Week 11 Hand and fingers Flashcards
joint classification of carpometacarpal (CMC) and intermetacarpal joints
thumb – synovial saddle
fingers (2-5) – synovial plane
bones and articular surface of carpometacarpal and intermetacarpal joints
thumb: base of metacarpal and trapezium
fingers 2-5: base of metacarpals and distal row of carpal bones, intermetacarpal bones
fibrous capsule of carpometacarpal and intermetacarpal joints
- continuous CMC 2-5
- thumb separate
ligaments of carpometacarpal and intermetacarpal joints
thumb:
- radial carpometacarpal
- anterior/ posterior oblique
fingers 2-5:
- palmar carpometacarpal
- dorsal carpometacarpal
- interosseous carpometacarpal
movements (stability) of carpometacarpal and intermetacarpal joints
-
thumb is extremetly mobile:
flexion/ extension
abduction/ adduction
circumduction
opposition - minimal movement in digits 2-3
- 5th finger is moderately mobile
joint classification of metacarpophalangeal joints
synovial condyloid joint
bones and articular surface of metacarpophalangeal joints
- head of metacarpals and bases of proximal phalanges
- sesamoid bones articulating with head of 1st metacarpal
ligaments of metacarpophalangeal joints
1. collateral
- proper (cord-like) 繩狀 and accessory (fan-shaped)
- Extension: proper collateral ligament lax = permit abduction by interossei
- Flexion: proper collateral ligament taut = prevents unwanted abduction of MC heads during grip
2. volar/ palmar plate (ligament)
- fibrocartilage
- increase stability and congruency
- prevents hyperextension
- deep transverse metacarpal
- extensor expansions (dorsal hood)
movements of metacarpophalangeal joints
flexion/ extension
abdcution/ adduction
circumduction
joint classification, bone and articular surfaces of interphalangeal joints
- synovial hinge joint
- median ridge
ligaments of interphalangeal joints
- collateral
- volar/ palmar plate (ligament)
movements of interphalangeal joints
- flexion: PIP (0-130 degrees), DIP (70-90 degrees)
- extension: volar plates and collateral ligs taut
- axis of movement is oblique, fingers move toward base of thumb, facilitating 方便 grasp and opposition
deep fascia of the hand
- binding of the skin creases 摺痕 to the deep fasica
- palmar aponeurosis (thick, central part of palmar fascia)
organisation of the palm
septa creating: hypothenar (medial), central and thenar (lateral) compartments
central further divided: midpalmar and thenar spaces
what are the three muscles of the thnear
abductor pollicus brevis
flexor pollicus brevis
opponens pollicis
proximal, distal attachment, innervation and main action of abductor pollicis brevis
proximal: flexor retinaculum and tubercles of scaphoid and trapezium
distal: lateral side of base of proximal phalanx of thumb
innervation: recurrent branch of median nerve (C8, T1)
main action: abducts thumb, helps oppose it
proximal, distal attachment, innervation and main action of flexor pollicis brevis
superficial and deep head
proximal: flexor retinaculum and tubercles of scaphoid and trapezium
distal: lateral side of base of proximal phalanx of thumb
innervation:
- superficial head: recurrent branch of median nerve (C8, T1)
- deep head: deep branch of ulnar nerve (C8, T1)
main action: flexes thumb
proximal, distal attachment, innervation and main action of opponens pollicis
proximal: flexor retinaculum and tubercle of scaphoid and trapezium
distal: lateral side of 1st metacarpal
innervation: recurrent branch of median nerve (C8, T1)
main action: oppose thumb, it draws metacarpal medially to center of palm and rotates it medially
proximal, distal attachment, innervation and main action of adductor pollicis
oblique and transverse head
proximal:
- oblique head: bases of 2nd and 3rd metacarpals, capitate and adjacent carpals
- transverse head: anterior surface of shaft of 3rd metacarpal
distal: medial side of base of proximal phalanx of thumb
innervation: deep branch of ulnar nerve (C8, T1)
main action: adducts thumb toward lateral border of palm
APB, FPB – distal attachment: lateral side of base of proximal phalanx of thumb
what are the three muscles of hypothenar
abductor digiti minimi
flexor digiti minimi brevis
opponens digiti
proximal, distal attachment, innervation and main action of abdcutor digiti minimi
proximal: pisiform
distal: medial side of base of proximal phalanx of 5th digit
innervation: deep branch of ulnar nerve (C8, T1)
main action: abducts 5th digit, assists in flexion of its proximal phalanx
proximal, distal attachment, innervation and main action of flexor digiti minimi brevis
proximal: flexor retinaculum and hook of hamate
distal: medial side of base of proximal phalanx of 5th digit
innervation: deep branch of ulnar nerve (C8, T1)
main action: flexes proximal phalanx of 5th digit
proximal, distal attachment, innervation and main action of opponens digiti
proximal: flexor retinaculum and hook of hamate
distal: medial border of 5th metacarpal
innervation: deep branch of ulnar nerve (C8, T1)
main action: draws 5th metacarpal anterior and rotates it, bringing 5th digit into opposition with thumb
proximal, distal attachment, innervation and main action of lumbricals
1st - 2nd digit
proximal:
1st and 2nd - lateral two tendons of flexor digitorum profundus (as unipennate muscles)
3rd and 4th - medial three tendons of flexor digitorum profundus (as bipennate muscles)
distal: lateral sides of extensor expansions of 2nd -5th digits
innervation:
1st and 2nd - median nerve (C8, T1)
3rd and 4th - deep branch of ulnar nerve (C8, T1)
main action: flexes MCP joints, extend IP joints of 2nd-5th
lumbricals 3rd-4th innervation is the same as dorsal and palmar interossei innervation
proximal, distal attachment, innervation and main action of dorsal interossei, 1st-4th
2-5 digit
proximal: adjacent 鄰近的 sides of two metacarpals (as bipennate muscles)
distal: bases of proximal phalanges, extensor expansions of 2nd-4th digits
innervation: deep branch of ulnar nerve (C8, T1)
main action: abdcuts 2nd-4th digits from axial line, acts with lumbricals in flexing MCP joints and extending IP joints
proximal, distal attachment, innervation and main action of palmar interossei, 1st-3rd
2, 4, 5 digits
proximal: palmar surfaces of 2nd, 4th and 5th metacarpals (as unipennate muscles)
distal: base of proximal phalanges, extensor expansions of 2nd, 4th and 5th digits
innervation: deep branch of ulnar nerve (C8, T1)
main action: adduct 2nd, 4th and 5th digits toward axial line, assist lumbricals in flexing MCP joints and extending IP joints, extensor expansions of 2nd-4th digits
4 layers of palm, from superficial to deep
thenar central hypothenar
layer 1 APB, FPB — APM, FDMB
layer 2 — lumbricals: tendons of FDS, FDP —
layer 3 opponens pollicis opp digiti minimi
layer 4 — palmar and dorsal interossei —
ulnar artery in the wrist and hand
- enters palm via Guyon’s canal
- divides into superficial palmar arch and deep branch
radial artery in the wrist and hand
- deep branch of ulnar artery to form ther deep palmar arch
median nerve in the wrist and hand
- deep to flexor retinaculum
- supplies thenar muscles via the recurrent branch
- motor: lateral 2 lumbricals
- sensory: palmar surface, sides and nail beds of lateral 3.5 digits
ulnar nerve in the wrist and hand
- terminates as superficial (sensory to palmar surface of medial 1.5 digits) and deep branch (motor to most intrinsics of the hand)
dermatomes to the skin over the hand
refer back to lecture notes
