Shoulder Girdle - Bones, Joints, and Muscles

Question 1

What are the 7 landmarks of the proximal end of Humerus?

Important ones you need to get

Answer 1

1. Humeral Head*
2. Anatomical Neck
3. Lesser tuberosity*
4. Intertubercular Sulcus* (groove)
5. Greater Tuberosity*
6. Surgical Neck
7. Shaft of Humerus

Question 2

What does the humeral head articulate with in the shoulder joint?

Answer 2

Glenoid Cavity (Labrum)

Question 3

What are the ligaments of the Glenoid Cavity (GC)?

Answer 3

Superior GH Ligament:
O = Upper Border of GC I = Upper Aspect of Lesser Tuberosity
Middle GH Ligament:
O = Upper Border of GC I = Anterior of Lesser Tuberosity
Inferior GH Ligament:
O = Both sides of GC (Ant & Post) I = Neck of Humerus
Thickenings in fascia
Coracohumeral Ligament
- Originates on the coracoid process and inserts to the margin of humeral head

Question 4

What is purpose of ligaments in the Glenoid Cavity?

Answer 4

Significantly, the ligaments are very active in rotational movements.
Neutrally these ligaments are relatively lax and DONT STABILISE THE JOINT

Question 5

What are the “dynamic ligaments” of the GH joint?

Answer 5

• Subscapularis
• Supraspinatus
• Infraspinatus
• Teres Minor

Question 6

Why are the rotator muscles considered as “dynamic ligaments” of the GH joint?

Answer 6

They encompassed GH joint and they individually tense to stabilise the joint.

Question 7

What is the function and name of a significant bursa in the GH joint?

Answer 7

Sub-Acrominal Bursa: Its functions to prevent the acromion process impinging and putting friction onto bicep tendon especially during abduction

Question 8

What are the insertions and actions of the Supraspinatus?

Answer 8

Originates = Supraspinatus fossa, above spine of scapula
Insertion = Runs laterally and under the acromion, inserts to superior aspect of the greater tuberosity.
Actions = Abduction

Question 9

What are the insertions and actions of Infraspinatus?

Answer 9

Originates = Infraspinatus fossa, beneath spine of scapula 
Insertion = Runs laterally, to insert into the posterior margin of the greater tuberosity of humerus 
Actions = Lateral rotation

Question 10

What are the insertions and actions of Teres Minor?

Answer 10

Originates = Lateral border of scapula 
Insertion = Runs underneath infraspinatus, and inserts to the posterior margin of the greater tuberosity of humerus 
Actions = Lateral Rotation

Question 11

What are the insertions and actions of Subscapularis?

Answer 11

Originates = Subscapular fossa 
Insertion = Runs laterally, inserts into the lesser tuberosity of humerus 
Actions = Medial Rotation

Question 12

What are the 5 muscles involved of moving the scapula?

Answer 12

Trapezius 
Serratus Anterior 
Rhomboid Minor 
Rhomboid Major 
Levator Scapulae

Question 13

What are the insertions of the Trapezius?

Answer 13

Upper Fibres: Cervical spinous processes, lateral aspect of the Clavicle and Superior Nuchal line of the occiput
Middle Fibres: Lower Cervical and Upper Thoracic spinous processes, and spine of scapula
Lower Fibres: Thoracic spinous process and medial border of scapula

Question 14

What are the actions of Trapezius?

Answer 14

Upper Fibres: Elevation
Middle Fibres: Retraction
Lower Fibres: Depression

Question 15

What are the insertions and actions of Serratus Anterior?

Answer 15

Originates = Medial and Inferior Borders of Scapula, anteriorly 
Insertions = Top 9 shafts of ribs; at the mid-axillary line
Actions = Protraction of Shoulder

Question 16

What movement is produced when serratus anterior and Trapezius are contracting?

Answer 16

The upper and lower fibres of Trapezius and Serratus Anterior cause LATERAL ROTATION of the scapula

Question 17

What are the insertions of Rhomboid Major/Minor and Levator Scapulae?

Answer 17

Rhomboid Major:
O = Medial Border of Scapula I = Spinous processes T2 - T6
Rhomboid Minor:
O = Medial Border of Scapula I = Spinous processes C7 and T1
Levator Scapulae:
O = Very top of Medial Border of Scapula I = Transverse processes of C1 -C4

Question 18

What are the actions of the Rhomboids and Levator Scapulae?

Answer 18

Rhomboids - Retraction of Scapula

Levator Scapulae - Elevation

Question 19

What the deep muscles are the anterior aspect of the shoulder girdle?

Answer 19

Pectoralis Minor

Subclavius

Question 20

What are the insertions and actions of the deep anterior muscles of the shoulder girdle?

Answer 20

Pectoralis Minor:
O = Coracoid process I = Anterior angle of ribs 3 - 5
Subclavius:
O = Inferior aspect process at the midpoint of the clavicle I = Anterior angle of rib 1
Actions: Protraction of shoulder

Question 21

What are the 5 muscles of the shoulder girdle that are involved in the glenohumeral joint?

Answer 21

Deltoids (Anterior, Superior and Posterior) 
Pectoralis Major 
Latissimus Dorsi 
Teres Major 
Coracobrachialis

Question 22

What are the origins of the 3 deltoid muscles?

Answer 22

Anterior fibres - Anterolateral aspect of the clavicle
Superior (Middle) fibres - Acromion process
Posterior fibres - Spine of Scapula

Question 23

What are the insertions of the 3 deltoid muscles?

Answer 23

All the fibres of Deltoid insert onto the deltoid tubercle of the humerus

Question 24

What actions do the separate deltoid fibres perform?

Answer 24

Anterior fibres - Abduction
Superior (Middle) fibres - Horizontal flexion, Medial Rotation
Posterior fibres - Horizontal flexion, Lateral Rotation
ALL FIBRES TOGETHER PERFORM ABDUCTION

Question 25

What are the 4 insertions of Pectoralis Major?

Answer 25

• Medial 2/3 of Clavicle
• Lateral Wall Intertubercular Sulcus of Humerus
• Sternum
• Lower Aspect of the Costal Cartilages 6 & 7

Question 26

What are the actions of Pectoralis Major?

Answer 26

ALL FIBRES TOGETHER PERFORM = Adduction and Medial Rotation
Clavicular fibres - Horizontal Flexion
Sternal Fibres - Extension from flexion, vice versa

Question 27

What are the insertions of Latissimus Dorsi?

Answer 27

• Spinous Processes from T7 - L5
• Sacrum
• The bed of Intertubercular Sulcus (Anterior)
• Iliac Crest*
• Lower Ribs*
• Inferior Angle of Scapula*

Question 28

What are the actions of Latissimus Dorsi?

Answer 28

• Adduction
• Medial Rotation
• Extension from flexion*

Question 29

What are the two deep posterior muscles of shoulder girdle involved with the glenohumeral joint?

Answer 29

• Teres Major

- Coracobrachialis

Question 30

What are the insertions and actions of the Teres Major?

Answer 30

Origin - Posterior aspect of the inferior angle of Scapula
Insertion - Runs anteriorly to the Intertubercular Sulcus medially
Actions - Adduction and Medial Rotation

Question 31

What are the insertions and actions of Coracobrachialis?

Answer 31

Origin - Coracoid Process
Insertion - Medial Aspect of the shaft of humerus
Action - Adduction

Question 32

What are the 7 bony landmarks of the scapula?

Answer 32

• Coracoid Process (Most Anterior)
• Acromion Process (Most Posterior and Superior)
• Glenoid Fossa
• Spine of Scapula
• Lateral, Inferior, Medial Borders

Question 33

What are the bony landmarks of the Clavicle?

Answer 33

• Articular surfaces for Sternum and Acromion
• Conoid Tubercle*
• Trapezoid Line* (Ligamentous attachments for the Coracoclavicular complex)
• Impression for Costoclavicular ligament

Question 34

What are the joints/articulation of the shoulder complex?

Answer 34

• Glenohumeral joint
• Sternoclavicular joint
• Acromioclavicular joint
• Scapulothoracic articulation*
• Subacromial articulation*

Question 35

What is the only bony structure which links the upper torso to the upper limb? What are its physical features?

Answer 35

Acromioclavicular Joint:

• Has a small articular disc
• Has superior and inferior coracoclavicular ligaments; stabilises the joint