Forearm, Wrist, & Hand Flashcards
The carpus is made up of how many bones?
8
What percentage of upper limb function does the hand account for?
90%
The thumb is involved in what percent of hand function?
40-50%
What type of joint is the distal radio-ulnar joint?
a double pivot joint that unites the distal radius with the ulna and an articular disc
Colles Fracture
aka dinner fork fracture
fracture of the radius within 20-35mm of the wrist with posterior angulation of the distal fragment
Smith’s fracture
aka garden spade deformity
fracture of the radius within 20-35 mm of the wrist joint with anterior angulation of the distal fragment.
TFCC
triangular fibrocartilage complex
fibrocartilage disc between the medial, proximal row of carpals and the distal ulna
What is the primary function of the TFCC
to improve joint congruency and cushion against compressive forces
transmits about 20% of the axial load from the hand to the forearm
What is the most commonly fractured carpal?
Scaphoid (aka navicular)
Mid Carpal Joints
lie between the two rows of carpals
a compound articulation because each row has both a concave and convex segment
Where are the concave and convex segments located on the proximal row of carpals?
convex laterally
concave medially
Carpometacarpal joints
articulation between the distal borders of the distal carpal row bones and the bases of the metacarpals
What provides stability for the carpometacarpal joints
the palmar and dorsal carpometacarpal and intermetacarpal ligaments
Metacarpophalangeal joints
biaxial joints
allow for flexion-extension and medial-lateral deviation
First carpometacarpal joint
sellar (saddle shaped) joint
functionally the most important CMC joint
what is the attitude of the hand at rest?
MCP’s and IP’s are held in a position of slight flexion
Bennett’s fracture
fracture through the base of the first metacarpal neck with dorsal and radial displacement of the shaft
Metacarpophalangeal joint of the thumb
hinge joint
consistes of a convex surface on the head of the metacarpal and a concave surface on the base of the phalanx
Bar room fracture
fracture of the fourth or fifth metacarpal neck with anterior displacement of the head
Boxer’s fracture
fracture of the second or third metacarpal neck with anterior displacement of the head
Interphalangeal Joints
adjacent phalanges articulate in hinge joints that allow motion in one plane
Herberden’s Nodes
distal joints are enlarged by hard nodules
painless, motion is unlimited
Where are herberden’s nodes not found?
the thumb
Herberden’s Nodes in women
localized process of OA
usually hereditary
commonly involves more than one joint
Herberden’s nodes in men
generally as a result of trauma
usually involves just one joint
Bouchard’s Nodes
abnormal fusiform enlargement at the pip joint which can indicate synovitis secondary to RA
Swan neck deformity
PIP joint deforms into hyperextension and the DIP is flexed
MOI of Swan Neck Deformity
Rheumatoid Arthritis
Boutonniere deformity
PIP is flexed, DIP is extended
central slip of the extensor digitorum communis tendon is avulsed from the insetion into the base of the middle phalanx
Which ligaments provide a majority of the wrist stability
extrinsic palmar ligaments
Which ligaments serve as rotational restraints in the wrist?
intrinsic ligaments
they bind the proximal row into a unit of rotational stability
carpal ligaments
the major ligaments of the wrist include the palmar intrisic ligaments, the volar extrinsic ligaments and the dorsal extrinsic and intrinsic ligaments
Radiocarpal joint
formed by the large articular concave surface of the distal end of the radius, the scaphoid, lunate, and the TFCC
Antebrachial fascia
a dense connective tissue bracelet that encases the forearm and maintains the relationships of the tendons that cross the wrist
Extensor retinaculum
serves to prevent the tendons from “bow-stringing” when they turn a corner at the wrist
what is the fibroosseous compartment
the tunnel like structure formed the the retinaculim and underlying bones
Flexor retinaculum
transforms the carpal arch into a tunnel
What is the proximal attachment of the flexor retinaculum
the tubercle of the scaphoid and pisiform
What is the distal attachment of the flexor retinaculum
to the hook of the hamate and the tubercle of the trapezium
Jersey Finger
avulsion of the flexor digitorum profundus tendon
What is the MOI of Jersey Finger
the finger gets caught in an object and actively flexed DIP joint is suddenly and forcibly extended resulting in a rupture
Carpal Tunnel
serves as a conduit for the median nerve and nine flexor tendons
What comprises the floor of the carpal tunnel
the palmar radiocarpal ligament and palmar ligament complex
What comprises the roof of the carpal tunnel
the flexor retinaculum aka the transverse carpal ligament
What makes up the ulnar border of the carpal tunnel?
the trapezium
what makes up the radial border of the carpal tunnel
the hook of hamate
Tunnel of Guyon
a depression superficial to the flexor retinaculum, located between the hook of hamate and pisiform
What makes up the roof of the tunnel of guyon?
the palmar (volar) carpal ligament, palmaris brecis muscle, and the palmar aponeurosis
What makes up the floor of the tunnel of guyon
the flexor retinaculum (aka transverse carpal ligament), pisohamate ligament, and pisometacarpal ligament
What runs through the tunnel of guyon?
the ulnar nerve and artery
Cyclist Hand
ulnar nerve and artery compression
palmar aponeurosis
a dense fibrous structure continuous with the palmaris longus tendon and fascia covering the thenar and hypothenar muscles
Dupuytren’s contracture
a fibrotic condition of the palmar aponeurosis that results in nodule formation or scarring of the aponeurosis which may cause finger flexion contractures
extensor hood
a complex tendon which covers the dorsal aspect of the digits, formed from a combination of the tendons of insertion from extensor digitorum, extensor indicis, and extensor digiti minimi
mallet finger
terminal phalanx of the finger is permanently flexed at the distal joint, it cannot be voluntarily extended
rupture of the extensor tendon that inserts on the terminal phalanx with possible fracture of the distal phalanx
synovial sheaths
long narrow balloons filled with synovial fluid, which wrap around a tendon so that one wall is directly on the tendon (visceral layer) and the other wall is separate (parietal layer)
Where is surgical no man’s land?
the distal palmar crease to the PIP joints
Trigger finger
usually involves the fourth or fifth finger
flexion of the finger feels normal, but re-extension is accompanied by a painful snap
Which muscles are superficial in the anterior compartment of the forearm
pronator teres, flexor capi radialis, palmaris longus, flexor carpi ulnaris
Which muscle is intermediate in the anterior compartment of the forearm
flexor digitorum superficialis
Which muscles are deep in the anterior compartment of the forearm
flexor pollicis longus, flexor digitorum profundus, pronator quadratus
Which muscles are superficial in the posterior compartment of the forearm
extensor carpi radialis longus and brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris
Which muscles are deep in the posterior compartment of the forearm
abductor pollicis longus, extensor pollicis longus and brevis, extensor indicis
What forms the floor of the anatomical snuff box?
the scaphoid
what forms the ulnar border of the anatomical snuff box
extensor pollicis longus tendon
what forms the radial border of the anatomical snuff box
abductor pollicis longus
De Quervains Disease
aka stenosing tenosynovitis
overuse and repetitious ulnar and radial deviation of the wrist
which are the short muscles of the thumb
abductor pollicis brevis, flexor pollicis brevis, opponens pollicis, adductor pollicis
Skier’s thumb
aka Gamekeeper’s thumb
ulnar collateral ligament avulsion of the MCP joint
which are the short muscles of the fifth digit
abductor digiti minimi, flexor digiti minimi, opponens digiti minimi
What is the function of the three palmar interossei muscles
each functions to adduct the digit to which it is attached toward the middle digit
What is the function of the four dorsal interossei muscles
each functions to abduct the index, middle, and ring fingers from the mid-line of the hand
What is the function of the lumbricales?
to perform the motion of IP joint extension with the MCP joint held in extension
what are the functional arches of the hand?
the transverse, metacarpal, longitudinal, and oblique arches
The transverse arch
formed within the palmar concavity of the carpal bones, scaphoid and trapezium laterall yand pisiform and hamate medially
The metacarpal arch
formed by metacarpal heads
the longitudinal arch
formed by the third and fifth digit, spans lengthwise, keystone at the MCP joints
The oblique arches
formed by the thumb in opposition to the other fingers
Keinboch’s Disease
aka avascular necrosis of lunate
usually unilateral after trauma or occupational excessive dominant hand use
presents with localized and radiating wrist pain, swelling & disability
What types of grips are known as power grips?
fist, cylindrical, ball, hook
digits work together to provide support and static control
Which grips are precision/prehension grips
chuck aka three finger pinch
lateral or key pinch grip
tip pinch grip
digits work provide control by working with the thumb to form a tripod for precision handling
Spoon nails
natural convexity is replaced by concave nails in a saucer form
nail plate is thinner and weaker
result of a severe fungus infection
Clubbed nails
pulmonary disease is the most common cause, followed by cardiovascular disease
Felon
inflammation of the terminal finger pad is confined by tough fascia attached to the periosteum
presence of pus is indicated by induration of the pulp and loss of resilience
pressure may cause the abscess to burst through the volar surface of the finger pad
Paronchia
aka hangnail
skin over the mantle of the nail and the lateral nail folds is swollen, reddened, painful and tender
thrower’s wrist
over extension of the carpals, possibly straining or spraining structures
