Shoulder and Scapular Region

Question 1

What bones comprise the pectoral girdle?

Answer 1

• Scapula (shoulder blade)
• Clavicle (collarbone)

Question 2

Define Articulation

Answer 2

• Place where two or more bone meet
• Can be immovable, slightly moveable or freely moveable

Question 3

Synovial Joint

Answer 3

• Freely Moveable
• Surrounded by a joint capsule
  
  • Contains synovial fluid that lubricates the bone ends

Question 4

Describe the relationship between stability and mobility of joints. Define close pack and loose pack positioning.

Answer 4

• Inverse relationship
• Close Pack:
  
  • Position of greatest stability (least mobility) of a joint
  • Ligaments are taught, bones in greatest contact
• Loose Pack:
  
  • Position of greatest mobility (least stability)
  • Ligaments are lax, less contact between bones

Question 5

Hilton’s Law

Answer 5

• Nerves supplying a joint also supply the muscles moving the joint and skin covering insertion of muscles

Question 6

“O’Loughlin’s Law”

Answer 6

• If a muscle crosses a joint, it must move that joint

Question 7

Shoulder Joint

Answer 7

• Consists of three joints:
  
  • Sternoclavicular Joint
  • Acromioclavicular Joint
  • Glenohumeral Joint (shoulder joint proper)
• Very mobile (relatively unstable)

Question 8

Sternoclavicular Joint

Answer 8

• Joint between clavicle and sternum (manubrium)
• Strong, Stable Joint (reinforced by many ligaments)
  
  • Rarely dislocates

Question 9

Acromioclavicular Joint

Answer 9

• Synovial joint between acromion and lateral end of clavicle
• Stabilized superiorly by the acromioclavicular ligament
• Lateral part of clavicle attached to coracoid process by coracoclavicular ligament

Question 10

Shoulder Separation

Answer 10

• Dislocation of acromioclavicular joint
  
  • Graded on Severity:
    
    • Type 1: mild sprain
    • Type 2: subluxation of joint (partial dislocation)
    • Type 3: complete dislocation and tear of cracoclavicular ligament

Symptoms:

• Pain when arm is aBducted more than 90 degrees
• Tenderness and edema
• Acromion prominent (sticks laterally) and superior movement of clavicle

Question 11

Glenohumeral Joint

Answer 11

“Shoulder Joint Proper”

• Ball and socket synovial joint
  
  • ​Between head of humerus and scapula
• Most mobile joint in body (most unstable)
  
  • Most frequently dislocated
• Stability comes from rotator cuff muscles

Structure:

• Thin capsule
• Several bursae (synovial fluid filled sacs)
  
  • Located where tendons rub against bone/ligaments or where skin moves over bony (areas of friction)
  • Inflammation leads to bursitis

Question 12

Shoulder Dislocation

Answer 12

• Dislocation of glenohumeral joint
• Inferior, anterior movement of humerus
• Unable to move joint (difference from shoulder separation)

Question 13

Deltoid Region

Answer 13

• Skin of posterior shoulder innervated by posterior rami
• Skin of lateral/anterior shoulder innervated by anterior rami

Question 14

What are the extrinsic muscles of the shoulder?

Answer 14

• Superficial Back Muscles

Question 15

What are the intrinsic muscles of the shoulder? Why are they called intrinsic?

Answer 15

• Muscles that both originate and insert on upper limb
  
  • Deltoid
  • Teres Major
  • Rotator Cuff Muscles

Question 16

Deltoid

Answer 16

Innervation:

• Axillary n. (Brachial Plexus; C5-C6)

Insertion:

• Deltoid tuberosity of humerus

Action:

• Primary aBductor of upper limb

Blood Supply:

• Posterior circumflex humeral a.

Question 17

Teres Major

Answer 17

Innervation:

• Lower subscapular n.

Origin:

• Inferior angle of scapula

Insertion:

• Intertubercular sulcus of humerus

Action:

• Extends, adducts and medially rotates humerus

Blood Supply:

• Circumflex scapular a.

Question 18

Which muscles comprise the rotator cuff?

Answer 18

• Subscapularis
• Supraspinatus
• Infraspinatus
• Teres Minor

Question 19

Subscapularis

Answer 19

Innervation

• Subscapular nn. (Upper and Lower)

Origin:

• Subscapular fossa

Insertion:

• Lesser tubercle of humerus

Action:

• Medially rotate arm

Blood Supply:

• Subscapular a.

Question 20

Supraspinatus

Answer 20

Innervation:

• Suprascapular n. (Brachial Plexus; Superior Trunk)

Origin:

• Supraspinous fossa

Insertion:

• Greater tubercle of humerus

Action:

• ABduct arm

Blood Supply:

• Suprascapular a.

Question 21

Infraspinatus

Answer 21

Innervation:

• Suprascapular n.

Origin:

• Infraspinous fossa

Insertion:

• Greater tubercle of the humerus

Action:

• Adduct and laterally rotates arm

Blood Supply:

• Suprascapular a.

Question 22

Teres Minor

Answer 22

Innervation:

• Axillary n.

Origin:

• Lateral border of scapula

Insertion:

• Inferior greater tubercle

Action:

• Adduct and laterally rotates arm

Blood Supply:

• Circumflex scapular a.

Question 23

Triangular Space Contents and Borders

Answer 23

• Circumflex Scapular a.
• Borders:
  
  • Teres Major
  • Teres Minor

Question 24

Quadrangular Space Contents and Borders

Answer 24

• Axillary Nerve
• Posterior Humeral Circumflex a.
• Borders:
  
  • Teres Minor
  • Teres Major
  • Long Head Triceps Brachii
  • Humerus

Question 25

Triceps Hiatus Contents and Borders

Answer 25

• Radial n.
• Deep Brachial a.
• Borders:
  
  • Triceps brachii
  • Humerus
  • Teres Major

Question 26

Arterial Supply to Upper Limb

Answer 26

• Subclavian a.
  
  • ​At lateral border of first rib renamed axillary a.
    
    • ​At inferior border of teres major renamed brachial a.

Question 27

Venous Drainage of Upper Limb

Answer 27

• Deep veins have same names as arteries
• Superficial veins:
  
  • Cephalic Vein: on preaxial border (thumb side)
  • Basilic Vein: on postaxial border (pinky side)
  • Median cubital vein: location of venipuncture