Atypical Innervation Of Palmaris Longus - A Case Report
Author(s): Chauhan, R.
Vol. 52, No. 2 (2003-07 - 2003-12)
Department of Anatomy, All India Institute of Medical Sciences, New Delhi- INDIA
Abstract
Palmaris longus muscle is gaining popularity for its role in reconstructive, plastic and cosmetic surgeries. Lip
augmentation and repair of congenital ptosis, collapsed lunate, acute thenar muscle injury and tendoachillis loss have been successfully
dealt using palmaris longus graft in one form or the other. Therefore, all possible variations in the innervation of such an important muscle
should be well known. In the present case median nerve innervated palmaris longus at the level of elbow (a usual site of innervation) and at
the level of distal third of forearm. The latter branch innervated the distal part of the tendon of palmaris longus and its aponeurosis. Clinical
importance of the knowledge of such kind of variation has been discussed in this paper.
Key words: Palmaris Longus, Innervation of Palmaris longus, median nerve, palmar aponeurosis.
Introduction:
A degenerate flexor muscle of the
metacarpophalangeal joint is the Palmaris longus.
Generally, it is innervated by a branch from the
median nerve in the proximal third of the forearm
usually near the elbow joint. Any variation in the
innervation of the palmaris longus is gaining
importance as it is becoming very popular amongst
graft material for reconstructive surgeries. Palmaris
longus muscle or its tendon have been used in
various combinations to repair oncologic defects of
head and neck, ptosis in children, arthritis of the
thumb with trapezium resection and in Camitz
opponensplasty for acute thenar muscle injury.
Complete knowledge of innervation of palmaris
longus is required by the operating surgeon to avoid
post operative complications in the donor hand and
for maintaining the required actions in operations
such as Camitz opponensplasty. Therefore, the
need to express the variation in the innervation of
palmaris longus in the left upper limb of the present
subject was realised.
Material and Methods:
During a routine dissection in the dissection
hall of Anatomy department of AIIMS, New Delhi, a
variation in the innervation of palmaris longus of left
upper limb of an adult male cadaver was noticed.
The region of interest was finely dissected and photographed.
Observations and Results:
In the left forearm and hand of an adult male
cadaver it was observed that the muscle belly of
palmaris longus received a branch from the median
nerve in the proximal third of the forearm near the elbow joint. With further progress of the dissection it
was noticed that another branch emerged from the
median nerve (arrow, fig.1) and ramified into a number of branches to innervate the distal most part of
the tendon and the proximal part of the palmar aponeurosis from its dorsal aspect (fig.2). These
branches further passed through the aponeurosis to
become cutaneous. Palmar cutaneous branch of the
median nerve emerged proximal to the branch for
the palmaris longus tendon (fig.1).
Discussion:
Palmaris longus, a muscle with small belly and
long thin tendon is becoming popular in reconstructive surgeries. Its presence in 70-85% population
(Wehbe, 1992) and its superficial location (Lam, et,
al 1998) makes it the most common donor material
for tendon and joint reconstructive surgeries (Lee,
1987) Palmaris longus is completely developed at
birth (Vastamaki, 1987), while fascia lata, which is
also used for reconstructive surgeries, is not so well
developed at that age. (Jordan and Anderson
1987). All these factors facilitate harvesting of
palmaris longus as the donor material in all age
groups.
Proximally, this muscle is attached to the
medial epicondyle of the humerus along with other
superficial flexors of the forearm. Distally its long
thin tendon forms the superficial portion of the mid
palmar fascia (Nigro, 2001). Skin and fascia of the
palm and digital webs give attachment to the fibres
of palmar fascia. The muscle is innervated by a
branch of the median nerve. Linell (1921) ;
Sunderland and Ray (1946) : Lazorthes (1955);
Bonnel and Mansat (1989) ; Canovas et al, (1998);
Gunther et al (1992) and Liu et al (1997) report that the distribution of median nerve is very variable. It is
important to bear a good knowledge of the
variations in innervation of the palmaris longus as it
is preferred for cosmetic, plastic and reconstructive
surgery. Lip augmentation is carried out using
palmaris longus muscle and its tendon (Davidson
1995) Collapsed lunate is replaced by tendon ball
implant made from the palmaris longus and
plantaris which frequently calcifies and ossifies post
operatively (Ueba 1999) Congenital ptosis is
successfully corrected using palmaris longus to
suspend frontalis (Lam et al, 1996). Autogenous
tendon is also used for ruptured extensor tendons in
the Rheumatoid hands (Mountney et al, 1998). In
acute thenar muscle injury when immediate Camitz
opponensplasty is performed by using palmaris
longus tendon with its distal palmar fascial extension
and suturing it to the insertion of the abductor
pollicis brevis under tension, it is seen that 79.7
90.1% opposition of the thumb to the fingers
(Kapandji test) is restored (Lin and Wei, 2000). For
improving thumb function especially opponens in
localized thenar muscle destruction, Cooney (1988);
Foucher et al (1991) and Terrono et al (1993) have
advocated palmaris longus transfer. Challenging
reconstructive problems like repair of loss of
tendoachillis with overlying skin has been
successfully dealt with radial forrearm palmaris
longus composite free flap (Isenberg and Fusi
1995). Postoperatively, according to these authors,
an ulnar drift of the wrist and abdominal laxity are
seen in donor for Flexor carpi radialis and External
oblique graft respectively. These post operative
complications in the donor can be avoided if
palmaris longus is used as a graft as loss of this
tendon results in no major abnormality of hand
function. But Mc Grouther (1996) states that the
main function of palmaris longus is to anchor the
skin and fascia of hand and hence to prevent
degloving of palmar skin from horizontal shearing
forces. Therefore, variations in the innervation of
such a clinically important muscle should be of
interest both to the academicians and clinicians.
In the present case a separate branch of
median nerve distal to the palmar cutaneous branch
of median nerve (fig.1) was given off which ramified
and then innervated the distal part of the tendon of
palmaris longus and the palmar aponeurosis from their dorsal aspect. The ramifications further
seemed to pierce the palmar aponeurosis, in which
case it is likely to innervate the palmar skin to a
variable extent. Very fine dissection of the nerve to
palmaris longus tendon and palmar aponeurosis was
not possible as the branches of the nerve were very
delicate and fragile and broke whenever
microdissection was attempted under dissecting
microscope.
Surgeons handling palmaris longus graft
should be aware of this kind of variation so as to
preserve the function of the palmar aponeurosis in
the donor hand. Accidental damage of this nerve if
present may result in degloving of the palmar skin in
the donor limb along with post operative tenderness
and dysaesthesia or occasional pain in the thenar
and hypothenar eminence. Accidental damage or
ignorance of the presence of this type of branch of
median nerve to the tendon and palmar aponeurosis
may lead to ineffective opponensplasty using
palmaris longus graft in thenar muscle damage.
Although occasional passage of palmar cutaneous
branch of the median nerve through the substance
of palmaris longus tendon has been reported
(Kleinert, et al 1991) but the variation noted in the
present case has no mention in the literature.
References:
- Bonnel, F., Mansat, M. (1989) : Nerfs Peripheriques
(anatomie et pathologic chirurgicale) Masson, Paris, Tome 1,
pp 110-132.
- Canovas, F., Mouilleron, P., Bonnel, F. (1998) : Biometry of
the muscular branches of the median nerve to the forearm.
Clinical Anatomy 11 : 239-245.
- Cooney, W. R. (1988) : Tendon transfer for median nerve
palsy. Hand Clinic. 4 : 155 - 165.
- Davidson, B. A. (1995) : Lip Augmentation using the Palmaris
Longus tendon Plastic and Reconstructive Surgery. 95 (6) :
1108 - 1110.
- Foucher, G., Malizon, C. Sammut, D., Braun, F.M. (1991) :
Primary Palmaris longus transfer as an opponensplasty in
carpal tunnel syndrome. Journal of Hand Surgery 16B : 56
60.
- Gunther, S. F., Di Pasquale, D., Martin, R. (1992) : The
Internal anatomy of the median nerve in the region of the
elbow. Journal of Hand Surgery. 17-A : 648-656.
- Isenberg, J.S., Fusi, S. (1995) : Immediate tendon Achilles
reconstruction with composite palmaris longus grafts. Annals
of Plastic Surgery 34 : 209-211.
- Jordan, R. and Anderson, R.L. (1987) : Obtaining fascia lata.
Archives of Ophthalmology. 105 : 139-140.
- Kleinert, H.E. Smith D., J., Pulvertaft, R.G.: Flynn's hand
surgery. 4th Edn. Williams and Wilkins. Baltimore. p 285.
(1991).
- Lam, D.S.C., Lam, T.P., Chen, I.N., Tsang, G.H., Gandhi,
S.R. (1996) : Palmaris longus tendon as a new autogenous
material for frontalis suspension surgery in adults. Eye. 10 :
38 - 42.
- Lam, D.S.C., NG, J.S.K. Cheng, G.P.M., Li, R.T.H. (1998) :
Autogenous Palmaris Longus Tendon as Frontalis
Suspension material for Ptosis Correction in children.
American Journal of Ophthalmology. 126 (1) : 109-115
- Lazorthes, G. : Le systeme nerveux peripherique. Masson,
Paris, pp 233. (1955).
- Lee, M.: Campbell's Operative Orthopaedics In : Tendon
Injuries. C.V. Mosby. St. Louis : pp 175. (1987).
- Lin C.H., Wei F.C. (2000) : Immediate Camitz
Opponensplasty in Acute Thenar Muscle Injury. Annals of
Plastic Surgery . 44 (3) : 270-276.
- Linell, E. (1921) : The distribution of the nerves in the upper
limb, with reference to variabilities and their clinical
significance. Journal of Anatomy 55 : 79-112.
- Liu, J., Pho, R., Pereira, B., Lau, H.K. (1997) : Distribution of
primary motor nerve branches and terminal nerve entry points
to the forearm muscles. Anatomical Record. 248 : 456-463.
- Mc Grouther, D.A. Gray's anatomy In: Muscle. 38th Edn;
Churchill Livingstone Edinburgh. p 846. (1996).
- Mountney, J., Blundell, C.M., McArthur, P., Stanley, D. (1998)
: Free tendon interposition grafting for the repair of ruptured
extensor tendons in the rheumatoid hand. A clinical and
biomechanical assessment. Journal of Hand Surgery (Br).
23 (5) : 662-665.
- Nigro,R.O. (2001) : Anatomy of the flexor retinaculum of the
wrist and the flexor carpi radialis tunnel. Hand Clinic 17 (1) :
61-64
- Sunderland, S., Ray, L. (1946) : Metrical and non metrical
features of the muscular rameaux of the median nerves.
Journal of Comparative Neurology 85 : 191-203.
- Terrono, A.L., Rose, J.H., Mulory, J., Millender, L.H. (1993) :
Camitz palmaris longus abductorplasty for severe thenar
atrophy secondary to carpal tunnel syndrome. Journal of
Hand Surgery. 18A : 204-206.
- Uba, Y., Nosaka, K. Seto, Y., lkeda, N., Nakamura, T. (1999) :
An operative procedure for advanced Kienbock's disease.
excision of lunate and subsequent replacement with a tendon
ball implant. Journal of Orthopaedic Science . 4 (3) :
207- 215.
- Vastamaki, M. (1987) : Median nerve as free tendon graft.
Journal of Hand Surgery. 12 : 187-188.
- Wehbe, M. A. (1992) : Tendon graft donor sites. Journal of
Hand Surgery. 17 : 1130-1132.
FIG-1
Photograph of the dissected left lower forearm, wrist and hand
showing a branch (arrow) of the median nerve (M) innervating
tendon (T) of palmaris longus muscle.
C : Palmar cutaneous branch of median nerve, P : Palmar
aponeurosis
FIG-2
Dissected left lower forearm, wrist and hand showing the branch
(arrow) of the median nerve (M) innervating tendon (T) of palmaris
longus muscle and palmar aponeurosis (P) from its dorsal aspect.
Department of Anatomy, All India Institute of Medical Sciences, New Delhi- INDIA
Abstract
Palmaris longus muscle is gaining popularity for its role in reconstructive, plastic and cosmetic surgeries. Lip augmentation and repair of congenital ptosis, collapsed lunate, acute thenar muscle injury and tendoachillis loss have been successfully dealt using palmaris longus graft in one form or the other. Therefore, all possible variations in the innervation of such an important muscle should be well known. In the present case median nerve innervated palmaris longus at the level of elbow (a usual site of innervation) and at the level of distal third of forearm. The latter branch innervated the distal part of the tendon of palmaris longus and its aponeurosis. Clinical importance of the knowledge of such kind of variation has been discussed in this paper.
Key words: Palmaris Longus, Innervation of Palmaris longus, median nerve, palmar aponeurosis.
Introduction:
A degenerate flexor muscle of the metacarpophalangeal joint is the Palmaris longus. Generally, it is innervated by a branch from the median nerve in the proximal third of the forearm usually near the elbow joint. Any variation in the innervation of the palmaris longus is gaining importance as it is becoming very popular amongst graft material for reconstructive surgeries. Palmaris longus muscle or its tendon have been used in various combinations to repair oncologic defects of head and neck, ptosis in children, arthritis of the thumb with trapezium resection and in Camitz opponensplasty for acute thenar muscle injury.
Complete knowledge of innervation of palmaris longus is required by the operating surgeon to avoid post operative complications in the donor hand and for maintaining the required actions in operations such as Camitz opponensplasty. Therefore, the need to express the variation in the innervation of palmaris longus in the left upper limb of the present subject was realised.
Material and Methods:
During a routine dissection in the dissection hall of Anatomy department of AIIMS, New Delhi, a variation in the innervation of palmaris longus of left upper limb of an adult male cadaver was noticed. The region of interest was finely dissected and photographed.
Observations and Results:
In the left forearm and hand of an adult male cadaver it was observed that the muscle belly of palmaris longus received a branch from the median nerve in the proximal third of the forearm near the elbow joint. With further progress of the dissection it was noticed that another branch emerged from the median nerve (arrow, fig.1) and ramified into a number of branches to innervate the distal most part of the tendon and the proximal part of the palmar aponeurosis from its dorsal aspect (fig.2). These branches further passed through the aponeurosis to become cutaneous. Palmar cutaneous branch of the median nerve emerged proximal to the branch for the palmaris longus tendon (fig.1).
Discussion:
Palmaris longus, a muscle with small belly and long thin tendon is becoming popular in reconstructive surgeries. Its presence in 70-85% population (Wehbe, 1992) and its superficial location (Lam, et, al 1998) makes it the most common donor material for tendon and joint reconstructive surgeries (Lee, 1987) Palmaris longus is completely developed at birth (Vastamaki, 1987), while fascia lata, which is also used for reconstructive surgeries, is not so well developed at that age. (Jordan and Anderson 1987). All these factors facilitate harvesting of palmaris longus as the donor material in all age groups.
Proximally, this muscle is attached to the medial epicondyle of the humerus along with other superficial flexors of the forearm. Distally its long thin tendon forms the superficial portion of the mid palmar fascia (Nigro, 2001). Skin and fascia of the palm and digital webs give attachment to the fibres of palmar fascia. The muscle is innervated by a branch of the median nerve. Linell (1921) ; Sunderland and Ray (1946) : Lazorthes (1955); Bonnel and Mansat (1989) ; Canovas et al, (1998); Gunther et al (1992) and Liu et al (1997) report that the distribution of median nerve is very variable. It is important to bear a good knowledge of the variations in innervation of the palmaris longus as it is preferred for cosmetic, plastic and reconstructive surgery. Lip augmentation is carried out using palmaris longus muscle and its tendon (Davidson 1995) Collapsed lunate is replaced by tendon ball implant made from the palmaris longus and plantaris which frequently calcifies and ossifies post operatively (Ueba 1999) Congenital ptosis is successfully corrected using palmaris longus to suspend frontalis (Lam et al, 1996). Autogenous tendon is also used for ruptured extensor tendons in the Rheumatoid hands (Mountney et al, 1998). In acute thenar muscle injury when immediate Camitz opponensplasty is performed by using palmaris longus tendon with its distal palmar fascial extension and suturing it to the insertion of the abductor pollicis brevis under tension, it is seen that 79.7 90.1% opposition of the thumb to the fingers (Kapandji test) is restored (Lin and Wei, 2000). For improving thumb function especially opponens in localized thenar muscle destruction, Cooney (1988); Foucher et al (1991) and Terrono et al (1993) have advocated palmaris longus transfer. Challenging reconstructive problems like repair of loss of tendoachillis with overlying skin has been successfully dealt with radial forrearm palmaris longus composite free flap (Isenberg and Fusi 1995). Postoperatively, according to these authors, an ulnar drift of the wrist and abdominal laxity are seen in donor for Flexor carpi radialis and External oblique graft respectively. These post operative complications in the donor can be avoided if palmaris longus is used as a graft as loss of this tendon results in no major abnormality of hand function. But Mc Grouther (1996) states that the main function of palmaris longus is to anchor the skin and fascia of hand and hence to prevent degloving of palmar skin from horizontal shearing forces. Therefore, variations in the innervation of such a clinically important muscle should be of interest both to the academicians and clinicians.
In the present case a separate branch of median nerve distal to the palmar cutaneous branch of median nerve (fig.1) was given off which ramified and then innervated the distal part of the tendon of palmaris longus and the palmar aponeurosis from their dorsal aspect. The ramifications further seemed to pierce the palmar aponeurosis, in which case it is likely to innervate the palmar skin to a variable extent. Very fine dissection of the nerve to palmaris longus tendon and palmar aponeurosis was not possible as the branches of the nerve were very delicate and fragile and broke whenever microdissection was attempted under dissecting microscope.
Surgeons handling palmaris longus graft should be aware of this kind of variation so as to preserve the function of the palmar aponeurosis in the donor hand. Accidental damage of this nerve if present may result in degloving of the palmar skin in the donor limb along with post operative tenderness and dysaesthesia or occasional pain in the thenar and hypothenar eminence. Accidental damage or ignorance of the presence of this type of branch of median nerve to the tendon and palmar aponeurosis may lead to ineffective opponensplasty using palmaris longus graft in thenar muscle damage. Although occasional passage of palmar cutaneous branch of the median nerve through the substance of palmaris longus tendon has been reported (Kleinert, et al 1991) but the variation noted in the present case has no mention in the literature.
References:
- Bonnel, F., Mansat, M. (1989) : Nerfs Peripheriques (anatomie et pathologic chirurgicale) Masson, Paris, Tome 1, pp 110-132.
- Canovas, F., Mouilleron, P., Bonnel, F. (1998) : Biometry of the muscular branches of the median nerve to the forearm. Clinical Anatomy 11 : 239-245.
- Cooney, W. R. (1988) : Tendon transfer for median nerve palsy. Hand Clinic. 4 : 155 - 165.
- Davidson, B. A. (1995) : Lip Augmentation using the Palmaris Longus tendon Plastic and Reconstructive Surgery. 95 (6) : 1108 - 1110.
- Foucher, G., Malizon, C. Sammut, D., Braun, F.M. (1991) : Primary Palmaris longus transfer as an opponensplasty in carpal tunnel syndrome. Journal of Hand Surgery 16B : 56 60.
- Gunther, S. F., Di Pasquale, D., Martin, R. (1992) : The Internal anatomy of the median nerve in the region of the elbow. Journal of Hand Surgery. 17-A : 648-656.
- Isenberg, J.S., Fusi, S. (1995) : Immediate tendon Achilles reconstruction with composite palmaris longus grafts. Annals of Plastic Surgery 34 : 209-211.
- Jordan, R. and Anderson, R.L. (1987) : Obtaining fascia lata. Archives of Ophthalmology. 105 : 139-140.
- Kleinert, H.E. Smith D., J., Pulvertaft, R.G.: Flynn's hand surgery. 4th Edn. Williams and Wilkins. Baltimore. p 285. (1991).
- Lam, D.S.C., Lam, T.P., Chen, I.N., Tsang, G.H., Gandhi, S.R. (1996) : Palmaris longus tendon as a new autogenous material for frontalis suspension surgery in adults. Eye. 10 : 38 - 42.
- Lam, D.S.C., NG, J.S.K. Cheng, G.P.M., Li, R.T.H. (1998) : Autogenous Palmaris Longus Tendon as Frontalis Suspension material for Ptosis Correction in children. American Journal of Ophthalmology. 126 (1) : 109-115
- Lazorthes, G. : Le systeme nerveux peripherique. Masson, Paris, pp 233. (1955).
- Lee, M.: Campbell's Operative Orthopaedics In : Tendon Injuries. C.V. Mosby. St. Louis : pp 175. (1987).
- Lin C.H., Wei F.C. (2000) : Immediate Camitz Opponensplasty in Acute Thenar Muscle Injury. Annals of Plastic Surgery . 44 (3) : 270-276.
- Linell, E. (1921) : The distribution of the nerves in the upper limb, with reference to variabilities and their clinical significance. Journal of Anatomy 55 : 79-112.
- Liu, J., Pho, R., Pereira, B., Lau, H.K. (1997) : Distribution of primary motor nerve branches and terminal nerve entry points to the forearm muscles. Anatomical Record. 248 : 456-463.
- Mc Grouther, D.A. Gray's anatomy In: Muscle. 38th Edn; Churchill Livingstone Edinburgh. p 846. (1996).
- Mountney, J., Blundell, C.M., McArthur, P., Stanley, D. (1998) : Free tendon interposition grafting for the repair of ruptured extensor tendons in the rheumatoid hand. A clinical and biomechanical assessment. Journal of Hand Surgery (Br). 23 (5) : 662-665.
- Nigro,R.O. (2001) : Anatomy of the flexor retinaculum of the wrist and the flexor carpi radialis tunnel. Hand Clinic 17 (1) : 61-64
- Sunderland, S., Ray, L. (1946) : Metrical and non metrical features of the muscular rameaux of the median nerves. Journal of Comparative Neurology 85 : 191-203.
- Terrono, A.L., Rose, J.H., Mulory, J., Millender, L.H. (1993) : Camitz palmaris longus abductorplasty for severe thenar atrophy secondary to carpal tunnel syndrome. Journal of Hand Surgery. 18A : 204-206.
- Uba, Y., Nosaka, K. Seto, Y., lkeda, N., Nakamura, T. (1999) : An operative procedure for advanced Kienbock's disease. excision of lunate and subsequent replacement with a tendon ball implant. Journal of Orthopaedic Science . 4 (3) : 207- 215.
- Vastamaki, M. (1987) : Median nerve as free tendon graft. Journal of Hand Surgery. 12 : 187-188.
- Wehbe, M. A. (1992) : Tendon graft donor sites. Journal of Hand Surgery. 17 : 1130-1132.
FIG-1
Photograph of the dissected left lower forearm, wrist and hand showing a branch (arrow) of the median nerve (M) innervating tendon (T) of palmaris longus muscle.
C : Palmar cutaneous branch of median nerve, P : Palmar aponeurosis
FIG-2
Dissected left lower forearm, wrist and hand showing the branch (arrow) of the median nerve (M) innervating tendon (T) of palmaris longus muscle and palmar aponeurosis (P) from its dorsal aspect.