Muscles Of The Hand

Front 1

Intrinsic Muscles of the Hand

Back 1

1) Intrinsic hand muscles are those that locates entirely within the hand
2) extrinsic hand muscles are muscles located in the forearm that send their tendons into the hand and serve too move the digits or the hand at the wrist

Front 2

Compartments of the Hand
x 4
1) Thenar Compartment

Back 2

- contains 1st metatarsal bone & intrinsic muscles for the thumb
a) flexor pollicis brevis, abductor pollicis brevis, opponens pollicis muscles

Front 3

Compartments of the Hand
x 4
2) Hypothenar Compartment

Back 3

- contains intrinsic muscles for the little finger
a) flexor digiti minimi, abductor digiti minimi, opponens digiti minimi muscles

Front 4

Compartments of the Hand
x 4
3) Central Compartment

Back 4

- contents
a) 4 metacarpal bones (#2-5)
b) dorsal & palmar interosseous muscles
c) adductor pollicis muscle
d) tendons of flexor digitorum superficialis & flexor digitorum profundus muscle
e) lumbrical muscles

Front 5

Compartments of the Hand
x 4
Palmar Aponeurosis

Back 5

- dense fascia layer found immediately under skin of palm
a) forms the roof of central compartment
b) serves as insertion for Palmaris Longus muscle

Front 6

Movements of the fingers (digits 2-5)

Back 6

1) movements at metacarpal-phalangeal joint: flexion-extension, abduction-adduction, & circumduction of fingers
a) abduction = spread fingers
b) adduction = bringing fingers together
2) interphalangeal joints allow for flexion-extension only

Front 7

Movements of the thumb

Back 7

1) flexion-extension - bending thumb toward-away from palm (away position forms 90 degree angle with index finger, in same plane as palm)
2) abduction-adduction - moving thumb anteriorly (perpendicular to palm) & posteriorly (toward-against) index finger
3) opposition - bringing pad of thumb to pad of little finger

Front 8

Muscles of the Thenar Compartment
x 3

Back 8

-- have origin from lateral carpal bones
-- all insert onto lateral side of thumb (muscles run parallel to 1st metacarpal bone)
-- all innervated by Median Nerve (after it passes through carpal tunnel)

Front 9

1) Abductor Pollicis Brevis Muscle

Back 9

Action - abducts thumb (with Abductor Pollicis Longus muscle of posterior forearm)

Front 10

2) Flexor Pollicis Brevis Muscle

Back 10

Action - flexes thumb (with flexor pollicis longus muscle of anterior forearm)

Front 11

3) Opponens Pollicis Muscle

Back 11

- located deep to abductor & flexor pollicis brevis muscles
Action - opposition of thumb ( pulls 1st metacarpal across palm of hand)

Front 12

Thumb Muscles of Central Compartment

Back 12

1) Adductor Pollicis Longus
Origin - from metacarpal & carpal bones of central palm
Insert - medial side of thumb
Innerv - ulnar nerve
Action - adducts thumb
-- strong muscle used during grasping
-- forms anterior side of thumb (first) web space
-- not located in thenar compartment - not innervated by median nerve

Front 13

Muscles of the Hypothenar Compartment

Back 13

-- having origin from carpal bones of medial wrist & insert into medial side of little finger
-- all innervated by ulnar nerve
1) Abductor Digiti Minimi
Action - abducts 5th digit
2) Flexor Digiti Minimi Muscle
Action - flexes 5th digit
3) Opponens Digiti Minimi Muscle - located deep to abductor & flexor digiti minimi muscles
Action - bring little finger into opposition with thumb

Front 14

Muscles of the Central Compatment
x 3

Back 14

-- tendons of Flexor Digitorum Superficialis & Flexor Digitorum Profundus pass through central compartment

Front 15

1) Lumbrical Muscles (four)

Back 15

origin - tendons of flexor digitorum profundus muscle
Insert - into extensor expansions of digits 2-5
Innerv - a) lumbricals 1 & 2 (lateral palm) - Median Nerve
b) lumbricals 3 & 4 (medial palm) - Ulnar nerve
Action - a) flex metacarpal-phalangeal joints (muscles cross palmar side of joint)
b) extend interphalangeal joints (via insertion into extensor expansion)

Front 16

2) Dorsal Interosseous Muscles

Back 16

Origin - metacarpal bones
Insert - proximal phalanx
Innerv - ulnar nerve
Action - abduct fingers - DAB (dorsal - abduct)
-- first muscle forms posterior side of thumb web space

Front 17

3) Palmar Interosseous Muscles

Back 17

origin - metacarpals
Insert - proximal phalanx
Innerv - ulnar nerve
Action - adducts fingers - PAD (palmar - adduct)