Shoulder/Upper Arm Anatomy

Question 1

Draw out the brachial plexus diagram

Answer 1

Compare to onenote

Question 2

Where in the spine does the brachial plexus orginate?

Answer 2

C5-T1 anterior rami

Question 3

Look at the diagram in onenote and label A-J on it

Answer 3

A - lateral pectoral nerve
B - musclocutaneous nerve
C - axillary nerve
D - median nerve
E - ulnar nerve
F - median cutaneous nerve of the arm
G - upper subscapular
H - long thoraric nerve
I - dorsal scapular nerve
J - suprascapular

Question 4

What are the 4 rotator cuff muscles?

What is the innervation of each?

What is the role of each?

Answer 4

SITS

supraspinatus
infraspinatus
teres minor
subscapularis

supra+infraspinatus - suprascapular
teres minor - axillary
subscapularis - upper and lower subscapular

supraspinatus = abducts arm 0-15 and assists deltoid for rest of abduction
infraspinatus + teres minor = lateral rotation
subscapularis = medial rotation

Question 5

What are the muscles of the anterior and posterior arm?

What innervates each?

Answer 5

Anterior

• Biceps brachii
• Brachialis
• Coracobrachialis

^musculocutaneous^

Posterior
- Triceps brachii

^radial^

Question 6

What is contained with the quadrangular space in the posterior shoulder?

What is it’s boundaries?

What muscles would loss function as a result of quadrangular space syndrome (QSS)?

Answer 6

Axillary nerve
Posterior circumflex humeral artery

Teres minor
Teres major
Surgical neck of the humerus
Long head of the triceps brachii

Teres minor
Deltoid

Question 7

What can be found in the suprascapular notch in the scapula?

Answer 7

Superior transverse scapular ligament

• Posteriorly = suprascapular nerve
• Anteriorly = suprascapular artery

Question 8

What space does the radial nerve enter the arm through?

What are it’s boundaries?

Answer 8

Triangular interval

Humerus
Teres major
Long head of triceps brachii

Question 9

What part of the arm’s sensory supply comes from the axillary nerve?

Answer 9

Badge patch region - think stone island

Question 10

What nerve runs through the spinal groove in the humerus?

Answer 10

Radial

Question 11

What nerve pierces through the coracobrachialis muscle?

Answer 11

Musculocutaneous

Question 12

What rotator cuff muscles insert into the greater tuberucle and what ones insert into the lesser tubercle of the humerus?

Answer 12

Greater =
supraspinatous
infraspinatous
teres minor

Lesser
= subscapularis