Upper Extremity Flashcards
What bone connects the upper limb to the axial skeleton?
clavicle
What additional motion of the clavicle on the sternum do we get with arm elevation, besides simply elevation of the clavicle?
posterior rotation
What does the costoclavicular ligament do?
connects clavicle to first rib, so prevents excessive elevation/protraction
T/F: The SC joint isn’t very stable.
false; because of all the ligaments (interclavicular, costoclavicular, etc) it’s VERY stable… more likely to break clavicle
What ligaments make up the AC joint?
1) coracoclavicular (two parts, trapezoid and conoid) -> this REALLY holds AC together
2) acromioclavicular (prevents post. translation)
What part of the clavicle is most likely to fracture?
between medial 2/3s and lateral 2/3, just medial to the attachment of coracoclavicular ligament
What spinal level is the spine of the scapula at?
T3 (superior border at T2)
What vertebral level is the inferior angle of the scapula at?
T7
What are the four joints of the upper extremity?
1) sternoclavicular
2) acromioclavicular
3) glenohumeral
4) scapulothoracic
What ligaments support the glenohumeral joint?
superior/inferior/middle glenohumeral ligaments resist excessive anterior translation
What are the 4 rotator cuff muscles?
supra
infra
subscap
teres minor
ALL insert into joint capsule
How much elevation occurs at the GH joint compared to the scapulothoracic joint?
120deg elevation at GH
60 deg elevation at scapulothoracic
Full scapular upward rotation requires what motion at the clavicle?
backward rotation (45-50deg)
What is the ratio for scapular to humeral motion with elevation?
1:2 (scapular:humeral)
aka scapulohumeral rhythm
What muscles cause upward rotation of the scapula during elevation?
upper trapezius and serratus anterior
What muscles cause downward rotation of the scapula during shoulder extension? (like chopping wood)
levator scapulae, rhomboids, pec minor
What muscles are active with shoulder protraction?
serratus anterior, pec minor
What muscles depress the scapula?
lower trap, pec minor, lat
What nerve is compressed in “crutch palsy”?
radial (formerly axillary a.)
Describe arterial flow in the upper extremity.
subclavian a. -> axillary a. -> brachial a. -> dive apart into radial and ulnar a.
THEN they kinda joint up in palmar arches in hand
What bony landmarks make up the humeroulnar joint?
trochlear notch of ulna, trochlea of humerus
What bony landmarks make up the radiohumeral joint?
capitulum of humerus and radial head
What is the capsular pattern of the humeral-ulnar joint?
flexion, extension
What is the capsular pattern of the humeral-radial joint?
flexion, extension, supination, pronation
In what position should you manipulate the humeral-ulnar joint?
70deg flex
10 deg sup
In what position should you manipulate the radio-humeral joint?
max extension, and supination
coincidentally the CLOSED pack position for humeroulnar
What kind of joint is the superior radioulnar joint?
pivot joint: radial head against medial proximal ulna in radial notch
What connects the middle of the radius and ulna?
interosseous membrane (stabilizes for pushing) and oblique cord (stabilizes for pulling)
What elbow flexor gets dual innervation?
brachialis:
1) musculocutaneous
2) radial nerve branch to brachialis
What is the main muscle of elbow flexion, working in all positions of the forearm?
brachialis
What muscles facilitate elbow extension in a closed-chain position?
pec major and anterior delt (like with push ups)
Elbow has to be in what position for biceps brachii to do supination?
90 deg elbow flexion
Describe pushing/pulling force coupling.
1) pushing = getting elbow extension with shoulder flexion, so need triceps extending elbow, biceps flexing shoulder and controlling ext.
2) pulling = doing opposite
T/F: Triceps are active when performing screwdriving motion.
yes, to resist elbow flexion as biceps works as a supinator
What is a Volkmann’s ischemic contracture?
occlusion/laceration of brachial a. in upper arm can result in ischemia in forearm, causing ischemic contracture permanently shortening the involved muscles
What is a Colles fracture, and what commonly causes it?
it’s a fracture at the distal radius, d/t fall on outstretched hand
In what area is the ulnar nerve most often compressed?
Osborne’s fascia, forming the cubital tunnel posterior to the medial epicondyle
Name the proximal row of carpal bones, lateral to medial.
schaphoid
lunate
triquetrum
pisiform
Name the distal row of carpal bones, lateral to medial.
Trapezium (thumb)
Trapezoid
Capitate
Hamate
What is the most frequently fractured carpal bone, and its common complication?
scaphoid
- avascular necrosis often occurs d/t poor blood supply that impacts healing
Name the three arches of the hand; what action do they support?
longitudinal
metacarpophalangeal transverse
carpal transverse
Assist with prehension (grasp)
In the distal radioulnar joint, what bone moves on what with supination/pronation?
radius moves on ulna
What bears more load, radius or ulna?
radius (60:40)
What is the most commonly dislocated carpal bone?
lunate (anteriorly) - can compress median nerve
What is the most active muscle with grasping?
ECRB, which holds wrist in extension
Describe the innervation of the hand.
all ulnar except 1/2 LOAF median:
1) lateral half of lumbricals
2) opponens pollicis
3) abductor pollicis
4) flexor pollicis brevis
Name the deep muscles of the anterior forearm.
1) flexor digitorum profundus
2) flexor pollicis longus
3) pronator quadratus
Innervation of the forearm?
all median except FCU and medial half of FDP
What are the two major wrist flexors?
FCU and FCR (FCR more effective)
- palmaris longus also does slight wrist flexion
A supercondylar fracture in the humerus can damage what artery?
radial a.
If a power grip is damaged in an individual, what nerve is thought to be damaged?
ulnar n.
If a precision grip is damaged, what nerve is thought to be the cause?
median n.
If a patient has trouble releasing an object, what nerve may be damaged?
radial n.
