Adductor pollicis muscle
Encyclopedia
In human anatomy
, the adductor pollicis muscle is a muscle
in the hand
that functions to adduct
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 and the interosseous muscles
.
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 and the transverse head of the adductor pollicis, is inserted into the ulnar side of the base of the proximal phalanx
of the thumb, a sesamoid bone being present in the tendon.
A considerable fasciculus, however, passes more obliquely beneath the tendon of the flexor pollicis longus to join the lateral portion of the flexor pollicis brevis and the abductor pollicis brevis.
It is triangular, arising by a broad base from the lower two-thirds of the palmar surface of the third metacarpal bone; the fibers converge, to be inserted with the medial part of the flexor pollicis brevis and the oblique head into the ulnar side of the base of the proximal phalanx
of the thumb
.
passes between the two heads, travelling from the back of the hand into the palm, where it forms the deep palmar arch
.
(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 deep palmar arch
.
Froment's sign
is used to test for a compromised adductor pollicis muscle.
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 flexor pollicis brevis
and the opponens pollicis
help in thumb adduction.
I muscle as man's ancestors' thumb
s and big toes became opposable. It might also contain an element of the thumb's interosseous muscle.
In the Pan-Homo LCA
the oblique head of the adductor pollicis probably had a relatively small physiological cross sectional area
(PCSA) and both heads probably acted as extensors and adductors at the carpometacarpal joint
. In humans the PCSA of the oblique head is relatively enlarged and both heads act as flexors at this joint.
Human anatomy
Human anatomy is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross anatomy is the study of anatomical structures that can be seen by the naked eye...
, the adductor pollicis muscle is a muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
in the hand
Hand
A hand is a prehensile, multi-fingered extremity located at the end of an arm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs...
that functions to adduct
Adduction
Adduction is a movement which brings a part of the anatomy closer to the middle sagittal plane of the body. It is opposed to abduction.-Upper limb:* of arm at shoulder ** Subscapularis** Teres major** Pectoralis major** Infraspinatus...
the thumb. It has two heads: transverse and oblique.
It is a fleshy, flat, triangular, and fan-shaped muscle deep in the thenar compartment
Thenar eminence
The thenar eminence refers to the group of muscles on the palm of the human hand at the base of the thumb...
beneath the long flexor tendons and the lumbrical muscles
Lumbricals of the hand
The lumbricals are intrinsic muscles of the hand that flex the metacarpophalangeal joints and extend the interphalangeal joints.-Structure:There are four of these small, worm-like muscles on each hand. These muscles are unusual in that they do not attach to bone...
at the center of the palm. It overlies the metacarpal bones and the interosseous muscles
Palmar interossei muscles
The palmar interossei are small muscles in the hand that lie on the anterior aspect of the metacarpals. They are smaller than the dorsal interossei of the hand, which lie between the metacarpals.-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 metacarpals, the intercarpal ligaments, and the sheath of the tendon of the flexor carpi radialis.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 and the transverse head of the adductor pollicis, is inserted into the ulnar side of the base of the proximal phalanx
Phalanx bones
In anatomy, phalanx bones are those that form the fingers and toes. In primates such as humans and monkeys, the thumb and big toe have two phalanges, while the other fingers and toes consist of three. Phalanges are classified as long bones.The phalanges do not have individual names...
of the thumb, a sesamoid bone being present in the tendon.
A considerable fasciculus, however, passes more obliquely beneath the tendon of the flexor pollicis longus to join the lateral portion of the flexor pollicis brevis and the abductor pollicis brevis.
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 metacarpal bone; the fibers converge, to be inserted with the medial part of the flexor pollicis brevis and the oblique head into the ulnar side of the base of the proximal phalanx
Phalanx bones
In anatomy, phalanx bones are those that form the fingers and toes. In primates such as humans and monkeys, the thumb and big toe have two phalanges, while the other fingers and toes consist of three. Phalanges are classified as long bones.The phalanges do not have individual names...
of the thumb
Thumb
The thumb is the first digit of the hand. When a person is standing in the medical anatomical position , the thumb is the lateral-most digit...
.
Relations
The radial arteryRadial artery
In human anatomy, the radial artery is the main blood vessel, with oxygenated blood, of the lateral aspect of the forearm.-Course:The radial artery arises from the bifurcation of the brachial artery in the cubital fossa. It runs distally on the anterior part of the forearm...
passes between the two heads, travelling from the back of the hand into the palm, where it forms the deep palmar arch
Deep palmar arch
The deep palmar arch is an arterial network found in the palm. It is usually formed mainly from the terminal part of the radial artery, with the ulnar artery contributing via its deep palmar branch...
.
Innervation
The adductor pollicis is innervated by the deep branch of the ulnar nerveUlnar nerve
In human anatomy, the ulnar nerve is a nerve which runs near the ulna bone. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest unprotected nerve in the human body , so injury is common...
(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 deep palmar arch
Deep palmar arch
The deep palmar arch is an arterial network found in the palm. It is usually formed mainly from the terminal part of the radial artery, with the ulnar artery contributing via its deep palmar branch...
.
Froment's sign
Froment's sign
Froment's sign is a special test of the wrist. It tests for palsy of the ulnar nerve, specifically, the action of adductor pollicis. Froment sign can also refer to cogwheel effect seen in essential tremor.-Process of examination:...
is used to test for a compromised adductor pollicis muscle.
Actions
While adductionAdduction
Adduction is a movement which brings a part of the anatomy closer to the middle sagittal plane of the body. It is opposed to abduction.-Upper limb:* of arm at shoulder ** Subscapularis** Teres major** Pectoralis major** Infraspinatus...
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 flexor pollicis brevis
Flexor pollicis brevis muscle
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:...
and the opponens pollicis
Opponens pollicis muscle
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, lying deep to the abductor pollicis brevis and lateral to the flexor pollicis brevis.-Structure:...
help in thumb adduction.
Evolution
The adductor pollicis evolved from the contrahensContrahens
The contrahentes are muscles widely present in the hands of mammals, including monkeys and gorillas. They are on the palmar/plantar side. There is one each for digits I II IV V but not III...
I muscle as man's ancestors' thumb
Thumb
The thumb is the first digit of the hand. When a person is standing in the medical anatomical position , the thumb is the lateral-most digit...
s and big toes became opposable. It might also contain an element of the thumb's interosseous muscle.
In the Pan-Homo LCA
Chimpanzee-human last common ancestor
The chimpanzee-human last common ancestor is the last species, a species of African apes, that humans, bonobos and chimpanzees share as a common ancestor....
the oblique head of the adductor pollicis probably had a relatively small physiological cross sectional area
Physiological cross sectional area
In pennate muscles, the physiological cross-sectional area , as opposed to the anatomical one , is the total area of the cross-sections perpendicular to the muscle fibers.- Definition :...
(PCSA) and both heads probably acted as extensors and adductors at the carpometacarpal joint
Carpometacarpal joint
The carpometacarpal joints are five joints in the wrist that articulates the distal row of carpal bones and the proximal bases of the five metacarpal bones....
. In humans the PCSA of the oblique head is relatively enlarged and both heads act as flexors at this joint.