shoulder Flashcards
The shoulder complex is made up of what 5 structures?
Sternum
Clavicle
Ribs
Scapula
Humerus
What is the shoulder trade-off?
Great ROM
Unstable joint (bc shape)
Ant surface of clavicle is convex ___ and concave ___
Medially
Laterally
How is the clavicle oriented anatomically?
Slightly above horizontal plane and ~20 degrees posterior to frontal plane
Angles of scapula (3)?
Superior, inferior, lateral
Borders of scapula (3)?
Superior, lateral, medial
What is the scapular plane?
Scapula angled superiorly ~4 degrees (horizontal plane) and anteriorly 35 degrees (frontal plane)
What is retroversion of head of humerus?
Rotated posteriorly ~30 degrees w/in horizontal plane
Do we normally have 65 degrees of humeral retroversion?
No, it de-rotates as age (~16-20 y.o.)
What musc attaches to lesser tubercle?
Subscapularis
What musc attaches to greater tubercle?
Upper facet: supraspinatus
Middle: infraspinatus
Lower: teres minor
What musc attaches to bicipital groove?
Long head tendon of biceps brachii (and latissimus dorsi at floor)
Which joint is a true joint?
SC (sternoclavicular) joint
What type of joint is the SC?
Saddle (concave and convex surfaces)
What musc add stability to the SC joint?
Ant: SCM
Post: sternohyoid and sternothyoid
Inf: subclavius
What tissues stabilize the SC joint?
Ant and post sternoclavicular lig
Interclavicular lig
Costoclavicular lig
Articular disc
T/F: the ligaments that stabilize the SC joint through all motions
F: except downward depression
Mvt of clavicle
Elev/dep
Prot/Ret
Ant/post rot
Elev/dep of SC occur in which plane?
Frontal (parallel) (ant, post axis of rot)
___ degrees of elev and ___ degrees of dep
35-45
10
Elevation of SC roll and glide
Roll sup
Glide inf
Depression of SC roll and glide
Roll inf
Glide sup
Pro/ret of SC occur in which plane?
Horiz (vertical axis of rot)
T/F: there is ~15-30 degrees of port/ret
T
Retraction concave on convex sternum results in
Roll and glide post
T/F: protraction of SC roll and glide post
F: roll and glide ant
Axial rot of clavicle rotates ___ 20-35 degrees
Post
Closed pack pos of clavicle
Full post rot (elevation)
Loose pack pos of clavicle
Arm at side
SC joint saddle joint: ant and post indicates___, while sup and inf indicates PIC
Concave
Convex
Coracoclavicular lig is made up of
Trapezoid (sup, lat) and conoid ligs
Tissues that support AC joint
Sup and inf acromioclavicular lig
Coracoclavicular lig
Articular disc
Deltoid and upper trap
MVT AC joint
Upward/downward rot
Rotational adjustment mvts
Up/downward rot of AC occurs in which plane?
Frontal
T/F: there is 30 degrees of upward rotation at the SC joint as the arm is fully raised above head
F: AC
Rotational adjustment mvt of AC occur in which plane?
Horiz
Horizontal plane adjusting of AC joint is also known
IR/ER (vertical axis)
Sagittal plane adjusting of AC joint is also known
Ant and post tilting (med lat axis)
What is the closed pack pos of AC joint?
Full upward rot
T/F: clavicle facet faces down and laterally, while acromion facet faces up and medially
T
Scapula and thorax are separated by
Subscapularis
Serratus ant
Erector spine
Resting posture of scapula is
10 degrees of ant tilt
5-10 degrees of upward rot
35 degrees of IR
ST mvt is a cooperation between which joints?
SC & AC
Neutral scapula position
Between ribs #2-7
6 cm away from spine
Slight ant tilt and upward rot
ST joint mvt
Elev/dep
Prot/ret
Up/downward rot
ST elev is a combination of ___ @ SC & ___ @ AC
Elev
Downward rot
ST protraction is a combination of ___ @ SC & ___ @ AC
Protraction
Slight IR
T/F: decreasing motion at AC will compensate by increasing motion at SC?
T
ST upward rot combination of ___ @ SC & ___ @ AC
Elev
Upward rot
30 degrees of the 60 degrees of upward rot at the ST joint results from
Upward rot of AC
Elev of clavicle?
What is the importance of full upward rotation of ST during elev?
- preserve Subacromial space
- maximal stability to support humerus by positioning glenoid fossa advantageously during elev
- maximal length tension rel of deltoid and supraspinatus (active insufficiency= musc shorten, weak position)
T/F: raising the arm overhead is called flexion when it is near the frontal/scapular plane
F: ABD
(flex= sagittal)
How is the articular surface of the glenoid fossa oriented in anatomical pos?
Ant-lat in scapular plane (sup)
In anatomical pos how is the humeral head pos?
Sup, med and post (retroversion) in scapular plane
T/F: in anatomical pos/ ADD pos, inferior portion of GH capsule (axillary pouch) appears taut (stretch)
F: ABD
What structures stabilize GH?
Passive: capsular lig
Active: rotator cuff musc, long head biceps tendon
Glenoid Labrum
ST posture (static stability)
What are the passive stabilizers of GH?
Everything except musc
What are the active stabilizers of GH?
Musc
T/F: GH is unstable bc rotator cuff musc insert into capsule?
F: stable
T/F: capsular lig and musc provide stability when stretched at extreme motions
F: musc prod stability at any joint position
T/F: long head biceps tendon = dynamic stabilizer of GH bc maint articular stability during active motions
F: rotator cuff musc
Sup GH capsular lig restricts?
Inf and ant translation
ER
ADD
What happens to the sup capsular lig when the GH joint is ABD beyond 35-45 degrees?
Slackens
Middle GH capsular lig restricts?
Ant translation
ER
Inf GH capsular lig restricts?
ABD
What happens to the inf capsular lig when the GH joint is ABD 90 degrees?
Taut (stretch, tight)
What are the 3 parts of the Inf GH capsular lig?
Anterior band
Axillary pouch
Posterior band
T/F: post band restricts/tenses during ER, ABD
F: IR
T/F: Coracohumeral is taut during ABD and stretches during ADD, and restricts inf translation
F: taut ADD, stretch ABD, restricts ER
T/F: glenoid labrum deepens fossa by 30%?
F: 20%
What does the glenoid labrum act like?
Suction cup (joint fluid provides stability)
When the scapula loses upward rot and capsular lig stretches, what happens to humerus?
Slides down
T/F: the height of the Subacromial space is about 2 cm when the arm is at the side
F: 1 cm
What structures are under the Subacromial arch?
Superior capsule
Supraspinatus
Long head Biceps brachii tendon
Subacromial bursa
What are the bursae around the shoulder?
Subacromial bursa
Subdeltoid bursa
Closed pack pos of GH
Full flex, ABD, ER
Full ext, ADD, IR
Loose pack pos of GH
30-30-10
ABD, flex, ER
Mvt at GH joint
Flex/ext
ABD/ADD
IR/ER
(Horizontal) ABD/ADD
GH ABD/ADD occur in which plane?
Frontal (ap axis)
T/F: normal person has ~120 degrees of ABD at GH
T
T/F: full ABD of shoulder complex requires 60 degrees of downward rot of scapula
F: upward rot
GH ABD roll and glide
Roll sup
Glide inf
T/F: Supraspinatus can pull sup capsule taut, thus pinching between the humeral head and undersurface of acromion
F: protects from pinch
GH flex/ext occur in which plane?
Sagittal (ml axis)
T/F: 180 degrees of flexion available at GH
F: 120
180 degrees includes upward rot of ST
Full ext of shoulder occurs to a pos of ___ degrees actively and ___ degrees passively behind the frontal plane
65
80
Flexion in respect to coracoacromial arch rolls ___ and glides ___
Anterior
Posterior
GH IR/ER (axial rot of humerus) occurs in what plane?
Horizontal (vertical axis)
GH ER: humeral head rolls ___ and glides ___
Post
Ant
When GH ER, Infraspinatus ___ while Subscapularis ___ resulting in co-cxn (dynamic stability)
Contracts (concentric)
Stretches (eccentric)
IMPORTANT YO
Scapulohumeral rhythm (2:1) states that
For every 3 degrees shoulder ABD, 2 degrees occur by GH ABD and 1 degree from ST upward rot
1st kinematic principle states of shoulder ABD that
Bc 2:1 scapulohumeral rhythm, full arc of 180 degrees of ABD results from 120 degrees GH ABD and 60 degrees of ST upward rot
2nd kinematic principle of ABD states that
60 degrees of upward rot of scapula during full shoulder ABD, results from elev clavicle at SC and upward rot of scapula at AC
3rd kinematic principle of ABD states that
Clavicle retracts at SC during full shoulder ABD
T/F: clavicle retracts greater distance during shoulder ABD in horizontal plane than during ABD in scapular plane or w/ flexion
F: frontal plane
4th kinematic principle of ABD states that
As shoulder reaches full ABD, upwardly rotating scapula post tilts and slightly ER
5th kinematic principle of ABD states that
Clavicle rotates posteriorly along own axis
6th kinematic principle of ABD states that
Humerus ER during shoulder ABD
In order to perform complete frontal plane ABD, what does the humerus need to do?
ER (to avoid hitting acromion)
T/F: Brachial plexus = ventral rami C8-T1
F: C5-T1
How to remember brachial plexus?
Real–> root
Therapists–> trunk
Drink–> divisions
Cold–> cord
Beer–> branches
Nerve roots C5-6 forms ___ trunk
Upper
T/F: nerve root C7 forms middle trunk
T
Nerve roots C8 and T1 forms ___ trunk
Lower
T/F: ant divisions of upper and middle trunk form the lateral cord
T
T/F: all ant divisions of the trunks form the posterior cord
F: all post divisions form cord
Lateral cord forms ___ and ___ nerves
Musculocutaneous
Median (other half = medial cord)
Post cord forms which 5 nerves
Subscapular (upper and lower)
Thoracodorsal
Axillary
Radial
Medial cord forms median and ___ nerve
Ulnar
What 2 regions of brachial plexus innervate shoulder complex?
Post cord
Prox segments: dorsal scapular, long thoracic, pectoral and suprascapular n
SC joint receives afferent innervation by __ and __ nerve roots from ___ plexus
C3 & C4
Cervical
AC and GH joints receives afferent innervation by __ and __ nerve roots via ___ and ___ nerves
C5 & C6
Suprascapular
Axillary
T/F: proximal stabilizers are musc that originate on scapula and clavicle, insert on humerus or forearm
F: distal mobilizers
(prox= musc originate on spine, ribs, cranium and insert on scapula and clavicle)
Examples of proximal stabilizers
Trapezius
Serratus ant
Examples of distal mobilizers
Deltoids
Biceps brachii
What are the ST elevator musc that support the shoulder girdle?
Upper trapezius
Levator scapulae
Rhomboids
A depressed clavicle results in __ dislocation at __ joint
Superior
SC
Depressors of ST joint
Lower trapezius
Latissimus dorsi
Pectoralis minor
Subclavius
T/F: subclavius stabilizes SC joint
T
Protractors of ST joint
Serratus ant
Retractors of ST joint
Middle trapezius
Rhomboids
Lower trapezius
Upward rotators of ST joint
Serratus ant
Upper and lower trapezius
Downward rotators of ST joint
Rhomboids
Pectoralis minor
GH joint musc that elevate arm
ABD: ant and middle deltoid, Supraspinatus
Flex: ant deltoid, Coracobrachialis, Biceps brachii
T/F: when deltoids are paralyzed, Supraspinatus is capable of fully ABD GH
T
T/F: when Supraspinatus is paralyzed, still able to fully ABD
F: difficult but still achievable
When both deltoid and Supraspinatus are paralyzed, is full ABD still possible?
No
What is Infraspinatus and Subscapularis role in GH ABD?
Have a limited potential to generate ABD torque, this occurs bc upper fibers pass slightly superiorly to ant-post AoR
ST joint musc that elevate arm
Upward rot: serrates ant and trapezius (upper and lower fibers)
Serratus ant pulls on inferior angle of scapula and rotates the glenoid fossa ___ and ___ during upward rot of scap
Upward
Laterally
Upper trapezius upwardly rotates scap indirectly through ___ and ___ pull on clavicle during upward rot of scap
Superior
Medial
Lower trapezius upwardly rotates the scap by inf and medial pull on ___ of the scapula
Spine
During full ABD of shoulder, thoracic spine naturally extends _____ degrees
10-15
Paralyzed trapezius = very difficult/unachievable to
Elevate arm in frontal plane (ABD) bc middle trapezius= required to generate strong retraction force on scap
T/F: paralysis of serrates ant = great difficulty actively elevating arm above the head in frontal plane
F: regardless of plane of motion
Supraspinatus drives the ___ roll of humeral head, while ITS musc drive ___ roll of humeral head during elevation of arm
Superior
Inferior
Traumatic dislocations occur in the ___ direction due to fall or forceful collision
Ant
Ant dislocation involves motion/position of
ABD, extreme ER
Ant dislocation often injures/overstretches which structures?
Rotator cuff musc
Middle and inf GH lig
Ant-inf portion of glenoid labrum
What is a Bankart lesion?
Part of capsule/labrum that detaches from glenoid fossa
T/F: posttraumatic dislocation don’t lead to future reoccurrence
F: leads to future reoccurrence
Atraumatic instability is when
Excessive ligamentous laxity
T/F: atraumatic instability is congenital
T (hereditary)
Acquired shoulder instability occurs in
Sports (high-velocity motions: extreme ER, ABD)
T/F: Subscapularis is the most used musc in shoulder complex
F: Supraspinatus
The Supraspinatus has an internal moment arm for shoulder ABD of about
2.5 cm (1 in)
When injure/tear Supraspinatus, you should hold obj close to you. Why?
To minimize force demand of musc (red external moment arm of load)
What predisposes Supraspinatus to degenerate?
Poor mechanical advantage
Small cross sectional area
Proximity to acromion
Compromised blood supply
1:20 Supraspinatus ratio meaning
Ratio of internal moment arm of musc to external moment arm of load
Supraspinatus needs to generate force 20x greater than load
What are the primary ADD and ext musc of shoulder?
Post deltoid
Latissimus dorsi
Teres major
Long head of triceps
Sternocostal head of pec maj
T/F: ABD and flexors are generate the largest torque of any musc group in shoulder
F: ADD and extensors
Which muscles have the largest moment arms for ADD and extension?
Latissimus dorsi
Terms major
Pectoralis major
When we fully extend shoulder beyond neutral, it is associated w/ ant tilting. What musc primarily drives this?
Pectoralis minor
T/F: none of the rotator cuff musc are activated during shoulder ADD and ext
F: all rotator cuff musc activated
What is the rhomboids role in ADD and ext?
Actively downward rot/prevent upward rot
What are the shoulder IR musc?
Subscapularis
Pec maj
Latissimus dorsi
Teres major
Ant deltoid
Which musc has the greatest moment arm for IR? Least
Subscapularis
Ant deltoid
When the scapula is fixed but the humerus moves we get a __ rel
Convex on concave (roll and glide oppo)
When the thorax moves and the humerus is fixed, we get a ___ rel
Concave on convex (roll and glide same)
What are the shoulder ER musc?
Infraspinatus
Teres minor
Posterior deltoid
What musc assists w/ ER provided at GH between neutral and full ER?
Supraspinatus
T/F: ext>flex, ADD>ADD, IR>ER
T
Factors assoc w/ subacromial impingement
Abnormal GH kinematics (humerus/scap)
Poor posture (pos of scap)
Poor motor control
Adhesive capsulitis. instability, tight pos
capsule
Swelling, joint osteocytes, abnormal
acromion
