Palmar interossei muscles
Encyclopedia
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.
and extensor expansion
of the extensor digitorum tendon to the same finger.
There are three palmar interossei:
The palmar interossei are unipennate.
From this account it may be seen that each finger is provided with two interossei, with the exception of the little finger, in which the abductor digiti minimi muscle takes the place of one of the dorsla interossei (abduction).
Some texts consider the medial head of the flexor pollicis brevis to be a palmar interosseous muscle. This muscle would then be considered the first palmar interosseous muscle, and the total number of palmar interosseous muscles in the hand would be four.
.
In addition (like dorsal interossei) they flex the finger at the metacarpo-phalangeal joint and extend the finger at the interphalangeal joint and thus assist the lumbricals.
Mnemonic to remember action: PAD DAB Palmar - adduct, Dorsal Interossei
- Abduct
Dorsal interossei of the hand
The dorsal interossei of the hand are muscles that occupy the space between the metacarpals.-Structure:There are four dorsal interossei in each hand...
, which lie between the metacarpals.
Structure
Each palmar interosseous muscle arises from the entire length of the metacarpal bone of one finger, and is inserted into the side of the base of the proximal phalanxPhalanx 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...
and extensor expansion
Extensor expansion
A extensor expansion is an anatomical term that refers to the special connective attachments by which the extensor tendons insert into the phalanges....
of the extensor digitorum tendon to the same finger.
There are three palmar interossei:
| # | Origin | Insertion >- | first |
from the ulnar side of the second metacarpal bone | index finger Index finger The index finger, , is the first finger and the second digit of a human hand. It is located between the first and third digits, between the thumb and the middle finger... >- | second |
from the radial side of the fourth metacarpal bone | ring finger Ring finger The ring finger is the fourth digit of the human hand, and the second most ulnar finger, located between the middle finger and the little finger. It is also called digitus medicinalis, the fourth finger, digitus annularis, digitus quartus, or digitus IV in anatomy.- Etymology :According to László A... >- | third |
from the radial side of the fifth metacarpal bone | into the same side of the little finger Little finger The little finger, often called the pinky in American English, pinkie in Scottish English , or small finger in medicine, is the most ulnar and usually smallest finger of the human hand, opposite the thumb, next to the ring finger.-Muscles:There are four muscles that... |
The palmar interossei are unipennate.
From this account it may be seen that each finger is provided with two interossei, with the exception of the little finger, in which the abductor digiti minimi muscle takes the place of one of the dorsla interossei (abduction).
Some texts consider the medial head of the flexor pollicis brevis to be a palmar interosseous muscle. This muscle would then be considered the first palmar interosseous muscle, and the total number of palmar interosseous muscles in the hand would be four.
Innervation
All of the interosseous muscles of the hand are 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...
.
Actions
The palmar interosseous muscles adduct the fingers towards the middle finger. This is in contrast to the dorsal interossei, which abduct the fingers away from the middle finger.In addition (like dorsal interossei) they flex the finger at the metacarpo-phalangeal joint and extend the finger at the interphalangeal joint and thus assist the lumbricals.
Mnemonic to remember action: PAD DAB Palmar - adduct, Dorsal Interossei
Dorsal interossei of the hand
The dorsal interossei of the hand are muscles that occupy the space between the metacarpals.-Structure:There are four dorsal interossei in each hand...
- Abduct
Pollical Palmar Interosseous Muscle (of Henle, PPIM)
It is currently accepted that more than 80% of individuals present a pollical palmar interosseous muscle (of the thumb) as suggested by Henle's description in 1858 and verified by numerous investigations such as those carried out by Randall S. Susman, Lukhanyo Nyati, and Mandeep S. Jassal.See also
- Plantar interossei musclesPlantar interossei musclesThe plantar interossei, three in number, lie beneath rather than between the metatarsal bones, and each is connected with but one metatarsal bone....
- Dorsal interossei of the footDorsal interossei of the footIn human anatomy, the dorsal interossei of the foot are four muscles situated between the metatarsal bones.- Origin :The four interossei muscles are bipenniform muscles each originating by two heads from the proximal half of the of the sides of adjacent metatarsal bones.- Insertion :The two heads...
- Dorsal interossei of the handDorsal interossei of the handThe dorsal interossei of the hand are muscles that occupy the space between the metacarpals.-Structure:There are four dorsal interossei in each hand...