Axilla, Brachial Plexus and Posterior Shoulder

Question 1

3 anterior axio-appendicular muscles?

Answer 1

Pectoralis major, pectoralis minor, serratus anterior

Question 2

Two major muscles of climbing?

Answer 2

Pectoralis major and latissimus dorsi

Question 3

Proximal and distal attachments of the pectoralis major? Actions?

Answer 3

Has two heads- clavicular (medial half of clavicle) and and sternocostal (goes to superior six costal cartilages)

Distal attachment is to anterior humerus

Actions: horizontal adduction of humerus (looks like the shoulder exercises) and slight flexion and extension of shoulder from the clavicular head.

Question 4

Proximal and distal attachments of pectoralis minor? Actions?

Answer 4

Proximal: 3rd-5th ribs near the costal cartilages
Distal: Coracoid process of scapula (process at the front)
Actions: pulls scapula forward on the rib cage stabilising it

Question 5

Serratus anterior proximal and distal attachments? Actions?

Answer 5

Proximal: External surfaces of the 1st-8th ribs
Distal: anterior surface of the scapula
Actions: protracts scapula (pulls scapula out —–> abduction, and holds it against thoracic wall; rotates scapula)

Question 6

Innervation of serratus anterior?

Answer 6

Long thoracic nerve

Question 7

Innervation of pectoralis major?

Answer 7

Medial and lateral pectoral nerve

Question 8

Innervation of pectoralis minor?

Answer 8

Medial pectoral nerve

Question 9

Posterior axio appendicular muscles?

Answer 9

Trapezius, latissimus dorsi, rhomboid minor and major

Question 10

Trapezius proximal and distal attachments? Actions?

Answer 10

Proximal: C7-12 spinous processes
Distal: acromion and spine of scapula
Action: upper fibres elevate the scapula, middle fibres adduct the scapula and lower fibres lower the scapula

Question 11

Innervation of trapezius?

Answer 11

Spinal accessory nerve

Question 12

Latissimus Dorsi proximal and distal attachments? Actions?

Answer 12

Proximal: T7-12 spinous processes, iliac crest and inferior 3/4 ribs
Distal: Humerus
Action: extends, adducts and medial rotates humerus

Question 13

Latissimus dorsi innervation?

Answer 13

Thoracodorsal nerve

Question 14

Rhomboid major and minor proximal and distal attachments? Actions?

Answer 14

Proximal: spinous processes
Distal: posterior scapula
Actions: retract scapula (pull scapula in—-> adduction)

Question 15

Innervation of rhomboid major and minor?

Answer 15

Dorsal scapular nerve

Question 16

Levator scapulae proximal and distal attachments? Actions?

Answer 16

Proximal: transerve processes of cervical vertebrae
Distal: superior to route of scapula spine in medial border
Actions: elevate scapula

Question 17

The axillary vein is a continuation of the _________1___________. It becomes the axillary vein at the lower border of____2____muscle.

Answer 17

1) brachial vein (deep vein of the arm)

2) teres major

Question 18

Teres major contributes to the posterior wall of the axilla; its ______ border corresponds to the inferior extent of the axilla.

Answer 18

inferior

Question 19

The brachial plexus supplies the upper limb and is formed from a very specific intertwining of the ….

Answer 19

anterior rami of spinal nerves C5 – T1

Question 20

Proximal to distal what does the brachial plexus consist of?

Answer 20

Roots
Trunks
Divisions
Cords
Named Nerves

Question 21

Describe the trunks of the brachial plexus?

Answer 21

Combinations of roots, which give rise to divisions.

• Superior = combined anterior rami of C5 & C6 spinal nerves
• Middle = anterior ramus of C7 spinal nerve
• Inferior = combined anterior rami of C8 & T1 spinal nerves

Question 22

Describes divisions of the brachial plexus?

Answer 22

Each trunk divides to give anterior and posterior divisions, which combine to give cords.

Question 23

Describe cords of the brachial plexus?

Answer 23

The cords are named according to their relationship to axillary artery.

• Medial = a direct continuation of the anterior division of the inferior trunk
• Lateral = formed from the anterior divisions of the superior and middle trunks
• Posterior = formed from the posterior divisions of all three trunks

Question 24

Describe the named nerves of the brachial plexus?

Answer 24

The cords combine to give the named nerves of the brachial plexus. - The ulnar nerve continues directly from the medial cord

• The musculocutaneous nerve continues directly from the lateral cord
• The posterior cord divides into the axillary nerve and radial nerve
• The medial and lateral cords both contribute the formation of the median nerve

Question 25

Describe the location of the brachial plexus

Answer 25

The roots and trunks lie mainly between the anterior and middle scalene muscles in the root of the neck.
The divisions lie immediately posterior to the subclavian vessels in the root of the neck (deep to the clavicle).
The cords lie around the axillary artery, which is distal to the first rib.

Question 26

Describe what the musculocutaneous nerve supplies?

Answer 26

The musculocutaneous nerve can be seen entering to supply the coracobrachialis muscle.
It also supplies the other muscles of the anterior compartment of the arm: biceps brachii and brachialis muscles.

Question 27

Describe the axillary nerve and what it supplies?

Answer 27

Supplies the shoulder joint, teres minor and deltoid muscles as well as skin of the superolateral arm

Question 28

When is the radial nerve vulnerable to injury? Why?

Answer 28

Mid shaft humeral fracture- the nerve wraps around the posterior aspect of the mid humerus

Question 29

What does the radial nerve supply?

Answer 29

All muscles of the posterior compartments of arm and forearm, lots of skin

Question 30

What does the ulnar nerve supply?

Answer 30

Flexor carpi ulnaris, and ulnar half of the flexor digitorium profundus, most intrinsic muscles of hand.

Question 31

What does the median nerve supply?

Answer 31

Muscles of anterior forearm compartment except for those supplied by ulnar nerve

Question 32

Muscles of the rotator cuffs?

Answer 32

Supraspinatus
Infraspinatus
Teres Minor
Subscapularis

Question 33

The distal tendons of all rotator cuff muscles blend with and reinforce the _______1________ This tendinous “cuff” stabilises the ________2________.

Answer 33

1) fibrous capsule of the shoulder joint.

2) shallow ball and socket of the shoulder join

Question 34

Where do all rotator cuff muscles attach?

Answer 34

Between the scapula and the humerus

Question 35

Which rotator cuff muscles attach to the greater tuberosity of the humerus?

Answer 35

Supraspinatus, infraspinatus and teres minor

Question 36

Which rotator cuff muscles attaches to the lesser tuberosity of the humerus?

Answer 36

Subscapularis

Question 37

Functions of the different rotator cuff muscles?

Answer 37

Supraspinatous does first 15 degree of abduction before deltoid takes over. The infraspinatous and theres minor will do external rotation (they sit on the back of the scapula so will pull the shoulder out. The subscapularis sits on the front of the scapular so will do internal rotation/ medial rotation.

Question 38

Impingement of supraspinatus tendon between the humerus and the acromion process can lead to “painful arc syndrome”

What will patients complain of? How will they present?

Answer 38

; patients with this condition typically complain of pain during 50-130° of abduction.

A patient with supraspinatus paralysis/tendon tear will throw their upper limb to the side to initiate abduction.

Question 39

What two nerves come off the roots of the brachial plexus and what do they supply? What root?

Answer 39

Dorsal scapular nerve: rhomboids and levator scapulae
Long thoracic nerve: serratus anterior
C5

Question 40

What two nerves come off the trunk of brachial plexus? What trunk and what do they supply?

Answer 40

The S nerves- al begin with S and come off the superior trunk
Suprascapular Nerve: supra and infraspinatus
Nerve to subclavius