Lecture 6
What are the motions of the glenohumeral joint?
- flexion
- extension
- abduction
- adduction
- external/ internal rotation
- horizontal abduction
What are the deltoids?
much of the force of the deltoid causes an upward compression of the humerus against the acromion
What does the anterior deltoid do?
It is the prime mover for flexion and horizontal adduction. it assists with abduction and internal rotation
What does the middle deltoid do?
it is the prime mover for abduction and horizontal abduction
what does the posterior deltoid do?
it is the prime mover for horizontal abduction and extension. it assists with external rotation
What does the latissimus dorsi do?
It is the prime movers for hyper extension and adduction especially when arm is raised 30 to 90 degrees. It is also prime movers for internal rotation. It assists with horizontal abduction
What does the terms major do?
It is the little helper of the latissimus dorsi. It is the prime mover for extension and adduction. It is also the prime mover for internal rotation
What does the pectorals major?
The sternal portion is the prime mover for adduction and horizontal adduction. It is the prime mover for extension when the arm begins in position of flexion at 180 degrees to 120 degrees.
The clavicular portion is the prime mover for flexion and horizontal adduction. It is the prime mover for flexion in first part of range from 0 to 60 degrees.
What is the coracobrachialis do?
the line of pull is in front of humerus (coracoid process of scapula to medial surface of humerus near midpoint)
It stabilizes the shoulder when carrying a heavy load (pulls the humeral head into the glenoid fossa)
It is the prime mover for horizontal adduction and shoulder flexion
What does the biceps do
It's primarily a muscle of the elbow.
At the shoulder it can assist shoulder muscles in flexion, adduction, abduction, internal rotation, and horizontal rotation.
When the elbow is straight both heads of the biceps are active during humeral flexion and abduction if resistance is applied in these motions.
What does the triceps do?
The primarily muscle of the elbow for extension.
long head crosses over shoulder and inserts on scapula on infraglenoid tubercle.
It assists with extension and adduction of humerus
What are the muscles of the rotator cuff and what do they stabilize?
Subraspinatus, Infraspinatus. Teres Minor, Subscapularis
They stabilize the glenohumeral joint
What is the supraspinatus
It acts with deltoids as prime mover for abduction. It stabilizes when carrying heavy loads due to horizontal orientation (pulls head of humerus towards glenoid fossa)
What is the infrespinatus do?
It is the prime mover for horizontal abduction and external rotation. It depresses head of the humerus during shoulder flexion and abduction (the sliding)
It also is muscular reinforcement of joint capsule
What is the teres minor
It is the prime mover for horizontal abduction and external rotation. It depresses head of the humerus during shoulder flexion and abduction (the sliding)
It also is muscular reinforcement of joint capsule
What does the subscapularis do?
It is the prime mover for internal rotation. It stabilizes the glenohumeral joint due to its distal attachment. It depresses head of humerus during abduction and flexion
What are the angles of pull?
It is a combination of muscular forces which results in nearly equal GH joint compression and humeral head depression during flexion and abduction.
Supraspinatus is horizontal which compresses the GH joint and also does abduction
What is the roll and slide
it is the articular surfaces of the GH joint and the vertical pull of the deltoid muscle. If the deltoid muscle acted alone it would pull the humeral head upward and impinge it under the coracoacromial arch
What is the force system for the deltoid and rotator cuff?
It is a force couple= downward pull of SITS muscles to counteract upward pull of deltoids
it is a neutralizing synergy because of some of the muscles internally roating and some externally rotating
What is shoulder elevation and abduction?
-Both supraspinatus and deltoids abduct humerus (deltoids force is more linear)
- early in abduction: concentric contraction of deltoid primarily elevates humeral head
- 3 factors prevent an undesirable elevation (impingement): supraspinatus, infraspintaus, teres minor and subscapularis
- as abduction progress--> line of pull of deltoid changes
What is prevention of downward displacement of the humeral head?
-biomechanical forces typically involved in stabilization of humeral head:
- biomechanics alignment: scapula/ glenoid fossa
- glenoid labrum
- capsule and ligaments
- supraspinatus
What is shoulder subluxation?
-glenohumeral (inferior) subluxation= downward displacement of humeral head
- scapular Mal-alignment as a primary "underlying problem"
- Intervention includes: Positioning, co contracting and weight bearing, modalities, strengthening to realign scapula
this occurs when the head of the humerus comes partly out of the glenoid fossa due to trauma, sports injury, or stroke
What is impingement syndrome?
- occurs when there is impingement of the tendons or burs in the sub- acromial space
- over time, the impingement leads to inflammation of the rotator cuff tendon (tendinitis) or of the subacromial bursa (bursitis)
- can eventually result in fraying or tearing of the tendon (surpaspintaus)
What is biceps tendinitis?
irritation and inflammation of the long head of the biceps tendon as it crosses under the acromion
- due to overuse and general wear and tear
-intervention: rest, ice, potentially, surgery
DONNEEE mother truckers
sorry dad