Hand muscles - Interossei (Dorsal and Palmar)
Bones
Radius
Ulna
Hand
Overview:
- The dorsal and palmar interossei lie between the metacarpals of the hand.
A helpful mnemonic:
- DAB: Dorsal interossei Abduct digits 2-4.
- PAD: Palmar interossei Adduct digits 1,2, 4, and 5.
- Abduction/Adduction are in reference to the midline of the hand; digit 3.
Dorsal interossei:
- Bipennate
- Originate on the adjacent sides of the metacarpals
- Insert onto the lateral sides of the proximal phalanges of digits 2 and 3, and onto the medial sides of the proximal phalanges of digits 3 and 4.
- Abduct digits 2-4; they do NOT act upon digits 1 and 5.
Palmar interossei:
- Unipennate
First palmar interossei (often poorly developed or absent)
- Originates on the medial side of the first metacarpal
- Inserts into the base of the proximal phalanx of digit 1.
Second palmar interossei
- Originates on the medial side of the second metacarpal
- Inserts into the proximal phalange of digit 2.
Third palmar interossei
- Originates on the lateral side of metacarpal 4
- Inserts into the lateral side of the proximal phalange of digit 4.
Fourth palmar interossie
- Originates on the lateral side of the 5th metacarpal
- Inserts into the proximal phalange of digit 5.
Both dorsal interossei and palmar interossei also insert into the extensor hoods.