Shoulder joint (Biomechanics, Anatomy, Kinesiology) by Muhammad Arslan Yasin, Anatomy Of Shoulder Joint, Muscles Of Shoulder Joint, Biomechanics Of Shoulder Joint, Common Injuries Of Shoulder Joint.

2. Shoulder Join
Topic:
Presenters:
MuhammadArslan Yasin
MuhammadHizqail
Umair Khilji

3. Learning Outcomes:
Anatomy Of Shoulder Joint
Muscles Of Shoulder Joint
Movements At Shoulder Joint
Biomechanics / Loads on The
Shoulder
Common Injuries of the Shoulder

4. “The shoulder is a large joint between the head
of humerus and glenoid fossa of scapula”.
Type: Ball and socket type of synovial joint
Articular surfaces are formed by
1. The head of humerus which is less than half
sphere and is covered by hyaline articular
cartilages.
2. The glenoid fossa of scapula is pear-shaped
and shallow and much smaller than head of
humerus
Shoulder Joint

5. Main
Features
Greater
Mobility
Lesser
Stability
Due to five separate
articulations
Due to small glenoid cavity
Proportion of head of
humerus to glenoid cavity is
4:1

6. Factors Maintaining Stability
1. Coracoacromial Arch
2. Musculotendinous Cuff (Rotator Cuff)
3. Glenoid Labrum
4. Muscles of Pectoral Girdle (Pectoralis Major)
5. Atmospheric Pressure

7. Coracoacromial Arch
B/W Coracoid and Acromion process
Secondary Socket
Prevent Upward Dislocation

8. Rim of soft tissue located on the periphery of
the glenoid fossa that adds stability to the
glenohumeral joint.
Glenoid labrum
Long head of biceps

9. Band of tendons of the, the subscapularis,
supraspinatus, infraspinatus, and teres minor,
which attach to the humeral head.
¹
² ³ ⁴
Medial rotation=1
Lateral rotation=2,3&4
Movement
Rotator cuff (Musculotendinous Cuff)

10. Muscles of Pectoral Girdle
(Pectoralis Major)
Atmospheric Pressure
Help in the stability of Shoulder Joint

11. Ligaments
1. Glenoid Labrum
2. Capsule
3. Coracoacromial ligament
4. Coracohumeral ligament
5. Transverse Humeral Ligament
6. Glenohumeral ligament

12. Surrounds the joint.
The capsule has two openings:
1. Opening for subscapular bursa
anteriorly.
2. Opening between two tuberosities
for giving passage to long tendon of
biceps brachii.
Articular capsule

13. The coraco-acromial ligament is triangular in shape and
extends between the tip of acromion and lateral border of
coracoid process.
Coraco-acromial ligament

14. The coracohumeral ligament extends between
the inferior surface of coracoid process and the
two tuberosities of humerus
Coracohumeral ligament

15. The transverse humeral ligament bridges the
gap between the two tuberosities of humerus,
through which the long tendon of biceps brachii
passes
Transverse humeral ligament

16. Glenohumeral ligament
Strengthens Capsule
Comprises of three parts:
I. Superior
II. Middle
III. Inferrior

18. Bursae
1.The sub-acromial bursa separates acromion process
from insertion of supraspinatus. Inflammation of this
bursa leads to painful abduction at shoulder joint.
2. The sub-scapular bursa lies deep to the tendon of
subscapularis.
3. The sub-deltoid bursa separates the deltoid muscle
with rotator cuff.
4. The infra-spinatus bursa lies deep to the tendon of
infraspinatus. It sometimes communicates with joint
cavity.
5. The synovial sheath of long tendon of biceps brachii
is an extension of synovial membrane of shoulder
joint.

20. Nerve Supply of joint:
-The axillary nerve
-The suprascapular nerve
-The lateral pectoral nerve
Arterial Supply of joint:
-The anterior & posterior circumflex humeral arteries
-The suprascapular artery

21. Important Relations
■ Anteriorly: The subscapularis muscle and the
axillary vessels and brachial plexus
■ Posteriorly: The infraspinatus and teres minor
muscles
■ Superiorly: The supraspinatus muscle,
subacromial bursa, coracoacromial ligament,
and deltoid muscle
■ Inferiorly: The long head of the triceps muscle,
the axillary nerve, and the posterior circumflex
humeral vessels.

22. Superior
Anterior
Inferior

23. The glenohumeral joint is considered to be the
shoulder joint.
The shoulder joint
The shoulder is the most complex joint in the
human body, largely because it includes five
separate articulations:
The glenohumeral joint
The sternoclavicular joint
The acromioclavicular joint
The coracoclavicular joint
The scapulothoracic joint

24. Sternoclavicular Joint
Sternoclavicular joint modified
ball-and-socket joint between
the proximal clavicle and the
manubrium of the sternum.
The clavicles and the scapulae
make up the shoulder girdle.
Most of the motion of the
shoulder girdle takes place at the
sternoclavicular joints.

25. Acromioclavicular Joint
Acromioclavicular joint irregular joint
between the acromion process of the
scapula and the distal clavicle.

26. Coracoclavicular Joint
Coracoclavicular joint syndesmosis with
the coracoid process of the scapula bound
to the inferior clavicle by the
coracoclavicular ligament.

27. Scapulothoracic Joint
The region between the anterior scapula and
the thoracic wall is sometimes referred to as
the scapulothoracic joint.

28. Glenohumeral joint ball-and-socket joint in which the
head of the humerus articulates with the glenoid fossa
of the scapula.
Glenohumeral Joint

29. Scapulohumeral Rhythm a regular pattern
of scapular rotation that accompanies and
facilitates humeral abduction.

30. Movements of Shoulder Joint:
Shoulder Joint
Extension
AbductionAdduction
Flexion
Medial Rotation
Lateral Rotation Lateral Rotation
Medial Rotation
Extension Abduction
Flexion AbductionFlexion Adduction
Extension Adduction

31. The shoulder joint is the most mobile joint of the body
– The factors responsible for mobility are
laxity of the capsule and large articular
surface of head as compared with glenoid
cavity.
The shoulder joint is multiaxial joint with movements
ocurring around three axes.
i. Around an antero-posterior axis abduction and adduction take
place.
ii. Around transverse axis flexion and extension take place.
iii. Around a vertical axis medial and lateral rotation take place.

32. Flexion
The muscles crossing the glenohumeral joint
anteriorly participate in flexion at the shoulder.
The prime flexors are the anterior deltoid and
the clavicular portion of the pectoralis major

33. Extension
When shoulder extension is unresisted, gravitational
force is the primary mover.
When resistance is present, contraction of the
muscles posterior to the glenohumeral joint,
particularly the sternocostal pectoralis, latissimus
dorsi, and teres major, extend the humerus.

34. Abduction
The middle deltoid and supraspinatus are the major
abductors of the humerus. Both muscles cross the
shoulder superior to the glenohumeral joint.

35. Adduction
Adduction in the absence of resistance results
from gravitational force.
With resistance added, the primary adductors are
the latissimus dorsi, teres major, and
sternocostal pectoralis, which are located on the
inferior side of the joint.

36. Medial Rotation
Medial, or inward, rotation of the humerus results
primarily from the action of the subscapularis and
teres major, both attaching to the anterior
side of the humerus

37. Lateral Rotation
Muscles attaching to the posterior aspect of the
humerus,particularly infraspinatus and teres
minor, produce lateral rotation

38. Horizontal Abduction
The major horizontal abductors are the middle and
posterior portions of the deltoid, infraspinatus, and
teres minor, with assistance provided by the teres
major and the latissimus dorsi.

39. Horizontal Adduction
The muscles anterior to the joint, including both
heads of the pectoralis major, the anterior deltoid,
and the coracobrachialis, produce horizontal
adduction, with the short head of the biceps brachii
assisting

40. LOADS ON THE SHOULDER
The glenohumeral joint provides direct mechanical
support for the arm, it sustains much greater loads
than the other shoulder joints.
When analyzing the effect of body position,
we may assume that body weight acts at
the body’s center of gravity.

43. COMMON INJURIES OF THE
SHOULDER
Dislocations
Glenohumeral dislocations typically occur when
the humerus is abducted and externally rotated,
with anterior-inferior dislocations more common
than those in other directions.
The strong coracohumeral ligament usually
prevents displacement in the superior direction.

44. Glenohumeral dislocation may result from sustaining
a large external force during an accident, such as in
cycling, or during participation in a contact sport
such as wrestling or football.
When a glenohumeral joint dislocation occurs, the
supporting soft tissues are often stretched beyond
their elastic limits, thus predisposing the joint to
subsequent dislocations.

45. Rotator Cuff Damage
A common injury among workers and athletes who
engage in forceful overhead movements typically
involving abduction or flexion along with medial
rotation is rotator cuff impingement syndrome.
Symptoms include hypermobility of the anterior
shoulder capsule, hypomobility of the posterior
capsule, excessive external rotation coupled with
limited internal rotation of the humerus, and
general ligamentous laxity of the glenohumeral joint.

46. This can result in inflammation of the underlying
tendons and bursae or, in severe cases, rupture of
one of the rotator cuff tendons.
The muscle most commonly affected is the
supraspinatus, possibly because its blood supply is
the most susceptible to pressure.
This condition is accompanied by pain and tenderness
in the superior and anterior shoulder regions, and
sometimes by associated shoulder weakness.

47. Rotational Injuries
Tears of the labrum, the rotator cuff muscles, and
the biceps brachii tendon are among the injuries
that may result from repeated, forceful rotation at
the shoulder.
Throwing, serving in tennis, and spiking in
volleyball are examples of forceful rotational
movements.

48. Other pathologies of the shoulder attributed to throwing
movements are calcifications of the soft tissues of the joint
and degenerative changes.
Bursitis, the inflammation of one or more bursae, is
another overuse syndrome, generally caused by friction
within the bursa
Ankylosis of shoulder joint may take place in old age with
limitation of movements accompanied by pain.

49. Subscapular Neuropathy
Subscapular nerve palsy, most commonly occurs in
athletes involved in overhead activities and weight
lifting.
The condition arises from compression of the
subscapular nerve, which occurs most commonly at
the suprascapular notch.