biomechanics

Question 1

What is the foramen of weitbrecht?

Answer 1

1. area of weakness in the anterior GH capsule between the midde and superior bands

Question 2

Dislocation of the shoulder typically occur where?

Answer 2

through the foramen of weitbracht

Question 3

What is the foreamen of Rouviere?

Answer 3

1. area of weakness between the middle and inferior band of GH ligament
2. synovial commuication can occur with the subcoracoid bursa at this point

Question 4

What are the attachments of the coracohumeral ligament?

Answer 4

1. orginates from the coracoid process
2. two bands
   - greater tubercle at the supraspinatus attachment
   - lessor tubercle at the subs cap attachment

Question 5

How is the coracohumeral ligament loaded?

Answer 5

1. anterior band taught in extension
2. posterior taut with flexion
3. both taut with ER

Question 6

why is the coraochumeral ligament important for stability

Answer 6

1. it blends with the RTC adn fills the interval between the supra and subscap
2. reenforces the biceps tendon sheath
3. helps prevent anterior dislocation during ER

Question 7

what is the musculotendonis glenoid?

Answer 7

structures that provide posterior stability of the GH including the supraspinatus, infraspinatus and teres minor

Question 8

why are inferior dislocations of the GH uncommon fro mthe resting position?

Answer 8

the self locking mechanism

• orientation of the glenoid places it under the humeral head
• passive tension on GH joint prevents it from sliding off
• supraspinatus and posterior deltoid reenforce horizontal tension

Question 9

what direction does the clavical rotate with shoulder elevation?

Answer 9

inferior and anterior

Question 10

How is the AC joint oriented?

Answer 10

the acromial surface in concave and faces medially and forward
2.the clavicualr part faces inferior, posterior and lateral

Question 11

what type of joint is the AC joint?

Answer 11

plane synovial

Question 12

what is the basic function of the AC joint

Answer 12

allow the scapula to move to maintain the glenoid in proper orientation to the humeral head

Question 13

what anatomical sturcutre is somtimes present in the shoulder?

Answer 13

a disc, rarely divides the joint

Question 14

what are the ligaments of the AC joint?

Answer 14

superior, strongest to do to reenforcments with trap and deltoid
inferior- indirect contact with subacromial bursa and RTC

Question 15

How is the scapula supplied with blood?

Answer 15

1. muscular vasculature
2. nutrient arteries in the suprascapular fossa
3. additional blood from suscapular, suprascapular, circumflex scapular, and acrominal artery

Question 16

what major ligaments attach to the scapula?

Answer 16

1. coracoclavicular
2. coracoacromial
3. glenohumeral
4. coracohumeral

Question 17

what attaches to the coracoid process?

Answer 17

1. shor head of biceps
2. coracobrachialis
3. pectoralis minor
4. coracacromial ligament
5. coarcoaclavicular ligament (conoid and trapezoid)
6. coracoglenoid ligament

Question 18

what are the attachments of the coracoglenoid ligament?

Answer 18

1. coracoid process between coracoacromial and coracohumeral ligaments
2. near the orgin of the biceps long head

Question 19

Where can the AC joint refer pain?

Answer 19

1. trap
2. neck
3. tip of acromium

Question 20

how do you mechanically compress the AC joint?

Answer 20

Hawkins Kennedy

1.closed pack positions

Question 21

AC is innervated by what nerve?

Answer 21

suprascapular

Question 22

When are the coracoclavicular ligaments tensioned in shoulder ROM

Answer 22

Conoid- begining and end

trapezoid- mid range

Question 23

what nerve entrapment can occur around the scapula?

Answer 23

suprascapular as it passes through the suprascapular notch

Question 24

what movement can lead to suprascapular nerve irritation?

Answer 24

1. sling effect- depression and reiteration
2. hyper abdution with ER
3. forceful horz adduction
4. typically in overhead athletes

Question 25

what are the coracoclavicular ligaments and their orientation

Answer 25

trapezoid- horizaontal | conoid- vertical

Question 26

what are the attachments of the conoid ligaments?

Answer 26

base of the coracoid process on the scapula, medial to the trapezoid ligament; above, by its expanded base, to the conoid tubercle on the under surface of the clavicle, and to a line proceeding medialward from it for 1.25 cm.

Question 27

What are the attachments of the trapezoid ligament

Answer 27

acromium to the oblique ridge on the under surface of the clavicle. Its anterior border is free; its posterior border is joined with the conoid ligament

Question 28

At what point in the ROM does movement of the AC joint occur?

Answer 28

1. first 30-60 degrees with 10 degress of upward rotation | 2. after 135 degree finishes rotating

Question 29

what parts of clavicular motion promote greater arm elevation?

Answer 29

the rotaiton of about 45 degress raises the clavical and the scapular about 30 more degrees

Question 30

what are the axis of motion of the AC joint?

Answer 30

1. longitudnal through the clavicle 2. CSH angle is motion through the horizontal plane about the vertical axis of the conoid directed by the trapezoid 3. CSV angle is motion through the transverse plane about eh horizontal axis of the trapezoid directed by the conoid

Question 31

What are the mechanics of the AC CSH angle of motions?

Answer 31

the movement of the coracoid forward and back ward tensions the trapezoid cause the spine about the conoid ligament -During abduction the angle decreases

Question 32

what are the mechanics of the AC CSV angle of motion?

Answer 32

scapular upward rotation tenstions the condoid causeing the rotation of the AC about the axis of the trapezoid

Question 33

what is the longitudinal axis of AC motion?

Answer 33

1. includes AC and SC motion of about 30 degrees of clavicular rotation 2. paces through the long axis of the clavicale

Question 34

How much motion does the clavicle demonstrate?

Answer 34

``` 30 degree rotaiton 60 elevation 20 depression 30 anterior 20 posterior ```

Question 35

What mechanical dysfunction will occur if the CSH angle does not derease with arm elevation?

Answer 35

you don't get the tension on the trapezoid to pull the clavical into rotation to allow for completion of arm elevation

Question 36

How is the SC joint shaped?

Answer 36

Saddle | 1.sturnum is convex A/P and concave med/lateral

Question 37

what unique articular structure is found in the SC joint?

Answer 37

disc 1. flat and circular 2. blends with the capsule 3. attaches to the first costal cartilage and sternum up to the clavical

Question 38

what muscle help strengthen the SC joint?

Answer 38

1. SCM anteriorly spans the joint 2. sternohyoid and sterhothyroid posteriorly 3. subclavius prevents excessive protraction and elevation

Question 39

what ligaments support the SC joint?

Answer 39

1. costoclavicular | 2. intraclavicular

Question 40

what are the attachments of the costoclavicular ligament

Answer 40

1. runs superiorly and laterally from the superior medial first rib 2. attaches to the inferior aspect of the clavicle

Question 41

Where is the relative axis of motion of the the SC joint?

Answer 41

just above the costoclavicular ligament about 2-3 c lateral to the the SC joint

Question 42

How much motion occurs at the SC joint with arm elevation?

Answer 42

10 degrees of arm = 4 degrees of SC

Question 43

What role does the clavicle play in arm elevation?

Answer 43

total of 60 degrees of elevation of the clavicle - 15 degrees in first 30 degrees - completes motion at 90 degrees - 1/2 is true elevation the other is from the crank shaft effect of the rotation

Question 44

what structures check scapular depression at the SC joint?

Answer 44

1. first rib | 2. superior capsule

Question 45

What SC structures check protraction and retractio?

Answer 45

``` retraction 1.SC ligament 2.posterior capsuel protraction 1.SC ligament 2.anteior capsule ```

Question 46

what shoulder movements effect function of the subclavian vein?

Answer 46

1. compressed with retraction | 2. expanded with protraction

Question 47

How does clavicular motion relate to scapular rotation?

Answer 47

The clavicle dictates the scapular rotation 1. 30 degrees of up rotation is from 30 degree of clavicular elevation 2. the second 30 degrees is from the crankshaft posterior rotation and influence of the acromioclavicular ligaments

Question 48

At what point in the movement of the arm does the clavicle reach its terminal position?

Answer 48

During the first 30 degrees it elevates 15 degrees and reaches its final position at about 90 degrees of arm elevation

Question 49

How will the supine versus the seated position effect your differentials and what are some examples?

Answer 49

1. the humeral head will ride higher supine | 2. tendonosis and bursitis will have a greater likelyhood of producing pain in supine and your testing is less sensitive

Question 50

How would you differentiate subclavius strain?

Answer 50

1. pain in same area as suboracoid bursa | 2. pain with scapular depression

Question 51

What must you rule out with subacromial bursitis?

Answer 51

1. AC joint strain- tender, painful horz add 2. tendonitis of RTC- painx3 MMT, decrease pain with distraction, less pain supine 3. subcoracoid bursa-coracoid pain and pain with ER 3. subclavius strain 5. coracoclaivicalar lig- mid clavical pain, pain greater abdcuted and ER to 90 6. aseptic necrosis- non capsular pattern with pain in all directions

Question 52

DD actue bursitis?

Answer 52

1. rapid onset, slight movement causes pain, empty end feel, flex and abduction most painful 2. rule out fracture, gout (capsular pattern of loss), septic arthritis (similar to acute with fever and warmth)

Question 53

What are the TUBS adn AMBRI classification of instability?

Answer 53

calssifications based on tryp of injury, direction/location, type of lesion and treatment 1. Traumatic unilateral.directional Bankart Surgery 2. atrumatic multidirection bilateral rehab inf cap shift

Question 54

What are the grades of instability in the GH joint>

Answer 54

grade I- rides up but not over the glenoid rim grade II- rides up and over and reduces grade III- rides up and over the glenoid rim and does not reduce

Question 55

How does anterior instbility lead to superior glenoid impingement?

Answer 55

1. To prevent the greater tuberosity from hitting the superior glenoid rim during elevation of the arm you must ER the arm 2. When you develop anterior laxity the humeral head will translate anterior and as a result the greater tuberosity will glide forward into the posterior glenoid rim 3. When ER the shoulder as you elevate the greater tuberosity clears the superior glenoid rim and moves behind the rim, but with anterior instability it glides forward and hits the glenoid 4. Some degree of contact is normal between the greater tuberosity and the posterior super glenoid rim 5. When there is contact with the glenoid rim you are pinching the supraspinatus

Question 56

What are the risk factors associated with cummulative trauma?

Answer 56

1. angle and position of work- outside optimal length tension 2. force requirements and its relative %MVC as it effect how hard the work is and blood flow 3. static contractions 4. grip and pinch 5. repeatition 6. acceleration of deceleration 7. vibration 8. impact 9. cold 10. individual 11. envrinment

Question 57

what is myofacial pain?

Answer 57

taut bands of skeletal muscle or fascia painful with compression and may refer pain or autonomic response

Question 58

what are the categories of myofacial pain?

Answer 58

1. active 2. latent 3. primary 4. associated 5. satellite 6. secondary

Question 59

what are the causes of myofascial pain?

Answer 59

1. hyper irritability from serotonin, histamine, bradykinin, protaglandin E 2. local increase in metabolic demand 3. actue connective tissue or muscle stain 4. tearing of sarcoplasmic reticulum and release of Ca++ stores

Question 60

what are some potential visceral sources of pain to the shoulder?

Answer 60

1. diaphragm 2. pulmonary infarct 3. myocardial ischemia 4. perforated abdominal viscera 5. gall bladder