Shoulder Flashcards
1
Q
What is the version of the proximal humerus in relation to the transepicondylar axis?
A
30 degrees retroverted
2
Q
What is the version of the glenoid?
scapular tilt?
A
Version 7 degrees retro to 10 degrees anteverted (average ~5 degrees anteverted)
Tilt –> 3-5 degrees upward
3
Q
What is the neck-shaft angle of the humerus? version of the neck (relative to what)?
A
130-150 degrees (130 degrees average)
30 degrees retroverted relative to transepicondylar axis of elbow
4
Q
What is the carrying angle in men and women?
A
Men: 10-15 degrees
Women: 15-20 degrees
5
Q
Describe Bauman’s angle. What is the normal value?
A
Angle formed by a longitudinal line down the humeral shaft and another along the open capitellar physis.
Normal: 70-75 degrees
6
Q
The suprascapular notch is bound by what ligament?Contains what structure?
What related structure is not within the notch?
A
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
7
Q
Where do the trunks of the brachial plexus lie?
A
Between and anterior and middle scalene muscles
8
Q
What are the attachments to the greater tuberosity?
A
Superior facet: supraspinatus
Middle facet: infraspinatus
Inferior facet: teres minor
9
Q
What is the attachment to the lesser tuberosity?
A
Subscapularis sometimes some of supraspinatus according to 2009 JBJS paper 2009;91
10
Q
How much of the trochlea is covered with articular cartilage? (how many degrees of the arc)
A
300 degree arc
11
Q
Which direction is the distal humeral articulation of the elbow rotated in the axial plane? In the long (sagittal) plane? Varus/valgus (Coronal plane)?
A
Axial: 5-7deg IR
Sagittal: 30deg anterior rotation
6-8deg valgus tilt
12
Q
What is the column theory of the distal humerus?
A
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
13
Q
What prevents AP displacement of the clavicle?
A
AC ligament
14
Q
What ligaments are included in the sternoclavicular joint (4)?
A
Anterior SC ligament
Posterior SC ligament
Interclavicular ligament
Costoclavicular ligament
15
Q
What constitutes the conjoint tendon of the shoulder?
A
Coracobrachialis & Short head of biceps
16
Q
What is the clinical effect of compression in the suprascapular notch?
A
Compression of the Suprascapular nerve affecting both supra and infraspinatus
17
Q
What is a Buford complex?
A
Normal anatomical variant:
Absence of anterosuperior labrum with cord-like MGHL
- 2% of population
18
Q
Sternocleidomastoid: OINA?
A
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
19
Q
Rhomboids: OINA
A
Origin:
- Rhomboids Minor SP C7-T1
- Rhomboids Major SP T2-5
Insertion: Medial scapula
Innervation: Dorsal scapular nerve
Action: Scapular adduction and rotation
20
Q
Levator Scapulae: OINA
A
Origin:
TP C1-4
Insertion: Superomedial scapula
Innervation: C3, C4 and dorsal scapular nerve
Action; Scapular elevation and rotation
21
Q
When does the clavicle ossify? when does it fuse?
A
clavicle is the first bone to ossify and last to fuse
ossify at 5 wks GA
fuse at 25yrs
22
Q
3 extrinsic ligamentous attachments to the scapula?
3 intrinsic ligaments of the scapula?
A
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)
23
Q
With respect to the spinoglenoid notch:
bound by what ligament?
what structure passes through here?
What muscle does it supply distal to this point?
A
inferior transverse scapular ligament.
contains suprascapular nerve
supplies infraspinatus distal to the notch
24
Q
List all attachments to the coracoid
A
- 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
25
List the static (5) and dynamic restraints of the shoulder (3).
**static:**
1. bony congruency
2. labrum
3. capsule
4. ligaments
5. negative pressure
**dynamic:**
1. cuff
2. biceps
3. scapulothoracic movement
26
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
27
SGHL resists what shoulder motion?
inferior translation
28
MGHL: restricts what shoulder movement in what position
limits anterior and posterior translation at 45 deg of abduction and ER
29
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)
30
CHL: attachments? restricts what shoulder motions?
from coracoid base to humerus anatomic neck superiorly
functions like SGHL: resists inferior translation and ER
31
What are the 5 muscles joining upper limb to spine? AKA Extrinsic back muscles
latissimus dorsi
rhomboid major/minor
trapezius
levator scapulae
Serratus posterior
32
What are the muscles connecting upper limb to thoracic wall?
serratus anterior
pec major
pec minor
33
what muscles act on the glenohumeral joint?
deltoid
4 cuff muscles
teres major
34
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"
35
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
36
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
37
OINA of Supraspinatus
O: Supraspinous fossa of scapulaI: Superior facet on greater tuberosityN: Suprascapular nerveA: adducts shoulder
38
OINA Infraspinatus
O: Infraspinous fossa of scapula
I: Middle facet of GT
N: Suprascapular nerve
A: ER shoulder
39
OINA of Subscapularis
O: Anterior wall of scapula
I: LT
N: Upper and lower Subscapular nerve
A: IR shoulder
40
OINA Teres Minor
O: Lateral border of scapula
I: Inferior facet of GT
N: Axillary
A: ER shoulder
41
OINA Deltoid
O: Distal clavicle, acromion, spine of scapulaI: Deltoid tuberosity of humerusN: AxillaryA: Abducts shoulder, flexes and extends
42
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
43
OINA Latissimus Dorsi
Origin:
* Spinous processes of vertebrae T7-L5
* thoracolumbar fascia
* iliac crest
* inferior 3 or 4 ribs
* inferior angle of scapula
I: Floor of intertubercular groove
N: Thoracodorsa
lA: Adducts, extends and IR shoulder
44
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 elbow Long head also adducts arm
45
draw the brachial plexus
see diagram
46
What are the boundaries of the axilla?
Posterior wall - subscapularis and teres major (lat dorsi too)
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
47
What are the boundaries of the quadrilateral space? What nerve and vessel run thru the quadrilateral space?
superiorly -teres major
Inferiorly - teres major
Laterally - surgical neck
Medially - long head of triceps
Axillary nerve
Posterior circumflex humeral artery
48
When does the axillary artery become the brachial artery?
At the lower border of teres major.
49
When does the brachial plexus start and finish?
Starts: lateral border of scalene anterior Finishes: lower border of pec minor
50
What are the ligaments that make up the acromioclavicular joint? And where are their attachments?
1. coracoacromial ligament- from the coronoid process to the acromium. These three structures form the coracoacromial arch. Prevents AP displacement of clavicle
2. Superior and inferior Acromioclavicular ligaments
51
What kind of joint is the AC joint?
A plane synovial joint or a plane gliding joint
52
What kind of joint is the SC joint?
A diarthrodial joint (synovial double plane joint) with an intraarticular disc.
53
What ligaments make up the SC joint (4)?
* - the anterior and posterior SC ligaments
* - Intraclavicular ligaments
* - Costoclavicular ligaments
54
What muscles attach to the clavicle(6)? Ligaments (6)?
1. Trapezius
2. Deltoid
3. Pec Major
4. Subclavius
5. Sternocleidomastoid
6. Sternohyoid
1. Trapezoid
2. Conoid
3. Costoclavicular
4. Sternoclavicular
5. intraclavicular
6. Acromioclavicular
55
What muscles attach to the scapula? (17 or 18)
1. supraspinatus
2. Infraspinatus
3. Subscapularis
4. Teres minor
5. Teres major
6. Serratus anterior
7. Deltoid
8. Rhomboids
9. Trapezius
10. Long head of triceps
11. Long head of biceps
12. Short head of biceps
13. Pec minor
14. coracobrachialis
15. Levator Scapulae
16. **Inferior belly of omohyoid**
17. Latissimus dorsi
56
What is the blood supply to the humeral head?
- From the axillary artery. - The arcuate artery which comes from an anastamosis between the anterior and posterior humeral circumflex arteries - The traditional teaching is the majority of the blood supply comes from the anterolateral branch of the anterior humeral circumflex but one study has challenged this saying that 64% of flow is from the posterior circumflex.
57
What shape is the glenoid cavity?
- pear shaped with it being ~20% narrower superiorly
58
How much bigger is the humeral head than the glenoid cavity?
3-4 times as big. Therefore only 25-30% of the humeral head is in contact at any one time.
59
When Abducting the shoulder, how much movement comes from the glenohumeral joint versus the scapulothoracic joint?
-After the humerus reaches 30 °, the rule is 2:1 so 120 ° from the shoulder and 60 ° from the scapula
60
What are the ligaments of the shoulder?
**Coracohumeral ligament -** only visible outside of capsule. From Coracoid to base of anatomical neck. Reinforces inferior stability along with SGHL. Restricts External rotation and inferior translation in adduction (and ER) **Glenohumeral ligaments** (3) 1) Superior - blends with the superior labrum and biceps tendon medially. Attaches at the lesser tuberosity 2) Middle - from glenoid to anterior humerus adjacent to lesser tuberosity. Limits ER, Inferior translation and anterior translation 3) Inferior - has discrete anterior and posterior bands, acts as a hammock. AIGHL is the primary static restraint against anterior-inferior dislocation of the GHJ in abduction and external rotation. PIGHL is the primary static restraint against posterio-inferior translation in IR and adduction. ATTACH FROM THE INFERIOR GLENOID TO THE ANATOMICAL NECK
61
What is the rotator interval? Contents?
this is the triangular space between supraspinatus and subscapularis. Reinforced by the coracohumeral ligament and the Superior glenohumeral ligament Contents of this interval include the CHL, SGHL, long head biceps and a thin layer of capsule.
62
What is the primary restraint to inferior translation in the adducted arm?
the SGHL and CHL
63
What is the primary static stabilizer to anterio-inferior translation in the ABducted arm in ER?
AIGHL
64
What is the primary static stabilizer to posterio-inferior translation in the ADducted arm in IR?
- PIGHL
65
What is Weitbrecht’s (oval) foramen?
the foramen between SGHL above, and MGHL below. aka the subscapularis fossa
66
What are 3 anatomical variations of the labrum?
1) Sublabral Foramen
2) Sublabral Foramen with a cord-like MGHL
3) Absent anterosuperior laburm with cord-like MGHL (Buford Complex)
4) Meniscoid labrum (vs triangular vs bumper)
Diagram
A - Normal
B - Sublabral foramen
C - Sublabral with cordlike MGHL
D - Absent anterosuperior laburm with cord-like MGHL (Buford Complex)
67
What is the ligament overlying the bicipital groove?
- the transverse humeral ligament
68
What attaches to the infraglenoid tubercle?
the long head of triceps
69
Does the subacromial bursa normally communicate with the shoulder joint?
No, not unless there is a tear.
70
Where is the long head of biceps tendon in relation to the CHL and SGHL?
*
- it is superior to the SGHL and inferior (right underneath) the CHL
These make up the biceps sling along with the superior edge of subscapularis
* Image from JBJS "
* The Biceps Tendon: From Proximal to Distal"
71
Is the long head of triceps intraarticular?
No
72
What nerves innervate the Pectoralis Major and Minor?
* major - medial and lateral pectoral nerves
* Minor - medial pectoral nerve
73
What structures pierce the clavipectoral fasica?
1. cephalic vein
2. thoracoacromial artery and vv
3. lateral pectoral nerve
4. lymphatics
74
What is the function of subclavius, what is its innvervation?
* depresses the clavicle, raises first rib
* Sublcavius nerve
* Goes from Rib 1 to the middle ⅓ of inferior clavicle.
75
What is the origin, insertion and function of the trapezius?
Originate:
1. spinous processes of C7 to T12.
Insertion:
1. on the external occipital protuberance
2. superior nuchal line
3. Spine of the scapula and acromium (anteriorly)
4. lateral ⅓ of the clavicle (posteriorly)
(The deltoid attaches to the lateral ⅓ anteriorly)
* The upper fibers shrug
* The middle fibers brace shoulder
* The lower fibers depress the medial border of the scapula
* The upper and lower fibers rotate the scapula
76
What is the attachments for the pectoralis muscles?
Pec Major
* Ribs 1-7
* sternum
* clavicle to the LATERAL lip of the inter tubercular (AKA bicipital)
Pec Minor
* ribs 3-5 to the coracoid
77
What is the insertion of latissimus dorsi?
The latissimus dorsi can be remembered best for insertion as "The Lady Between Two Majors". As the latissimus dorsi inserts into the floor of the inter tubercular groove (Bicipital groove) of the humerus it is surrounded by two major muscles. The teres major inserts medially on the medial lip of the intertubercular groove and laterally the pectoralis major inserts into the lateral lip.
78
What artery runs through the triangular space?
the circumflex scapular artery
79
Where on the plexus does the dorsal scapular nerve come from and what muscles does it innervate?
comes from the ROOT of C5 Innervates the rhomboids and the levator scapulae
80
What is the only muscle in the upper limb innervated by all of the roots of the brachial plexus?
**pectoralis major**
* Clavicular head - C5,6 Lateral pectoral nerve
* Sternocostal head C7,8 T1 medial pectoral nerve
81
What are the branches of the thoracoacromial artery?
* **Acromial**
* **Clavicular**
* **Deltoid**
* **Pectoral**
82
When does the subclavian artery become the axillary artery?
at the outer border of the first rib
83
When does the axillary artery become the brachial artery?
when it leaves the axilla beyond the inferior border of teres major!
84
What is the boundries of the axilla?
APEX
* outer border of first rib
* Upper border of scapula
* Posterior border of lateral ⅓ of clavicle
LATERAL WALL
* Bicipital Groove of humerus (pec major and lat dorsi/teres major)
MEDIAL WALL
* Upper 5 ribs and intercostal spaces Serratus anterior
POSTERIOR WALL - posterior axillary fold
* Latissimus Dorsi
* Subscapularis
* Teres Major (most inferior)
* scapula
ANTERIOR WALL (anterior axillary fold)
* Pec major (most inferior)
* Pec minor
* Clavipectoral fascia
* Subclavius
* Suspensory ligament
85
What nerve roots comprise the brachial plexus dorsal or ventral?
Ventral rami of nerve roots C5-T1
86
What are the borders and the contents of the Quadrangular space?
- medial - lateral border of long head of triceps - lateral - humeral shaft - inferior - superior border of teres major - superior - Inferior border of teres minor - CONTENTS - Axillary nerve, posterior circumflex aa and vv
87
What runs through the Quadrangular space? Triangular space? Triangular interval?
* Quad space: Axillary nerve, posterior circumflex aa and vv
* Triang Space: circumflex scapular artery
* triang Interval: radial nerve, profunda brachii
88
What are the borders and the contents of the triangular interval/Triceps hiatus?
Medial - Long head triceps Lateral - humerus Superior - inferior border of teres major CONTENTS - radial nerve, profunda brachii
89
What are the borders and the contents of the Triangular Space?
Inferior - teres major
Lateral - long head of triceps
Superior - inferior border of teres minor
* CONTENTS - circumflex scapular artery
90
The axillary sheath is formed from what layer of the cervical fascia (pretracheal, prevertebral, investing, or cartotid sheath)?
* prevertebral fascia.
* The axillary sheath is a fibrous sheath that encloses the first portion of the axillary artery, together with the axillary vein and the brachial plexus (though some sources suggest the axillary vein lies entirely outside the sheath[1]). It is an extension of the prevertebral fascia of the deep cervical fascia.
91
How many segments/parts are their to the axillary artery and what are it’s branches(6)?
3 parts:
1. First part - the part of the artery medial to pectoralis minor
2. Second part - the part of the artery that lies behind pectoralis minor
3. Third part - the part of the artery lateral to pectoralis minor
The branches go by the mnemonic “Screw the lawyers, Save a Patient”
1. 1st part:
1. Superior Thoracic artery (1)
2. 2nd part:
1. - Thoracoacromial artery (2) - 4 branches - deltoid, pectoral, acromial, clavicular
2. - Lateral Thoracic artery (3)
3. 3rd part:
1. Subscapular Artery (4)- branches into the thoracodorsal br and the scapular circumflex br
2. Anterior humeral circumflex artery (5)
3. Posterior humeral circumflex artery (6)
92
Which segment of the Axillary artery is most vulnerable to traumatic injury?
the 3rd segment which is distal to the edge of Pec Minor.
93
What are the branches of the brachial artery?
1. **Profunda brachii**
2. **Humeral Nutrient artery**
3. **Superior Ulnar Collateral artery** - runs with ulnar nerve until it anastomoses with the posterior ulnar collateral at the elbow (branch from ulnar artery)
4. **Inferior ulnar Collateral artery** - anastomoses with the anterior ulnar collateral artery at elbow (branch from ulnar artery)
5. **Radial artery**
6. **Ulnar artery**
94
What are the branches of the profunda brachii?
1. **Nutrient artery**
2. **Deltoid branch**
3. **Middle collateral**
4. **Radial collateral artery** which anastomose with the recurrent interosseous artery (from Ulnar AA) and theradial recurrent artery (from radial aa) at the elbow.
95
What are the branches of the ulnar artery?
1. **Anterior ulnar recurrent artery -** anastomoses with the inferior ulnar collateral artery from the brachial artery
2. **Posterior ulnar recurrent artery** - anastomoses with the superior ulnar collateral artery from the brachial artery
3. **Recurrent interosseous artery** - anastomoses with the middle collateral artery (branch of the profunda) on the lateral elbow
4. **Common interosseous artery** - gives off anterior and posterior branches to supply either side of the IOM
5. **volar carpal branch-** to volar carpal arch
6. **dorsal carpal** - to dorsal carpal arch
7. **deep palmar branch** - to deep palmar arch
8. **Terminal branch - to superficial palmar arch (distal, ulna is predominant supply)**
96
What are the branches of the radial artery?
**In the forearm:**
1. **Radial recurrent artery**
2. **Palmar carpal branch of radial artery**
3. **Superficial palmar branch of the radial artery -** arises from the radial artery, just where this vessel is about to wind around the lateral side of the wrist
**\*At the wrist:**
1. **Dorsal carpal branch of radial artery**
2. **First dorsal metacarpal artery.**
\*In the hand:
1. **Princeps pollicis artery**
2. **Radialis indicis**
3. **Deep palmar arch**
97
What aspect of the brachial plexus is found behind the clavicle?
the divisions
Trunks come out between Anterior and middle scalene
Divisions behind clavicle
Cords inferior to clavicle
nerves inferior to pec minor (9?)
Note axillary artery becomes brachial artery inferior to teres major
98
What causes horner’s syndrome if you are thinking about an injury to the neck/plexus?
- to the stellate ganglia (T1) in the sympathetic chain
99
Where do the roots of the plexus leave the neck?
* - between the anterior and middle scalene, when they leave the neck they become the trunks. They become divisions behind the clavicle and cords after the clavicle
* Once they pass between the scalenes they go through the posterior triangle (borders - SCM, Trapezius, clavicle)
100
What deficit would a preganglionic brachial plexus lesion lead to what constellation of symptoms (5)? (i.e. root avulsion)
Injuries to:
1. Sympathetic chain
2. long thoracic - winging
3. phrenic -elevated hemidiaphragm
4. dorsal scapular
5. High cervical sensory branches
* Medial winging of the scapula (loss of the long thoracic nerve)
* Anaesthesia above the clavicle
* Elevation of the hemidiaphragm (phrenic nerve)
* Weak levator scapula and rhomboids (both dorsal scapular nerve)
* Horner’s syndrome - loss of the sympathetic chain - caused by avulsion of the T1 root resulting in interruption of the T1 sympathetic ganglion;
101
What causes Lateral versus medial winging of the scapula?
* Lateral winging - due to trapezius dysfunction (Spinal Accessory nerve XI) or Rhomboid dysfunction ( dorsal scapular nerve)
* Medial winging - injury to the long thoracic nerve and serratus anterior.
102
What are the boundries of the axillary artery?
What are the branches of the axillary artery? What are the 3 parts of the artery and how are they defined?
outer border of first rib and the inferior edge of teres major
3 parts:
- First part - the part of the artery medial to pectoralis minor
- Second part - the part of the artery that lies behind pectoralis minor
Third part - the part of the artery lateral to pectoralis minor
The branches go by the mnemonic “Screw the lawyers, Save a Patient”
1st part:
- Superior Thoracic artery (1)
2nd part:
- Thoracoacromial artery (2)
- Lateral Thoracic artery (3)
3rd part:
Subscapular Artery (4)- branches into the thoracodorsal br and the scapular circumflex br
Anterior humeral circumflex artery (5)
Posterior humeral circumflex artery (6)
103
What is a laterjet procedure and what are 3 ways it helps with instability?
transfer of the coracoid process and its attached soft tissues to the anterior aspect of the glenoid for recurrent anterior instability in the setting of bone loss.
3 ways it helps:
Provides a mechanical bony block to anterior subluxation.
Provides a soft tissue sling (conjoint tendon) to support the subscap and anterior capsule
Capsular plication by way of repair to the coracoacromial ligament stump
104
What is the quadrangular space, triangular space, and triangular interval
quadrangular space - humerus, long head triceps, teres minor, teres major, axillary nerve and posterior circumflex artery
Triangular space long head triceps, teres major and minor. circumflex scapular artery
Triangular interval. Teres major, long head, humerus, Radial nerve and profunda brachialis
105
What is the posterior approach to the shoulder?
horizontal incision along the scapular spine or a vertical incision 10-15cm directly inferiorly from the tip of the posterior acromium.
interval is between teres minor and infraspinatus. (stay away from below teres minor as this is where the spaces/intervals are)
106
What is the innervation of the cuff muscles?
What about teres major?
Supraspinatus - Suprascapular nerve
Infraspinatus - Suprascapular nerve
Subscapularis - Upper and Lower Subscapular nerve
Teres Minor - Axillary nerve
Teres Major - Lower subscapular nerve
107
Describe the anatomy of the coracoclavicular ligaments.
Coracoclavicular ligaments - prevents inferior displacement of shoulder
* **Conoid ligament -** to coronoid tubercle POSTEROMEDIALLY on clavicle 4.5 CM FROM THE AC JOINT
* **Trapezoid ligament** to trapezoid ridge ANTEROLATERALLY, 3CM FROM THE AC JOINT
