Muscles and Fascia of Hand Flashcards
numbering of metacarpals and phalanges
1 to 5, beginning with the thumb and ending with little finger
skeleton of the hand
carpals in the wrist, metacarpals in the hand proper, phalanges in the fingers
palmar aspect of hand features central concavity that separates two eminences
lateral, more prominent thenar eminence at the base of the thumb
medial, smaller, hypothenar eminence proximal to the base of the 5th finger
fascia of palm
continuous with antebrachial fascia and fascia of dorsum of hand
thin over thenar and hypothenar eminences, but thivk centrally where it forms fibrous palmar aponeurosis and in the fingers where it forms the digital sheaths
palmar aponeurosis
strong, well defined part of deep fascia of palm
covers soft tissues and overlies long flexor tendons
poximal end or apex: continuous with the flexor retinaculum and the palmaris longus tendon
distal to apex: forms four longitudinal digital bands that radiate from the apex and attach distally to the bases of the proximal phalanges, where they become continuous with the fibrous digital sheaths
fibrous digital sheaths
ligamentous tubes that enclose flexor tendons and synovial sheaths that surround them as they pass along the palmar aspect of their respective digit
medial fibrous septum
extends deeply from medial border of palmar aponeurosis to the 5th metacarpal
hypothenar compartment
medial to septum
contains hypothenar muscles
lateral fibrous septum
extends deeply from the lateral border of the palmar aponeurosis to the 3rd metacarpal
thenar compartment
lateral to lateral fibrous septum
contains thenar muscles
central compartment
between hypothenar and thenar compartments
contains flexor tendons and their sheaths, lumbrical muscles, superficial arterial arch and digital vessels and nerves
adductor compartment
deepest muscular plane of the palm
contains adductor pollicis
two potential spaces
between flexor tends and fascia covering deep palmar muscles
thenar space and midpalmar space
bounded by fibrous septa passing from edges of palmar aponeurosis to metacarpals
between two spaces is lateral fibrous septum, attached to 3rd metacarpal
midpalmar space continuous with anterior compartment of forearm via carpal tunnel
five compartments of intrinsic muscles of hand
thenar compartment hypothenar compartment adductor compartment central compartment interosseous compartments
muscles in thenar compartment
thenar muscles
abductor pollicis brevis, flexor pollicis brevis, opponens pollicis
muscles in hypothenar compartment
hypothenar muscles
abductor digiti minimi
flexor digiti minimi brevis
opponens digiti minimi
muscle in adductor compartment
adductor pollicis
central compartment contents
lumbricals: short muscles of hand
with long flexor tendons
interosseous compartments
contain interossei in separate ones between the metacarpals
thenar muscles chiefly responsible for
opposition of thumb
freedom of movement of thumb results from
1st metacarpal being independent
abduction of thumb
APL and abductor pollicis brevis
adduction of thumb
adductor pollicis and 1st dorsal interosseous
extension of thumb
EPL, EPB and APL
flexion of thumb
FPL and flexor pollicis brevis
opposition of thumb
opponens pollicis
opposition occurs at
carpometacarpal joint of thumb
begins with thumb in extended position and initially involves abduction and medial rotation of1st metacarpal: opponens pollicis and then flexion at metacarpophalangeal joint
reinforcing action of AD and FPL increases pressure
palmarisbrevis in hypothenar einence
small muscle in subcutaneous issue
wrinkles the skin, deepeing the hollow of the palm, thereby aiding the palmar grip
covers and protects the ulnar nerve and artery
attached proximally to the medial border of the palmar aponeurosis and to the skin on the medial border of the hand
short muscles of hand
four slender lubrical muscles
four dorsal interosseous: DAB
three palmar interosseous: on palmar surfaces of 2nd 4th and 5th metacarpals: PAD
opponens policis origin
flexor retinaculum and tubercles of scaphoid and trapezium
opponens pollicis insertion
lateral side of 1st metacarpal
opponnens pollicis innervation
recurrent branch of median nerve
C8, T1
opponens pollicis action
to oppose thumb, it draws 1st metacarpal medially to center of palm and rotates it medially
abductor pollicis brevis origin
flexor retinaculum and tubercles of scaphoid and trapezium
abductor pollicis brevis insertion
lateral side of base of proximal phalanx of thumb
abductor pollicis brevis innervation
recurrent branch of media nerve
C8, T1
abductor pollicis brevis action
abducts thumb, helps oppose it
flexor pollicis brevis origin
flexor retinaculum and tubercles of scaphoid and trapezium
flexor policis brevis insertion
lateral side of base of proximal phalanx of thumb
flexor pollicis brevis innervation
superficial head: recurrent branch of median nerve
C8, T1
deep head: deep branch of ulnar nerve
C8, T1
flexor pollicis brevis action
flexes thumb
adductor policis origin
oblique head: bases of 2nd and 3rd metacarpals, capitate, adjacent carpals
transverse head: anterior surface of shaft of 3rd metacarpal
adductor pollicis insertion
medial side of base of proximal phalanx of thumb
adductor pollicis innervation
deep branch of ulnar nerve
C8, T1
adductor pollicis action
adducts thumb toward lateral border of palm
abductor digiti minimi origin
pisiform
abductor digiti minim insertion
medial side of base of proximal phalanx of 5th finger
abductor digiti minimi innervation
deep branch of ulnar nerve c8, T1
abductor digiti minimi action
abducts 5th finger, assists in flexion of its proximal phalanx
flexor digiti minimi brevis origin
hook of hamate and flexor retinaculum
flexor digiti minimi brevis insertion
medial side of base of proximal phalanx of 5th finger
flexor digiti minimi brevis innervation
deep branch of ulnar nerve
C8, T1
flexor digiti minimi brevis action
flexes proximal phalanx of 5th finger
opponens digiti minimi origin
hook of hamate and flexor retinaculum
opponens digiti minimi insertion
medial border of 5th metacarpal
opponens digiti minimi innervation
deep branch of ulnar nerve
C8, T1
opponens digiti minimi action
draws 5th metacarpal anterior and rotates it, bringing 5th finger into opposition with thumb
lumbricals origin
1 and 2: lateral two tendons of flexor digitorum profundus (as unipennate muscles)
3 and 4: medial three tendons of flexor digitorum profundus (as bipennate muscles)
lumbricals insertion
lateral sides of extensor expansions of 2nd-5th fingers
lumbricals innervation
1 and 2: median nerve (C8, T1)
3 and 4: deep branch of ulnar nerve (C8, T1)
lumbricals action
flex metacarpophalangeal joints
extend interphalangeal joints of 2nd to 5th fingers
dorsal interossei 1-4 origin
adjacent sides of two metacarpals (as bipennate muscles)
dorsal interossei insertion
bases of proximal phalanges
extensor expansions of 2nd to 4th fingers
dorsal interossei innervation
deep branch of ulnar nerve: C8, T1
dorsal interossei action
abduct 2nd to 4th fingers from axial line
act with lumbricals in flexing metacarpophalangeal joints and etending interphalangeal joints
palmar interossei 1-3 origin
palmar surfaces of 2nd, 4th and 5th metacarpals (as unipennate muscles)
palmar interossei insertion
bases of proximal phalanges; extensor expansions of 2nd, 4th and 5th fingers
palmar interossei innervation
deep branch of ulnar nerve C8, T1
palmar interossei action
adduct 2nd, 4th and 5th fingers toward axial line
assist lumbricals in flexing metacarpophalangeal joints and extending interphalangeal joints
