This presentation describes the anatomy of the shoulder. It discusses all the bones that make up the shoulder joint and also the muscles that are embedded in those bones. It further discusses the blood supply and innervation to those muscles.
4. GLENOHUMERAL JOINT
Most commonly dislocated joint
Synovial multiaxial “ball & socket” joint
Between head of humerus and glenoid cavity of scapula
Accommodates one third of the humerus head
Mobility gained at the expense of stability
Stability depends on the surrounding muscular and soft tissue
5. GLENOID LABRUM
Fibrocartilaginous rim
Triangular in section
Base attached to margin
of the fossa
Free inner edge as
continuation of curve of
glenoid cavity
6. GLENOID LABRUM CONTD..
FUNCTION
Deepens the glenoid cavity
Protects the edges of bone
Acts as a lubricant
7. ARTICULATING SURFACES
Reciprocally curved and ovoids
The area of the humeral convexity exceeds that of the glenoid concavity
Remaining articular surface in contact with the capsule and contact on
glenoid fossa is more uniformly distributed over its entire articular surface
Articular surfaces covered by hyaline cartilage
thickest centrally, thinner peripherally over the humerus and the
reverse in the glenoid cavity
9. MOBILITY AND STABILITY
Factors contributing to mobility
Type of joint – Ball and socket
Bony surfaces – Shallow glenoid cavity and large humeral
head
Laxity of the joint capsule
10. MOBILITY AND STABILITY CONTD
Factors contributing to stability
Rotator cuff muscles
Surround the shoulder joint
Attached to the tubercles of the humerus and joint capsule
Resting tone act to ‘pull’the humeral head into the glenoid cavity
Glenoid labrum
Ligaments – The ligaments act to reinforce the joint capsule and forms
the coraco-acromial arch
12. MUSCLES SUPPORTING THE CAPSULE
Superiorly Supraspinatus
Inferiorly Long Head of
Triceps
Posteriorly Tendons of
Infraspinatus and Teres Minor
Anteriorly Tendon of
Subscapularis
13. OPENINGS IN THE FIBROUS CAPSULE
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 tendon
Posteriorly
Not constant where a
communication exists
between joint and a bursal
sac belonging to
Infraspinatus muscle
14. SYNOVIAL MEMBRANE
Lines the inner surface of the
fibrous capsule
At humerus covers the anatomical
neck upto margin of the articular
surface of humerus head and
medially a part of shaft below the
epiphyseal line
At glenoid goes to margin and
covers both surfaces of glenoidal
labrum
Communicates with subscapular
bursa or infraspinatus bursa
15. BURSA AROUND GH JOINT
1. Acromial: upper surface of
acromian process
2. Subacromial: inferiorly to the
deltoid and acromion
3. Subcoracoid bursa
4. Infraspinatus bursa
5. Subscapular bursa: between the
subscapularis tendon and
scapula
16. LIGAMENTS OF THE SHOULDER JOINT
Act as static stabilisers
Three in numbers
Glenohumeral (superior,
middle and inferior)
Coraco humeral
Transverse humeral
17. GLENOHUMERAL LIGAMENT
Three fibrous bands derived from thickening
of the anterior part of fibrous capsule
All 3 Converge upward and medially blend
with glenoid labrum:
SUPERIOR BAND : attached to the upper
end of lesser tubercle
MIDDLE BAND : attached to lower part of
lesser tubercle
INFERIOR BAND : lower part of
anatomical neck of humerus
18. TRANSVERSE HUMERAL LIGAMENT
Broad band of fibrous
tissues
Connects the two lips of
the upper part of
intertubercular sulcus
Acts as a retinaculum to
keep the long tendon of
biceps in position
19. CORACO-HUMERAL LIGAMENT
Broad thick Band
Strengthens Upper part of
Capsular Ligament
Attachments
Arises from outer border of
coracoid process
Blended with tendon of
supraspinatus muscles
United to capsule in greater
part of its extend.
21. NERVE SUPPLY
Glenohumeral joint
Posterior cord of the
brachial plexus
Capsule
Suprascapular nerve
(posterior and superior parts)
Axillary nerve (antero
inferior)
Lateral pectoral nerve (antero
superior)
22. MUSCLES AROUND SHOULDER JOINT
Primary role
a. Movements of arm
b. Dynamic stabilisation of glenohumeral joint
There are 14 muscles divided into 4 functional groups
1. Three heads deltoid (anterior, middle, posterior)
2. Four rotator cuff muscles and biceps muscle
3. Two axio humeral muscles(pectoralis major and latismus dorsi)
and teres major
4. Scapular muscle group –serratus anterior , trapezius, rhomboid
major and minor and levator scapulae
23. 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
25. FLEXION
Plane of Motion:
Sagittal Plane
Axis of Motion:
Transverse Axis through the
center of the humeral head
Muscles Involved:
Pectoralis major
Anterior Fibres of Deltoid
Coracobrachialis
Biceps (when the forearm is
flexed)
Range of Motion
0 – 170 degrees
26. EXTENSION
Plane of Motion:
Sagittal Plane
Axis of Motion:
Transverse Axis through the
center of the humeral head
Muscles Involve:
Latissimus dorsi
Teres major
Posterior fibers of Deltoid
Triceps (When forearm is
extended)
Range of Motion
0 – 60 degrees
27. ABDUCTION
Plane of Motion:
Frontal Plane
Axis of Motion:
Sagittal axis through the centre of the
humeral head
Muscles Involve:
Deltoid
Supraspinatus
Range of Motion
Total : 0 – 170 degrees
28. ADDUCTION
Plane of Motion:
Frontal Plane
Axis of Motion:
Sagittal axis through the centre of the
humeral head
Muscles Involve:
Subscapularis
Pectoralis Major
Latissimus dorsi
Teres major
29. INTERNAL ROTATION
Plane of Motion:
Transverse Plane
Axis of Motion:
Vertical axis through the centre of
humeral head
Muscles Involve:
Subscapularis
Pectoralis Major
Latissimus dorsi
Teres major
Range of Motion:
0-70º as the arm at 90º of shoulder
abduction and 90º elbow flexion
0-60° if abduction not possible
30. EXTERNAL ROTATION
Plane of Motion:
Transverse Plane
Axis of Motion:
Vertical axis through the center
of humeral head
Muscles Involve:
Infraspinatus
Teres Minor
Range of Motion
0-90º as the arm at 90º of
shoulder abduction and 90º
elbow flexion
0-80° if abduction not possible
31. CIRCUMDUCTION
A combination of flexion, abduction, extension, and adduction or in the reverse
sequence.
Occurs in a cone whose apex is the head of humerus
glenohumeral flexion abduction extension adduction
glenohumeral extension abduction flexion adduction
32. SCAPULOHUMERAL RHYTHM
The first 30 degrees
At gleno-humeral joint with slight movement of clavicle
From 30 to 120 degrees
1/3 of movement coming from scapula rotating on thorax
From 120 to 180 degrees
Movement mainly scapulo-thoracic
Sterno-clavicular joint participates in movements close to the trunk
Acromioclavicular joint moves in the last 60 degrees of abduction
33. ROTATOR CUFF
Group of four muscles to hold the head of humerus into the glenoid fossa
They are
Supraspinatus
Teres Minor
Infraspinatus
Subscapularis
34. FUNCTION OF ROTATOR CUFF
Important in movements and maintaining joint stability
Abduction: Concavity compression
Rotator cuff muscles also perform
Abduction
Internal rotation
External rotation of the shoulder