Lumbricals: Difference between revisions

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Lumbricals are located both in the hands and foot.  
The '''lumbricals''' are four small, intrinsic muscles located in the [[hand]]. They are unique in that they do not attach directly to bone, but rather originate from the tendons of the [[flexor digitorum profundus]] and insert into the extensor expansions of the fingers. These muscles play a crucial role in the fine motor movements of the hand, particularly in the flexion of the [[metacarpophalangeal joints]] and the extension of the [[interphalangeal joints]].
[[File:1121 Intrinsic Muscles of the Hand.jpg|Intrinsic Muscles of the Hand|thumb]]
==Anatomy==


==Lumbricals of hand==
===Origin===
The '''lumbricals''' of the [[hand]] are muscles that [[flexion|flex]] the [[metacarpophalangeal joint]]s and [[extension (kinesiology)|extend]] the [[Interphalangeal articulations of hand|interphalangeal joints]].
The lumbricals originate from the tendons of the [[flexor digitorum profundus]] muscle. Specifically, the first and second lumbricals arise from the radial sides of the tendons of the index and middle fingers, respectively. The third and fourth lumbricals originate from the adjacent sides of the tendons of the middle, ring, and little fingers.


==Origin==
===Insertion===
They attach proximally to the tendons of [[flexor digitorum profundus]],
The lumbricals insert into the extensor expansions on the dorsal aspect of the proximal phalanges of the fingers. This insertion allows them to influence both the flexion and extension of the fingers.
[[File:1121 Intrinsic Muscles of the Hand Superficial sin.png|thumb|right|Lumbricals labeled at bottom left. Left hand, palmar view.]]


===Blood supply===
===Innervation===
Four separate sources supply blood to these muscles: the [[superficial palmar arch]], the [[common palmar digital artery]], the [[deep palmar arch]], and the [[dorsal digital arteries of hand|dorsal digital artery]].
The lumbricals are innervated by two different nerves:
* The first and second lumbricals (lateral two) are innervated by the [[median nerve]].
* The third and fourth lumbricals (medial two) are innervated by the [[ulnar nerve]].


===Nerve supply===
===Blood Supply===
The first and second lumbricals (the most radial two) are [[Nerve|innervated]] by the [[median nerve]].
The blood supply to the lumbricals is provided by the [[superficial palmar arch]], the [[common palmar digital arteries]], and the [[deep palmar arch]].
The third and fourth lumbricals (most ulnar two) are innervated by the [[ulnar nerve]].


The lumbrical muscles, with the help of the interosseous muscles, simultaneously flex the [[metacarpophalangeal joint]]s while extending both [[Interphalangeal articulations of hand|interphalangeal joint]]s of the digit on which it inserts.  
==Function==
 
The primary function of the lumbricals is to flex the [[metacarpophalangeal joints]] while extending the [[interphalangeal joints]] of the fingers. This action is essential for the "upstroke" of writing and for many other fine motor tasks that require precision and dexterity.
The lumbricals are used during an upstroke in writing.
<gallery>
File:Gray416.png|Tendons of forefinger and vincula tendina
File:Slide2yyy.JPG|Lumbricals of the hand
File:Slide5RRR.JPG|Lumbricals of the hand
File:Slide14RRR.JPG|Lumbricals muscle
File:Slide6PPP.JPG|Lumbricals muscle
File:Slide4VVV.JPG|Lumbricals muscle
File:Slide4AAAA.JPG|Lumbricals muscle
File:Slide9AAAA.JPG|Lumbricals muscle
File:Slide1MAI.JPG|Muscles of hand, cross section
File:Slide1dsds.JPG|Wrist joint. Deep dissection.Anterior, palmar view
File:Slide2dsds.JPG|Wrist joint. Deep dissection.Anterior, palmar view
File:Slide3dsds.JPG|Wrist joint. Deep dissection.Anterior, palmar view
</gallery>
 
==Lumbricals of the foot==
The lumbricals in the foot skeletal muscles located in the deeper layers of the foot - there are a total of about 4 of them in each foot.
 
[[File:Lumbricales pedis.png|Lumbricals|right]]
 
These muscles are accessory to the tendons of the [[flexor digitorum longus muscle]]. They are numbered from the medial side of the foot.
 
==Origin==
They originate at the tendons of flexor digitorum longus in the foot
 
==Insertion==
medial surface of extensor expansion of proximal phalanges of lateral four toes


==Blood supply==
==Clinical Significance==
lateral plantar artery, plantar arch, four plantar metatarsal arteries


==Nerve supply==
===Lumbrical Plus Finger===
lateral plantar nerve (lateral three lumbricals) and medial plantar nerve (first lumbrical)
A condition known as "lumbrical plus finger" can occur when there is an imbalance in the function of the lumbricals, often due to injury or surgical intervention. This condition results in paradoxical extension of the interphalangeal joints when attempting to flex the fingers.


==Function==
===Injury and Dysfunction===
They help maintain extension of digits at interphalangeal joints
Injury to the nerves supplying the lumbricals, such as in [[carpal tunnel syndrome]] (affecting the median nerve) or [[ulnar nerve entrapment]], can lead to weakness or paralysis of these muscles. This can result in difficulty with finger movements and a characteristic "claw hand" deformity.


===Additional images===
==See Also==
<gallery>
* [[Flexor digitorum profundus]]
File:Gray416.png|Tendons of forefinger and vincula tendina
* [[Extensor expansion]]
File:Slide2yyy.JPG|Lumbricals of the hand
* [[Median nerve]]
File:Slide5RRR.JPG|Lumbricals of the hand
* [[Ulnar nerve]]
File:Slide14RRR.JPG|Lumbricals muscle
==External Links==
File:Slide6PPP.JPG|Lumbricals muscle
* [https://www.ncbi.nlm.nih.gov/books/NBK537086/ Lumbricals of the Hand - NCBI Bookshelf]
File:Slide4VVV.JPG|Lumbricals muscle
* [https://www.anatomy.tv/3d-atlas/muscles/lumbricals Anatomy.tv - Lumbricals]
File:Slide4AAAA.JPG|Lumbricals muscle
File:Slide9AAAA.JPG|Lumbricals muscle
File:Slide1MAI.JPG|Muscles of hand, cross section
File:Slide1dsds.JPG|Wrist joint. Deep dissection.Anterior, palmar view
File:Slide2dsds.JPG|Wrist joint. Deep dissection.Anterior, palmar view
File:Slide3dsds.JPG|Wrist joint. Deep dissection.Anterior, palmar view
</gallery>
{{stub}}
{{Muscles of upper limb}}
{{Muscles of upper limb}}
{{Authority control}}
{{anatomy}}
 
[[Category:Muscles of the upper limb]]
[[Category:Muscles of the upper limb]]
[[Category:Hand]]
[[Category:Hand anatomy]]
 
[[Category:Intrinsic muscles of the hand]]
{{Muscles_of_lower_limb}}
{{nt}}
{{Portal bar|Anatomy}}
{{Authority control}}
 
[[Category:Foot muscles]]
[[Category:Muscles of the lower limb]]
 
{{muscle-stub}}
{{adapted}}

Latest revision as of 23:52, 4 January 2025

The lumbricals are four small, intrinsic muscles located in the hand. They are unique in that they do not attach directly to bone, but rather originate from the tendons of the flexor digitorum profundus and insert into the extensor expansions of the fingers. These muscles play a crucial role in the fine motor movements of the hand, particularly in the flexion of the metacarpophalangeal joints and the extension of the interphalangeal joints.

Intrinsic Muscles of the Hand

Anatomy[edit]

Origin[edit]

The lumbricals originate from the tendons of the flexor digitorum profundus muscle. Specifically, the first and second lumbricals arise from the radial sides of the tendons of the index and middle fingers, respectively. The third and fourth lumbricals originate from the adjacent sides of the tendons of the middle, ring, and little fingers.

Insertion[edit]

The lumbricals insert into the extensor expansions on the dorsal aspect of the proximal phalanges of the fingers. This insertion allows them to influence both the flexion and extension of the fingers.

Innervation[edit]

The lumbricals are innervated by two different nerves:

  • The first and second lumbricals (lateral two) are innervated by the median nerve.
  • The third and fourth lumbricals (medial two) are innervated by the ulnar nerve.

Blood Supply[edit]

The blood supply to the lumbricals is provided by the superficial palmar arch, the common palmar digital arteries, and the deep palmar arch.

Function[edit]

The primary function of the lumbricals is to flex the metacarpophalangeal joints while extending the interphalangeal joints of the fingers. This action is essential for the "upstroke" of writing and for many other fine motor tasks that require precision and dexterity.

Clinical Significance[edit]

Lumbrical Plus Finger[edit]

A condition known as "lumbrical plus finger" can occur when there is an imbalance in the function of the lumbricals, often due to injury or surgical intervention. This condition results in paradoxical extension of the interphalangeal joints when attempting to flex the fingers.

Injury and Dysfunction[edit]

Injury to the nerves supplying the lumbricals, such as in carpal tunnel syndrome (affecting the median nerve) or ulnar nerve entrapment, can lead to weakness or paralysis of these muscles. This can result in difficulty with finger movements and a characteristic "claw hand" deformity.

See Also[edit]

External Links[edit]

Muscles of the arm
Shoulder
Arm
(compartments)
Forearm
Hand



Anatomy and morphology
Fields
Bacteria and fungi
Protists
Plants
Invertebrates
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