Biomechanics Quiz 9 Flashcards
Glenohumeral (GH) Joint is comprised of what parts?
Large convex humerusand shallow concave glenoid fossa
The Glenohumeral (GH) Joint capsule is how many times the size of the humeral head (loose fitting)
twice the size
What tissues stabilize the GH joint?
- joint capsule and capsular ligaments (GH – sup, mid, inf)
- Coracohumeralligament
- rotator cuff muscles
- long head of biceps brachii
- glenoid labrum (50% depth of glenoid fossa)
glenoid labrum makes up what % of the overall depth of the glenoid fossa?
50%
What are the joint capsule and capsular ligaments
GH ligament: sup, mid, inf
What are the parts of the glenoid fossa?
- biceps tendon
- glenoid labrum
- glenoid fossa
- head of humerus
(GH joint kinematics) what is the anatomic position of the GH joint in degrees?
0* / neutral position
The GH joint is what kind of planar?
tri-planar
Tri-Planar of the GH joint specifies what axes?
Ab / Adduction
Flex / Extension
Int / External Rotation
All purposeful motion of the GH joint involves movements at what joints?
SC and AC joints
(GH joint kinematics)
Abduction requires what plane of motion about the A/P axis
frontal plane
Normal abduction at GH joint is how many degrees?
120*
Full abduction of the shoulder requires what degrees of upward rotation of the scapula
50*
The the GH joint is in abduction, the convex humeral head does what?
rolls superior and slides inferior
GH joint in adduction – the convex humeral head does what?
(opposite of abduction) slides superior and rolls inferior
(GH kinematics)
In GH flexion, the sagittal plan motion moves about what axis?
M/L
In GH flexion, what is normal degrees of flexion?
120*
Full flexion requires how many degrees of upward rotation and of what joint?
180* upward rotation of the scapulothoracic joint
GH extension normal extension is what degrees?
65* active extension
and 80* passive extension
(GH kinematics)
GH external rotation is transverse plane motion about what axis?
vertical axis?
Normal GH external rotation is what degrees?
65-75* (when in neutral position)
Normal internal rotation is what degrees?
75-80*
What is the source of GH-joint stability
rotator cuff
out of 26 muscles controlling shoulder, only how many play a roll in dynamic joint stability
4 muscles
What are the 4 parts of rotator cuff?
- supraspinatus
- infraspinatus
- teres minor
- teres major
Muscles that flex:
primary muscles:
anterior deltoid, long head biceps brachii, coracobrachilis
Muscles that Adduct or Extend
posterior deltoid, lat. dorsi, teresmajor, long head triceps brachia
Muscles that Interally Rotate
subscapularis, anterior deltoid, pectoralismajor, lat. dorsi, trees major
Muscles that Exterally Rotate
infraspinatus, teresminor, posterior deltoid
The elbow is made up how many bones and how many joints?
3 bones
4 joints
What are the 4 joints of the elbow?
- proximal radio-ulnarjoint
- distal radio-ulnarjoint
- humero-ulnarjoint
- humeroradial joint
Humero-ulnarJoint moves on what axis?
M/L axis
M/L axis passes through the vicinity of what?
lateral epicondyle
Tilted superior from M to L due to
medical lip of trochlea
The normal cubital valgus of the M/L humeri-ulnar joint is how many degrees?
13*
Excessive cubitus valgus is how many degrees?
20*
Cubitus valgus of HM joint is how many degrees?
0* or negative*
(arthrology)
articular capsule encloses what 4 joints
- humeri-ulnar
- humeroradial
3+4. proximal radio-ulnarjoints
The anterior band of the medial collateral ligament is strongest when?
taut with valgus and sagittal plane
The posterior band of the medial collateral ligament is less defined when?
taut with valgus and extreme flexion
The transverse band of the medial collateral ligament is on same bone when?
poorly developed
dynamic medial stabilizers
proximal fibers of wrist flexors and pronators
The proximal attachment site of the Humero-ulnar is the medial collateral ligaments / ulnar collateral ligament (same thing) – what are the 3 parts?
- anterior
- posterior
- transverse
The angular ligament secures what 2 parts of the elbow?
the radial head to ulna
What does elbow flexion serve humans daily?
feeding, grooming, lifting
What does elbow extension serve humans daily?
throwing, pushing, reaching
elbow extension is limited due to what?
flexion contracture
Maximal Range of Passive Motion
-5°to 145° flexion
What is the functional range of motion of the elbow?
30-130*
the medial epicondyle contains what ?
wrist and finger flexors
the lateral epicondyle contains what?
wrist and finger extensors
the HM joint is for flex/ext on what axis?
M/L
Proximal and Distal Radio-Ulnar Joints anatomic position:
bones parallel
The ulna is stationary during what type of actions?
pronation and supination
In supination, the radius and ulna are in what position?
parallel
In pronation, what is the radius’ position?
rotates over ulna
The proximal radio-ulnar joint is made up of what cartilage?
fibrocartilage
The fiber-osseous ring is comprised of what % of?
75% annular ligaments
25% radial notch of ulna
annular ligament: internal circumference is lined with what?
cartilage
Distal Radio-UlnarJoint: convex head of ulna articular how?
with shallow ulnar notch on radius and articular disc
The distal-radial ulnar joint is made up of what cartilage?
hyaline cartilage
The distal-radial ulnar joint is what type of joint?
synovial joint
Pronation and Supination Requires what simultaneous movement:
proximal and distal radio-ulnarjoints AND adjacent humeroradialjoint
Neutral Position of radial-ulnar joint?
“thumb-up”
ROM of radial-ulnar joint? in degrees
pronation: 75*
supination: 85*
Functional Arc (“excursion”)of radial-ulnar joint? in degrees
100* overall at least
Humeroradial Joint - the fovea spins on what type parts of elbow?
- radial head
2. capitulum of humerus
