Arm/Forearm/Hand Anatomy Flashcards
what comprises the humeroradial joint?
head of radius, annular ligament, and capitulum of humerus
where does the radius attach?
at humerus capitulum with annular ligament
and from that ligament to the radial notch of ulna
does to annular ligament move?
no, radius moves inside of it
humero-ulnar joint
trochlear notch/olecranon of ulna and trochlea of humerus
what muscles extend the forearm
triceps brachii and anconeus
plus soome forearm extensors
what muscles flex elbow
biceps and brachialis, helped by bracioradialis
where do forearm extensors and flexors originate ?
extensors from lateral epicondyle of the humerus
flexors from medial epicondyle of humerus
major upper arm supinator?
biceps brachii
carpals articulate with radius or ulna
radius
carpals rows % involvement with flexion and extension
flexion - 60% distal row
Extension - 60% proximal row
“cant do push up”…why?
ganglion cyst in scaphoid-lunate ligament –> pinches bone in extension
how should you cast a metacarpal-phalange joint?
flexion is position of safety….NOT extension!!
metacarpal collateral ligaments
loose in extension and tight in flexion
PIP proximal interphalange
collateral ligaments tight in all phases f flexion and extention due to origin in the center of the arc of rotation
monteggia fracture
olecranon fracture of ulna at radial attachement
carpal lunate dislocation
“burning”, affects median nerve
Cs (capitate lunate radius) out of algnment
look from lateral xray!!
Kienbocks aseptic necrosis of the lunate
loss of blood supply to lunate
secondary dislocation, stress, cortisone-induced
often spontaneous
both 4th and 5 metacarpals articulate with..
hamate carpal
best view for a 4th/5th MC-hamate fracture
xray 15 degrees pronation and 5 degrees lateral
can only bend PIPs not DIPs
flexor digitorum profundus rupture
game keepers thumb
avulsion of ulnar collateral ligament at MP junction of the thumb
cant pinch against thumb since there is no stability
wing scapula
long thoracic nerve issue
serratus anterior deficit and scapula comes away from wall
pec major deficit
usually from large force
can tear off of humerus
findings: echymoises bruising, depression in lateral chest
where to inject around acromion?
dont inject below two fingers of acromion edge so that you dont inject the axillary artery
what innervates trapezius?
accessory nerve cnxi
what does first 15% of arm abduction?
supraspinatous
what three nerves make repairing a distal biceps rupture diffilcut?
posterior interosseus branch of radial nerve, superficial sensory branch of radial nerve, and lateral antebrachial cutaneous nerve
effects due to laceration of ulnar nerve?
a laceration at any level will disrupt the coordination of hand muscles and movement
clumsy (no longer can play musical instrument)
what nerve coordinates many fast motor movements of hand?
ulnar
effects of median nerve laceration?
numbness of the hand since most of the palm and radial 3.5 digits are numb
innability to elevate thumb away from palm plane (opposition)
lateral epicondylitis
inflammation of the periosteum of the lateral epicondyle of the humerus
elbow tendinitis
tennis elbow
repeated use of superficial extensor muscles of forearm–> strain on common lateral extensor tendon producing lateral epicondylitis
mallet/baseball finger
DIP is flexed down like a mallet;
from suddenly being forced into extreme flexion tearing the attachment of the tendon to the distal phalanx
olecranon fracture
fall on elbow + sudden powerful triceps contraction –>fractured olecranon is pulled away by triceps tendon
pronator syndrome
nerve entrapment – the compression of median nerve near elbow
symptoms: proximal anteriorforearm pain and hypesthesia (decreased sensation) in palmars aspects of the radial 3.5 digits
anterior interosseus syndrome
when attempting to make ok sign, a pinch posture results due to abcense of flexion in IP joint of thumb and DIP of 2nd finger
effects of median nerve laceration
-no flexion of 1-3 PIPs (4th/5th weakened)
