Which of the following muscles do not contribute to the marked tendon:
Ans. (B) 2nd Palmer interossei(Ref: Grays Anatomy 41st Ed; Page No- 884)Marked tendon (dorsal digital expansion) belongs to the extensor digitorum of the middle finger; which don't receive insertion of any palmer interossei.Dorsal InterosseiThe four dorsal interossei muscles are bipennate in nature.They are larger in size compare to palmar interossei.They are arising from the adjacent sides of two metacarpal bones.The first and largest muscle is called as abductor indicis. It is attached to the radial side of the proximal phalanx of the index finger.The second attached to the radial and third are attached to the ulnar sides of the middle finger.The fourth may be wholly attached to the digital expansion, but it often sends an additional slip to the proximal phalanx.Palmar InterosseiPalmar interossei are smaller compare to dorsal interossei and lie on the palmar surfaces of the metacarpal bones rather than between them.The first arises from the ulnar side of the palmar surface of the base of the first metacarpal bone and is inserted into a sesamoid bone on the ulnar side of the proximal phalanx.The middle finger has no palmar interosseous.The second arises from the ulnar side of the second metacarpal bone and is inserted into the same side of the digital expansion of the index finger.The third arises from the radial side of the fourth metacarpal bone and is inserted together with the third lumbrical.The fourth arises from the radial side of the fifth metacarpal bone and is attached with the fourth lumbrical and to the base of the proximal phalanx.Action the Interossei MusclesIt unipennate in nature.Location: On the palmar surface between the metacarpals.All fingers have palmar interossei; except; Middle finger.They are arising from palmar aspects of the metacarpals.It adduct the fingers towards the longitudinal axis of the middle fingerDorsal interosseiIt abducts the fingers away from the longitudinal axis of the middle finger.Note:Fifth finger is not abducted by dorsal interossei.Lumbrical MusclesLumbricals take their origin from the tendons of flexor digitorum profounds and insert into dorsal digital expansion for interphalangeal extension.Lumbricals 1 and 2 arise from lateral side of lateral two tendons of the flexor digitorum profounds.Lumbricals 3 and 4 arise from adjacent sides of medial three tendons of the flexor digitorum profundusExtra MileInterosseiMuscleOriginInsertionNerve supplyNerve rootAction Dorsal interossei (4) (bipennate)Adjacent sides of metacarpal bonesLateral sides of bases of proximal phalanges; extensor expansionUlnarC8; T1Abduct fingers; flex metacarpophalangeal joints; extend interphalangeal jointsPalmar interossei (3) (unipennate)Medial side of second metacarpal; lateral sides of fourth and fifth metacarpalsBases of proximal phalanges in same sides as their origins; extensor expansionUlnarC8; T1Adduct fingers; flex metacarpophalangeal joints; extend interphalangeal jointsMovement at the Metacarpophalangeal JointDorsal interosseiAbductionPalmar interosseiAdductionExtensor digitorumExtensionLumbricals and interosseiFlexion
2nd Dorsal interossei
2nd Palmer interossei
Lumbricals
Extensor digitorum
Upper Extremity