Module 8: Biomechanics and Motor Control of the Upper Extremity Flashcards
What are the bones that form the upper extremity?
scapula, clavicle, humerus, radius, ulna, hand bones
What is the function of the shoulder girdle?
provide stability to allow for the function of the upper extremity
What are the joints of the shoulder girdle?
Acromioclavicular joint (AC)
Sternoclavicular (SC)
Scapulothoracic (ST)
Glenohumeral
What are the characteristics of the AC joint?
very little movement, strong ligaments to stabilize, scapula movements are translated to the clavicle
Characteristics of the SC joint?
only true link of the shoulder girdle to the axial skeleton
supported by strong ligaments, allows for clavicular elevation
Characteristics of ST joint?
not a true bony joint
essential for proper movement of upper limb
Characteristics of glenohumeral joint?
3 degrees of freedom
- unstable joint, needs muscles to allow for mobility and stability
What are the different stabilizers of the glenohumeral joint?
Dynamic stabilizers: keeps joint in alignment - rotator cuff (subscap, infraspinatus, supraspinatus, teres minor)
Structural stabilizers: inert to keep in alignment - labrum, ligaments, capsular tissue
What is the role of each structural stabilizer at the glenohumeral joint?
Ligaments: provide stability anteriorly and posteriorly
Labrum: increase the depth of the glenoid cavity to center the humeral head
Capsule: stabilizes the humeral head
Describe the relationship between the upper extremity and trunk in regards to movement?
movements at glenohumeral don’t occur in isolation - position of scapula on trunk and trunk in space are critical for shoulder health
What is the continous battle that the shoulder girdle fights?
Against gravity. muscle action is always pulling upwards on the humeral head
What is scapulohumeral rhythm?
relationship of movement between scapula and humerus during shoulder abduction
- lots of variability between people
What are some potential causes of shoulder pain in the subacromial space?
Rubbing of bursa, capsule and tendons due to weak rotator cuff muscles, structural damage, poor scapular control
What are the joints at the elbow?
Humeroulnar joint (true elbow joint, flexion and extension)
Humeral radial
superior radioulnar (supination and pronation proximally)
Inferior radioulnar (supination and pronation distally)
What are the muscles that act on the elbow joint?
Elbow flexors, extensors, pronators, supinators
What are the joints of the wrist and what movements are possible?
Radiocarpal: flexion/ext, ulnar and radial deviation
Carpal joints: flexion/extension
What makes the hand movements unique?
bone and soft tissue configuration allow for fine motor and gross motor skills
Describe the sensation in the hand?
Skin is a large sensory organ, in the brain the hand has a large sensory representation
Describe the differences between the types of grips that the hand can be in?
Power grip - holding a hammer (fingers curled with thumb over top the pointer finger)
Hook grip - holding a suitcase by the handle (fingers curled with the thumb as support)
Pinch grip - putting pointer and thumb together
Key grip - thumb on top of the pointer finger
What are the differences between an open and closed kinetic chain?
Closed - distal section is fixed and the proximal section moves (pushup)
Open - proximal section is fixed and the distal portion moves (bicep curl)
