Anatomy of shoulder, prepared by Dr.KF, kandahar, Afghanistan

2. Prepared by: Dr.Sayed Abdul Qahir
PGR1, Orthopedic surgery
MRH, Kandahar, Afghanistan
Supervisor: Dr. Niamatullah shehzad
Trainer specialist, Orthopedic surgery
MRH, Kandahar, Afghanistan

3. CONTENTS
1. Surface and bone anatomy
2. Articulations and adjoining structures
3. Ligaments and articulating structures
4. Bursae and relation of shoulder
5. Muscular and neurovascular anatomy
6. Range of motion of shoulder joint
7. References
3

4. 1. Surface and bone
anatomy

5. 1.1. Surface anatomy
 Anteriorly - Clavicle
- Tip of coracoid process of scapula
- Greater tubercle of humerus
- Deltoid counter
- Axilla and its folds
 Posteriorly - Acromion (scapula)
- Crest of spine(scapula)
- Medial and lateral borders (scapula)
- Inferior angle (scapula)
 Medial epicondyle shows head of humerus direction while lateral shows greater
tuberosity direction
5

6. 1.2. Clavicle
 It’s long bone placed horizontally
and is a bridge between upper limb
and trunk
 Clavicle is S shaped and has:
Two borders (Anterior and Posterior)
Two surfaces(superior and inferior)
Two ends {medial(quadrangular) and
lateral (flat)}
 It has no medullary cavity
 It ossifies at 12-19 yrs and fuses at
22-25 years
6
Lateral Medial
Surface for
articulation
with acromion
Superior view
Anterior view
Conoid tubercle
Inferior view
Surface for articulation with
Manubrium sterni and
First costal cartilage
Trapezoid line
Conoid tubercle

7. 1.3. Scapula
 it’s a large flat triangular bone and
has:
Three angles (Lateral, Superior and
Inferior)
Three borders (Superior, Lateral
and medial)
Two surfaces (costal and posterior)
Three processes (Acromion, spine
and coracoid)
7
Articular surface for clavicle
Superior border
Superior angle
Medial border
Subscapular fossa
Inferior angle
Articular surface for clavicle
Acromion
Greater scapular notch
Glenoid cavity
Infraglenoid tubercle
Lateral border
Inferior angle
Anterior view
Posterior view
Infraspinous
fossa
Spine of scapula
Medial border
Supraspinous
fossa
Superior angle
Superior border
Lateral border
Notch
Infraglenoid tubercle
Glenoid cavity
Coracoid process
Acromion

8. 1.4. Proximal Humerus
 Proximal part of humerus contains
head, neck(surgical and anatomical)
and proximal shaft
 Surgical neck is the weakest part of
humerus therefore its most common
site of fracture, structures around this
neck (Axillary nerve, post.
Circumflex artery) may be damaged
8
Superior facet
(supraspinatus)Greater tubercle
Intertubercular sulcus
Lesser tubercle
(subscapularis)
Intertubercular sulcus
Anterior view
Lateral view
Posterior view
Surgical neck
Surgical neck
Head
Anatomical neck
Attachment for
pectoralis major
muscle
Deltoid
Tuberosity
(deltoid)
Greater
tubercle
Superior facet
(supraspinatus)
Middle facet
(infraspinatus)
Inferior facet
(teres minor)
Anatomical neck
Attachment for
coracobrachialis
Deltoid tuberosity
(deltoid
Lateral lip, floor
and medial lip of
intertubercular
sulcus (pectoralis
major, latissimus
dorsi, and teres
major respectively)

9. 2. Articulations and
adjoining structures

10. 2.1. Glenohumeral joint
 Type: multiaxial synovial ball and
socket joint
 Articulation: head of humerus and
glenoid cavity of scapula
 Articular surface is PEAR shaped and
is relatively small and flat
 Only 1/4th of humeral head is in
contact with glenoid cavity hence
greater mobility is seen
 Nerve supply: Axillary and
suprascapular nerves
 Ligaments: Glenohumeral, transverse
humeral and coracohumeral ligaments
10
Glenoid labrum
Glenoid cavity
Tendon of long
head of biceps
brachii muscle
Head of
humerus
Transverse
humeral ligament

11. Clinical notes
 Dislocation of this joint is so common
 1. Anterior dislocation(95%)
This usually occurs by excessive extension and lateral rotation
 2. Posterior dislocation(4%)
 3. Inferior dislocation(1-2%)
 Superior dislocation of shoulder may not occur due to coracoacromial arch
11

12. 2.2. Acromioclavicular joint
 Type: plane synovial joint
 Articulation: articular facets of lateral
end of clavicle and medial acromial
margin
 Nerve supply: suprascapular nerve
 Movements: gliding movement
 Ligaments: superior and inferior
acromioclavicular ligaments
 Relations: anteriorly to deltoid M.
posteriorly to trapezius M. and
superiorly to skin
12
Trapezoid
ligament
Conoid
ligament Conoid tubercle
Suprascapular notch
Glenoid
cavity
Coracoid
process
Acromion
Acromioclavicular
ligament

13. 2.3. Sternoclavicular joint
 Type: synovial plane joint
 Articulation: sternal end of clavicle,
manubrium sterni and 1st costal
cartilage
 Nerve supply: supraclavicular nerve
and nerve to the subclavius muscle
 Ligaments: sternoclavicular ligaments
 Movements: forward, backward,
elevation and depression of clavicle
13
Articular disc
(capsule and ligaments
removed anteriorly
to expose joint)
Clavicular notch
Interclavicular
ligament
Anterior
sternoclavicular
ligament
Manubrium of
sternum
Attachment site
for rib II
Sternal angle
Rib I
Costoclavicular
ligament
First costal
cartilage

14. 2.4. Scapulothoracic articulation
 It’s not a true joint and has no bony
articulation
 Scapula is attaching thorax via muscular
attachments
14

15. 3. Ligaments and articulating
structures

16. 3.1. Glenoid labrum
 It’s a fibrocartilagenous rim attached to
margin of glenoid cavity and increase
concavity by 50% and surface area of
humeral attachment by 75%
 It further strengthens by long head of
biceps origin and superior glenohumeral
ligament
 It’s a static stabilizer of joint and prevents
excessive rollback of humerus
16

17. 3.2. Joint capsule
 It is lax and attaches along epiphyseal
lines of glenoid and humeral head and
extends onto surgical neck medially (that’s
why infection of upper shaft spreads
directly to joint)
 Capsule is surrounded by synovial
membrane which prolongs along tendon
of bicep at tubular sheath
 Inferior part is the weakest- mostly
resulting in dislocation
 Relations: medially supraglenoid tubercle
and labrum, laterally anatomical neck of
humerus, inferiorly surgical neck
17

18. 3.3. Glenohumeral ligament
Superior GH
 It’s the most superior capsular thickening
from labrum anterior to long head of
biceps at level of coracoid base
 It passes under supraspinatus and
inserts on anatomical neck medial to
anterosuperior base of lesser tuberosity
Middle GH
 Most variable in size, arises just inferior
to superior GHL and inserts along middle
area of anatomical neck opposite to
lesser tuberosity
18

19. 3.3. Glenohumeral ligament cont.
Inferior GH
 it’s the thickest part and is very broad
arising from lower half of labrum
 It’s thick superior margin is called superior
band, rest of it is called axillary pouch
 Superior band and anterior band insert on
anatomical neck while the posterior pouch
on surgical neck
 It limits external rotation at 45-90 degree of
abduction(mainly superior band)
19

20. 3.4. Coracohumeral ligament
 Arises from lateral base of coracoid
process and extends onto both
tuberosities
 It forms roof of bicepital tendon sheath
and strengthens capsule anteriorly
20

21. 3.5. Transverse humeral ligament
 Bridges upper part of bicipital groove
through which long head of biceps
passes down
21

22. 3.6. Coracoacromial ligament
 It’s a trapezoidal ligament from base of
acromion to epiphysis of coracoid
 It along with coracoid and acromion
forms coracoacromial arch which is
secondary socket to humerus
 It plays role in resisting upward
displacement of humerus
22

23. 3.7. Coracoclavicular ligament
 Very strong ligament from outer and
inferior clavicular surface to coracoid
base
 It has two components:
- Conoid and Trapezoid
 Conoid portion is primary restraint to
anterior and superior rotation and
anterior and superior displacement of
clavicle
 Trapezoid has relatively less role than
conoid part
23

24. 4. Bursae and relation of
shoulder

25. 4.1. Bursae
 Subacromial bursa:
sites superior to rotator cuff tendons in
subacromial space
 Subscapularis bursa:
 Coracoclavicular bursa:
 Subcoracoid bursa:
 Supraacromial bursa:
25

26. 4.2. Relation of shoulder joint
 Superiorly: coracoacromial arch,
subacromial bursa, supraspinatus,
deltoid
 Inferiorly: Long head of triceps
 Anteriorly: Subscapularis,
coracobrachialis, biceps(short head),
deltoid(ant. fibers)
 Posteriorly: Infraspinatus, teres
minor, deltoid
 Within joint: long head of biceps
26
Subacromial bursa (subdeltoid)
Long head of biceps brachii tendon
Subtendinous bursa
of subscapularis
Coraco-acromial ligament
Pectoralis major
Short head of biceps brachii
and coracobrachialis
Long head of triceps
brachii
Latissimus dorsi
Teres major
Teres minor
Infraspinatus
Supraspinatus
Deltoid
Acromion

27. 5. Muscular and neurovascular
anatomy

28. 5.1. Muscular Anatomy
 Muscles acting on humerus:
 Rotator cuff(SITS)
 Deltoid
 Biceps
 Pectoralis major
 Latissimus dorsi
 Teres major
 Long head of triceps
 coracobrachialis
 Muscles acting on scapula:
 Rhomboids
 Levator scapulae
 Serratus anterior
 Pectoralis minor/major
 Trapezius
 Latissimus dorsi
28

29. Supraspinatus
 Origin:
Supraspinous fossa
 Insertion:
Greater tuberosity
 Innervation:
Suprascapular nerve ()
 Action:
Abducts and externally rotates
humerus
29

30. Infraspinatus
 Origin:
Infraspinous fossa
 Insertion:
Greater tuberosity
 Innervation:
Suprascapular nerve (c?)
 Action:
Externally rotates humerus
30

31. Teres Minor
 Origin:
Axillary (lateral) border of scapula
 Insertion:
Greater tuberosity
 Innervation:
Axillary nerve(c?)
 Action:
Externally rotates humerus
31

32. Subscapularis
 Origin:
Subscapular fossa
 Insertion:
Lesser tuberosity
 Innervation:
Upper and lower subscapular nerves
 Action:
Internally rotates humerus
32

33. Deltoid
 Origin:
Anterior fibers – distal clavicle, Middle fibers
– acromion process, Posterior fibers – spine of
scapula
 Insertion:
Deltoid tuberosity
 Innervation:
Axillary nerve (c?)
 Action:
Ant. Fibers – shoulder flexion, adduction and
internal rotation. Middle fibers – shoulder
abduction. Post. Fibers – shoulder extension,
abduction and external rotation
33

34. Biceps Brachii
 Origin:
Long head: superior glenoid rim/tuberosity
Short head: coracoid process
 Insertion:
Radial tuberosity
 Innervation:
Musculocutaneous (C)
 Action:
Elbow and shoulder flexion
34

35. Pectoralis Major
 Origin:
medial half of clavicle, lateral portion of
sternum
 Insertion:
Lateral lip of biciptal grove
 Innervation:
Medial and lateral pectoral
 Action:
Sternal head: shoulder depression and
horizontal adduction
Clavicular head: flexion, internal rotation
and horizontal adduction
35

36. Latissmus Dorsi
 Origin:
T6-12 spinous processes, thoracolumbar
fascia, iliac crest
 Insertion:
intertubercular(biciptal) groove
 Innervation:
Thoracodorsal (middle subscapular)
 Action:
Adduction, internal rotation, extension
36

37. Teres Major
 Origin:
Inferior angle of scapula, Axillary border
of scapula
 Insertion:
Medial lip of bicipital groove
 Innervation:
Lower subscapular
 Action:
Internal rotation, adduction, extension
37

38. Long head of Triceps
 Origin:
Inferior glenoid tuberosity
 Insertion:
Olecranon process
 Innervation:
Radial nerve
 Action:
Extend elbow, long head adducts and
extends humerus
38
Triceps barchii
medius
Lateral head
Tendon
Triceps barchii
medius
Long head

39. Coracobrachialis
 Origin:
Coracoid process
 Insertion:
Medial humeral shaft
 Innervation:
Musculocutaneous
 Action:
Flexion and adduction
39

40. Rhomboids
 Origin:
Major: T2-5 spinous processes, Minor:
C7-T1 spinous process
 Insertion:
Vertebral border of scapula
 Innervation:
Dorsal scapular
 Action:
Scapular retraction, elevation,
downward rotation
40

41. Levator scapulae
 Origin:
C1-4 transverse processes
 Insertion:
Superior angle of scapula
 Innervation:
Dorsal scapular(C)
 Action:
Scapular elevation, downward rotation
41

42. Serratus Anterior
 Origin:
Anterior portion of ribs 1-8
 Insertion:
Vertebral border of scapula from superior
angle to inferior angle
 Innervation:
Long thoracic nerve(C)
 Action:
Scapular protraction and upward
rotation, fixates vertebral border of scapula
to thorax
42

43. Pectoralis Minor
 Origin:
Anterior portion of ribs 3-5
 Insertion:
Coracoid process
 Innervation:
Lateral pectoral
 Action:
Anterior tilt of scapula
43

44. Trapezius
Upper fibers: Base of occiput/upper cervical
spinous processes to distal clavicle
Action: Elevate and upwardly rotate scapula
Middle fibers: Lower cervicle/upper thoracic
spinous processes to acromion process
Action: Retract scapula
Lower fibers: Lower thoracic spinous processes
to spine of scapula
Action: Depress and upwardly rotate scapula
 Innervation:
Accessory nerve (c)
44

45. 5.2. Nerve supply
 Axillary nerve
 Musculocutaneous nerve
 Suprascapular nerve(arise directly from brachial
plexus from superior trunk)
 Lateral pectoral nerve(arise from lateral cord)
 Medial pectoral nerve(arise form medial cord)
 Long thoracic nerve(arise from roots)
 Dorsal scapular(arise from roots)
 Upper and lower subscapular(arise from posterior
cord)
 Thoracodorsal(arise from posterior cord)
45

46. Axillary Nerve
 It’s a major peripheral nerve of the upper
limb
 Spinal roots: C5 and C6
 Sensory function: gives rise to upper
cutaneous nerve of arm which innervate
the skin over and lower deltoid
 Motor function: teres minor and deltoid
muscles
 Course: it’s a direct continuation of post.
Cord, it leaves axilla via quadrangular
space and around surgical neck it is
divided into its terminal branches
46

47. 47

48. Musculocutaneous nerve
 It’s another major nerve of upper limb
 Spinal roots: C5-C7
 Motor function: innervates the muscles of
anterior compartment of arm
 Sensory function: gives rise to lateral
cutaneous nerve which innervates skin of
lateral surface of forearm
 Course: It’s the terminal branch of lateral
cord, it leaves axilla and pierce the
coracobrachialis muscle then it passes down
the flexor compartment of arm, it then pierce
the deep fascia lateral to bicep and enters
forearm
48

49. 5.3. Vascular anatomy
 Anterior circumflex humeral artery
subclavian artery becomes axillary artery as it passes first rib, which becomes
brachial artery as it passes distal to teres major
 Posterior circumflex humeral artery
Ant. And Post. Arteries are both branches of axillary arteries
 Suprascapular(arise from the subclavian artery at the thyrocervical trunk) and
subscapular arteries
49

50. 50
Rib I Transverse cervical artery
Suprascapular artery
Clavicle
Subscapular artery
Anterior circumflex
humeral artery
Posterior circumflex
humeral artery
Circumflex scapular artery
Profunda brachii artery
Brachial artery
Deep branch of
transverse
cervical artery
Axillary artery
Right subclavian artery
Thyrocervical trunk
Right common carotid artery

51. 6. Range of motion of
shoulder joint

52. Active range of motion
 Flexion:
180 degree
 Extension:
60 degree
 Abduction:
180 degree
 Adduction:
45 if shoulder flexed
 Internal rotation:
70-80 degree at 90 angle(limited by body in
natural position)
 External rotation:
40-50 in natural position, 80-90 at 90 angle
52

53. 7. References
 Clinical anatomy by regions, Richard S. Snell, 9th edition
 Gray’s anatomy for students, Richard L. Drake, 2nd edition
 Image source:
- Washington university radiology department
- Orthobullets.com
53

54. Any query?54