpal tunnel. The lack of differentiation in the FDP musculature in baboons makes it unlikely that this monkey can control individual fingers independently.
[9]
^ abLutsky KF, Giang EL, Matzon JL (January 2015). "Flexor tendon injury, repair and rehabilitation". Orthopedic Clinics of North America. 46 (1): 67–76. doi:10.1016/j.ocl.2014.09.004. PMID 25435036.
^Lobo, Errol P.; Pellegrini, Francesca; Pusceddu, Elisabetta (2009-01-01), Eisele, David W.; Smith, Richard V. (eds.), "CHAPTER 1 - Anesthesia Complications in Head and Neck Surgery", Complications in Head and Neck Surgery (Second Edition), Philadelphia: Mosby, pp. 3–27, doi:10.1016/b978-141604220-4.50005-5, ISBN 978-1-4160-4220-4, retrieved 2020-10-22
^ abFernández de las Peñas, César; Ge, Hong-You; Arendt-Nielsen, Lars; Dommerholt, Jan; Simons, David G. (2011-01-01), Fernández de las Peñas, César; Cleland, Joshua A.; Huijbregts, Peter A. (eds.), "Chapter 32 - Referred pain from muscle/myofascial trigger points", Neck and Arm Pain Syndromes, Edinburgh: Churchill Livingstone, pp. 404–418, doi:10.1016/b978-0-7020-3528-9.00032-7, ISBN 978-0-7020-3528-9, retrieved 2020-10-22
^Moscony, ANNE M. B. (2007-01-01), Cooper, Cynthia (ed.), "Chapter 12 - Common Peripheral Nerve Problems", Fundamentals of Hand Therapy, Saint Louis: Mosby, pp. 201–250, doi:10.1016/b0-32-303386-5/50015-1, ISBN 978-0-323-03386-2, retrieved 2020-10-22
^ abTubbs, R. Shane; Goodrich, Dylan; Watanabe, Koichi; Loukas, Marios (2015-01-01), Tubbs, R. Shane; Rizk, Elias; Shoja, Mohammadali M.; Loukas, Marios (eds.), "Chapter 43 - Anatomic Landmarks for Selected Nerves of the Head, Neck, and Upper and Lower Limbs", Nerves and Nerve Injuries, San Diego: Academic Press, pp. 575–588, doi:10.1016/b978-0-12-410390-0.00045-7, ISBN 978-0-12-410390-0, retrieved 2020-10-22
^Ross, Allison Kinder; Bryskin, Robert B. (2011-01-01), Davis, Peter J.; Cladis, Franklyn P.; Motoyama, Etsuro K. (eds.), "CHAPTER 16 - Regional Anesthesia", Smith's Anesthesia for Infants and Children (Eighth Edition), Philadelphia: Mosby, pp. 452–510, doi:10.1016/b978-0-323-06612-9.00016-x, ISBN 978-0-323-06612-9, retrieved 2020-10-22
^Levangie, Pamela K; Norkin, Cynthia C (2011). Joint Structure and Function: A Comprehensive Analysis (5 ed.). F.A. Davis. p. 326. ISBN 978-0803626348.
Platzer, Werner (2004). Color Atlas of Human Anatomy, Vol. 1: Locomotor System (5th ed.). Thieme. ISBN 3-13-533305-1.
Tocheri, MW; Orr, CM; Jacofsky, MC; Marzke, MW. (April 2008). "The evolutionary history of the hominin hand since the last common ancestor of Pan and Homo". J. Anat. 212 (4): 544–62. doi:10.1111/j.1469-7580.2008.00865.x. PMC2409097. PMID 18380869. (Abstract, PubMed) (PDF Archived 2013-12-09 at the Wayback Machine, Smithsonian)
External linksedit
Illustration: upper-body/flexor-digitorum-profundus from The Department of Radiology at the University of Washington