hand Flashcards
prehension
the act of grasping or seizing
Essential function of the hand
prehension
Key to prehension
thumb orientation and rich supply of sensory receptors
how mann bones are there distal to the carpals
19 bones distal to the carpals
5 rays comprised of: Metacarpals (5); Proximal phalanges (5); Middle phalanges (4); Distal phalanges (5)
MCP joints
between the metacarpal and the phalages
where are sesamoid found
under the thumb
Longitudinal arch of the hand
Carpometacarpo-phalangeal arches
Transverse arch of the hand
Proximal transverse
Distal transverse
proximal transverse
carpal arch
Distal transverse
level of metacarpal heads
Oblique arch
Thumb during opposition with other fingers
Flexion Creases
Wrinkles - Present to stress and stretch the hand without tensioning the skin
is the fascia of the palm thicker on the thumb or pinky side
thumb
Dupuytren’s contracture
Increase in fibrous tissue of palmar aponeurosis
Pt get flexion contraction of the finger – normally 4th and 5th digits
Treat with splinting and stretching – sometime need a surgical release – slice open the fascia
MCP joints
condyloid (2DF)
MCP joints movement
flexion and extension
abd and add
IP joints
bicondylar
IP joints movement
Most: Flex and ext (active)
Do have some passive rotation
IP joints vex and cave
biconvex head of phalanx and biconcave base of middle/distal phalanx
MCP 2nd - 5th Fingers vex and cave
Proximal: convex (oval MC head)
Distal: concave base (oval phalanx)
MCP 2nd - 5th Fingers actions
Flex/Ext - Sagittal plane about transverse axis
Abd/Add - Frontal plane about A-P axis
Circumduction
MCP Thumb
flexion/extension and limited abd/add
where do we find the sesamoid bones of the hand
distal aspect of the 1st metacarpal, there are 2 sesamoid bones
Sesamoids are incorporated into the fibrocartilage of the volar plate
MCP – 1st to 5th digits capsule
Dorsally fibrous; continuous volarly with volar plate
Lax in extension
Ligaments of the MCP 1-5
: 2 Collateral, 2 Accessory & Volar Plate
MCP collateral ligamaents
Strong, oriented obliquely
Tension increases with flexion
Resist Abd/Add
MCP Accessory ligaments
In flexion firmly holds volar plate against volar surface of MC head
Volar Plate MCP ligament - loction
Proximal: at the metacarpal head, loosely attached by membranous portion of volar plate
Distal: at the base of proximal phalanx, firmly attached, fibrocartilage
volar plate function in extesnion
increases contact surface with MC head / resists hyperextension
volar plate function in flexion
glides proximally / prevents flexor tendon pinching
transverse metacarpal ligament
Connects metacarpal heads and adjacent volar plates
volar plates blend with transverse metacarpal ligament
Hold heads of MC together
Facilitate adaptability to size and shape of objects
what forms the tunnel that surrounds the flexor tendons
transverse metacarpal ligament and volar plate
MCP: 2nd - 5th Fingers and gripping
Mechanically stabilized for gripping at 70 to 90 degrees flexion
what muscle is connected o the volar plate of the thumb
Tunnel of FPL
connecting the lateral ligaments and the volar plate with the sesamoids
what is a common ligament MCP issue in the thumb
UCL injury
Gamekeeper’s or Skiers thumb
extension active range of motion and passive in the MCP jts (2-5)
Ext: 30 - 40 AROM; 90 PROM (large difference)
flexion in the MCP joints (2-5)
Flex: 90 deg. index; progressive increase to 110 at 5th digit
thumb MCP felxion
Flexion 50 degrees; Extension 0 degrees
closed packed position for MCP joint
full flexion
open packed for MCP
slight flexion
IP vex and cave
Distal: bi-convex head
Proximal: bi-concave base
IP are what kind of joint
hinge or bicondylar
movement seen at IP
Transverse axis results in flex/ext
PIP - Volar Plate
has thick distal insertion and two check ligaments proximally
Prevents hyperextension
Ruptures occur in the thicker distal insertion
Reinforced by pulleys of flexor sheath
PIP transverse ligament
this is none
PIP flexion
Flexion 110 degrees, more at 5th than 2nd. Thumb 90 degrees.
PIP extension
Extension limited, except thumb IP up to 50 degrees.
DIP flexion and extension
Flex. 90 degrees with ulnarward increase; hyperext up to 30 degrees
what side produces a tighter grip the ulnar or the radial side
ulnar side
Closed / Open Pack: all (PIP and DIP)
Closed: full ext
Open: slight flexion
where do we see OA more DIP or PIP
PIP
when does OA increase
with age and in women
Joints of the Digits vasculature
Digital aa
joints of the digits Innervation
Digital nn
Flexors of the fingers
Flexor Digitorum Superficialis (FDS) and Profundus (FDP)
Flexor Pollicis Longus (FPL)
Extensors of the fingers
Extensor Digitorum (ED)
Extensor Digiti Minimi (EDM)
Extensor Indicis (EI)
Extensor Pollicis Brevis (EPB)
Extensor Pollicis Longus (EPL)
Abductor Pollicis Longus (APL)
FDS action
Flexes PIP
Power grip muscle
FDS can flex wrist and MCP when PIP is fully flexed
FDP actions
Only tendon to insert on distal phalanx
Function
DIP flexion
FDP help with PIP ,MCP and wrist flexion
Origin of lumbrical muscles
FPL action
Flex IP
Ineffective as IP flexor during wrist flexion
APL action
Abd the CMC, radially deviates wrist
EPB action
Same as APL and extend MCP
EPL action
Extends IP
Extends MCP, ext CMC joint
Can’t extend IP with wrist, CMC, & MCP extended
ED
Pass beneath Ext Retinaculum / Sheaths/ No pulleys – Almost all extrasynovially
ONLY muscle capable of extending MCP
CANNOT extend PIP & DIP alone
EI & EDM action
Independent control 2nd & 5th
Extensor Mechanism
Complex broad, flat aponeurotic band
Composed of extrinsic extensor tendon that continues as the central band
cover the entire dorsal surface of the finger
Mallet finger
Rupture at the terminal extensor tendon or bony avulsion at its attachment into distal phalanx
Swan-neck Deformity
hyperextended PIP, flexed DIP
Superior subluxation of lateral bands
Boutonniere Deformity:
flexed PIP, hyperextended DIP
Injury to the central slip with inferior subluxation of lateral bands
thenar compartment
the bulk of muscle tissue over the thumb side of the palm and contains 3 thenar muscles.
hypothenar compartment
the bulk of muscle tissue over the pinky side of the palm and contains 3 hypothenar muscles.
central compartment
lies in between, and mostly contains your extrinsic flexor tendons plus the intrinsic lumbrical muscles.
the adductor compartment
lies deep to the central and hypothenar compartments and just contains 1 muscle, the adductor pollicis.
Intrinsic Thenar (Thumb) Muscles
Abductor Pollicis Brevis (AbPB)
Flexor Pollicis Brevis (FPB)
Opponens Pollicis (OP)
Adductor Pollicis (AdP)
only 3 of them are considered thenar muscles because they share the same fascial compartment
AbPB innervation
median n.
FPB - Two heads innervation
Lateral or superficial (median n.) inserts with AbPB assisting Abd.
Medial or deep (ulnar n.) inserts with AdP assisting Add.
OP innervation
medial nerve
OP action
Only intrinsic thenar to insert on 1st metacarpal
Effective in positioning metacarpal in abd, flex and rotation
Adductor Pollicis innervation
deep ulnar nerve
Adductor Pollicis action
has two heads (oblquie and trnasverse)
Thumb adduction
Stabilizes thumb against opposed finger
Hypothenar Muscles
Abductor Digiti Minimi
Flexor Digiti Minimi
Opponens Digiti Minimi
Hypothenar Muscles innervation
Deep branch ulnar n
Lumbricals attachments
Proximal: FDP tendons
Distal: lateral bands of extensor mechanism
Lumbricals innervation
Two nerves (1,2-median; 3,4-ulnar)
lumbrical action
Extend IPs and flex MCP
Interossei innervation
deep branch of the ulnar nerve
mnomics Interossei
DAB – Dorsal ABduct
PAD – Palmar ADduct
Both help lumbricals
MCP Joint in Extension and interossi movement
Mechanical advantage for Abd/Add
MCP Joint in Flexion and interossei movment
movement in abd and ad is restricted
