1. Biomechanics of Human Upper Extremity
ENT 214 Biomechanics
Biomechanics of Human Upper Extremity
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3. Manubrium Sternum Retrieved from

4. Structure of the Shoulder
Sternoclavicular joint
Acromioclavicular joint
Coracoclavicular joint
Glenohumeral joint
Scapulothoracic joint

5. Structure of the Shoulder
Interclavicular ligament
Clavicle
Sternoclavicular ligament
Costoclavicular ligament
Sternum
Articular disk
Costal cartilage (1st rib)
Sternoclavicular joint: modified ball and socket joint between the proximal clavicle and the manubrium of the sternum

6. Structure of the Shoulder
Coracoclavicular ligament
Anterior view
Posterior view
Clavicle
Verterbal border
Acromioclavicular joint
Acromion process
Coracoacromial ligament
Coracoid process
Glenoid fossa
Axillary border
Inferior angle
Scapular spine
Vertebral border
Acromioclavicular joint: irregular joint between the acromion process of the scapula and the distal clavicle

7. Structure of the Shoulder
Coracoclavicular ligament
Anterior view
Posterior view
Clavicle
Verterbal border
Acromioclavicular joint
Acromion process
Coracoacromial ligament
Coracoid process
Glenoid fossa
Axillary border
Inferior angle
Scapular spine
Vertebral border
Coracoclavicular joint: syndesmosis with the coracoid process of the scapula bound to the inferior clavicle by the coracoclavicular ligament

8. Structure of the Shoulder
Acromion process
Coracohumeral ligament
Long head of biceps
Humerus
Coracoid process
Articular capsule
Scapula
Glenohumeral joint: ball and socket joint in which the head of the humerus articulates with the glenoid fossa of the scapula

9. Structure of the Shoulder
What is the scapulothoracic joint?
articulation between the anterior scapula and the thoracic wall

10. Bursae
A small fluid-filled sac located between movable parts of the body especially at joints
Reduce friction between layers of collagenous tissue

11. Movements of the Shoulder Complex
scapulohumeral rhythm: a regular pattern of scapular rotation that accompanies and facilitates humeral abduction

12. Movements of the Shoulder Complex
First 30o humeral elevation, contribution of scapula only 1/5 of glenohumeral joint
Beyond 30o, scapula rotates 1o for every 2o of humerus movement
First 90o of arm elevation, clavicle elevated 35o to 45o of motion at sternoclavicular joint.

13. Movements of the Shoulder Complex
What muscles contribute to flexion at the glenohumeral joint?
anterior deltoid
clavicular pectoralis major
assisted by:
coracobrachialis
short head of biceps brachii

14. Retrieved from

15. Movements of the Shoulder Complex
What muscles contribute to extension at the glenohumeral joint?
sternal pectoralis major
latissimus dorsi
teres major
assisted by:
long head of triceps brachii

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17. Movements of the Shoulder Complex
What muscles contribute to abduction at the glenohumeral joint?
middle deltoid
supraspinatus

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19. Movements of the Shoulder Complex
What muscles contribute to adduction at the glenohumeral joint?
latissimus dorsi
teres major
sternal pectoralis major
assisted by:
short head of biceps brachii
long head of triceps brachii

20. Movements of the Shoulder Complex
What muscles contribute to medial rotation of the humerus?
subscapularis
teres major
assisted by:
pectoralis major
anterior deltoid
latissimus dorsi
short head of biceps brachii

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22. Movements of the Shoulder Complex
What muscles contribute to lateral rotation of the humerus?
infraspinatus
teres minor
assisted by:
posterior deltoid

23. Movements of the Shoulder Complex
What muscles contribute to horizontal adduction of the humerus?
pectoralis major
anterior deltoid
coracobrachialis
assisted by:
short head of biceps brachii

24. Movements of the Shoulder Complex
What muscles contribute to horizontal abduction of the humerus?
infraspinatus
middle and posterior deltoid
teres minor
assisted by:
teres major
latissimus dorsi

25. Torque at shoulder
Torque created by weight of arm is the product of arm weight and perpendicular distance between arm’s COG and the shoulder

26. Torque at shoulder

27. Sample Problem 1
If the weight of the arm is 33 N, moment arm for the total arm segment is 30 cm, moment arm for deltoid muscle (Fm) is 3 cm.
How much force must be supplied by deltoid to maintain the arm in this position?
What is the magnitude of the joint reaction force (R)? wt

28. Common Injuries of Shoulder
Dislocation
Rotator Cuff Damage
Rotator cuff - anatomical term given to the group of muscles and their tendons that act to stabilize the shoulder
Example – supraspinatus, infraspinatus, teres minor, subscapularis muscles
Rotational Damage

29. Humeroulnar Joint Retrieved from

30. Structure of the Elbow
What is the humeroulnar joint?
hinge joint in which the humeral trochlea articulates with the trochlear fossa of the ulna
considered to be the elbow joint

32. Structure of the Elbow What is the humeroradial joint?
gliding joint in which the capitellum of the humerus articulates with the proximal end of the radius

33. Structure of the Elbow What are the radioulnar joints?
the proximal and distal radioulnar joints are pivot joints
the middle radioulnar joint is a syndesmosis

34. Movements at the Elbow
What muscles contribute to flexion at the elbow?
brachialis
biceps brachii
brachioradialis

35. Movements at the Elbow
What muscles contribute to extension at the elbow?
triceps brachii
assisted by:
anconeus
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36. biceps be
fore
force?

37. Common Injuries of Elbow
Sprains and dislocation
Epicondylitis
Inflammation and sometimes microrupting of collagenous tissue at distal humerus

38. Wrist
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39. Structure of the Wrist What are the radiocarpal joints?
condyloid articulations between the radius and the three carpal bones
these joints comprise the wrist

40. Structure of the Wrist
What is the function of the retinacula at the wrist?
these fibrous bands of fascia form protective passageways through which tendons, nerves, and blood vessels pass

41. Movements at the Wrist
What muscles contribute to flexion at the wrist?
flexor carpi radialis
flexor carpi ulnaris
palmaris longus
assisted by:
flexor digitorum superficialis
flexor digitorum profundus

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43. Movements at the Wrist
What muscles contribute to extension at the wrist?
extensor carpi radialis longus
extensor carpi radialis brevis
extensor carpi ulnaris
assisted by:
other wrist extensor muscles

44. F I N G E R
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45. Structure of the Hand Joints
What are the carpometacarpal joints?
the carpometacarpal joint of the thumb is a saddle joint
the other carpometacarpal joints are gliding joints

46. Structure of the Hand Joints
What are the intermetacarpal joints?
irregular joints between the metacarpals that share joint capsules with the carpometacarpal joints

47. Structure of the Hand Joints
What are the metacarpophalangeal joints?
condyloid joints between the rounded distal heads of the metacarpals and the concave proximal ends of the phalanges
these joints form the knuckles of the hand

48. Structure of the Hand Joints
What are the interphalangeal joints?
the proximal and distal interphalangeal joints of the fingers and the single interphalangeal joint of the thumb are all hinge joints

49. Movements of the Hand flexion
What motions are permitted at metacarpophalangeal joints 2-5?
flexion
extension
abduction
adduction
circumduction

50. Movements of the Hand
What muscles are responsible for motions of the hand?
there are nine extrinsic muscles with attachments both proximal and distal to the wrist
there are ten intrinsic muscles with both attachments distal to the wrist

53. Common Injuries of Wrist & Hand
Fracture - boxers
Injury - golfers
Carpal tunnel syndrome
Passageway between carpal bone and flexor retinaculum
Symptom : pain, numbness along median nerve, clumsiness of finger function, atrophy of muscle

54. Summary Shoulder Structure Movement and muscle involve Common injuries
Elbow
Wrist
Hand
Force initiated and torque - calculation