Thenar eminence

Thenar eminence

Infobox Muscle
Name = PAGENAME
Latin = eminentia thenaris
GraySubject = 126
GrayPage = 546



Caption = The mucous sheaths of the tendons on the front of the wrist and digits.



Caption2 = Transverse section across the wrist and digits. (Muscles of thumb labeled at upper left.)
Origin =
Insertion =
Blood =
Nerve = median nerve
Action = control movement of the thumb
Antagonist =
DorlandsPre = t_07
DorlandsSuf = 12801990
The thenar eminence is the body of muscle on the palm of the human hand just beneath the thumb. The skin overlying this region is the area stimulated when trying to elicit a palmomental reflex.

Muscles

The muscles in this location are usually innervated by the recurrent branch of the median nerve. They all control movement of the thumb.

The following three muscles are considered part of the thenar eminence:cite web |url=http://www.wheelessonline.com/ortho/intrinsic_muscles_of_the_hand |title=Intrinsic Muscles of the Hand - Wheeless' Textbook of Orthopaedics |accessdate=2008-01-16 |format= |work=]

* Abductor pollicis brevis abducts the thumb. This muscle is the most proximal of the thenar group.

* Flexor pollicis brevis, which lies next to the abductor, will flex the thumb, curling it up in the palm.

* Opponens pollicis lies deep to abductor pollicis brevis. As its name suggests it opposes the thumb, bringing it against the fingers. This is a very important movement, as most of our dexterity comes from this action.

The innervation of these muscles by the median nerve is unusual, as most of the intrinsic muscles on the palm of the hand are supplied by the ulnar nerve. The lateral two lumbrical muscles are the other exception.

Another muscle that controls movement of the thumb is adductor pollicis. It lies deeper and more distal to flexor pollicis brevis. Despite its name, its main action is mainly rotation and opposition. It is not in the thenar group of muscles, so is supplied by the ulnar nerve.cite web |url=http://www.med.mun.ca/anatomyts/msk/hand.htm |title=Applied MSK anatomy of the hand |accessdate=2008-01-16 |format= |work=]

Mnemonic

A good way to remember what muscles are in the thenar eminence is "OAF"; oafs have big thenar eminences. 'O' = opponens, 'A' = abductor, 'F' = flexor. There is only one opponens. The other two muscles each have a long partner and thus are called "brevis."

Meat-LOAF: the "M" in the word "Meat" helps you remember that the LOAF muscles of the hand are innervated by the Median Nerve

ABOF (pronounced "above") the Law muscles. The law states muscles of the hand are supplied by ulnar nerve. However, ABOF the Law muscles are supplied by MEDIAN nerve. 'AB' = abductor, 'O' = Opponens, 'F' = Flexor, Law 'L' = Lateral Lumbricals (2).

ee also

* Hypothenar eminence


=Additional

References

External links

*


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Look at other dictionaries:

  • thenar eminence — n the ball of the thumb * * * thenar (def. 1) …   Medical dictionary

  • thenar eminence — noun see thenar I, 1a …   Useful english dictionary

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  • Thenar — The nar, n. (Anat.) (a) The palm of the hand. (b) The prominence of the palm above the base of the thumb; the thenar eminence; the ball of the thumb. Sometimes applied to the corresponding part of the foot. [1913 Webster] …   The Collaborative International Dictionary of English

  • thenar — Term applied to any structure in relation with the base of the thumb or its underlying collective components. SYN: thenal. See t. eminence. [G. the palm of the hand] * * * the·nar thē .när, nər adj of, relating to, involving, or constituting the… …   Medical dictionary

  • thénar — [ tenar ] n. m. • tenar XVIe; gr. thenar « paume » ♦ Anat. Thénar, ou en appos. éminence thénar : saillie formée sur la paume de la main par les muscles courts du pouce. ⇒ hypothénar. ● thénar adjectif (grec thenar, paume) Éminence …   Encyclopédie Universelle

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  • éminence — [ eminɑ̃s ] n. f. • 1314; lat. eminentia 1 ♦ Anat. Saillie, protubérance. Les éminences osseuses. ⇒ apophyse, tubercule, tubérosité. 2 ♦ Cour. Élévation de terrain relativement isolée. ⇒ butte, élévation, hauteur, monticule, tertre. Observatoire… …   Encyclopédie Universelle

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