Anatomy and biomechanics of Sternoclavicular joint Acromioclavicular joint Glenohumeral joint kinematics movement of shoulder joint kinetics

1. BIOMECHANICS OF THE
SHOULDER JOINT COMPLEX
Dr. SYED ADIL - MPT (MUSCULOSKELETAL)

2. • Shoulder joint is the complex joint compised of clavicle,
humerus and scapula.
• It links the upper extremity to the axial skeleton/thorax.

3. • It consists of three joints –
1. Sternoclavicular joint
2. Acromioclavicular joint
3. Glenohumeral joint

4. Sternoclavicular joint
• Sc joint is fine by the medial end of the clavicle and
superolateral surface of the manubrium.
• Type - True synovial joint
• It has a fibrocartilaginous articular disc that divide into 2
compartment.

5. • Upper and lower portion
• Upper portion of the disc is attached to the posterosuperior aspect of
clavicle
• lower portion is attached to the manubrium and first costal cartilage.
• During shoulder motion, disc acts like a hinge or a pivot point for
medial end of clavicle.

6. Ligaments –
• Sternoclavicular ligament
• Interclavicular ligament
• Costoclavicular ligament

7. Kinematics
• There are three rotatory degrees of freedom-
1. Elevation/ depression (around A-P axis )
• Convex side of clavicle moves on the concave notch of
manubrium
• With elevation lateral end of clavicle rolls upward medial
side of clavicle slides downward.
• In depression lateral end of clavicle rolls downward medial
side of clavicle slides upward.
• ROM – elevation 48 degree, depression less than 15 degree

9. 2. Protraction/ retraction ( vertical axis )
• With protraction lateral end of clavicle move anterior or in
retraction move posterior .
• Concave side of clavicle moves on the convex part of
manubrium
• ROM- protraction 15-20 degree, retraction 30 degree or
more

12. 3. Anterior/ posterior rotation ( longitudinal axis )
• Rotation of the clavicle Occurs as a spine between the
saddle shape surface of medial Clavical and manubrium
• The clavicle rotates posteriorly bringing the inferior surface
of the clavicle to face anteriorly.
• The clavicle rotate anteriorly bringing the superior surface to
fae anteriorly.
ROM
• Anterior <10 degree
• Posterior -50 degree

14. ACROMIOCLAVICULAR JOINT

15. • Between the lateral end of the clavicle and the acromian of
scapula.
• Type- synovial joint
• Articular disc- present
• Articular disc : it is present to give cushaning effect and take
the forcess and act as a meniscoid disc
• Ligamentss are – superior and inferior AC ligament,
coracoclavicular ligament ( conoid and trapezoid part )

16. • Capsule of AC joint is weak and can not maintain integrity of joint
without reinforcement from 3 ligament

18. Kinematics
Mobility of AC joint allow the scapula to move in 3 dimensions .
3 rotatory movement :
• internal /external rotation
• anterior/ posterior tilting
• Upward / downward rotation

19. INTERNAL AND EXTERNAL ROTATION
• In internal rotation glenoid is coming anteromedially
• In external rotation it is going posteriorly
• Smaller value (20 to 35) degree have been present
during arm motion.
• Up to 40 to 60 degree may be possible with full range of
motion reaching forward and across the body

21. ANTERIOR AND POSTERIOR TILTING:
• Anterior /posterior tilting of the scapula in relation to the clavicle
around in oblique coronal axis
• Anterior tilting result in acromion tilt forward and inferior angle tilting
backwards .
• Posteriorly tilting rotates the acromion backward and inferior angle
forward
• Elevation or the shoulder shrugging can result in anterior tilting
• In flexion or abduction of the arm the scapula till posteriorly on the
thorax

23. UPWARD AND DOWNWARD ROTATION.
• It is occur around an oblique AP axis .
• upward rotation moves the glenoid fossa upward
• downward rotation move the glenoid fossa downward .
• available PROM into upward downward rotation at
acromioclavicular joint is limited by the attachment of
coracoclavicular ligament
• Upward = 30 degree
• Downward= 17 degree of rotation

25. SCAPULOTHORAcIC JOINT

26. SCAPULOTHORACIC JOINT
• Scapulothoracic joint is formed by articulation of scapula with
thorax
• It is false joint there is no proper articulation between joint
• Scapulothoracic joint depend on Acromioclavicular and
Sternoclavicular joint and it is important for smooth motion of
scapula

27. POSITION
• 2 inches away from midline
• present between 2 to 7 th rib
• internal rotation is about 30 to
45 degree from coronal plane
• upward rotation is about 5 to 10
degree

28. MOTION
primary and secondary
1- In primary :
• elevation depression
• protraction retraction
• upward and downward rotation
2- In Secondary :
• Internal and external rotation
• Anterior and posterior tipping

29. ELEVATION AND DEPRESSION
• scapular elevation depression can be isolated by shrugging of
shoulder up and dressing the shoulder down .
• elevation and depression of scapula on the thorax commonly
describe as translatory motion.

30. PROTRACTION AND RETRACTION
• protraction and retraction of scapula on the thorax are described as
translatory motion away from or towards the vertebral column
• In protraction or abduction of scapula on the thorax occur pure
translatory movement, glenoid fossa facing anteriorly , retraction
glenoid fossa facing posteriorly

32. UPWARD AND DOWNWARD ROTATION
Motion of scapula of observed during
active elevation of arm.
• ROM is around 50 to 60 degree of
upward rotation of scapula on the
thorax.

33. INTERNAL AND EXTERNAL ROTATION
• internal and external rotation of scapula accompany protraction and
retraction of clavicle at sternoclavicular joint
• 15 to 16 degree of internal rotation occur at acromioclavicular joint
during normal elevation of arm.
• large amount of internal rotation at scapula that result in prominence
of vertebral border of scapula and loss of contact with thorax and
refered as scapular winging

35. ANTERIOR POSTERIOR TILTING
• Scapulothoracic anterior and posterior tilting coupled with elevation
and depression of clavicle at sternoclavicular joint
• Anterior tilting will result in prominence of inferior angle of scapula

36. GLENOHUMERAL JOINT
• Gleno-humeral joint made up of glenoid fossa of scapula and head of
humerus.
• Glenoid fossa is facing laterally upward and 6 to 7 degree retroverted
facing posteriorly
• Humeral head faces medially superiorly and posteriorly with regard to
shaft of the humerus and humoral condyle

37. • Angles:
• Angle of inclination
• angle of torsion
1. Angle of inclination: is the angle
between shaft and neck of
humerus it is normally 130 to 150
degree

38. 2. Angle of torsion: is formed by
an axis through humeral head
and neck in relation to an axis
through the humeral condyle .
• Average angle of torsion is 56
degree and retroversion is 33
degree

39. KINEMATICS
• Flexion
• Extension
• Abduction
• Addiction
• External rotation
• Internal rotation

40. Flexion/extension
• ROM –
• Flexion : 120 degree
• Extension : 50 degree
• Frontal axis / Sagittal plane
• During flexion humerus Rolls superiorly glids inferiorly

41. Abduction / Adduction
• ROM –
• 120 degree
• Sagittal axis / frontal plane
• In Abduction,
• During abduction humerus Rolls superiorly glids inferiorly

42. Medial / Lateral rotation
• ROM –
• Internal rotation - 70 degree
• External rotation – 90 degree
• Vertical axis / transverse plane

43. Thank you