EXAM 2 Anatomy: Shoulder and Pec Region

Question 1

Explain the anatomical location of the following bones in comparison to one another:

Radius and ulna

Tibia and fibula

Answer 1

In the anatomical position:

Radius (lateral), ulna (medial)

Fibula (lateral) tibia (medial)

Question 2

Facial Compartments of the Shoulder/Pec Region:

_________ covers the pectoralis major

_________ is a continuation of pectoral facia laterally

_______ deep to pec major: encloses subclavius and pec minor

Answer 2

Pectoral Fascia: covers pec major muscle

Axillary fascia: continuation of pectoral fascia laterally

Clavipectoral fascia: deep to pec major, encloses subclavious m. and pectoralis minor m.

Question 3

Be able to identify all of the parts of the:

humerus

clavicle

scapula

(this card indicates go over to lumen learn ‘em)

Question 4

Explain the following muscles:

Pectoralis Major

Pec minor

Answer 4

Pectoralis Major: large, fan shaped muscle covering most of anterior thoracic wall

Pec minor: useful landmark for axillary artery components

Question 5

________: sawtoothed muscle helps stabilize scapula (boxer’s muscle)

What nerve innervates this muscle?

Explain how it is attached to the scapula

Answer 5

Serratus anterior: sawtoothed muscle helps stabilize scapula (boxer’s muscle)

The serratus anterior muscle is innervated by the long thoracic nerve

This muscle attaches to MEDIAL border of scapula, keeps it from “floating off ribcage”, protracts (pulls forward) and rotates scapula…. aka to punch

Question 6

Muscles of anterior shoulder:

If you want to abduct your arm (move your humerus away from your body outward and towards your head) what muscles are involved?

What muscle initiates the first abduction, then what muscle abducts the humerus to 90 degrees and then what muscle completes the movement?

Answer 6

Muscles of anterior shoulder:

Supraspinatus initiates first 10-15 degrees

Deltoid abducts the humerus to 90 degrees

and then the trapezius completes it to 180 degrees

Question 7

Name the four rotator cuff muscles

Which one is the most frequently torn in rotator cuff injuries

(Hint: the pneumonic for rotator cuff muscles is SitS)

Answer 7

Rotator Cuff Muscles:

Supraspinatus , infraspinatus, teres minor, and Subscapularis

• Supraspinatus is the most frequently torn

Note: you should be able to label these on lumen learn ‘em

Question 8

Explain the movement of the various rotator cuff muscles (how they move the shoulder joint). Also give the innervation of each rotator cuff muscle:

1. Supraspinatus
2. Infraspinatus
3. Teres minor
4. Subscapularis

Answer 8

1. Supraspinatus : innervated by the suprascapular neve, works to ABduct
2. Infraspinatus: innervated by the suprascapular nerve, works as a lateral rotator
3. Teres minor: innervated by the axillary nerve, also works as a lateral rotator
4. Subscapularis: innervated by the upper and lower subscapular nerve, works as a medial rotator

Note: to remember the innervations:

• the suprascapular nerve innervates both supraspinatus and infraspinatus
• axillary nerve innervates teres minor
• subscapular nerve innervates subscapularis

Question 9

Think of the posterior shoulder:

Explain the various movements and innervations of the following muscles (you should also be able to label these on lumen learn ‘em)

Teres Major

Lattisimus dorsi

Levator scapulae (innervation not on chart)

Rhomboids (innervation not on chart)

Answer 9

1. Teres Major: adducts and medially rotates arm (innervated lower subscapular)
2. Latissimus dorsi: extends, adducts, and medially rotates humerus (innervated by thoracodorsal nerve)
3. Levator scapulae: elevates scapula medially, rotates glenoid cavity inferiorly
4. Rhomboids: allows you to drop your shoulder

Question 10

Give the innervation of the following muscles

1. Pec major and pec minor muscles
2. Deltoid
3. Teres minor
4. Lattimus dorsi
5. Serratus anterior

Answer 10

Innervations:

1. Pec major (medial and lateral pectoral nerves) and pec minor (medial pectoral nerve)

2/3. Both deltoid and teres minor (axillary nerve)

4. Lattisimus dorsi (thorocodorsal nerve)
5. Serratus anterior (long thoracic nerve)

Question 11

Subclavian Artery Branches:

(There is a nice pneumonic to name the branches of the subclavian artery)

What are the three parts of the subclavian artery?

Which part does the suprascapular artery branch off of?

Answer 11

Subclavian artery:

VIT amin C and D

First part (VIT): Vertebral, Thyrocervical, and Internal Thoracic

Second part: Costocervical trunk

Third part: Dorsal subscapular

Note: the suprascapular artery comes off the thyrocervical trunk of the subclavian artery

Question 12

Axillary Artery Branches:

The branches of the axillary artery are related to _________ muscle

Explain the branches of the axillary artery : reminder, there is a pneumonic about a lawyer

Note: you should also be able to label these on lumen learn ‘em

Answer 12

Axillary Artery Branches:

The branches of the axillary artery are related to the pectoralis minor m.

Branches: (Screw the Lawyer Save A Patient

1: Superior Thoracic
2. Thoracoacromial trunk and Lateral thoracic arteries
3. Subscapular, Anterior and Posterior circumflex humeral arteries

Question 13

Explain from proximal to distal, or medial to lateral how the artery supply to the shoulder region goes?

Answer 13

Subclavian ——-> Axillary ——–> Brachial

Question 14

Explain how the axillary artery can become blocked, but you won’t lose feeling or blood flow to your fingers.

Answer 14

If the axillary artery gets blocked, blood can keep flowing through suprascapular artery, around the back of the scapula and into the circumflex scapular artery and down into the brachial artery

(If confused look at attached picture)

Question 15

Explain which artery and nerve lies within each region in the posterior shoulder:

Suprascapular Notch

Quadrangular Space

Triangular Space

Triangular Interval

Answer 15

Suprascapular Notch: Suprascapular artery and nerve (Army over Navy….. artery on top, nerve underneath)

Quadrangular Space: axillary nerve and posterior circumflex humeral artery (“question all patients”)

Triangular space: circumflex scapular artery

Triangular Interval: profunda brachii artery and radial nerve

Question 16

Arteries of posterior shoulder

Identify which “unique space” each artery can be seen in:

Suprascapular artery

Posterior circumflex humeral artery

Circumflex scapular artery

Profunda brachii artery

Answer 16

Suprascapular artery: suprascapular notch

Posterior circumflex humeral artery: quandrangular space

Circumflex scapular artery: triangular space

Profunda brachii artery: triangular interval

Question 17

Axilla:

a pyramid shaped space inferior to the ______ and superior to the _____

Serves as a protected passageway for what vascular structures?

Answer 17

Axilla:

a pyramid shaped space inferior to the glenohumeral joint and superior to the axillary fascia

Serves as protected passageway for neurovascular structures of (axillary artery and axillary vein and the brachial plexus)

Question 18

Explain within which “unique space” of the posterior shoulder do these nerves lie within:

Suprascapular nerve

Axillary nerve

Radial nerve

Answer 18

Suprascapular nerve: suprascapular notch

• reminder: runs under suprascapular artery

Axillary nerve: Quandrangular space

• reminder, is with posterial humeral circumflex artery

Radial Nerve: triangular interval

• reminder: is with profunda brachii artery

Question 19

TopHat Questions:

1. The lattisimus dorsi muscle is innervated by which nerve?
2. Which artery runs with axillary nerve through the quadrangular space?
3. Which muscle the rotator cuff muscle that LATERALLY rotates the shoulder?

Answer 19

1. Latissimus dorsi is innervated by thorocodorsal nerve
2. Axillary nerve and posterior humeral circumflex a. are within the quandrangular space
3. Infraspinatus (rotator cuff muscle) laterally rotates the shoulder