OIIA- Hand and Wrist Muscles
what muscles make up Hypothenar Eminence/Intrinsic Muscle?
Abductor Digiti Minimi, Flexor Digiti Minim, Opponens Digiti Minimi, Palmaris Brevis (hyPothenar=4= on pinky side)
what muscles make up Thenar Eminence/Intrinsic Muscle?
Abductor Pollicis Brevis, Flexor Pollicis Brevis, Opponens Pollicis (THENAR=THREE=THUMB)
Not that the additional activation of the finger extensor muscle (extensor digitorum) causes the ECRL to relax. Explain the reduction in wrist extensor muscle activation.
Because extensor digitorum is also a wrist extensor
Abductor Pollicis Brevis Action:
CMC abduction
Adductor Pollicis Action:
CMC adduction and MCP flexion
ECRB Why is this muscle's radial deviation tendency considered as slight and not primary?
Due to its proximal attachment at lateral epicondyle and distal attachment at 3rd metacarpal. It would shorten the moment arm of muscle to produce radial deviation.
How can extensor indicis supinate the forearm?
EI origin=lateral epicondyle; crosses to 1st digit across pronation-supination axis
How can FCR flex the elbow and pronate the forearm?
FCR origin= medial epicondyle; crosses the medial to lateral over pronation- supination axis of rotation
Lumbricals Action:
Flex MCP; MCP deviation: index-ulnar, ring and small-radial; IP extension via extensor mechanism
Flexor Carpi Radialis Action:
Flexion and Radial deviation of wrist
Palmar Interossei Action:
MCP flexion, MCP deviation: index-ulnar; radial and small-radial; IP extension
Abductor Digiti Minimi Action:
MCP ulnar deviation and MCP flexion
Lumbricals O: I:
O: Medial 2: sides of flexor digitorum tendons 3,4,5 digits Lateral 2: lateral side of FDP of 2 & 3 digits I: extensor mechanism
Adductor Pollicis O: I:
O: Oblique head: Base of 2nd and 3rd metacarpal, capitate O: Transverse head:3rd metacarpal I: Base of he proximal phalanx
Abductor Digiti Minimi O: I:
O: Pisiform, tendon of FCU I: proximal phalanx of 5th digit; extensor mechanism
Palmar Interossei O: I:
O: Shaft of metacarpal bone of the digit on which they act on I: proximal phalanges and dorsal extensor expansion on ulnar- index, ring and little-radial
Dorsal Interossei O: I:
O: adjacent sides of metacarpals (attaches to 2 metacarpals) I: radial or ulnar side of oblique fibers of dorsal hood or base of proximal phalanx
Flexor Pollicis Longus Origin: Insertion:
O: anterior surface of radius and interosseous membrane I:base of distal phalanx of thumb
Opponens Pollicis O: I:
O: flexor retinaculum, trapezium I: shaft of 1st metacarpal
Extensor Digitorum Origin: Insertion:
O: lateral epicondyle of humerus, I:distal phalanges of fingers 2-5
Flexor Carpi Ulnaris Origin: Insertion:
O: medial epicondyle of humerus I: pisiform and hamate
Abductor Pollicis Brevis O: I:
O: transverse carpal ligament, palmar tubercles of trapezium and scaphoid I: base of proximal phalanx of thumb and dorsal aponeurosis
Opponens Digiti Minimi O: I:
O:flexor retinaculum, hook of hamate I: 5th metacarpal
Flexor Digitorum Superficialis Origin: Insertion:
O:medial epicondyle of humerus , as well as parts of radius and ulna I: base of middle phalanx of 4 fingers
Extensor Pollicis Brevis Origin: Insertion:
Origin: Posterior radius Interosseous membrane Insertion: base of proximal phalanx of thumb
Abductor Pollicis Longus Origin: Insertion:
Origin: Shaft of Ulna and Radius Insertion: First Metacarpal
Palmaris Longus Origin: Insertion:
Origin: medial epicondyle Insertion: flexor retinaculum & palmar aponeurosis
Flexor Digitorum Profundus Origin: Insertion:
Origin: proximal 3/4 of the anterior and medial ulna Insertion: base of the distal phalanxes of the 4 fingers
How could FCU theoretically flex the elbow?
because it crosses anterior to elbow joint, runs perpendicular to frontal axis of rotation; it could function as an elbow flexor
How could ECU theoretically extend the wrist?
because it crosses posterior to elbow joint and runs perpendicular to frontal axis of rotation it can function as elbow extension
Explain how ECRL could be described as having weak supination ability?
because its line of force crossed the axis of supination
extensor carpi ulnaris Action:
extension of wrist and ulnar deviation
Dorsal interossei Action:
flex MCP, Extend IP; MCP deviation- small and ring-radial; index-ulnar
where do extensor muscles typically originate?
lateral epicondyle
where do flexor muscles typically orginate?
medial epicondyle
Opponens Digiti Minimi Action:
opposition of digit 5 at CMC joint
Opponens Pollicis Action:
opposition of thumb CMC joint, flex and abduction of thumb CMC and rotation
flexor carpi radialis Origin: Insertion:
origin: medial epicondyle insertion: base of metacarpals 2 and 3
Extensor Carpi Radialis Brevis Action:
wrist extension, radial deviation
Extensor Carpi Radialis Longus (ECRL) Action:
wrist extension, radial deviation
Flexor Carpi Ulnaris Action:
wrist flexion, ulnar deviation
