Shoulder Flashcards
What is the version of the proximal humerus in relation to the transepicondylar axis?
30 degrees retroverted
What is the version of the glenoid?
scapular tilt?
Version 7 degrees retro to 10 degrees anteverted (average ~5 degrees anteverted)
Tilt –> 3-5 degrees upward
What is the neck-shaft angle of the humerus? version of the neck (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: 70-75 degrees
The suprascapular notch is bound by what ligament?Contains what structure?
What related structure is not within the notch?
Superior transverse scapular ligament.
Suprascapular vessels are above the nerves and are not under the ligament
Army over Navy”
i.e. the notch contains the suprascapular nerve, with the ligament overlying it and the vessels just above the ligament
Where do the trunks of the brachial plexus lie?
Between and anterior and middle scalene muscles
What are the attachments to the greater tuberosity?
Superior facet: supraspinatus
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
Tied together at the bottom by the distal column
What prevents AP displacement of the clavicle?
AC ligament
What ligaments are included in the sternoclavicular joint (4)?
Anterior SC ligament
Posterior SC ligament
Interclavicular ligament
Costoclavicular ligament
What constitutes the conjoint tendon of the shoulder?
Coracobrachialis & Short head of biceps
What is the clinical effect of compression in the suprascapular notch?
Compression of the Suprascapular nerve affecting both supra and infraspinatus
What is a Buford complex?
Normal anatomical variant:
Absence of anterosuperior labrum with cord-like MGHL
- 2% of population
Sternocleidomastoid: OINA?
O: Mastoid
I: Manubrium (vs body of sternum), 1/3 sternal end of clavicle
N: Accessory nerve XI
A: Head extension, lateral tilt, contralateral rotation
Rhomboids: OINA
Origin:
- Rhomboids Minor SP C7-T1
- Rhomboids Major SP T2-5
Insertion: Medial scapula
Innervation: Dorsal scapular nerve
Action: Scapular adduction and rotation
Levator Scapulae: OINA
Origin:
TP C1-4
Insertion: Superomedial scapula
Innervation: C3, C4 and dorsal scapular nerve
Action; Scapular elevation and rotation
When does the clavicle ossify? when does it fuse?
clavicle is the first bone to ossify and last to fuse
ossify at 5 wks GA
fuse at 25yrs
3 extrinsic ligamentous attachments to the scapula?
3 intrinsic ligaments of the scapula?
extrinsic:
- Coracohumeral
- conoid
- trapezoid
intrinsic:
- Coracoacromial
- superior transverse scapular ligaments (over supraglenoid notch - can compress suprascapular nn to Supra/infrapsin)
- inferior transverse scapular ligaments (over spinoglenoid notch - can also compress suprascapular nn but only affects infra)
With respect to the 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
- Coracohumeral ligament
- Coracoclavicular ligaments
- conoid
- trapezoid
- coracobrachialis
- short head biceps
- pec minor
- Superior transverse scapular ligament - from the base of the coracoid to the medial portion of the suprascapular notch
List the static (5) and dynamic restraints of the shoulder (3).
static:
- bony congruency
- labrum
- capsule
- ligaments
- negative pressure
dynamic:
- cuff
- biceps
- scapulothoracic movement
What are the boundaries of the rotator interval?what are its contents?
•Boundaries
–Supraspinatus
–Subscapularis
–Coracoid process
–Intertubercular groove
•Contents
–Anterior capsule
–CHL
–SGHL
- Biceps tendon
SGHL resists what shoulder motion?
inferior translation
MGHL: restricts what shoulder movement in what position
limits anterior and posterior translation at 45 deg of abduction and ER
IGHL: what are the two parts?
What motion does it resist and in what positions?
anterior and posterior bands, i.e. AIGHL and PIGHL
AIGHL restricts anterior-inferior dislocation in 90 deg abduction and ER (position of anterior dislocation)
PIGHL resists posterior-inferior dislocation in adduction and IR (position of posterior dislocation)
CHL: attachments? restricts what shoulder motions?
from coracoid base to humerus anatomic neck superiorly
functions like SGHL: resists inferior translation and ER
What are the 5 muscles joining upper limb to spine? AKA Extrinsic back muscles
latissimus dorsi
rhomboid major/minor
trapezius
levator scapulae
Serratus posterior
What are the muscles connecting upper limb to thoracic wall?
serratus anterior
pec major
pec minor
what muscles act on the glenohumeral joint?
deltoid
4 cuff muscles
teres major
There are 3 muscle insertions of the anterior proximal humeral shaft that are 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”
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 (amongst other things):
Trunks of brachial plexus which emerges between anterior and middle scalene muscles
where does the subclavian artery become the axillary artery?
When does it become the brachial artery?
Once it crosses the inferior border of first rib
Once is crosses Teres major
OINA of Supraspinatus
O: Supraspinous fossa of scapulaI: Superior facet on greater tuberosityN: Suprascapular nerveA: 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: Upper and lower 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 scapulaI: Deltoid tuberosity of humerusN: AxillaryA: 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