The Shoulder

1. THE
SHOULDER
LESSON 7

2. BONES OF THE
SHOULDER
GIRDLE
LESSON 7

3. Shoulder
 The human shoulder is made up of three
bones: the clavicle, scapula and the humerus
as well as associated muscles, ligaments and
tendons.

4. Bones of the Shoulder Girdle
(Pectoral Girdle)
 Shoulder or Pectoral girdle consist of the shoulder blades ( scapulae
), and collar bones ( clavicles ). There are 5 joints and about 20
muscles involved in the pectoral girdle on each side.
 The anatomical mechanism that allows for all upper arm and
shoulder movements.
 Function:
The pectoral / shoulder girdle connects the upper
limbs to the axial skeleton and serves as the
attachment site for the muscles of the upper back
chest and neck.

7.  In humans, the shoulder
girdle consists of the:
1. Scapula
2. Clavicle
3. Sternum

9. The Scapula ( Shoulder Blades )
The bone that connects the humerus ( upper arm
bone) with the clavicle ( collar bones )
The scapula forms the back of the shoulder girdle .
Some people call these as shoulder blade or
“wings” of a person.
The scapulae are paired, with the scapula as the
left side of the body, being roughly a mirror image
of the right scapula.

10.  Function :
To attach the upper arm to the
thorax, or trunk of the body. This
connection stabilizes the arm and
provides for arm movement at the
shoulder.

11. The Clavicle ( Collar Bone )
 A long bone between the shoulder blade and the sternum
(chest bone ).
 There are two clavicles, one on the right and one on the left.
 The only long bone in the body that lies horizontally.
 Together with the scapula it makes up the shoulder girdle.
 It is a palpable bone and in people who have less fat in this
region, the location of the bone is clearly visible, as it creates a
bulge in the skin.

13. The Sternum ( Breast bone )
 A long flat bone shaped like a necktie located in the center
of the chest.
 It connects to the ribs via cartilage, forming the front of the
rib cage, and thus helps to protect the heart, lungs and
major blood vessels from injury.
 The sternum is one of the largest and longest flat bones of
the body.

16. BONES OF THE
SHOULDER JOINT

17. The “ball” of the shoulder joint is the structure
known as the head of the humerus.
 This chapter discusses the humerus only
because it is involved with the shoulder joint.
The humerus as its distal end is discussed
further in the chapter on the elbow joint.

19. The bones of the shoulder joints consists of:
1. scapula ( shoulder blades )
2. clavicle ( collar bone )
3. humerus ( upper arm bone )

20. The Humerus
 A long bone of the upper limb which connects the shoulder with
the elbow.
 the word “humerus” literally means upper arm and is the only
bone in the upper arm.
 The most common bone to get fractured in arm wrestling.

22.  Functions:
1. Serves as an attachment to 13 muscles and 3 very
important nerves which control the functions of hand and
elbow pass through the humerus.
2. Known as “HUMOROUS” bone because sometimes we
have that funny feeling when strike the medial part of
our elbow ( humerus ) against a table. This funny feeling is
because of the tingling sensation coming from the ulnar
nerve which is just placed subcutaneously.
3. Another important function like all other long bones is
blood formation by the bone narrow inside the medulla of
the bone.

28. LIGAMENTS OF
THE SHOULDER
GIRDLE

29. The Shoulder girdle has two joints,
one at either end of the clavicle,
known as the acromioclavicular (AC)
and sternoclavicular (SC) joints.
Movement in the SC joint is slight in all
directions and of a gliding, rotational
type.

32. JOINTS AND
LIGAMENTS OF THE
SHOULDER GIRDLE
AND JOINTS

33. Shoulder
Girdle
• an “open” mechanical
system
– R and L sides not
directly attached so
can move
independently
• sternoclavicular jt
• acromioclavicular jt
• scapulothoracic jt

35. TWO JOINTS OF THE SHOULDER
GIRDLE
• Acromioclavicular Joints (AC)
• Sternoclaviculae Joints (SC)

36. Acromioclavicular Joints (AC)
is the articulation between the
acromion process of the scapula and
the acromial end of the clavicle.
FUNCTION
AC joint tie together and totally
surrounding the lateral end of the
clavicle and acromion process of the
scapula.

37. 37

38. Sternoclavicular Articulation
• is formed from the articulation of the medial aspect of the
clavicle and the manumbrium of the sternum.
FUNCTION
Movement (Elevation, Depression, Protraction, Retraction
and Rotation)

40. Scapulothoracic Articulation
has none of the usual joint
characteristic (Union by Fibrous,cartilaginus
or synovial tissues)

42. LIGMENTS OF THE SCAPULA

43. 43
LIGAMENTS
1. The glenohumeral
ligaments are three
weak bands of fibrous
tissue that strengthen
the front of the capsule.
2. The transverse
humeral ligament
strengthens the
capsule and bridges the
gap between the two
humeral tuberosities.
3. The coracohumeral ligament
strengthens the capsule from
above and stretches from the root
of the coracoid process to the
greater tuberosity of the humerus.
Accessory ligaments:
The coracoacromial ligament
extends between the coracoid process
and the acromion. Its function is to
protect the superior aspect of the
joint.

44. 44
SYNOVIAL MEMBRANE
• It lines the fibrous capsule.
• It is attached to the margins of the cartilage covering the articular
surfaces.
• It forms a tubular sheath around the tendon of the long head of the
biceps brachii.
• It extends through the anterior wall of the capsule to form the
subscapularis bursa beneath the subscapularis muscle.

45. 45
• Flexion
• Extension
• Abduction
• Adduction • Lateral rotation
• Medial rotation
Circumduction
The following movements
are possible:

46. Fundamental
Movements and Muscles
of the Shoulder Girdle

47. Shoulder Girdle
The shoulder girdle or pectoral
girdle is the set of bones in the
appendicular skeleton which
connects to the arm on each
side. It consists of the clavicle
and scapula

49. Movements of the Shoulder Girdle
Protraction (move forward)
Retraction (move backward)
Elevation (lifting)
Depression (lowering)

50. Muscles of the Shoulder Girdle
Six muscles are primarily involved
in producing the fundamental
movements of the shoulder girdle.
Three muscles are anatomically
anterior and three are posterior to it

51. Anterior Muscles
Pectoralis minor
Serratus anterior
Subclavian muscle

52. Pectoralis minor
The pectoralis minor originates from the third,
fourth and fifth ribs and inserts on the coracoid
process of the scapula. (shoulder girdle downward
rotation or adduction)
Serratus anterior
Originating from the anterior lateral aspects
of the upper nine ribs, the serratus anterior inserts
on the anterior surface of the vertebral (medial)
border of the scapula (upward rotation and lateral
tilt)
Subclavian muscle
originates on the first rib and inserts on the
subclavian groove of the clavicle (provides stability to
the joint)

54. Posterior Muscles
Levator scapulae
Rhomboids
Trapezius

55. Levator scapulae
Originates on the transverse processes of the first four cervical
vertebrae and inserts on the superior aspect of the vertebral border of
the scapula. (to lift the scapula)
Rhomboids
These are actually two muscles (major and minor) that are
usually considered as one because they both perform the same function.
Originate on the spinous processes of the seventh cervical through the
fifth thoracic vertebrae and insert on the vertebral (medial) border of the
scapula. (downward rotation of the shoulder girdle)
Trapezius
This large, triangular muscle originates on the external occipital
protuberance at the base of the skull and the spinous processes of all
cervical and thoracic vertebrae and inserts on the spine of the scapula
and posterior surface of the clavicle. Because of the size of the muscle
the angle of its various fibers and its numerous functions the muscle is
divided into four separate sections (upper, upper middle, lower middle
and lower). Upper fibers perform similar functions elevation and
adduction (downward rotation) of the shoulder girdle. Lower fibers
contributes to abduction (upward rotation)

58. Fundamental Movements &
Muscles of the Shoulder Joint

59. Movements of the
Shoulder Joint

60. • The shoulder (glenohumeral) joint is
classified as a triaxial joint because it is
capable of the movement in all three
cardinal planes: flexion and extension,
abduction and adduction & internal and
external rotation
• Eleven major muscles function to
accomplish the six fundamental
movements of the shoulder joint: four
anterior, two superior, two posterior
and three inferior to the joint

62. Anterior Muscles of the
Shoulder Joint
 Pectoralis major
 Coracobrachialis
 Biceps brachii
 Subscapularis

63. Anterior Muscles of the
Shoulder Joint
 Pectoralis major
- originates on the second to the sixth ribs,
the sternum, and medial half of the clavicle
and inserts on the anterior area of the
surgical neck of the humerus just distal to
the greater tuberosity.

64. - Contraction of
pectoralis
major muscles
produces
flexion, and
internal rotation
of the shoulder
joint.

65. Anterior Muscles of the
Shoulder Joint
Coracobrachialis
- Originates on the coracoid process of the
scapula and inserts on the middle of the
medial side of the humerus opposite the
deltoid tubercle on the lateral side

66. - The coracobrachialis flexes the shoulder
joint and, because of its angle of pull,
assists with abduction of the joint.

67. Anterior Muscles of the
Shoulder Joint
Biceps brachii
- Considered a flexor of the elbow, both the
long-head tendon and short-head tendon of
the biceps brachii cross the shoulder joint
- Actions produced by contraction of this
muscle at the shoulder joint include flexion
and abduction by long-head tendon and
flexion, adduction, and internal rotation by the
short-head tendon.

69. Anterior Muscles of the
Shoulder Joint
Subscapularis
- is located on the anterior surface of the
scapula between scapula and the thorax.
- When it contracts, it produces internal
rotation and flexion at the shoulder joint.

71. Superior Muscles of the
Shoulder Joint
 Deltoid
 Supraspinatus

72. Superior Muscles of the
Shoulder Joint
 Deltoid
- is a very large muscle consisting of three
parts: anterior (clavicular), middle
(acromial), and posterior (scapular)
- It covers the shoulder joint, so it is often
referred to as the shoulder cap muscle.

74. Deltoid
Contraction
o Anterior - adduction, flexion, internal rotation
o Middle - abduction
o Posterior – adduction, extension, external rotation

75. Superior Muscles of the
Shoulder Joint
Supraspinatus
- Located beneath the deltoid muscle. The
supraspinatus muscle originates on the
supraspinous fossa of the scapula and
inserts on the proximal facet of the greater
tuberosity of the humerus.
- The muscle abducts the shoulder joint.

77. Posterior Muscles of the
Shoulder Joint
Infraspinatus
 Teres minor

78. Posterior Muscles of the
Shoulder Joint
Infraspinatus
- Originates on the infraspinous fossa
beneath the inferior surface of the spine of
the scapula and inserts on the middle
facet of the greater tuberosity of the
humerus.
- Contraction of the infraspinatus muscle
produces external rotation and extension
of the shoulder joint.

79. Posterior Muscles of the
Shoulder Joint
Teres minor
- Originates on the upper and middle
portions of the lateral border of the
scapula and inserts on the distal facet of
the greater tuberosity of the humerus.
- Contraction of the teres minor muscle
produces external rotation and extension
of the shoulder joint.

86. LATISSIMUS DORSI

91. Dislocation-severe spraining of the ligaments and
straining of the muscles that cross joint.