Week 4 Flashcards
What are the 4 joints of the shoulder complex?
- sternoclavicular joint
- acromioclavicular joint
- glenohumeral joint
- scapulothoracic
What are the characteristics (articulation and what joint type) of the sternoclavicular joint?
- medial clavicle with notch of manubrium and 1st costal cartilage
- saddle joint - convex on concave
Describe the orientation of the saddle joint of the SC joint in the superior to inferior direction and in the anterior to posterior direction.
- superior/inferior - convex on concave (elevation/depression)
- medial/lateral - concave on convex (protraction/retraction)
What is the function of the sternoclavicular fibrocartilage?
- promotes stability
- increase joint congruence
- absorbs forces
- helps limit medial movement of clavicle
What are the osteokinematics of the SC joint?
- elevation/depression
- protraction/retraction
- anterior/ posterior rotation
What are arthrokinematics of elevation/depression of SC joint?
Convex on concave
Elevation
- superior roll, inferior glide
Depression
- inferior roll, superior glide
What are arthrokinematics of protraction/retraction of SC joint?
concave on convex
Protraction
- anterior roll and glide
Retraction
- posterior roll and glide
What are arthokinetmatics of anterior/posterior rotation of SC joint?
Spin
Posterior Rotation
- Inferior surface turns anteriorly (backward rotation)
Anterior Rotation
- Inferior surface returns to inferior position - only occurs after posterior rotation
What is the closed packed position for the SC joint?
full posterior rotation
What is the function of the AC joint and what osteokinematic motions are associated with the AC joint?
- allow the scapula to rotate during arm movement
- internal/external rotation
- anterior/posterior tilting
- upward/downward rotation
Describe the plane of the scapula.
- around 35 degrees off the frontal plane
- plane where scapula is best in contact with the rib cage
What is the purpose of internal/external rotation of AC joint?
important for maintaining contact of scapula on curved thorax during protraction and retraction of clavicle
What is the purpose of anterior/posterior tilting of AC joint?
Important for maintaining contact of scapula on curved thorax during elevation and depression of clavicle
What is the purpose of upward/downward rotation of AC joint?
Important for positioning glenoid fossa in optimal position in order to maintain contact with humerus
What shoulder motions move the scapula in an upward rotation?
flexion and abduction
What shoulder motions move the scapula in a downward rotation?
adduction and extension
What is closed packed position of the AC joint?
full upward rotation - full shoulder abduction and/or flexion
What are the primary and secondary osteokinematic motions associated with the scapulothoracic joint?
Primary
- elevation/depression
- protraction/retraction
- upward/downward rotation
Secondary
- Anterior/posterior tilting
- internal/external rotation
Elevation/depression of scapulothoracic joint is a combination of what 2 joint movements?
Elevation
- SC joint elevation and AC joint downward rotation
Depression
- SC joint depression and AC joint upward rotation
Protraction/retraction of scapulothoracic joint is a combination of what 2 joint movements?
Protraction
- SC joint protraction and slight AC joint IR
Retraction
- SC joint retraction and slight AC joint ER
Upward rotation/downward rotation of scapulothoracic joint is a combination of what 2 movements?
Upward Rotation
- SC joint elevation and AC joint upward rotation
- observed during shoulder flexion/abduction
Downward Rotation
- SC joint depression and AC joint downward rotation
Describe and define the angle of inclination and the angle of torsion at the GH joint.
Angle of Inclination - 130-150 degrees in frontal plane
Angle of torsion
- orientation of humeral head w/ the condyles - 30 degrees posterior in traverse plane
Define retroversion of the GH joint. What function does normal retroversion serve?
- posterior orientation of humeral head w/ regard to the condyles
- keeps humeral head in contact with glenoid during movement
Describe the characteristics and functions of the glenoid labrum and joint capsule.
Glenoid labrum
- Enhances concavity and increases articular surface
- Resists humeral head translations, dissipates forces, protects bony edges
- Attachment of glenohumeral ligaments and tendon of biceps long head
Joint Capsule
- Significant laxity, minimal stability provided
- Potential volume size is 2x size of humeral head
- Reinforced by thicker external ligaments
- Inferior portion is slack in adducted position creating axillary pouch
What are the ligaments of the glenohumeral joint?
- superior glenohumeral ligament
- middle glenohumeral ligament
- inferior glenohumeral ligament
- coracohumeral ligament
What is the function of the superior glenohumeral ligament?
- Limits external rotation and anterior & inferior translation at 0° abduction
- Slackens when abducted beyond 35-45 degrees
What is the function of the middle glenohumeral ligament?
- limits anterior translation from 45-90 degrees abduction and extremes of external rotation
What are the components and what is the function of the inferior glenohumeral ligament?
3 components
- anterior band, posterior band, and axillary pouch
- primary stabilizer beyond 45 degrees of abduction or with combined abduction and rotation
With abduction, the axillary pouch of the inferior glenohumeral ligament resists _____ & ______ translation
inferior and anterior-posterior
With abduction and lateral rotation, the anterior band of the inferior glenohumeral ligament resists _______ translation.
anterior
With abduction and medial rotation, the posterior band of the inferior glenohumeral ligament resist _______ translation
posterior
What is the function of the coracohumeral ligament?
limits inferior translation and external rotation of the humeral head w/ the arm in the dependent position
Describe the function of the rotator cuff.
- reinforce the GH joint capsule
- stabilize GH joint w/ dynamic activities
Where does the rotator cuff not reinforce the GH joint?
inferiorly and region between subscapularis and supraspinatus
What are the osteokinematics and arthrokinematics of the GH joint?
Osteokinematics
- flexion/extension
- adduction/abduction
- external/internal rotation
Arthrokinematics
- spin
- superior/inferior glide
- anterior/posterior glide
What are arthrokinematics during flexion/extension of GH joint?
convex on concave
Flexion
- superior roll, inferior slide
Extension
- inferior roll, superior glide
What are arthrokinematics during adduction/abduction of GH joint?
Convex on concave
Adduction
- inferior roll, superior glide
Abduction
- superior roll, inferior glide
What movement accompanies full abduction of GH joint?
external rotation
What are the arthokinematics of external/internal rotation of GH joint?
convex on concave
External rotation: posterior roll, anterior glide
Internal rotation
- anterior roll, posterior glide
What is closed packed position of the GH joint?
90 degrees and full external rotation or full abduction and external rotation
What is the capsular pattern of the GH joint?
external rotation > abduction > internal rotation
Describe scapulohumeral rhythm.
Ratio of 2 degrees of glenohumeral to 1 degree of scapular motion during arm elevation/abduction
- 2:1
Discuss the 6 principles associated with full abduction of the shoulder.
1) 2: scapulohumeral rhythm - active shoulder abduction of about 180 degrees occurs as a result of simultaneous 120 degrees of GH joint abduction and 60 degrees of scapulothoracic upward rotation
2) The 60 degrees of upward rotation of the scapula during full shoulder abduction is the result of a simultaneous elevation at the SC joint combined with upward rotation at the AC joint
3) The clavicle retracts at the SC joint during shoulder abduction
4) The upwardly rotating scapula posteriorly tilts and, less consistently, externally rotates slightly during full shoulder abduction
5) The clavicle posteriorly rotates around its own axis during shoulder abduction
6) The GH joint ER during shoulder abduction
What is the ideal position for shoulder girdle posture?
- Slightly elevated and relatively retracted scapula
- Results in glenoid fossa facing slightly upward
Describe the position of the shoulder girdle in rounded shoulders posture. What could this posture predispose an individual to?
- Slight depression, downward rotation and protraction of scapula
- predisposes to individual to impingement
What muscles act as a force couple to produce upward rotation at the GH joint?
serratus anterior, upper trapezius, and lower trapezius
What joints comprise the elbow complex?
- humeroulnar and humeroradial
- proximal and distal radioulnar
Describe the characteristics of the joint capsule of the elbow complex.
- Large, loose and weak anteriorly and posteriorly
- Contains folds that are able to expand to allow for a full range of elbow motion
- Fat pads located between the capsule to decrease friction
- Reinforced laterally by collateral ligaments
What is the carrying angle and why is it significant?
- valgus angulation of forearm
- allows for a person to carry object away from side of the thigh
- 8-15 degrees
What are the ligaments of the elbow joint?
- Medial collateral ligament - anterior, posterior, and transverse
- Lateral collateral ligament complex - lateral (radial) collateral ligament, lateral ulnar collateral ligament, and annular ligament
What are the functions of the medial and lateral collateral ligaments of the elbow?
medial - prevent valgus
lateral - prevent varus
Describe what happens at the elbow as a result of an extreme valgus-producing force?
May result in rupture of medial collateral ligament and/or compression force within the humeroradial joint
What are arthrokinematics of flexion/extension of elbow joint?
concave on convex
flexion - roll anterior, slide anterior
extension - roll posterior, slide posterior
What is closed packed position of the elbow joint?
- Humeroulnar: Full extension and supination
- Humeroradial: 90° elbow flexion and 5° supination
What is open packed position of the elbow joint?
- Humeroulnar: Flexed 70°, supinated 10°
- Humeroradial: Full extension and supination
What is the capsular pattern of the elbow joint?
flexion > extension
What are the osteokinematics and arthokinematics at proximal radioulnar joint?
- supination - lateral rotation
- pronation - medial rotation
What are the osteokinematics and arthokinematics at distal radioulnar joint?
concave on convex
- supination - roll and slide laterally
- pronation - roll and slide medially
What compensatory shoulder motion could help someone who is lacking in forearm pronation and/or supination to increase this forearm ROM in OKC?
- supination - external rotation of shoulder
- pronation - internal rotation of shoulder rotation
Describe what happens in closed chain supination and pronation.
- humerus and ulna rotate relative to a fixed radius/hand
- pronation is a result of shoulder external rotation
- supination is a result of internal rotation
What is the closed packed position of the proximal and distal radioulnar joints?
Proximal
- 5° of supination
Distal
- 5° of supination
What is the open packed position of the proximal and distal radioulnar joints?
Proximal
- 70° of flexion, 35° of supination
Distal
- 10° of supination
What is the capsular pattern of the proximal and distal radioulnar joints at the elbow?
supination = pronation
Describe the relationship of flexion torque with the elbow in a supinated position compared to a pronated position.
- 20-25% more force in supinated position
- this is because biceps is stretched during pronation - passive insufficiency
Describe the relationship of elbow pronation and supination with shoulder IR and ER
- pronation - associated with shoulder IR
- supination - associated with shoulder ER
- Important to keep in mind when testing forearm pronation and supination - hold elbow at 90 and pressed to side to block humerus torque
Describe what happens when a task requires high-power supination torque
- biceps is recruited
- triceps must co-contract to prevent biceps from flexing elbow and shoulder
- ex: turning a screwdriver
What is the law of parsimony? Give some examples of parsimony at work in the musculoskeletal system.
- nervous system tends to activate the fewest muscles or muscle fibers possible for the control of a given joint action
- ex: Lower powered activities utilize pronator quadratus while higher powered activities also recruit pronator teres
Name the joints of the wrist and hand complex.
- distal radioulnar
- radiocarpal and midcarpal
- carpometacarpal
- metacarpophalangeal
- interphalangeal
Describe the benefit of the wrist joint being compromised of the radiocarpal and midcarpal joints
- Permits large ROM with less exposed articular surface and tighter joint capsules
- Less tendency for structural pinch at extremes of motion
- Allows for flatter multi-joint surfaces that are more capable of withstanding imposed pressures
Describe the function of the extensor retinaculum and palmar carpal ligament
- prevent bowstringing during wrist movements
What bones are in the 1st row (proximal) of carpals?
- lunate, scaphoid, triquetrum
What bones are in the 2nd row (distal) of carpals?
- pisiform
- hamate
- capitate
- trapezoid
- trapezium
What factors may result in carpal tunnel syndrome?
- overcrowding
- excessive mechanical stress
- fibrotic changes of connective tissues
What are the osteokinematcs at the wrist joint?
- flexion/extension
- radial/ulnar deviation
What are arthrokinematics at wrist joint during flexion/extension?
convex on concave
Flexion
- anterior roll, posterior glide
Extension
- posterior roll, anterior glide
What are arthrokinematics at wrist joint during radial/ulnar deviation?
convex on concave
radial deviation
- lateral roll, medial glide
ulnar deviation
- medial roll, lateral glide
What is the closed packed position of the wrist joint?
Full extension with radial deviation
What is the open packed position of the wrist joint?
Neutral flexion/extension with slight ulnar deviation
What is the capsular pattern at the wrist joint?
flexion = extension, slight radial and ulnar deviation
Describe the length tension relationship of grip strength
- Max grip at 30 degrees of extension
- as you move into more flexion and extension, you lose power - active insufficiency
How do the FCU and the FCR act synergistically when performing active wrist flexion?
FCU and FCR act synergistically to oppose ulnar and radial deviation during active wrist flexion
Describe the function of the ulnar collateral ligament and the radial collateral ligament in the 1st CMC joint.
ulnar collateral ligament
- prevent excessive ulnar deviation
radial collateral ligament
- prevent excessive radial deviation
What are the osteokinematics of the 1st CMC joint?
- flexion/extension
- abduction/adduction
- opposition/reposition
What are arthrokinematics of flexion/extension at 1st CMC joint?
Concave on convex
Flexion
- medial roll and glide
Extension
- lateral roll and glide
What are arthrokinematics of adduction/abduction of 1st CMC joint?
Convex on concave
Adduction
- anterior roll, posterior glide
Abduction
- posterior roll, anterior glide
What motions happen during opposition and reposition at 1st CMC joint?
opposition
- abduction, flexion, and internal rotation
reposition
- adduction, extension, and external rotation
What is the closed packed position of the carpometacarpal joints?
full oposition
What is the open packed position of the carpometacarpal joints?
mid flexion/extension and mid abduction/adduction
What is the capsular pattern at the 1st CMC joint?
abduction
What are osteokinematics at MCP joints?
- flexion/extension
- abduction/adduction
- circumduction
What are arthrokinematics of flexion/extension at MCP joints?
concave on convex
Flexion
- anterior roll and glide
Extension
- posterior roll and glide
What are arthrokinematics of abduction/adduction at MCP joints?
concave on convex
Abduction
- roll and glide away from 3rd digit
Adduction
- roll and glide toward 3rd digit
What is closed and open packed position of MCP joints?
closed - full flexion
open - slight flexion
What is capsular pattern of MCP joints?
flexion = extension
What are the osteokinematics and arthrokinematics of IP joints?
concave on convex
Flexion - roll palmar/anterior, slide palmer/anterior
Extension - roll dorsal/posterior, slide dorsal/posterior
What is closed and open packed position of IP joints?
closed - full extension
open - slight flexion
What is capsular pattern at IP joints?
flexion = extension
What is the function of the flexor mechanism?
Function to prevent bowstringing of the tendons with contraction of extrinsic finger flexors
What is the position of function of the wrist, fingers and thumb.
Wrist
- 20-30 degrees of extension with slight ulnar deviation
Fingers
- 35-45 degrees of MCP flexion & 15-30 degrees of PIP and PIP joint flexion
Thumb
- 35-45 degre3es of CMC joint abduction
What is the function of the extensor mechanism?
- primary distal attachment for extensor digitorum, extensor indicis, and extensor digiti minimi
