Palmaris Longus: Difference between revisions

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== Description  ==
== Description  ==
[[File:Palmaris-longus.jpg|thumb|<ref name=":0">Derek Moore. ''Palmaris Longus''. Available from: https://www.orthobullets.com/anatomy/10023/palmaris-longus [Accessed: 12 June 2018]</ref> Pictorial representation of an isolated Palmaris Longus muscle in the flexor compartment of the forearm]]
[[File:Palmaris-longus.jpg|thumb|<ref name=":0">Derek Moore. ''Palmaris Longus''. Available from: https://www.orthobullets.com/anatomy/10023/palmaris-longus [Accessed: 12 June 2018]</ref> Pictorial representation of an isolated Palmaris Longus muscle in the flexor compartment of the forearm]]
The Palmaris longus (PL) muscle is a long, slender muscle which is usually present in the volar compartment of the forearm, interposed between the flexor carpi ulnaris and the flexor carpi radialis muscles.  
The Palmaris longus (PL) muscle is a long, slender muscle which is usually present in the volar compartment of the forearm, interposed between the Flexor Carpi Ulnaris and the Flexor Carpi Radialis muscles.  


However, it is currently accepted as a vestigial muscle since studies have shown that almost 30% of the population could be lacking this muscle either in one forearm (unilateral) or both the forearms (bilateral) but the percentage can always vary. The peculiarity associated with this muscle is not merely its presence or absence, but it's high degree of anatomical variations even when present.
However, it has been accepted as a vestigial muscle since studies have shown that almost 30% of the population could be lacking this muscle either in one forearm (unilateral) or both the forearms (bilateral) but the percentage can always vary. The peculiarity associated with this muscle is not merely its presence or absence, but it's high degree of anatomical variations even when present.


Apart from its anatomical anomalies, there are other categories of variations of the Palmaris Longus muscle in terms of its prevalence amongst different ethnicities, it's absence being more common in women and bilateral as well as the higher occurrence on the left upper limb when unilateral<ref>Sebastin SJ, Lim AY, Wong H. [https://pdfs.semanticscholar.org/ec8c/2fae00d35494c4695c72c226f427845714d8.pdf Clinical assessment of absence of the palmaris longus and its association with other anatomical anomalies-a Chinese population study. Annals-academy of Medicine Singapore]. 2006 Apr 1;35(4):249.</ref>.
Apart from its anatomical anomalies, there are other categories of variations of the Palmaris Longus muscle in terms of its prevalence amongst different ethnicities, it's absence being more common in women and bilateral as well as the higher occurrence on the left upper limb when unilateral<ref>Sebastin SJ, Lim AY, Wong H. [https://pdfs.semanticscholar.org/ec8c/2fae00d35494c4695c72c226f427845714d8.pdf Clinical assessment of absence of the palmaris longus and its association with other anatomical anomalies-a Chinese population study. Annals-academy of Medicine Singapore]. 2006 Apr 1;35(4):249.</ref>.
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=== '''''Origin'''''<ref name=":1">Snell RS. ''Clinical Anatomy By Regions.'' 9th edition. Philadelphia: Lippincott Williams & Wilkins; 2012.</ref> ===
=== '''''Origin'''''<ref name=":1">Snell RS. ''Clinical Anatomy By Regions.'' 9th edition. Philadelphia: Lippincott Williams & Wilkins; 2012.</ref> ===
Medial epicondyle of the humerus via the common flexor tendon
Medial epicondyle of the [[Humerus]] via the common flexor tendon


=== '''''Insertion'''''<ref name=":1" />  ===
=== '''''Insertion'''''<ref name=":1" />  ===
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=== '''''Nerve Supply'''''<ref name=":1" /> ===
=== '''''Nerve Supply'''''<ref name=":1" /> ===
Median Nerve
[[Median Nerve]]


=== '''''Arterial supply'''''<ref name=":0" />  ===
=== '''''Arterial supply'''''<ref name=":0" />  ===
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== Function ==
== Function ==
* Palmaris longus synergistically works with the long flexors of the forearm to bring about flexion at the radiocarpal joint.  
* Palmaris longus synergistically works with the long flexors of the forearm to bring about flexion at the wrist joint and small joints of the hand.  
* Apart from this, the muscle also helps in tightening the palmar aponeurosis.
* Apart from this, the muscle also helps in tightening the palmar aponeurosis.


== Tests to determine the presence/absence of the muscle ==
== Clinical Examination ==
Over the years, several clinical tests have been developed by practitioners from around the world to accurately detect the Palmaris Longus muscle. These tests merely rely upon certain positions of the wrist and hand in order to put the muscle in a state of tension so that it's tendon is both visible and palpable. The validity and reliability of the tests, however, show variations amongst each other<ref name=":2">Kigera JW, Mukwaya S. [[Clinical Assessment of the Palmaris Longus–Accuracy of common tests]]. Annals of African Surgery. 2012;9(2).</ref>.
Over the years, several clinical tests have been developed by practitioners from around the world to accurately detect the Palmaris Longus muscle. These tests merely rely upon certain positions of the wrist and hand in order to put the muscle in a state of tension so that it's tendon is both visible and palpable. The validity and reliability of the tests, however, show variations amongst each other<ref name=":2">Kigera JW, Mukwaya S. [[Clinical Assessment of the Palmaris Longus–Accuracy of common tests]]. Annals of African Surgery. 2012;9(2).</ref>.  


==== 1. Schaeffer's Test<ref name=":2" /> ====
==== 1. Schaeffer's Test<ref name=":2" /> ====
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==== 5. "Two Finger Sign" - Pushpakumar's Test<ref name=":2" /> ====
==== 5. "Two Finger Sign" - Pushpakumar's Test<ref name=":2" /> ====
* The subjects are made to completely extend the 2nd and 3rd digits, flex the 4th and 5th digits with the first digit fully opposed and flexed.
==== 6, "Four Finger Sign" ====
*  
*  



Revision as of 19:41, 16 June 2018

Original Editor -

Top Contributors - Mudra Shah, Mandeepa Kumawat, Admin, Nikhil Benhur Abburi and Manisha Shrestha

Description[edit | edit source]

[1] Pictorial representation of an isolated Palmaris Longus muscle in the flexor compartment of the forearm

The Palmaris longus (PL) muscle is a long, slender muscle which is usually present in the volar compartment of the forearm, interposed between the Flexor Carpi Ulnaris and the Flexor Carpi Radialis muscles.

However, it has been accepted as a vestigial muscle since studies have shown that almost 30% of the population could be lacking this muscle either in one forearm (unilateral) or both the forearms (bilateral) but the percentage can always vary. The peculiarity associated with this muscle is not merely its presence or absence, but it's high degree of anatomical variations even when present.

Apart from its anatomical anomalies, there are other categories of variations of the Palmaris Longus muscle in terms of its prevalence amongst different ethnicities, it's absence being more common in women and bilateral as well as the higher occurrence on the left upper limb when unilateral[2].

Anatomy[edit | edit source]

Origin[3][edit | edit source]

Medial epicondyle of the Humerus via the common flexor tendon

Insertion[3][edit | edit source]

Palmar Aponeurosis and Flexor Retinaculum at the wrist joint

Nerve Supply[3][edit | edit source]

Median Nerve

Arterial supply[1][edit | edit source]

Ulnar Artery

Function[edit | edit source]

  • Palmaris longus synergistically works with the long flexors of the forearm to bring about flexion at the wrist joint and small joints of the hand.
  • Apart from this, the muscle also helps in tightening the palmar aponeurosis.

Clinical Examination[edit | edit source]

Over the years, several clinical tests have been developed by practitioners from around the world to accurately detect the Palmaris Longus muscle. These tests merely rely upon certain positions of the wrist and hand in order to put the muscle in a state of tension so that it's tendon is both visible and palpable. The validity and reliability of the tests, however, show variations amongst each other[4].

1. Schaeffer's Test[4][edit | edit source]

  • The first test developed in 1909
  • Involves maintaining the forearm at 90 degrees first followed by moving the thumb in opposition towards the little finger with the wrist partially flexed.

2. Mishra's Test[4][edit | edit source]

  • Involves passive hyperextension of the Metacarpophalangeal Joints along with mild active wrist flexion.

3. Thompson's Test[4][edit | edit source]

  • Maneuver involves first making a fist with the testing hand, followed by wrist flexion against the resistance with the thumb flexed over the other digits.

4, Gangata's Test[4][edit | edit source]

  • The initial testing position is the thumb in abduction. The subject is then asked to resist both thumb abduction and wrist flexion.

5. "Two Finger Sign" - Pushpakumar's Test[4][edit | edit source]

  • The subjects are made to completely extend the 2nd and 3rd digits, flex the 4th and 5th digits with the first digit fully opposed and flexed.

6, "Four Finger Sign"[edit | edit source]

Clinical Significance[edit | edit source]

References[edit | edit source]

  1. 1.0 1.1 Derek Moore. Palmaris Longus. Available from: https://www.orthobullets.com/anatomy/10023/palmaris-longus [Accessed: 12 June 2018]
  2. Sebastin SJ, Lim AY, Wong H. Clinical assessment of absence of the palmaris longus and its association with other anatomical anomalies-a Chinese population study. Annals-academy of Medicine Singapore. 2006 Apr 1;35(4):249.
  3. 3.0 3.1 3.2 Snell RS. Clinical Anatomy By Regions. 9th edition. Philadelphia: Lippincott Williams & Wilkins; 2012.
  4. 4.0 4.1 4.2 4.3 4.4 4.5 Kigera JW, Mukwaya S. Clinical Assessment of the Palmaris Longus–Accuracy of common tests. Annals of African Surgery. 2012;9(2).