Chapter 7 Flashcards
Motions of the Shoulder Girdle
and Glenohumeral (GH) Joint
Scapular Motions
•Elevation
•Depression
•Retraction
•Protraction
•Upward rotation
•Downward rotation
Motions of the Shoulder Girdle
and Glenohumeral (GH) Joint
GH Joint Motions
•Flexion
•Extension
•Abduction
•Adduction
•Internal rotation
•External rotation
•Horizontal abduction
•Horizontal adduction
•Scaption
Scapulohumeral Rhythm
The movement relationship between the shoulder girdle and shoulder joint
•Synchronization of the combined movements of the scapula and humerus during flexion and abduction
•Motions of the scapula, humerus, and clavicle all working together to achieve full arm flexion or abduction
Scapulohumeral Rhythm
2:1 Ratio
The scapula abducts and upwardly rotates; however, movement is not consistent throughout the full range of movement.
•Setting phase - first 30 degrees of GH flexion or abduction, minimal scapulothoracic movement with more GH joint motion
•2nd phase – between 30 and 90 degrees, 1 degree of motion for every 2 degrees of humeral flexion or abduction; 2:1 ratio
•3rd phase – more scapular movement
Purpose of Scapulohumeral Rhythm
Allow muscles to sustain their force throughout a larger portion of range of motion
•To deter subacromial impingement from occurring
Strength Characteristics of the
Shoulder Girdle and GH Joint
Synergists are muscles that work together to increase the strength of a desired movement as they work in unison. If stability is the goal rather than increased strength, then muscles will work in unison to counter each other, thus stabilizing a joint.
•Antagonists are muscles that work against each other to equal or cancel out the movement and therefore gain stability.
Strength Characteristics of the
Shoulder Girdle and GH Joint
Force couple
Muscles that act as synergists to one another provide a stronger action on the joint.
•Resulting movement must be rotary in nature.
•The line of force and the pull or angle of muscle fibers of all muscles involved must be in opposing directions.
Common Problems With the
Shoulder Girdle and GH Joint
Primary Adhesive Capsulitis: “Frozen shoulder”
•Three clinical stages in primary adhesive capsulitis
•First stage is called the painful stage.
●The shoulder begins to lose range of motion
•Second stage is called the stiffening phase.
●More ROM loss and complaints of an inability to use the affected extremity in activities of daily living
•Third stage is called the thawing stage.
●Client begins to regain lost range of motion
Four Problems of the
Shoulder Girdle and GH Joint
Shoulder Hemiplegia and Subluxation
Erb’s Palsy or Upper Obstetric Brachial Plexus Palsy
Rotator Cuff Tendinitis and Shoulder Impingement
Structural risk factors include degenerative spurring of the acromion process, inflammation of the bursa, calcification or thickening of the rotator cuff tendon, or tears of the rotator cuff.
Body Structures of
the Shoulder Complex
A significant number of muscles control movement at the shoulder complex.
•Functional roles of the shoulder complex include scapular pivoters, humeral positioners, humeral propellers and shoulder protectors.
Scapular Pivoters
Include the trapezius, serratus anterior, levator scapulae, pectoralis minor, and the rhomboid major and minor muscles
•The serratus anterior muscle holds the vertebral border of the scapula against the ribs preventing the “winging of the scapula.”
•The proper function of these scapular pivoters is important to normal movement of the entire shoulder complex and functional tasks involving the upper extremity
Humeral Positioners
Are muscles that position the humerus in space during or after actions of the scapular pivoters
•Include the anterior middle and posterior deltoid
Humeral Propellers
Are muscles that propel the humerus
•Include the latissimus dorsi and the pectoralis major and teres major
Shoulder Protectors
The shoulder protectors act as a force couple with the humeral positioners (the anterior, middle and posterior deltoid) to keep the structures of the shoulder complex safe.
•The shoulder protectors are known as the rotator cuff muscles and consist of the supraspinatus, infraspinatus, teres minor, and subscapularis muscles.
•The muscles of the rotator cuff assist in rotation of the GH joint. They also stabilize the humeral head in the glenoid cavity during functional tasks of the upper extremities, especially when the arms are abducted to 45 degrees and externally rotated.
Muscles, Nerves, and
Spinal Cord Levels
The majority of the muscles in the shoulder complex are innervated by nerve roots C3 to C6 with C7, C8, and T1 playing a lesser role.
In general, the muscles that act on the scapula originate on the trunk and insert on the scapula.
•Muscles that act at the GH joint also originate on the trunk, as well as on the scapula, but insert on the humerus.
