lecture 9 Flashcards
the hand function
grasp power
pinch precision
feel
communicate
the hand must have:
- Strong mobile framework
- Non-slip, pliable gripping surface
- Strong muscles without bulk
- Sensitivity – external environment
- internal for control
bones and joints of the hand
finger movements
extrinisic muscles have their origin on the —— and have tendons that insert onto the —–
forearm
hand
intrinsic muscles originate inside the —– and insert onto the —–
hand
hand
4 main groups
interossei
lumbericals
thenar muscles
hypothenar muscles
extrinsic finger flexors
flexor digitorum superficialis
flexor digitorum profundus
fleor digitorum superficialis
origin
insertion
innervation
action
Origin: Humeroulnar Head- Medial
Epicondyle of the humerus, ulnar
collateral ligament, and coronoid
process of the ulna;
Radial head –superior half of the
anterior border of the radius.
Insertion: Shafts of the middle
phalanges of digits 2-5.
Innervation: Median Nerve (C7 & C8,
T1)
Action: Flexes middle phalanges a the
PIP joints. With stronger contractions it
can also flex MCP joints, and the wrist
joint.
flexor digitorum profundus
origin
insertion
innervation
action
Origin: proximal 3/4 of medial and
anterior surfaces of ulna and
interosseous membrane
Insertion: Base of the distal phalanx
of digits 2- 5
Innervation: Medial part: ulnar nerve
(C8 and T1); Lateral part: anterior
interosseous branch of median nerve (C8
and T1) (C8, T1)
Action: Flexes distal phalanges at distal
interphalangeal joints of medial four
digits; assists with flexion of the wrist
extensor digitorum
Origin: Lateral epicondyle of humerus
Insertion: Extensor expansions of medial
four digits
Innervation: Deep Branch of the Radial
Nerve (C7, C8).
Action: Extends medial four digits at
metacarpophalangeal joints; Extends
hand at wrist joint
extensor digiti minimi
Origin: Lateral epicondyle of
humerus
Insertion: Extensor expansion of
5th digit
Innervation: Deep Branch of the
Radial Nerve (C7, C8).
Action: Extends 5th digit at
metacarpophalangeal and
interphalangeal joints
extensor indicis
Origin: Posterior surface of ulna and
interosseous membrane
Insertion: Extensor expansion of 2nd digit
Innervation: Posterior interosseous nerve
(C7 and C8), the continuation of the deep
branch of the radial nerve (C7, C8)
Action: Extends 2nd digit and helps to
extend hand at the wrist joint
thumb movements
muscles that act on the thumb from the forearm (extrinsic thumb muscles)
- Flexor Pollicis Longus
- Abductor Pollicis Longus
- Extensor Pollicis Longus
- Extensor Pollicis Brevis
flexor pollicis longus
Origin: Anterior surface of radius and
adjacent interosseous membrane.
Insertion: Base of distal phalanx of
thumb
Innervation: Anterior interosseous nerve
from median nerve (C8 and T1) (C8, T1)
Action: Flexes phalanges of 1st digit
(thumb)
abductor pollicis longus
Origin: Posterior surfaces of ulna, radius and
interosseous membrane
Insertion: Base of 1st metacarpal
Innervation: Posterior interosseous nerve (C7
and C8), the continuation of the deep branch
of the radial nerve
Action: Abducts thumb and extends it at
carpometacarpal joint
extensor pollicis longus
Origin: Posterior surface of middle
1/3 of ulna and interosseous
membrane
Insertion: Base of distal phalanx of
thumb
Innervation: Posterior interosseous
nerve (C7 and C8), the continuation
of the deep branch of the radial
nerve.
Action: Extends distal phalanx of
thumb at carpometacarpal and
interphalangeal joints
extensor pollicis brevis
Origin: Posterior surfaces of radius and
interosseous membrane
Insertion: Base of proximal
phalanx of thumb
Innervation: Posterior interosseous
nerve (C7 and C8), the continuation of
the deep branch of the radial nerve
Action: Extends proximal phalanx of
thumb at carpometacarpal joint
anatm=omical snuff box
intrinsic hand muscles
**interossei (7 muscles- 3 palmar 4 dorsal)
abduct and adduct the fingers
**lumbericals (4 muscles)
flex the MCPs, while keeping the PIP and DIP joint extended
**thenar muscles (4 muscles)
instrinsic muscles acting on the thumb
**hypothenar muscles (4 muscles)
instrinic muscls acting on the 5th digit
intrinsic muscles
7 interossei
3 palmar
4 dorsal
Origin: shafts of the metacarpals
Insertion: Bone & extensor expansion of
the proximal phalanges of 2-5.
Innervation: Deep branch of the ulnar
nerve (C8, T1)
Action: adduct & abduct
palmar vs dorsal interossei
4 lumbericals
Origin: (1st & 2nd) Lateral two tendons of
FDP (as unipennate muscles).
(3rd & 4th) Medial three tendons of FDP (as
bipennate muscles).
Insertion: Lateral sides of the
extensor expensions of the 2nd-5th digits.
Innervation: (1 & 2) Median Nerve (C8, T1),
(3 & 4) Deep branch of the ulnar nerve (C8,
T1).
Action: ** Flexes MCPs, and extend IP
joints 2nd-5th digits. **
