Hand Flashcards
palmar aponeurosis
• Resists shear & compression forces when gripping • Palmarisbrevis – Origin: • palmaraponeurosis&flexor retinaculum – Insertion: • dermisonmedialmarginofhand – Action: • deepens cup of palm, possibly to improve grip – Innervation: • ulnarnerve(superficialbranch)
fibrous digital sheaths
• Tunnelshousing synovial sheaths, &, within them, FDS & FDP tendons. • Prevent these tendons from bowing when the digits are flexed.
extensor hoods
Expansions of extensor digitorum & extensor pollicis longus over dorsal surface of proximal phalanges
Joined by extrinsic mm: extensor digiti minimi, extensor indicis, & extensor pollicis brevis
Most intrinsic mm attach
apex attached to distal phalanx
Allows intrinsic mm to simultaneously:
– flex the metacarpophalangeal joints
– & extend the interphalangeal joints
muscle groups
Thenar(4)
– Abductor pollicis brevis
– Flexor pollicis brevis
– Opponens pollicis
– Adductor pollicisfs
Hypothenar(3)
– abductor digiti minimi
– flexor digiti minimi brevis
– opponens digiti minimi
Lumbricals(4)
Palmar & Dorsal Interossei (4 each)
Digitflexors& extensors
abductor pollicis brevis
• Thenar muscles (4):
- abductor pollicis brevis
• Origin
– Tuberclesoftrapezium& scaphoid & flexor retinaculum
• Insertion
– Proximalphalanx&extensor hood of thumb
• Innervation
– Mediannerve(recurrent branch)
• Action
– Abduct thumb at carpometacarpal & metacarpophalangeal joints
flexor pollicis brevis
• Thenarmuscles:
- flexor pollicis brevis
• Origin
– Tubercleoftrapezium & flexor retinaculum
• Insertion
– Proximalphalanxof thumb
• Innervation
– Mediannerve (recurrent branch)
• Action
– Flexthumbat metacarpophalangeal joint
opponens pollicis
• Thenarmuscles:
- Opponens pollicis
• Origin
– Tubercleoftrapezium & flexor retinaculum
• Insertion
– MC1lateral&palmar surfaces
• Innervation
– Mediannerve (recurrent branch)
• Action
– Mediallyrotatethumb
adductor pollicis
Muscles
• Thenarmuscles:
- Adductor pollicis
• Origin
– Transversehead:MC3
– Obliquehead:capitate
& bases of MC2 & MC3
• Insertion
– Proximalphalanxbase & extensor hood
• Innervation
– Ulnarnerve(deep branch)
• Action
– Adductthumb
abductor digiti minimi
Hypothenar(3):
- abductor digiti minimi
• Origin
– Pisifom,pisohamate ligament, FCU tendon
• Insertion
– Proximalphalanxof digit 5
• Innervation
– Ulnarnerve(deep branch)
• Action
– Abduct digit 5 at metacarpophalangeal joint
flexor digiti minimi brevis
• Hypothenar(3):
- Flexor digiti minimi brevis
• Origin
– Hamatehook&flexor retinaculum
• Insertion
– Proximalphalanxof digit 5
• Innervation
– Ulnarnerve(deep branch)
• Action
– Flexdigit5at metacarpophalangeal joint
opponens digiti minimi
- Opponens digiti minimi
• Origin
– Hamatehook&flexor retinaculum
• Insertion
– MC5medialaspect
• Innervation
– Ulnarnerve(deep branch)
• Action
– LaterallyrotateMC5
lumbricals
– Origin
• Tendonsofflexor digitorum profundus
– Insertion
• Extensorhoodsof digits 2-5
– Innervation
Medial2:Ulnarnerve (deep branch)
Lateral2:Median nerve (digital branches)
– Action
• Flex MCP joints while extending IP joints
dorsal interossei
• Dorsalinterossei(4)
– Origin
• adjacent sides of 2 MCs
– Insertion
• Extensorhoods&baseof proximal phalanges of digits 2-4
– Innervation
• Ulnarnerve(deepbranch)
– Action
• Abductdigits2-4at metacarpophalangeal joints
palmar interossei
• Palmarinterossei(4)
– Origin
• Side of 1 MC
– Insertion
• Extensorhoodsofdigits 1,2,4,5 & proximal phalanx of digit 1
– Innervation
• Ulnarnerve(deep branch)
– Action
• Adductdigits1,2,4,5at metacarpophalangeal joints
grips
power grip
– Object is held between fingers and palm.
– Performed by extrinsic muscles that originate in the forearm and insert in the hand.
precision grip
– Object is held between two or more fingers, not the palm.
– Performed by intrinsic muscles that occur entirely in the hand.
hook grip
– primarily a function of the fingers, excluding the thumb
