- Dorsal Interossei
- Palmar Interossei
- Hypothenar Eminence:
- muscles of hypothenar eminence are abductor, flexor, opponens digiti minimi, & palmaris brevis;
- muscles of hypothenar eminence are innervated by ulnar nerve;
- Thenar Eminence:
- muscles of thenar eminence are APB, flexor pollicis brevis, & opponens pollicis;
- muscles of thenar eminence, w/ exception of deep head of FPB, which is innervated by ulnar nerve, are supplied by median;
- all thenar & hypothenar muscles, except abductor minimi, originate partly from transverse carpal ligament;
- their insertions are primarily on base of proximal phalanx of thumb & little finger, except for both opponens muscles,
which insert on their respective metacarpals.
- 7 in number, 4 are dorsal & 3 volar.
- their origin is from the metacarpal shafts.
- dorsal interossei:
- 1st & 4th dorsal interossei insert on radial aspect of index & ulnar side of ring fingers;
- 2nd & 3rd insert on radial & ulnar sides of long finger respectively;
- occassionally, short masses of muscle originate from carpal bones or from base of metacarpals on dorsum
of hand & appear as enlargements similar to cysts or other bone or soft tissue lesions;
- these accessory muscle masses are similar to muscle belly of extensor digitorum brevis on the dorsum of the foot;
- recognition of these muscle abnormalities is important in diff dx;
- dorsal Interossie abduct index & ring fingers & adduct long finger to either side of a line drawn through its longitudinal axis;
- palmar interossei:
- 1st volar interosseous inserts on ulnar side of index digit, and 2nd & 3rd insert on radial aspect of ring and little fingers;
- volar interossei are thus positioned to adduct these digits toward the long finger;
- site of insertion of these muscles accounts for development of ulnar deviation of little finger if motor branch of ulnar nerve is injured;
- interossei, along w/ 4 lumbricals, also flex MP & extend IP joints;
- radial interossei tend to insert into bone w/ lesser insertions into extensor hood;
- volar interossei & lumbricals usually insert into lateral band expansion;
- lumbricales arise from tendonns of FDP in mid-palmar area & insert into radial aspect of dorsal hood.
- all interossei & 3rd & 4th lumbricale s are innervated by ulnar nerve;
- first and second lumbricales are supplied by median;
- Bunnel test for intrinsic tightness:
- side to side confrontational test:
- bring ulnar sides of little fingers into opposition and press together;
- bring radial sides of thumbs into opposition and press together;
- weakness is readily demonstrated, as the fingers on the weakened hand will bunch together;
- Pathologic Conditions:
- intrinsic minus - claw hand:
- intrinsic plus hand:
- saddle deformity:
- condition which results from traumatic adhesions between interosseous and lumbrical muscles which causes
symptomatic impingement on the deep transverse metacarpal ligament during intrinsic contraction;
- etiology: crush injuries or direct blow;
- clinical findings:
- pain located in the distal intermetacarpal space;
- pain w/ prolonged gripping of objects or w/ making a fist;
- seen most often in ring and long finger;
- Bunnel test is positive in the majority of patients;
- treatment release of adhesions between the lubrical and interosseous muscle, in addition to release of the transverse metacarpal ligament;
- Saddle Deformity. Posttraumatic interosseous-lumbrical adhesions: review of eighty-seven cases.
Flexor digitorum superficialis tendon transfer for intrinsic replacement. Long-term results and the effect on donor fingers.
Opponensplasty in intrinsic-muscle paralysis of the thumb in leprosy.
Patterns of movement of totally intrinsic-minus fingers based on a study of one hundred and forty-one fingers.
Movement patterns of interosseus-minus fingers.
Abductor pollicis longus transfer for replacement of first dorsal interosseous.