5) Hand Muscles Flashcards
Muscles that flex the fingers
Flexor digitorum superficialis
Flexor digitorum profundus
Lumbricals
Flexor digiti minimi
Flexor digitorum superficialis
S: Large muscle anterior compartment
O: (2) heads
Medial: medial epicondyle of humerus,
ant ulnar collateral ligament, medial part coronoid process sublime tubercle
Lateral: upper 2/3 anterior boarder of radius
I: palmar surface base of middle phalanx of all fingers
D: distally
A: flexes metacarpals and proximal interphalangeal and wrist
F: griping
NS: median nerve C7,8 T1
Flexor digitorum profundus
S: strap like
O: medial side of coronoid process upper 3/4 of anterior and medial surfaces of ulna medial 1/3 of anterior surface interosseous membrane, posterior boarder of ulna via aponeurosis
I: palmar surface base distal phalanx all fingers
D: distally
A: flexion interphalangeal joints meta phalange always and wrist
F:
NS:
index+middle fingers: (anterior Interosseous branch median nerve C7,8 T1)
Little finger + ring finger (ulnar nerve C8,T1)
Lumbricals
S: 4 small round muscles
O: lateral side of flexor digitorum profundus tendons
I: lateral edge dorsal digital expansions of same finger
D: Distally
A: flex metacarpalphalangeal extend both interphalangeal
F:
NS: Lateral 2: median nerve T1
Medial 2: ulnar nerve T1
Flexor digiti minimi brevis
S: small
O: hook of hamate and flexor retinaculum
I: base proximal phalanx of little finger
D: Distally
A: flexes the metacarpalphalangeal joint of little finger
F:
NS: Median nerve T1
Attatchments flexor retinaculum
Thickening of the fascia anterior to carpus
Long flexor tendons are held in place at wrist and prevented from bowstringing strong band
Converts the carpal sulcus into a tunnel
Attachments:
Laterally: Tubercle of scaphoid lips of trapezium
Medially: pisiform hook of hamate
Arrangement of tendons at the wrist
See diagram
Individual and shared tendon sheaths of the wrist
Tendons protected by synovial tendon sheaths= protection reduces friction when tendons pass under ligaments
Is it double walled sheath of synovial membrane extends around tendon like a tube.
2 layers=
Parietal layer: outer layer
Cavity contains synovial fluid facilitates friction free movement
visceral layer: surrounds tendon
Extensor digitorum
S:
O: lateral epicondyle humerus via common extensor tendon
I: via dorsal digit expansion to base of posterior surface distal and middle phalanges
D:
A: extends x2 interphalangeal joints metacarpalphalangeal and wrist
F:
NS: posterior interosseous branch of radial nerve C7,8
Extensor indicis
S:
O: lower part posterior surface of ulna and adjacent interosseous membrane
I: joins dorsal digital expansions of index finger
D:
A: extends index finger
F:
NS: posterior interosseous branch radial nerve C7,8
Extensor digiti minimi
S:
O: lateral epicondyle of humerus via common extensor tendon
I: joins dorsal digital expansions of little finger
D:
A: extends little finger
F:
NS: posterior interosseous branch radial nerve C7,8
Extensor retinaculum attatchments
Thickening of the deep fascia
Attachments:
Laterally: distal part of the anterior surface of radius
Medially: distal end ulna pisiform triquetral UCL
Septa run from its deep surface to the distal ends of the radius and ulna converting the grooves on the dorsum of the wrist into 6 separate tunnels each lined by synovial sheath
Arrangement of tendons at the wrist
X
Individual and shared tendons sheaths at the wrist
I: Abductor pollicis longus + Extensor pollicis brevis= shared sheath
II: Extensor carpi radialis longus + brevis= shared sheath
III: Extensor pollicis longus
IV: Extensor digitorum +indicis = shared sheath
V: Extensor digiti minimi
VI: Extensor carpi ulnaris
Dorsal Digital Expansion (Extensor hood)
Forms dorsal posterior part of the capsule of the metacarpalphalangeal joint extends forwards either side of the metacarpal head and fuses deep transverse metacarpal ligament
At distal end of proximal phalanx it divides into 3
- central part continuous with extensor digitorum inserts into posterior base of middle phalanx
- X2 lateral parts reunite to insert into the posterior aspect base of distal phalanx
