Shoulder region

Question 1

What are the major features of the clavicle?

Answer 1

Subcutaneous and easily palpable bone
Articulates with the manubrium of the sternum at the sternoclavicular joint.
Articulates with the acromium of the scapula at the acromioclavicular joint.
Attached to the coracoid process of the scapula through a ligament from the conoid tubercle and trapezoid ridge.
Acts to: attach the upper limb to the trunk, protect neurovascular structures, transmits force from upper limb to the axial skeleton.
Falls may cause fracture, most likely to occur at the middle.

Question 2

What are the major features of the scapula?

Answer 2

Triangular flat bone
Articulates with the humerus at the glenohumeral joint, and with the clavicle at the acromioclavicular joint.
Costal side it has a subscapular fossa and the coracoid process (hook-like).
Posteriorly there is a the scapular spine with the supraspinatous fossa above and the infraspinatous fossa below.
Damage to the long thoracic nerve which innervates the serratus anterior can cause ‘winged scapula’.

Question 3

What are the major features of the humerus?

Answer 3

Forms the glenohumoral joint when the head of the humerus enters the glenoid fossa of the scapula.
At the head, there is a greater tubercle (articulation with almost all rotator cuff muscles) and the lesser tubercle (articulation with subscapularis.
Intertubercular groove - houses head of bicep brachii long head
Axillary nerve and circumflex humeral vessels lie against the surgical head.
Deltoid muscle attaches at deltoid tuberosity.
Radial groove holds the radial nerve and profunda brachii artery.
Posteriorly are the medial and lateral epicondyles.
Trochlea is medial and articulates with the trochlear notch of the ulnar.
Capitulum is lateral and articulates with the head of the radius.

Question 4

Which muscles attach to the shaft of the humerus?

Answer 4

The coracobrachialis, deltoid, brachialis, brachioradialis and triceps brachii all attach to the shaft.

Question 5

How does the ulnar nerve reach the forearm?

Answer 5

The ulnar nerve passes in a groove on the posterior aspect of the medial epicondyle.

Question 6

What makes up the pectoral girdle?

Answer 6

Consists of the scapula, clavicle, all the muscles attached to these and the latissimus dorsi muscle.

Question 7

What’s the difference between the arm, the forearm and the hand?

Answer 7

The ARM is between the shoulder and elbow joints, the FOREARM between the elbow and wrist joints and the HAND everything distal to the wrist.

Question 8

What movements occur at the shoulder joint?

Answer 8

Movement of the shoulder joint - flexion, extension, abduction, adduction
It is unusual to only have movement at the shoulder joint; almost all movements of the arm also involve movement of the scapula over the chest wall.

Question 9

What movements occur with the scapula?

Answer 9

For every two degrees of abduction at the shoulder joint there is one degree of rotation of the scapula.
The scapula can also be brought forward on the chest wall this is called protraction and when it is pulled backwards, retraction.

Question 10

What movements occur with the humerus?

Answer 10

Humerus can be laterally and medially rotated around a vertical axis

Question 11

What are the major features of the trapezius?

Answer 11

Broad, flat, triangular muscle.
Most superficial of all the back muscles.
Originates from the skull, nuchal ligament and spinous processes of C7-T12.
Fibres attach to the clavicle, acromion and scapula spine.
Innervated by the accessory nerve.
Acts to elevate the scapula and rotate it during abduction of the arm.

Question 12

What are the major features of the latissimus dorsi?

Answer 12

Originates from the spinous processes of T7-T12, iliac crest, thoracolumbar fascia and the inferior 3 ribs.
Attaches to the intertubercular sulcus of the humerus.
Innervated by the thoracodorsal nerve.
Acts to extend, adduct and medially rotate the upper limb.

Question 13

What are the major features of the levator scapulae?

Answer 13

Deep muscle
Small strap-like muscle.
Originates from the transverse processes of C1-C4 and attaches to the medial border of the scapula.
Innervated by the dorsal scapular nerve.
Acts to elevate the scapula.

Question 14

What are the major features of the rhomboid major?

Answer 14

Below the rhomboid minor.
Originates from the spinous process of T2-T5 vertebrae.
Attaches to the medial border of the scapula.
Innervated by the dorsal scapular nerve.
Acts to retract and rotate the scapula.

Question 15

What are the major features of the rhomboid minor?

Answer 15

Above the rhomboid major.
Originates from the spinous process of C7-T1 vertebrae.
Attaches to the medial border of the scapula, at the level of the spine of the scapula.
Innervated by the dorsal scapular nerve.
Acts to retract and rotate the scapula.

Question 16

What is the action of the rhomboids?

Answer 16

Rotate and retract the scapula

Question 17

What are the 6 intrinsic muscles of the shoulder?

Answer 17

Teres major
Rotator cuff muscles:
- Teres minor
- Subscapularis
- Suprascapularis
- Infrascapularis
Deltoid

Question 18

What are the major features of the deltoid?

Answer 18

Originates from the clavicle, the acromion and the spine of the scapula.
Multipennate arrangement from the acromion.
Attaches to the deltoid tuberosity.
Innervated by the axillary nerve.
Anterior fibres acts to flex and medially rotate.
Posterior fibres act to extend and laterally rotate.
Middle fibres are the major abductor of the arm (takes over from the supraspinatus).

Question 19

What are the major features of the teres major?

Answer 19

Originates from the inferior angle of the scapula.
Attaches to the intertubercular groove of the humerus.
Innervated by the lower subscapular nerve.
Acts to adduct and medially rotate the arm.

Question 20

What are the major features of the supraspinatous?

Answer 20

Rotator cuff muscle
Originates from the supraspinatus fossa of the scapula.
Attaches to the greater tubercle of the humerus.
Innervated by the suprascapular nerve.
Acts to abduct the arm for the first 15 degrees (before deltoid takes over)

Question 21

What are the rotator cuff muscles?

Answer 21

Supraspinatous
Infraspinatous
Subscapularis
Teres minor

Question 22

What is the collective action of the rotator cuff muscles?

Answer 22

All originate from the scapula and attach to the greater tubercle of the humerus. Collectively act to pull the humeral head into the glenoid fossa, this gives the glenohumeral joint a lot of additional stability.

Question 23

What are the major features of the infraspinatous?

Answer 23

Originates from the infraspinatus fossa of the scapula.
Attaches to the greater tubercle of the humerus.
Innervated by the suprascapular nerve.
Acts to laterally rotate the arm.

Question 24

What are the major features of the subscapularis?

Answer 24

Originates from the subscapular fossa.
Attaches to the greater tubercle of the humerus.
Innervated by the upper and lower subscapular nerves.
Acts to medially rotate the arm.

Question 25

What are the major features of the teres minor?

Answer 25

Originates from the posterior surface of the scapula, along the lateral border.
Attaches to the greater tubercle of the humerus.
Innervated by the axillary nerve.
Acts to laterally rotate the arm.

Question 26

What is the pathway of the axillary nerve?

Answer 26

Just under the lower border of teres minor the axillary nerve leaves the axilla to enter the posterior compartment and can be found running across the posterior surface of the humerus it supplies teres minor and deltoid.

Question 27

Which nerves/arteries are prone to damage in a shoulder dislocation?

Answer 27

Axillary nerve
Posterior circumflex humeral artery

Run together

Question 28

What’s the pathway of the radial nerve?

Answer 28

The radial nerve runs on the surface of the humerus in the ‘spiral groove’.

Question 29

What is the frozen shoulder?

Answer 29

The tendon of the supraspinatus passes through a tight gap between the humerus and the acromion. If the tendon becomes inflamed it will cause pain due to the swelling. There is a painful arc (no pain, pain, no pain) as the tendon passes through the gap.

Question 30

What is axillary nerve palsy?

Answer 30

The axillary nerve runs against the neck of the humerus and can be damaged with posterior dislocation of the shoulder and fracture of the humerus neck. This will cause paralysis of the deltoid muscle and a numb patch of skin on the lateral arm.

Question 31

What is a radial nerve palsy?

Answer 31

Radial nerve runs in the spiral groove directly against the humerus. It can easily be damaged by a fracture of the humerus or by direct pressure. AKA Saturday night palsy.

Question 32

What is a ulnar nerve palsy?

Answer 32

“Funny bone”

The ulnar nerve passes behind the medial epicondyle of the humerus. When this is knocked, it leads to severe pain and pins and needles in the skin supplied by the nerve.