Anatomy of Shoulder Joint

1. The Shoulder
Joint
By : Gan Quan Fu, PT, MSc. Human Anatomy (Batch 3)

2. Content
• Introduction
• Glenoid Cavity
• Ligaments Surrounding the joint
• Bursae in Relation to the Shoulder Joint
• Muscles Acting on Shoulder Joint
• Blood and Nerve Supply
• Joint Movement
• Close and Loose Pack Position
• Applied Anatomy

3. Overview

4. Introduction
• Enarthrodial or Ball-and-Socket joint
• Bones Involve
o Large globular head of humerus
o Glenoid cavity of scapula
• Protected against displacement by
tendons and by atmospheric pressure.
• Ligaments around gleno-humeral joint;
Limit the amount of joint movement
o Capsular
o Coracohumeral
o Transverse Humeral
o Glenoid Ligament
• Above protected by arched vault
formed by:
o Under surface of coracoid process
o Under surface of acromion process
o Coraco-acromial ligament

5. Glenoid Cavity
• Pear Shape
• Shallow
• Directed Laterally and
Upward
• Only1/3rd of the humeral
head comes in contact
with the glenoid cavity at
any position.
• Glenoid Fossa is
deepened by a fibro-
cartilaginous rim of
Glenoid labrum.

6. ARTICULATING
SURFACE

8. Capsular Ligament
• Encircles entire
glenohumeral joint.
• Attached:
o Medially: Above to the
circumference of glenoid
cavity beyond the
glenoid ligament
o Laterally: Below to
anatomical neck of the
humerus
• Thicker above and below.
• Loose and lax
• Allow bone to be
separated from each
other more than an inch

9. Muscles Supporting
Capsular Ligament
• Superiorly 
Supraspinatus
• Inferiorly  Long Head
of Triceps
• Posteriorly  Tendons of
Infraspinatus and Teres
Minor
• Anteriorly  Tendon of
Subscapularis

10. Openings of Capsular
Ligament
3 Openings
o Anteriorly
• Below coracoid Process,
connection between
synovial membrane of the
joint and a bursa beneath
the tendon of subscapularis
muscle.
• Between the 2 tuberosities,
passage of the biceps long
head.
o Posteriorly
• Not constant, where a
communication exists
between joint and a bursal
sac belonging to
Infraspinatus muscle.

11. Supplemental Bands of
Capsular Ligament
• Strengthen capsular ligament in the interior of the
joint.
• Flood’s Ligaments
o Situated on inner side of joint
o Passes from inner edge of glenoid cavity
o Attached to lower part of lesser tuberosity of humerus.
• Schlemm’s Ligaments
o Situated at lower part of the joint
o Passes from under edge of glenoid cavity
o Attached to under part of neck of humerus
• Glenohumeral Ligaments
o Situated at upper part of the joints, projects into its interior (can only be
seen when capsule is open). Attached above apex of glenoid cavity
close to root of coracoid process, attached below lesser tuberosity of
humerus (Forms inner boundary of upper part of bicipital groove)

12. Glenohumeral Ligaments
• 3 fibrous bands derived from
thickening of the anterior
part of fibrous capsule.
• All 3 Converge upward and
medially blend with glenoid
labrum:
o SUPERIOR BAND :
attached to the upper
end of lesser tubercle
o MIDDLE BAND : attached
to lower part of lesser
tubercle
o INFERIOR BAND : lower
part of anatomical neck
of humerus.

13. CORACO-HUMERAL LIGAMENT
• Broad Thick Band
• Strengthens Upper
part of Capsular
Ligament
• Attachments
o Arises from outer border of
coracoid process
o Blended with tendon of
supraspinatus muscles
• United to capsule in
greater part of its
extend.

14. TRANSVERSE HUMERAL
LIGAMENT
• Broad band of fibrous
tissues
• Connects the two lips of
the upper part of
intertubercular sulcus and
acts as a retinaculum to
keep the long tendon of
biceps in position.

15. GLENOID LABRUM
• Fibro-cartilage rim
attached around
margin of glenoid
cavity.
• Triangular on section
• Thickest portion at
circumference of
cavity, free edge is
sharp and thin
• Continuous above with
long head of biceps
• Deepens cavity for
articulation and
protects edges of bone
• Lined by synovial
membrane

16. SYNOVIAL MEMBRANE
• Reflected from
margin of glenoid
cavity over fibro-
cartilaginous rim
surrounding it.
• Over internal surface
of capsular ligaments.
• Covers lower part
and sides of
anatomical neck of
humerus.

18. BURSAE IN RELATION TO THE SHOULDER
JOINT
1) SUBSCAPULAR
BURSA
2) INFRASPINATUS
BURSA
3) SUBACROMIAL
BURSA
(SUBDELTOID)
4) SUBCORACOID
BURSA

19. BURSA
• SUBSCAPULAR BURSA
Intervenes between the tendon of subscapularis and fibrous capsule.
Communicates with the joint cavity through oval gap between superior
and middle glenohumeral ligaments.
• Infraspinatus bursa
Communicates with the joint from behind
• Subacromial bursa
Largest bursa of the body intervenes between supraspinatus and coraco-
acromial arch.
It does not communicate with the joint.
It is of great value in the abduction of arm at the shoulder joint where is
protects the supraspinatus tendon against friction with the acromion

21. Muscles in Relation to the
Joint
• Above  Supraspinatus
• Below  Long head of
Triceps
• Front  Subscapularis
• Behind  Infraspinatus and
Teres Minor
• Deltoid is placed most
externally and covers the
articulation from its outer
side, as well as in front and
behind.

23. Blood and Nerve Supply
• Blood Supply
1.Anterior circumflex humeral
vessels
2.Posterior circumflex humeral
vessels
3.Suprascapular vessels
• NERVE SUPPLY
1) Axillary nerve
2) Musculocutaneous
nerve
3) Suprascapular Nerve
4) Lateral pectoral nerve

24. Summary on Should Joint
Anatomy

26. MOVEMENTS AT THE SHOULDER
JOINTS
• Movement in every direction (Flexion, extension, abduction,
adduction, rotation, circumduction)
• Highly mobile due to:
o Large size of head of humerus in comparison with the depth of
glenoid cavity (Even when supplemented by glenoid ligament)
o Looseness of the capsule of the joint (Laxity of fibrous capsule)
o When movements of arm are arrested by contact of the bony
surface  Tension of corresponding fibers and muscles acting on
accessory ligaments farther movements of scapula and
accessory structures to the shoulder joint (acromio and sterno-
clavicular joints).
• Spinal Cord regulating Shoulder movements (C5, C6, C7 & C8)
o Flexion, Abduction, & lateral rotation (C5, C6,).
o Extension, Adduction, & Medial rotation is (C6, C7, C8)

27. Osteo- & Arthrokinematics of
Shoulder Joint
• Osteokinematics
o Flexion
o Extension
o Hyperextension
o Abduction
o Adduction
o Medial rotation (internal rotation)
o Lateral rotation (external rotation)
o Horizontal abduction
o Horizontal adduction
o Circumduction
• Concave-convex rule
o Convex humeral head moves within the concave glenoid fossa
o The Convex joint surface (Humeral Head) moves in a direction opposite to
the movement of the body segment (Humeral Shaft)

28. Flexion
• Plane of Motion:
o Sagittal Plane
• Axis of Motion:
o Transverse Axis through the center of the
humeral head
• Muscles Involved:
o Pectoris major
o Anterior Fibres od Deltoid
o Coraco-brachialis
o Biceps (When the foreare is flexed)
• Humeral head glides posterior
laterally in the glenoid cavity
• Range of Motion
o 0 – 90 degrees

29. Factors Limiting Shoulder
Flexion
• Inferior Glenohumeral ligament
• Tightness of posterior joint capsule

30. Extension
• Plane of Motion:
o Sagittal Plane
• Axis of Motion:
o Transverse Axis through the center of
the humeral head
• Muscles Involve:
o Latissimus dorsi
o Teres major
o Posterior fibers of Deltoid
o Triceps (When forearm is extended)
• Humeral head glide anterior
medially in glenoid cavity
• Range of Motion
o 0 – 45 degrees or 60 degrees

31. Factors Limiting Shoulder
Extension
• Superior and medial gleno-humeral ligament

32. Abduction
• Plane of Motion:
o Frontal Plane
• Axis of Motion:
o Sagittal axis through the center of the
humeral head
• Muscles Involve:
o Deltoid
o Supraspinatus
• Humeral head glide inferiorly in
glenoid cavity
• Range of Motion
o Total : 0 – 165 degrees or 175 degrees
o Full internal rotation of humerus: 0 – 60
degrees
o Full external rotation of Humerus: 0 – 90
degrees

33. Factors Limiting Shoulder
Abduction
• Inferior glenohumeral ligament
• Tightness of the inferior joint capsule of the
glenoumeral joint

34. Adduction
• Plane of Motion:
o Frontal Plane
• Axis of Motion:
o Sagittal axis through the center of the
humeral head
• Muscles Involve:
o Subscapularis
o Pectoralis Major
o Latissimus dorsi
o Teres major
• Humeral head glide
superiorly in glenoid cavity
• Factors Limiting:
o Trunk

35. Internal Rotation
• Plane of Motion:
o Transverse Plane
• Axis of Motion:
o Vertical axis through the center of humeral
head
• Muscles Involve:
o Subscapularis
o Pectoralis Major
o Latissimus dorsi
o Teres major
• Humeral head glide
posteriorlaterally in glenoid
cavity
• Range of Motion
o 0-70º as the arm at 90º of shoulder
abduction and 90º elbow flexion
o If the elbow is extended, shoulder rotation
occurs simultaneously with forearm
rotation.

36. Factors Limiting Internal
Rotation
• Posterior Capsule

37. External Rotation
• Plane of Motion:
o Transverse Plane
• Axis of Motion:
o Vertical axis through the center of
humeral head
• Muscles Involve:
o Infraspinatus
o Teres Minor
• Humeral head glide
anteriomedially in glenoid
cavity
• Range of Motion
o 0-90º as the arm at 90º of shoulder
abduction and 90º elbow flexion
o If the elbow is extended, shoulder rotation
occurs simultaneously with forearm
rotation.

38. Factors Limiting External
Rotation
• Coracohumeral ligament
• 3 glenohumeral ligaments

39. Circumduction
• A combination of flexion, abduction, extension,
and adduction or in the reversed sequence
o glenohumeral flexion  abduction  extension  adduction
o glenohumeral extension  abduction  flexion  adduction

41. Close and Loose Packed
Position
• Close Packed position
o Position where the articular
surfaces of joint are in maximal
congruency status, resulting in
greatest mechanical stability.
o Most ligament and capsule
surrounding joint are taut.
o 90° of glenohumeral abduction
and full external rotation
• Loose Packed position
o Position where the articular
surface of joint are in minimal
congruency status.
o Supporting structures are most
lax.
o 55° of semi-abduction and 30°
of horizontal adduction

43. Dislocation
• Humeral head is hold in place
by the Rotator cuff (S,I,T,S)
Muscles.
• Humeral Head separated from
scapula at glenohumeral joint.
• Commonly downward
dislocation because Rotator
Cuff protects joints in all
direction except inferiorly.
• Hemiparesis/Hemiplegia
patients prone to dislocate
their shoulder  their Rotator
cuff muscles are weak to hold
the shoulder joint in place.

44. Adhesive Capsulitis
• Frozen Shoulder
• Pain and Stiffness in the
Shoulder
• Shoulder capsule thickens and
becomes tight. Stiff bands of
tissue — called adhesions —
develop. In many cases, there
is less synovial fluid in the joint.
• Unable to move your shoulder
- either on your own or with
the help of someone else.

45. Stages of Adhesive
Capsulitis
• It develops in three stages:
o Freezing (Pain worsens, shoulder loses range of
motion. Typically lasts from 6 weeks to 9 months.)
o Frozen (Painful symptoms may actually improve
during this stage, but the stiffness remains. During
the 4 to 6 months of the "frozen" stage, daily
activities may be very difficult.)
o Thawing (Shoulder motion slowly improves.
Complete return to normal or close to normal
strength and motion. Typically takes from 6
months to 2 years.)

46. SLAP LESION
• Injury to the labrum of the
shoulder.
• SLAP = Superior Labrum
Anterior and Posterior.
• In a SLAP injury, the superior
part of the labrum is injured.
This top area is also where
the biceps tendon attaches
to the labrum.
• SLAP tear occurs both in
front (anterior) and back
(posterior) of this attachment
point.
• The biceps tendon can be
involved in the injury as well.

47. Bankart Lesion
• Tear of the labrum and
attached joint capsule along
the anterior inferior quadrant
of the Glenoid
ligament/Inferior
glenohumeral ligament.
• Associated with shoulder
dislocation.
• Bony Bankart is when some of
the glenoid bone is broken off
with the anterior inferior
labrum (Shoulder joint more
unstable than Bankart Tear)

48. Shoulder Bursitis
• Inflammation of shoulder
Bursa
• Commonly Subacromion
Bursa
o Usually related to shoulder
impingement of Subacromion Bursa
between rotator cuff tendon and
acromion
• Subdeltoid bursa less
commonly inflammed
• Commonly co-exists with
rotator cuff tears or
tendonitis

49. Surgical Intervention
• Front of the shoulder joint is
commonly approached for
surgical intervention
• Aspiration needle maybe
introduced through deltopectoral
triangle (closer to deltoid)

50. References
• Gray, H. (2012) Gray’s Anatomy; The classic
Anatomical Handbook for Doctors, Students and
Artist, 15th edn. London; Bounty Books.
• Saladin, K. S. (2007) Anatomy and Physiology: The
Unity of Form and Function. 4th edn. New York;
McGraw-Hill.