The Shoulder Joint (Glenohumeral Joint)

1
The Shoulder Joint(Glenohumeral Joint)
What bones make up the shoulder joint?
2
(No Transcript)
3
The Shoulder Joint
Many variable movements occur at the
shoulder. Movement of the humerus usually
involves movement at the shoulder girdle, known
as scapulohumeral rhythm.
What are the 8 movements that occur at the
shoulder joint?
4
Shoulder Girdle Movements
Shoulder Girdle Shoulder Joint
Protraction Horizontal Adduction
Retraction Horizontal Abduction
Upward Rotation Abduction
Downward Rotation Adduction
Elevation Shoulder shrug
Depression Shoulder depression

• What shoulder joint (glenohumeral) motions occur
  with each shoulder girdle (scapular) motion?

5
The Shoulder Joint
To study the 9 muscles of the shoulder joint, we
will break them into intrinsic and
extrinsic groups. The intrinsic group originate
on the clavicle and scapula.
What are the 7 intrinsic muscles of the
shoulder joint?
6
The Shoulder Joint
What are the two extrinsic muscles of
the shoulder joint?
7
Rotator Cuff
8
Supraspinatus
9
The Shoulder Joint
A. Supraspinatus muscle - This muscle is most
superior of the rotator cuff. It pulls the
head of the humerus into the glenoid fossa
to initiate abduction and provide an
effective angle of pull for the deltoid.
It helps reinforce the shoulder joint.
Actions - assist abduction, stabilize head of
humerus
10
The Shoulder Joint
Testing the supraspinatus for injury
1. Resisting against abduction - if the patient
has trouble abducting the arm against
resistance and tries to substitute the
scapular muscles, it can indicate
supraspinatus damage.
2. Drop arm test - if the patient can not
slowly lower the arm from an abducted
position, it can indicate supraspinatus
injury.
11
Infraspinatus
12
The Shoulder Joint
B. Infraspinatus muscle - located just inferior
to the supraspinatus, it also helps
reinforce the shoulder capsule and
stabilize the humerus during abduction.
Actions of the infraspinatus
External rotation - most powerful
external rotator of SITS muscles
Extension of humerus
Horizontal abduction
13
The Shoulder Joint
Exercises involving the infraspinatus
Chinning, dips, rope climbing. Any exercise in
which the arms are pulled down forcefully. Works
in conjunction with teres major and latissimus
dorsi.
14
Teres Minor
15
The Shoulder Joint
C. Teres minor - Inferior to the infraspinatus,
this muscle also reinforces the shoulder
capsule and helps stabilize the head of the
humerus during abduction.
Actions of the teres minor
16
The Shoulder Joint
Exercises to strengthen the teres minor
Same as infraspinatus - chinning, rope
climbing, dips, any movement in which arms go
down forcefully.
17
Subscapularis
18
The Shoulder Joint
D. Subscapularis - the final muscle in the four
rotator cuff muscles. As with the
others, helps stabilize shoulder capsule.
This is the only rotator cuff muscle to
originate on the anterior surface of the
scapula.
Actions of the subscapularis
Internal rotation - main action
Adduction
Extension - from flexed position
19
The Shoulder Joint
Exercises involving the subscapularis
As with infraspinatus and teres minor, it is
involved in chinning, dips and rope climbing.
A specific exercise for this muscle is
internal rotation against resistance.
20
Deltoid
21
Shoulder Joint Muscles
The deltoid muscle is divided into three
portions, and hence is sometimes called
deltoids muscle. The three portions are
anterior, middle, and posterior.
22
Shoulder Joint Muscles
What are the actions of the anterior deltoid?
What are the actions of the middle deltoid?
Abduction
What are the actions of the posterior deltoid?
23
Shoulder Joint Muscles
Exercises to strengthen the deltoid muscle
Supine horizontally adducted dumbbell raises will
strengthen the anterior deltoid.
Prone horizontally abducted dumbbell raises will
strengthen the posterior deltoid
24
Coracobrachialis(not brachialis)
25
Shoulder Joint Muscles
B. Coracobrachialis muscle - This muscle is
named for its origin and insertion.
What actions does the coracobrachialis perform?
Exercises to strengthen would include
Not particularly strong, most functional in
Horizontal Adduction
26
Teres Major
27
Shoulder Joint Muscles
C. Teres Major muscle - Together with the
infraspinatus and teres minor, it helps
stabilize the humerus during abduction. It
is also known as the latissimus dorsis
little helper.
What are the actions of the teres major?
28
Shoulder Joint Muscles
Exercises to strengthen the teres major muscle
As with the coracobrachialis, this muscle is
not very powerful on its own.
29
Shoulder Joint Muscles

• Latissimus dorsi latissimus means widest
• dorsi means back (Latin). Powerful in adduction,
  extension and internal rotation of humerus.
• Powerful contraction in chinning. Assisted in all
  
• actions by teres major.

What are the actions of the latissimus dorsi?
Horizontal abduction
30
Latissimus Dorsi
31
Shoulder Joint Muscles
What are some activities involving or
strengthening the Latissimus dorsi?
Lat pull downs Chinning Rope climbing
Dips Rowing Pull over
32
Pectoralis Major
33
Shoulder Joint Muscles

• Pectoralis Major (pectus, breast bone)
• works closely with anterior deltoid.
• It is divided into upper and lower sections.

Actions of Pectoralis Major
Upper fibers (clavicular head) internal
rotation, horizontal adduction, some flexion,
some abduction
Lower fibers (sternal head) internal rotation,
horizontal adduction, extension, some adduction
34
Shoulder Joint Muscles
Exercises or activities involving the
pectoralis major?
Bench press Push ups Dumbell flies Pull
ups Incline press Decline press
Incline press muscles combine bench overhead
presses. Decline press made up of bench press
the dip.
35
Shoulder Joint Muscles

• Biceps brachii (short and long heads) originate
  on the scapula and insert on the radius. It
  crosses two joints. Short head assists flexion,
  adduction Long assists with abduction.
• Triceps brachii (long head) originates on the
  scapula just below the glenoid fossa. It assists
  with shoulder extension and adduction.

36
Shoulder Joint Injuries

• Dislocation the head of the humerus is pushed
  out of the glenoid fossa. The glenohumeral joint
  is the most commonly dislocated joint in the
  body.
• Rotator cuff damage this is the most common
  disorder of the shoulder. Supra-spinatus is most
  commonly injured.

37
Shoulder Joint Injuries

• Rotational injuries tears of the labrum, the
  rotator cuff muscles, and the biceps brachii
  tendon among injuries resulting from repeated,
  forceful rotation at shoulder. Tears of rotator
  cuff attributed to extreme tension during
  deceleration phase of throwlike motion.
• Subscapular neuropathy compression of
  subscapular nerve.