human anatomy The human body is the structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organ systems. They ensure homeostasis and the viability of the human body. It comprises a head ...

, the adductor pollicis muscle is a

muscle Skeletal muscles (commonly referred to as muscles) are Organ (biology), organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other ...

in the

hand A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each " ...

that functions to

adduct An adduct (from the Latin ''adductus'', "drawn toward" alternatively, a contraction of "addition product") is a product of a direct addition of two or more distinct molecules, resulting in a single reaction product containing all atoms of all co ...

the thumb. It has two heads: transverse and oblique. It is a fleshy, flat, triangular, and fan-shaped muscle deep in the thenar compartment beneath the long flexor tendons and the lumbrical muscles at the center of the palm. It overlies the

metacarpal bones In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ar ...

and the interosseous muscles.

Structure

Oblique head

The oblique head (Latin: ''adductor obliquus pollicis'') arises by several slips from the capitate bone, the bases of the second and third

metacarpal In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ...

s, the intercarpal ligaments, and the sheath of the tendon of the flexor carpi radialis. Gray's Anatomy 1918. (See infobox) From this origin the greater number of fibers pass obliquely downward and converge to a tendon, which, uniting with the tendons of the medial portion of the

flexor pollicis brevis The flexor pollicis brevis is a muscle in the hand that flexes the thumb. It is one of three thenar muscles. It has both a superficial part and a deep part. Origin and insertion The muscle's superficial head arises from the distal edge of the f ...

and the transverse head of the adductor pollicis, is inserted into the ulnar side of the base of the proximal

phalanx The phalanx ( grc, φάλαγξ; plural phalanxes or phalanges, , ) was a rectangular mass military formation, usually composed entirely of heavy infantry armed with spears, pikes, sarissas, or similar pole weapons. The term is particular ...

of the thumb, a

sesamoid In anatomy, a sesamoid bone () is a bone embedded within a tendon or a muscle. Its name is derived from the Arabic word for 'sesame seed', indicating the small size of most sesamoids. Often, these bones form in response to strain, or can be prese ...

bone being present in the tendon. A considerable fasciculus, however, passes more obliquely beneath the tendon of the

flexor pollicis longus The flexor pollicis longus (; FPL, Latin ''flexor'', bender; ''pollicis'', of the thumb; ''longus'', long) is a muscle in the forearm and hand that flexes the thumb. It lies in the same plane as the flexor digitorum profundus. This muscle is uniq ...

to join the lateral portion of the

and the

abductor pollicis brevis The abductor pollicis brevis is a muscle in the hand that functions as an abductor of the thumb. Structure The abductor pollicis brevis is a flat, thin muscle located just under the skin. It is a thenar muscle, and therefore contributes to the ...

Transverse head

The transverse head (Latin: ''adductor transversus pollicis'') is deeply seated. It is triangular, arising by a broad base from the lower two-thirds of the palmar surface of the third

bone; the fibers converge, to be inserted with the medial part of the

and the oblique head into the ulnar side of the base of the proximal

of the

thumb The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position (where the palm is facing to the front), the thumb is the outermost digit. The Medical Latin English noun for thu ...

Relations

The

radial artery In human anatomy, the radial artery is the main artery of the lateral aspect of the forearm. Structure The radial artery arises from the bifurcation of the brachial artery in the antecubital fossa. It runs distally on the anterior part of th ...

passes between the two heads, travelling from the back of the hand into the palm, where it forms the

deep palmar arch The deep palmar arch (deep volar arch) is an arterial network found in the palm. It is usually primarily formed from the terminal part of the radial artery. The ulnar artery also contributes through an anastomosis. This is in contrast to the superf ...

Innervation

The adductor pollicis is innervated by the deep branch of the

ulnar nerve In human anatomy, the ulnar nerve is a nerve that runs near the ulna bone. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest in the human body unprotected by muscle or bone, so injury is c ...

(C8–T1). Between the oblique and transverse heads is a thin fibrous arcade which the nerve passes as it traverses the palm laterally. The nerve is accompanied by the

Function

While

adduction Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relati ...

of the thumb (bringing it back into the plane of the palm of the hand from its previously abducted position) is mainly produced by the adductor pollicis, it can also bring the thumb to the side of the palm and index finger and the

and the

opponens pollicis The opponens pollicis is a small, triangular muscle in the hand, which functions to oppose the thumb. It is one of the three thenar muscles. It lies deep to the abductor pollicis brevis and lateral to the flexor pollicis brevis. Structure The o ...

help in thumb adduction.

Clinical significance

Froment's sign is used to test for a compromised adductor pollicis muscle. In neuromuscular monitoring, the

is stimulated and the strength of adductor pollicis contraction is measured.

Other animals

The adductor pollicis evolved from the contrahens I muscle as man's ancestors'

s and big toes became opposable. It might also contain an element of the thumb's

interosseous muscle {{short description, Muscles between certain bones Interossei refer to muscles between certain bones. There are many interossei in a human body. Specific interossei include: On the hands * Dorsal interossei muscles of the hand * Palmar interosse ...

. In the Pan-Homo LCA the oblique head of the adductor pollicis probably had a relatively small

physiological cross sectional area In muscle physiology, physiological cross-sectional area (PCSA) is the area of the cross section of a muscle perpendicular to its fibers, generally at its largest point. It is typically used to describe the contraction properties of pennate mus ...

(PCSA) and both heads probably acted as extensors and adductors at the

carpometacarpal joint The carpometacarpal (CMC) joints are five joints in the wrist that articulate the distal row of carpal bones and the proximal bases of the five metacarpal bones. The CMC joint of the thumb or the first CMC joint, also known as the trapeziometa ...

. In humans the PCSA of the oblique head is relatively enlarged and both heads act as flexors at this joint.

Additional images

Image:Musculusadductorpollicis.png, The muscles of the thumb. (Adductor pollicis transversus is red band at bottom, and adductor pollicis obliquus is red band immediately above it.) File:Dissection of hand.jpg, Adductor pollicis muscle File:Gray422.png, Transverse section across the wrist and digits. File:Gray427.png, The muscles of the left hand. Palmar surface. File:Gray527.png, The radial and ulnar arteries. File:Gray815.png, Superficial palmar nerves. File:Gray817.png, Deep palmar nerves. File:Gray415.png, Front of the left

forearm The forearm is the region of the upper limb between the elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb, but which in ...

. Deep muscles. (Adductor pollicis visible at bottom center.) File:Froment's_sign.jpg, Negative (above) and positive Froment's sign File:Slide8AAAA.JPG, Adductor pollicis muscle File:Slide6BBBB.JPG, Adductor pollicis muscle File:Slide15BBBB.JPG, Adductor pollicis muscle File:Slide4OOOO.JPG, Adductor pollicis muscle File:Slide14OOOO.JPG, Adductor pollicis muscle

References

* * * * {{Authority control Muscles of the upper limb Hand