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LAB MANUAL
|Topic and Text Reference | Learning Objectives | Special Instructions | Clinical Exercises | Key Structures
TOPIC AND TEXT REFERENCE: SUPERFICIAL BACK, UPPER LIMB AND SHOULDER REGION PP. 7-9, 15-19
Video demonstration of Shoulder by Dr. Ort
LEARNING OBJECTIVES: (Click on a Learning Objective to go to the relevant section of the Study Module.)
Learn how to turn the cadaver over properly.
Video instruction for properly turning the cadaver.
Identify the surface anatomy of the back and upper limb.
Begin to learn the art of dissection.
Identify the cutaneous nerves as well as the superficial veins of the upper limb.
Identify the bony landmarks of the scapula, clavicle and humerus on a skeleton.
Identify the rotator cuff muscles and back muscles that move the shoulder.
Identify the borders of the quadrangular space and learn what important neurovascular structures pass through it.
SPECIAL INSTRUCTIONS FOR LAB TODAY:
Pg 7-9: Follow the directions as written in the dissector EXCEPT for cutting the latissimus dorsi muscle and the rhomboids. Do NOT cut these muscles. You may however cut the trapezius muscle. STOP before you do the intermediate muscles of the back.
Pg. 15: Observe the superficial anatomy of the posterior upper limb and then turn the cadaver over into the supine position using the technique shown in the video. If you have questions, please ask for help.
Pg. 15-16: You will see that the upper limb has already been almost fully skinned using slightly different skin incisions. The lateral antebrachial, medial antebrachial, and posterior antebrachial nerves as well as the cephalic, basilic and median cubital veins were all preserved if possible. Identify them on your cadaver or a neighboring cadaver if necessary.
Pg. 17: To dissect the shoulder you will have to turn the cadaver back to the prone position but now you are experts.
Pg. 18-19: Dissect as directed. However you can cut the supraspinatus muscle with your scissors. You do not need a scalpel. The suprascapular ligament is quite deep. Clean dissection of the surrounding muscles allows for optimal viewing. Note the relationship with the suprascapular artery and nerve (mnemonic= hint: army/navy).
CLINICAL CORRELATIONS AND ACTIVITIES:
1. Place your hand on your lab partner’s shoulder and press down as you raise their arm flexed at the elbow. Note that it will not rise above the level of the shoulder. Why?
It will not rise above the shoulder because your hand is preventing your lab partner from rotating their scapula. This movement is an important clinical test for isolating the action of the rotator cuff muscles.
2. Palpate the back of the elbow of your lab partner to feel the epicondyles of the distal humerus. Now palpate the olecranon process. Note that these three bony landmarks describe an equilateral triangle. When this is disrupted, it is a clear sign of injury to the elbow.
3. Why is the scapular anastomotic network important during long term blockage of the axillary or subclavian artery? Is this true for surgical ligations?
The entire blood supply for the upper limb comes from the subclavian artery as it changes its name to the axillary at the level of the clavicle. Therefore if the axillary or subclavian arteries become obstructed the only hope of rescuing the upper limb will be to use anastomotic connections between the two arteries. Think about where blockages could be circumnavigated and where there is no hope. Surgical ligations do not work unless there is already a robust collateral circulation.
4. In which direction is the shoulder more likely to dislocate? Why?
Inferiorly and anteriorly. It typically dislocates inferiorly and then gets pulled anteriorly by the action of the pectoralis minor and major.
KEY STRUCTURES:
You should be able to identify in a cadaver all the structures listed under key words unless they have an asterisk.
Click "I" for images and drawing from our lab, from Netter's, and Gold Standard. Click "S" for relevant pages in the Study Module.
structure |
Netter's |
Gold Standard |
structure |
Netter's |
Gold Standard |
strucuture |
Netter's |
Gold Standard |
| accessory nerve |
|
G1 |
deep fascia |
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subscapularis muscle |
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| anterior axillary fold |
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dorsal scapular nerve |
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superficial fascia |
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| anterior cutaneous nerve |
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infraspinatus muscle |
|
G1 | G2 |
suprascapular ligament |
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| axillary artery |
|
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lateral antebrachial cutaneous nerve |
|
G1 |
suprascapular artery |
|
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| axillary fossa |
|
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lateral cutaneous nerve |
|
|
suprascapular nerve |
N1 |
|
| axillary vein |
|
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latissimus dorsi muscle |
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supraspinatus muscle |
|
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basilic vein
|
|
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levator scapulae muscle |
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teres major muscle |
|
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| bony landmarks of humerus |
N1 |
|
medial antebrachial cutaneous nerve |
|
|
teres minor muscle |
|
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| bony landmarks of clavicle |
N1 |
|
median cubital vein |
|
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thoracodorsal artery |
|
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| bony landmarks of scapula |
N1 |
|
posterior antebrachial cutaneous nerve |
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thoracodorsal nerve |
|
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| brachial plexus |
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G1 |
quadrangular space |
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trapezius muscle |
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| cephalic vein |
N1 |
G1 |
rhomboid minor muscle |
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cubital fossa |
N1 |
G1 |
rhomboid major muscle |
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|Topic and Text Reference | Learning Obje
ctives | Special Instructions | Clinical Exercises | Key Structures
