The Shoulder (Gleno-Humeral) Joint, Rotator Cuff and Shoulder Musculature

Question 1

The 2 main bursae in the shoulder are the?

Answer 1

• subacromial (subdeltoid) bursa
• subscapular bursa

Question 2

which bursa communicates with the gleno-humeral (shoulder) joint cavity?

Answer 2

subscapular bursa

Question 3

what is the role of the subacromial bursa

Answer 3

serves as a gliding mechanism between the rotator cuff and coracoacromial arch

Question 4

what common sporting injury damages the subacromial bursa?

Answer 4

rotator cuff injury

Question 4

which muscle is highlighted?

Answer 4

subscapularis

Question 5

what is the proximal and distal attachment of the subscapularis muscle?

Answer 5

• proximal = medial 2/3 of costal aspect of scapula
• distal = greater tuberosity of humerus

Question 6

what movement at the shoulder joint does the subscapularis permit?

Answer 6

medial rotation

Question 7

what is the highlighted muscle?

Answer 7

supraspinatus

Question 8

what are the proximal and distal attachments of the supraspinatus?

Answer 8

• proximal = medial 2/3 of costal aspect of scapula
• distal = greater tuberosity of humerus

Question 9

what movement at the shoulder joint does the supraspinatus permit?

Answer 9

abduction

Question 10

what is the highlighted muscle?

Answer 10

infraspinatus

Question 11

what are the superior and inferior attachments of the infraspinatus?

Answer 11

• proximal = medial 2/3 of costal aspect of scapula
• distal = greater tuberosity of humerus

Question 12

what movement at the shoulder does the infraspinatus permit?

Answer 12

lateral rotation

Question 13

what is the highlighted muscle?

Answer 13

teres minor

Question 14

what are the proximal and distal attachments of teres minor?

Answer 14

• proximal = upper 2/3 of lateral aspect of scapula
• distal = lesser tuberosity of humerus

Question 15

what movement at the shoulder joint does teres minor permit?

Answer 15

lateral rotation

Question 16

Although the rotator cuff muscles have a role in movement at the glenohumeral joint, what is their primary function?

Answer 16

Stabilization of glenohumeral joint by compressing the humeral head against the glenoid, keeping the head of the humerus from sliding out of its socket

Question 17

what is the proximal and distal attachment of the deltoid muscle?

Answer 17

It arises from the lateral spine of the scapula, passing across the acromion to the lateral third of the clavicle. Its distal attachment is to the deltoid tuberosity of the humerus

Question 18

the anterior fibres of the deltoid allow for which movement at the shoulder joint?

Answer 18

Anterior fibres of deltoid – flexion and medial rotation at the shoulder joint

Question 19

the middle fibres of the deltoid allow for which movement at the shoulder joint?

Answer 19

Middle fibres abduct the arm at the shoulder joint *major abductor of the arm

Question 20

the posterior fibres of the deltoid muscle allow for which movement at the shoulder joint?

Answer 20

Posterior fibres – extension and lateral rotation at the shoulder joint

Question 21

what is the nerve supply to the deltoid?

Answer 21

axillary nerve

Question 22

in what common injury is the axillary nerve often trapped and therefore damaged?

Answer 22

Anterior shoulder dislocation

Question 23

As the axillary nerve is a mixed nerve, where would you test for loss of sensation to determine is a nerve injury had occurred?

Answer 23

Shoulder area, weakness in deltoid and teres minor muscles, or pain in deltoid and anterior shoulder

Question 24

what is the origin and insertion of the pectoralis major muscle?

Answer 24

- extensive origin from the medial third of the clavicle, sternum and costal cartilage of the first 6 ribs and rectus sheath! - The distal attachment of this muscle is to the anterior lip of the bicipital groove of the humerus

Question 25

what is the action of the pectoralis major muscle at the shoulder joint?

Answer 25

Its action on the shoulder joint is to adduct the shoulder and internally/medially rotate the humerus at the glenohumeral joint.

Question 26

why is the pectoralis minor muscle anatomically important?

Answer 26

Pectoralis minor lies deep to the pectoralis major muscle and is important anatomically as it splits the axillary artery into 3 parts.

Question 27

what is the action of the pectoralis minor muscle?

Answer 27

Along with the serratus anterior it serves to stabilise the scapula during limb movements by keeping it pulled against the thoracic cage.

Question 28

what is the origin and insertion of the serratus anterior?

Answer 28

The Serratus Anterior arises as interdigitations from the ribs and inserts into the scapula.

Question 29

what is the action of the serratus anterior muscle?

Answer 29

It has an important role in protraction of the scapula.

Question 30

Mrs Smith is 64 years old and had a left mastectomy with axillary lymph node clearance for breast cancer. Oddly she’s recently found that she can feel her scapula protruding outwards from her back when she’s been showering, and she is struggling to lift items on her left side. Why has this occurred, which nerve has been damaged in the procedure?

Answer 30

Winged scapula is a complication that may occur due to damage of thoracic nerve during axillary lymphadenectomy.

Question 31

Answer 31

1. trapezius 2. lattisimus dorsi 3. teres major 4. deltoid

Question 32

what is the action of the superior fibres of the trapezius?

Answer 32

Superior fibres of trapezius elevate the scapula

Question 33

what is the action of the middle fibres of the trapezius?

Answer 33

Middle fibres of trapezius retract the scapula (move it back on the thorax)

Question 34

what is the action of the inferior fibres of the trapezius?

Answer 34

depression of the scapula

Question 35

which nerve innervates the trapezius?

Answer 35

CN XII accessory nerve

Question 36

which foramen of the skull does the accessory nerve pass through?

Answer 36

jugular foramen

Question 37

which shoulder joint muscles allow for flexion of the shoulder in the sagittal plane?

Answer 37

1. Pectoralis major 2. Anterior deltoid 3. Biceps brachii & Coracobrachialis

Question 38

which shoulder joint muscles allow for extension of the shoulder in the sagittal plane?

Answer 38

1. Posterior deltoid 2. Latissimus dorsi

Question 39

which shoulder joint muscles allow for adduction of the shoulder joint?

Answer 39

1. Pectoralis major 2. Latissimus dorsi 3. Teres major

Question 40

which shoulder joint muscles allow for abduction of the shoulder? | degree margins

Answer 40

0 to 90 degrees 1. Supraspinatus (0-15) 2. Middle deltoid (15-90) 90 to 180 degrees 1. Trapezius 2. Serratus anterior

Question 41

which shoulder joint muscles allow for medial or internal rotation?

Answer 41

1. Subscapularis 2. Anterior deltoid 3. Pectoralis major 4. Teres major

Question 42

which intrinsic shoulder joint muscles allow for lateral or external rotation of the shoulder?

Answer 42

1. Infraspinatus 2. Teres minor 3. Posterior deltoid