Shoulder & Humerus (brian) Flashcards
What is the version of the glenoid? relative to what?
scapular tilt?
scapula position relative to chest wall?
Average 5 degrees. Range 7 retro to 10 anteverted
75% retroverted 7 degrees
25% anteverted 2-10 degrees
relative to the long axis of the scapula - on axial slice, a line connecting midpoint of glenoid with medial apex of scapula
tilted 3-5 degrees upwards
scapula positioned 30 degrees anterior relative to chest wall/coronal plane
What is the version of the proximal humerus in relation to the transepicondylar axis?
30 degrees retroverted
What is the neck-shaft angle of the humerus?
version? relative to what?
130-150 degrees (130 degrees average)
30 degrees retroverted relative to transepicondylar axis of elbow
What is the carrying angle in men and women?
Men: 10-15 degrees Women: 15-20 degrees
Describe Bauman’s angle. What is the normal value?
Angle formed by a longitudinal line down the humeral shaft and another along the open capitellar physis. Normal: 72 degrees
suprascapular notch: bound by what ligament?
contains what structure?
What related structure is not within the notch? relationship to the ligament?
Superior transverse scapular ligament. Suprascapular vessels are over the nerves “Army over Navy” “Army over, Navy under”
i.e. the notch contains the suprascapular nerve, with the ligament overlying it and the vessels just above the ligament
What are the muscles and nerves affected in medial/lateral scapular winging?
Medial winging: serratus anterior: long thoracic nerve
Lateral winging: Trapezius: CN 11, or accessory nerve
Rhomboids: dorsal scapular n
Name 3 anatomic variants of the shoulder labrum aside from the normal:
Buford complex: absence of the anterosuperior labrum with a thickened MGHL
Sublabral foramen - anterosuperior labrum appears detached from glenoid - looks like a tear
sublabral recess - superior labrum appears detached from glenoid - looks like a SLAP tear
describe the path of the axillary artery and its branches
once subclavian artery crosses first rib, becomes axillary artery
part I (1 branch): before (medial to) pec minor–gives off supreme thoracic branch
part II (2 branches): deep to pec minor–gives off thoracoacromial artery and lateral thoracic artery
part III (3 branches): lateral to pec minor–gives off subscapular artery, anterior and posterior humeral circumflex arteries
crosses teres major and becomes brachial artery
where does the subclavian artery become the axillary artery?
At the lateral edge (after) the 1st rib
Where does the brachial plexus become superficial?
At the distal end of clavicle
Where do the trunks of the brachial plexus lie?
On the anterior scalene muscles
What are the attachments to the greater tuberosity?
Superior facet: supraspinatus (s=s, super = supra) Middle facet: infraspinatus Inferior facet: teres minor
What is the attachment to the lesser tuberosity?
Subscapularis
sometimes some of supraspinatus according to 2009 JBJS paper 2009;91
How much of the trochlea is covered with articular cartilage? (how many degrees of the arc)
300 degree arc
Which direction is the distal humeral articulation of the elbow rotated in the axial plane? In the long (sagittal) plane? Varus/valgus (Coronal plane)?
Axial: 5-7deg IR Sagittal: 30deg anterior rotation 6-8deg valgus tilt
What is the column theory of the distal humerus?
3 column theory: - Medial, lateral, distal columns (like a spool in your fingers) - Medial column diverges from humeral shaft at 45 deg - Lateral column diverges from humeral shaft at 20 deg
What prevents AP displacement of the clavicle?
AC ligament
What ligaments are included in the sternoclavicular joint?
Anterior SC ligament
Posterior SC ligament
Interclavicular ligament
Costoclavicular ligament
What constitutes the conjoint tendon of the shoulder?
Coracobrachialis & Short head of biceps
Suprascapular notch; Compression here affects what?
Suprascapular nerve - Affects both supra and infraspinatus
What is a Buford complex?
Normal anatomical variant: Congenital absence of anterosuperior labrum with cord-like middle GH ligament - 2% of population - Normal variant
Stermocleidomastoid: OINA?
O: Mastoid I: sternal manubrium, 1/3 sternal end of clavicle N: Accessory nerve A: Head extension, lateral tilt, contralateral rotation
Trapezius: OINA
O: External occipital protuberance, superior nuchal line, SP C7-T12 I: Scapular spine, acromial 1/3 of clavicle N: Accessory nerve A: elevates shoulder girlde, rotate scapula
Rhomboids: OINA
O: - Major SP T2-5 - Minor SP C7-T1 I: Medial scapula I: Dorsal scapular nerve A: Scapular adduction and rotation
Levator Scapulae: OINA
O: TP C1-4 I: Superomedial scapula I: C3, C4 A; Scapular elevation and rotation
When does the clavicle ossify? when does it fuse?
ossify at 5 wks GA, fuse at 25yrs
clavicle is the first bone to ossify and last to fuse
4 extrinsic ligamentous attachments to the scapula?
2 intrinsic ligaments of the scapula?
extrinsic: CA, CH, conoid, trapezoid
intrinsic: superior and inferior transverse scapular ligaments
17 muscular attachments to the scapula?
Supraspinatus
infraspinatus
teres minor
subscapularis
teres major
rhomboid major
rhomboid minor
trapezius
levator scapulae
pec minor
deltoid
latissimus dorsi
serratus anterior
biceps
coracobrachialis
omohyoid (inferior belly)
triceps long head
spinoglenoid notch: bound by what ligament?
what structure passes through here? What muscle does it supply? distal to this point?
inferior transverse scapular ligament.
contains suprascapular nerve
supplies infraspinatus distal to the notch
list all attachments to the coracoid
CA ligament
conoid
trapezoid
coracobrachialis
short head biceps
pec minor
primary blood supply to the humeral head?
posterior humeral circumflex a.
from 2010 JBJS paper
classical teaching was the arcuate artery, from anterior humeral circumflex a., running along lateral side of bicipital groove
shoulder joint: list the static and dynamic restraints
static: bony congruency, labrum, capsule, ligaments, negative pressure
dynamic: cuff, biceps,scapulothoracic movement
boundaries of the rotator interval?
what are its contents?
triangular space on superoanterior shoulder bound by subscap, supraspinatus (and coracoid)
contains CHL, SGHL, biceps long head tendon, capsule
SGHL resists what shoulder motion?
inferior translation, ER
MGHL: restricts what shoulder movement?
most effective at what shoulder position?
limits ER, inferior translation, anterior translation
most effective at 45 degrees abduction
IGHL: what are the two parts?
resists what shoulder motion?
most effective at what shoulder position?
anterior and posterior bands, i.e. AIGHL and PIGHL
AIGHL restricts anterior-inferior dislocation in 90 deg abduction and ER
PIGHL resists posterior-inferior dislocation in adduction and IR
CHL: attachments?
restricts what shoulder motions?
from coracoid base to humerus anatomic neck superiorly
functions like SGHL: resists inferior translation and ER
muscles joining upper limb to spine?
latissimus dorsi
rhomboid major
rhomboid minor
trapezius
levator scapulae
muscles connecting upper limb to thoracic wall?
serratus anterior
subclavius
pec major
pec minor
what muscles act on the glenohumeral joint?
deltoid
4 cuff muscles
teres major
3 muscle insertions of the anterior proximal humeral shaft. proximally continuous with the bicipital groove.
from lateral to medial, what are they?
pec major (lateral bicipital groove), lat dorsi (floor of the groove), teres major (medial bicipital groove)
i.e. the “lady between 2 majors”
what are the preclavicular branches of the brachial plexus?
what do they supply?
long thoracic nerve: serratus anterior
nerve to subclavius: subclavius
suprascapluar nerve: supraspinatus, infraspinatus
dorsal scapular nerve: rhomboids, levator scapulae
posterior triangle of the neck: what are the boundaries?
what important structure lies here?
It emerges between which two muscles?
boundaries: sternocleidomastoid, clavicle, trapezius
contains brachial plexus which emerges between anterior and middle scalene muscles
scapular winging:
which nerve affected? which muscles? what direction for each?
medial winging: long thoracic n, serratus anterior
lateral winging:
CN 11 (accessory n) - trapezius
OR
dorsal scapular nerve - rhomboids
Erb’s palsy: what is it, what are the muscles involved, what is the position of the arm, and is prognosis good/moderate/poor?
upper trunk injury C5, C6. deltoid, rotator cuff, wrist extensors, elbow flexors
get waiter’s tip position with shoulder adducted, elbow extended, wrist flexed
good prognosis
Klumpke’s palsy: what is it, what muscles involved, what arm position, and prognosis is good/moderate/bad?
lower trunk injury C8, T1
weakness of finger flexors, wrist flexors, hand intrinsics
wrist extended, fingers flexed/clawed (loss of hand intrinsics)
T1 involvement - can present with Horner’s syndrome
prognosis is moderate/poor
total plexus palsy: what muscles affected, what arm position, and what is prognosis?
affects everything supplied by brachial plexus
flaccid arm
worst prognosis
what is parsonage-turner syndrome?
brachial plexus neuritis
rare
sudden onset shoulder pain radiating to arm, with senosry and motor loss
commonly affects suprascapular nerve, long thoracic n, axillary n
self limited, prolonged recovery (1-2 yrs)
Quadrangular space:
boundaries and contents
humerus, teres major, long head of triceps, teres minor
contains axillary nerve, posterior humeral circumflex artery
(QUAD space, 4 syllable nerve, 4-word artery)
Triangular space: borders and contents
long head of triceps, teres major, teres minor
circumflex scapular artery
(TRI Space, 3-word artery with S in it)
triangular interval: borders and contents
humerus, long head of triceps, teres major
radial nerve, profunda brachii artery
(TRIangular, 3-syllable nerve, 3-word artery with i in name)
describe the path of the axillary nerve after it leaves the brachial plexus
runs anterior to subscap, 5cm distal to lateral acromion
passes through quadrangular space
wraps around surgical neck of humerus on underside of deltoid giving off 3 branches: anterior, posterior, articular branch
anterior branch wraps around surgical neck of humerus on undersurface of deltoid, supplying anterior deltoid
posterior branch supplies teres minor and posterior deltoid, then pierces the depe fascia and terminates as superior lateral cutaneous nerve of arm (seargent patch)
articular branch enters shoulder joint inferior to subscap
describe the path of the radial nerve as it leaves the brachial plexus up to the elbow
arises from posterior cord, traveling along anterior surface of posetrior wall of axilla: on top of subscap, la dorsi, teres major
gives off 3 branches in axilla:
- posterior cutaneous nerve of arm, branch to long head of triceps, branch to medial head of triceps
goes through triangular INTERVAL (with profunda brachii a.) and wraps around humerus shaft in the “spiral groove” from medial to lateral, deep to triceps
in the groove, it gives off 3 branches: inferolateral cutaneous nerve of arm, posterior cutaneous nerve of forearm, lateral hhead of triceps, medial head of triceps+anconeus
exits groove around 14cm proximal to lateral epicondyle
pierces lateral intermuscular septum about 10cm proximal to trochlea surface (never less than 7.5cm)
enters anterior compartment between lateral IM septum and brachialis
emerges between BR and brachialis about 7.5cm proximal to trochlea, anterior to lateral epicondyle
branches here to lateral brachialis, BR, ECRL
stays deep to brachioradialis at elbow, divides into PIN and superficial branch…
(continued in elbow section)
describe the path of the musculocutaneous nerve as it leaves the brachial plexus up to the elbow
arises from lateral cord
travels anteromedially on subscap (like the rest of the plexus branches)
pierces conjoint tendon 5-8cm distal to coracoid, from P-A
gives off branches to coracobrachialis (after piercing), then continues between brachialis and biceps
gives off branches to brachialis, biceps
pierces deep fascia lateral to distal biceps tendon and becomes terminal branch - lateral antebrachial cutaneous nerve, AKA lateral cutaneous nerve of the forearm
emerges at volar-lateral elbow between brachialis and biceps
describe the path of the median nerve as it leaves the brachial plexus up to when it enters the elbow
emerges from plexus from both medial and lateral cords
travels anteromedial to humerus
travels LATERAL to brachial artery within anterior compartment
crosses over artery before the elbow and then runs MEDIAL to brachial a.
enters elbow medial to biceps, superficial to brachialis, and dives under lacertus, still MEDIAL to the artery
describe the path of the ulnar nerve as it leaves the brachial plexus up to where it enters the elbow
emerges from medial cord
runs posterior-Medial to brachial artery in upper 1/2 of arm
it pierces medial IM septum and runs just posterior to it, deep to triceps at the arcade of struthers - 8cm from medial epicondyle
passes into cubital tunnel posterior to medial epicondyle and enters forearm between heads of FCU…
where does the axillary artery become the brachial artery?
once it crosses the teres major
OINA of Supraspinatus
O: Supraspinous fossa of scapula
I: Superior facet on greater tuberosity
N: Suprascapular nerve
A: adducts shoulder
OINA Infraspinatus
O: Infraspinous fossa of scapula
I: Middle facet of GT
N: Suprascapular nerve
A: ER shoulder
OINA of Subscapularis
O: Anterior wall of scapula
I: LT
N: Subscapular nerve
A: IR shoulder
OINA Teres Minor
O: Lateral border of scapula
I: Inferior facet of GT
N: Axillary
A: ER shoulder
OINA Deltoid
O: Distal clavicle, acromion, spine of scapula
I: Deltoid tuberosity of humerus
N: Axillary
A: Abducts shoulder, flexes and extends
OINA Teres Major
O: Lateral border of scapula, inferior to teres minor
I: Medial lip of bicipital groove
N: Lower subscapular nerve
A: Adducts, IR shoudler
OINA Latissimus Dorsi
O: Spinous processes of vertebrae T7-L5, thoracolumbar fascia, iliac crest, inferior 3 or 4 ribs and inferior angle of scapula
I: Floor of intertubercular groove
N: Thoracodorsal
A: Adducts, extends and IR shoulder
OINA Triceps
Origin:
Long head: infraglenoid tubercle of scapula
Lateral head: Above radial sulcus
Medial head: Below radial sulcus
I: Olecranon
N: Radial
A: Extends elblwo
Long head also adducts arm
draw the brachial plexus
see diagram
What are the boundaries of the axilla?
Posterior wall - subscapularis and teres major
Anterior wall - pectoralis major/minor, subclavius, and clavipectoral fascia (this fascia encloses pec minor and subclavius. Below pec minor it forms the suspensory ligament of the axilla and attaches inferiorly to suspend the axillary fascia) page 39 lasts, plate 411
Medial wall - upper part of serratus anterior, the lower limit is the fourth rib
