1. The Biomechanics of the Human Upper Extremity
Dr Ayesha Basharat

3. Shoulder Girdle Includes: G-H joint Subacromial space S-T joint
A-C joint
S-C joint

5. Sternoclavicular Joint
Provides major axis of rotation for movement of clavicle and scapula
Freely permitted frontal and transverse plane motion.
Close pack position is with maximum shoulder elevation

6. Sternoclavicular Joint
Joint capsule
Anterior & posterior S-C ligaments
Intra-articular disc
Interclavicular ligament
Costoclavicular ligament

8. Sternoclavicular Joint
Motions:
Protraction/retraction
Elevation/depression
Axial rotation (spin)

9. Acromioclavicular Joint
Irregular Diarthrodial joint between the acromion process of the scapula and the distal clavicle.
allows limited motions in all three planes.
Rotation occurs during arm elevation
Close-packed position with humerus abducted to 90 degrees
In close- Packed position there is maximum contact between the articulating surfaces and stability is also maximum.

10. Acromioclavicular Joint
Joint capsule
A-C ligaments
Intra-articular disc
Coracoclavicular ligaments

12. Coracoclavicular Joint
A syndesmosis with coracoid process of scapula
bound to the inferior clavicle by the Coracoclavicular ligament.
Permits little movement

13. Glenohumeral Joint Most freely moving joint in human body
Glenoid Labrum composed of: fibrocartilage rim &
Joint capsule
Tendon of long head of biceps brachii
Glenohumeral ligaments
Rotator Cuff Muscles
Most stable in close-packed position, when the humerus is abducted and laterally rotated.

14. Glenohumeral Motion Passive restraints Active restraints
Controlled by:
Passive restraints
Active restraints

15. Glenohumeral Motion Passive Restraints: Bony geometry Labrum
Capsuloligamentous structures
Negative intra-articular pressure

16. Capsuloligamentous Structures
SGHL
MGHL
IGHL complex
anterior band
posterior band
axillary pouch

17. Restraints to External Rotation
Dependent on arm position:
00 - SGHL, C-H & subscapularis
450 - SGHL & MGHL
900 - anterior band IGHLC

18. Restraints to Internal Rotation
Dependent on arm position:
00 - posterior band IGHLC
450 - anterior & posterior band IGHLC
900 - anterior & posterior band IGHLC

19. Restraints to Inferior Translation
Dependent on arm position:
00 - SGHL & C-H
900 - IGHLC

20. Scapulothoracic Joint
Region between the anterior scapula and thoracic wall.
Functions of muscles attaching to scapula:
Contract to stabilize shoulder region
Facilitate movements of the upper extremity through appropriate positioning of the Glenohumeral joint.

21. Movements of the Shoulder Complex
Humerus movement usually involves some movement at all three shoulder joints
Positioning further facilitated by motions of spine
Scapulohumeral Rhythm

22. Scapulohumeral Rhythm
The ratio has considerable variation among individuals but is commonly accepted to be 2:1 (2 of glenohumeral motion to 1 of scapular rotation) overall motion.
During the setting phase (0 to 30 abduction, 0 to 60 flexion), motion is primarily at the glenohumeral joint, whereas the scapula seeks a stable position.
During the mid-range of humeral motion, the scapula has greater motion, approaching a 1:1 ratio with the humerus
later in the range, the glenohumeral joint again dominates the motion

24. Movements of the Shoulder Complex
Muscles of the Scapula
Muscles of the Glenohumeral Joint
Flexion
Extension
Abduction
Adduction
Medial and Lateral Rotation of the Humerus
Horizontal Adduction and Abduction at the Glenohumeral Joint

25. Horizontal Adduction and Abduction at the Glenohumeral Joint
HORIZONTAL ADDUCTION: Anterior to joint:
Pectoralis major (both heads), anterior deltoid, Coracobrachialis
Assisted by short head of biceps brachii
HORIZONTAL ABDUCTION: Posterior to joint:
Middle and posterior deltoid, infraspinatus, teres minor
Assisted by teres major, Latissimus dorsi

26. Loads on the Shoulder
Shoulder joint has to bear most of the weight amongst all other articulations of the shoulder girdle
Shoulder has to provide direct mechanical support
Large leverage
More compressive forces on the shoulder joint
Deltoid produces upward shear forces as compared to rotator cuff which produces downward shear forces.

27. Arm Abduction and Flexion27

28. Muscle Action on the Shoulder Girdle28

29. Loads on the Shoulder Arm segment moment arm:
Perpendicular distance between weight vector and shoulder
Large torques from extended moment arms countered by shoulder muscles
Load reduced by half with maximal elbow flexion

30. Common Shoulder Injuries
Dislocations
Rotator Cuff Damage
Impingement Theory
Subscapular Neuropathy
Rotational Injuries
Ectopic calcification
Hardening of organic tissue through deposit of calcium salts in areas away from the normal sites

31. Subscapular Neuropathy
The typical patient is a young overhead athlete who reports vague posterior shoulder pain. Although, the athlete can have painless atropy presenting as supraspinatus and/or infraspinatus weakness, depending on the location of the suprascapular nerve.
Because of the anatomy (see Functional Anatomy), more distal nerve injuries are often relatively painless. In particular, nerve injuries at the spinoglenoid notch that result in selective denervation of the infraspinatus muscle may be painless condition..
Based on anatomic considerations, athletes with more proximal lesions of the suprascapular nerve that affect both the supraspinatus and infraspinatus muscles are more likely to have pain and symptom- limited function.

32. Dislocations
Loose structure of shoulder leads to extreme mobility = less stability
It may be Posterior, Anterior or inferior dislocation
Mechanism??////
Contact sports
Glenohumeral capsular laxity
Strengthening of shoulder musculature
posterior dislocations that combines flexion, adduction, and internal rotation, such as falling on an outstretched arm. Ant.dislocation:abduction and external rotation forces .

33. Anterior dislocation

34. Elbow Articulations Humeroulnar Joint Humeroradial Joint
True elbow joint
Strong bony configuration
Hinge joint
Humeroradial Joint
Slides along capitulum
Modified ball and socket joint
Provides no ABD or ADD
Proximal Radioulnar Joint
Annular ligament
Movements
Interosseous membrane

35. Joint Capsule Anterior Posterior Medial Lateral Large, loose and weak
Reinforced by other ligaments

36. Loads on the Elbow
Large loads generate by muscles that cross elbow during forceful pitching/throwing
Also in weight lifting, gymnastics
Extensor moment arm shorter than flexor moment arm
Tricep attachment to ulna closer to elbow joint center than those of the brachialis on ulna an biceps on radius
Moment arm also varies with position of elbow

37. Wrist and Hand Bones Wrist Scaphoid Lunate Triquetrium Pisiform
Trapezium
Trapezoid
Capitate
Hamate

38. Wrist and Hand Bones Hand Metacarpals Phalanges 2-5 Proximal Middle
Distal
Phalange 1 (Thumb)

39. Closer Look at the Carpal Tunnel
Structures within Tunnel
FDS
FDP
FPL
Median Nerve

40. Movements of the Wrist Sagittal and frontal plane movements
Rotary motion
Flexion
Extension and Hyperextension
Radial Deviation
Ulnar Deviation

41. Joint Structure of the Hand
Carpometacarpal (CM)
Metacarpophalangeal (MP)
Interphalangeal (IP)

42. Common Injuries of the Wrist and Hand
Sprains and strains fairly common, due to breaking a fall on hyperextended wrist
Certain injuries characteristic of sport type
Metacarpal fractures and football
Ulnar collateral ligament and hockey
Wrist fracture and skate/snowboarding
Wrist in non-dominant hand for golfers
Carpal Tunnel Syndrome

43. Swan neck deformity=== mallet finger Boutonniere deformity
Swan neck:t (DIP Phyperflexion with PIP hyperextension).  BUTTONAIRE:way (PIP flexion with DIP hyperextension). It

44. Mallet finger
In medicine, mallet finger, also baseball finger,[1] dropped finger, dolphin finger, "Virgin Finger", "Hannan Finger" and (more generally) extensor tendon injury, is an injury of the extensor digitorum tendon of the fingers at the distal interphalangeal joint (DIP).[2] It results fromhyperflexion of the extensor digitorum tendon, and usually occurs when a ball (such as a softball,basketball, or volleyball), while being caught, hits an outstretched finger and jams it - creating a ruptured or stretched extensor digitorum tendon.