4 JOINTS of the Shoulder Complex
1. Glenohumeral 2. Sternoclavicular 3. Scauplothoracic 4. Acromioclavicular
Within Functional Limits
The patient could complete movement with some pain. They were still functional.
The scapula remains stable & fixed b/c:
In order for the arm to move accurately in space, the scapula needs to stay stable and fixed to hold the arm in place. This is so the arm can move distally in a coordinated way, like a closed chain movement. Example: Push-up
Transmits force from arms to thorax/ chest. Most frequently broken bone in the body. allows for Flexion, Extension, Elevation, Depression & Limited Rotation. These movements usually occur in association with the scapula.
Sternoclavicular Joint (SC)
Part of the clavicle. This is a "Saddle Joint". *This joint allows for Flexion, Extension, Elevation, Depression & Limited Rotation. These movements usually occur in association with the scapula.
Acromioclavicular Joint (AC)
A loose joint is formed between the clavicle attatching laterally on the acromion process of the scapula. But this joint recieves support from coracoclavicular & acromioclavicular ligaments.
Scapulothoracic Joint (ST)
Depends on the AC & SC joints for contact with the axial skeleton. The ULTIMATE function: to provide a stable base for the humeral head's movement. Example: Dynamic Stabilization, which is being stable while moving. Protraction occurs @ this joint.
Movements of the Scapula
1. Elevation 2. Depression 3. Protraction (ABD 4. Retraction (ADD) 5. Medial or Downward Rotation 6. Lateral or Upward Rotation
Medial or Downward Rotation of Scapula
Medial refers to the inferior angle movement. Downward refers to the glenoid fossa, which goes down. RHOMBOIDS, LEVATOR SCAPULAE
Lateral or Upward Rotation of Scapula
Lateral refers to the inferior angle movement. Upward refers to the gleniod fossa, which goes up. SERRATUS ANTERIOR, UPPER & LOWER TRAPEZIUS
Glenohumeral Joint (GH)
Ball & Socket Joint. Articular surface of glenoid fossa lies nearly perpindicular to the humeral shaft. (Not a stable joint) Glenoid labrum deepens the fossa. Reinforced by superior, middle & inferior glenohumeral ligs & SITS muscle tendons. (Part of the joint capsule)
Relationship of Humerus & Scapula
Notice how little of the humeral head can rest in the glenoid fossa. The lack of bone provides great MOBILITY, but also POOR STABILITY.
1. Subscapularis 2. Infraspinatus 3. Teres Minor 4. Supraspinatus **Serve to provide support for the head of the humerus.
Muscles Anchoring Scapula
TRAPEZIUS, RHOMBOID MAJOR & MINOR, LEVATOR SCAPULAE, PECTORALIS MINOR, SERRATUS ANTERIOR
Synchronous movement of scapula & humerus. 2 degress of glenohumeral movement to 1 degree of scapular rotation.
When this occurs subluxation occurs, where the humerus head falls out of the glenoid fossa because of a "winged scapula". This can be due to flaccidity or low muscle tone.
Originates from spinal levels C5 to T1. Responsible for innervation of entire UE (upper extremity).
Terminal Branches--MEDIAN N.
Comes from medial & lateral divisions. Creates: ARM FLEXION, ABDUCTION & PRONATION.
Brachial Plexus Injury (ERB's PALSY)
Occurs when the baby is passing through the birth canal. The baby's shoulders may become impacted, causing the brachial plexus nerves to stretch or tear. Occurs in 2 out of a 1,000 babies.
Scaption (Scapular Abduction)
Refers to the forward elevation of the internally rotated arm in the scapular plane, with the thumb pointed to the floor. This motion isolates the action of the supraspinatus muscle, which is responsible for the first 30 degrees of abduction.
Internal Rotation @ Shoulder (Rot. Cuff)
Also called Medial Rotation. This movement is created by the SUBSCAPULARIS.
A fluid filled sac that reduces the friction between tendons & bones. This bursa is located between the supraspinatus & acromion process.