Lab_6_The_Upper_Extremity_1

The Upper extremity I 0 BIO 446L Human Microscopic & Gross Anatomy Laboratory Manual Spring 2023 Visible Body Team Soroosh Sadeh, M.S. Gonie Altman, B.S. Supplies and Equipment: All students must wear long pants and closed toe shoes in lab. Please do NOT bring FOOD OR DRINK into lab.

The Upper extremity I 1 Lab 6: The Upper Extremity I Objectives: 1. Be familiar with the brachial plexus. 2. Be familiar with bones of the upper limb and know the main features and landmarks (clavicle, scapula and humerus). 3. Be familiar with the shoulder joint, rotator cuff muscles and its common injury. 4. Know the functions and innervation of the muscles listed in the manual (main shoulder and elbow movers). 5. What happens to the functionality of a joint if there is a nerve damage? 6. Be familiar with joints range of motion. 7. Can you investigate potential problems with a fractured clavicle?

The Upper extremity I 3  In the search bar, type in each of the following nerves to see their path and the muscles/regions they innervate. o Musculocutaneous nerve o Median nerve o Ulnar nerve o Radial nerve o Axillary nerve o Thoracodorsal nerve o Upper subscapular nerve o Suprascapular nerve o Lower subscapular nerve  These are some of the major branches. You must know them and the muscles they innervate. The muscles you need to know with their innervation will be introduced during this lab and the next lab. Section: Shoulder and Arm Anatomy Resources to use:  Visible Body Human Anatomy Atlas App.  Disarticulated skeleton model in the lab. Activity 1: Bones of the Shoulder Girdle and their Landmarks  Be able to identify the bones of the shoulder girdle and the upper arm as well as their bony landmarks: clavicle , scapula, and humerus.  Clavicle + Scapula: Make up the pectoral/shoulder girdle and are responsible for attaching the upper limbs to the skeleton and provide attachment points for the shoulder muscles.  In Human Anatomy Atlas app, i n the Skeletal System Views, select View 16. Axillary Region to observe how muscles attach to the clavicles and scapulae. o You can select the systems icons on the left side of the screen to hide blood vessels, lymphatic vessels, and nerves.  The shoulder has the greatest range of motion of any joint in the body, and the many muscles that attach here are known as stabilizer muscles due to its large range of motion (ROM). Scapula  In the Human Anatomy Atlas app click on the scapula and isolate the bone. Find the landmarks listed below and then do the same with the models on your table.  Note: You are only responsible for knowing the landmarks that are italicized. o Glenoid cavity o Spine o Acromion o Coracoid process o Infraspinous fossa o Supraspinous fossa o Subscapular fossa o Inferior angle o Superior angle o Lateral border

The Upper extremity I 4 o Medial border o Neck o Acromial angle  Describe how you would distinguish between a right and left scapula. Clavicle  Next isolate the clavicle and find the following landmarks. Then try and find these same landmarks on the model. (you may add the image of your labeled bone here)  Note: You are only responsible for knowing the landmarks that are italicized . o Acromial end o Sternal end o Shaft o Conoid tubercle  Describe in which direction the clavicle curves and how it articulates with other bones. Humerus  Isolate the humerus bone and find the following landmarks. Then try and find these same landmarks on your disarticulated skeleton.  Note: You are only responsible for knowing the landmarks that are italicized . o Head o Anatomical neck o Surgical neck o Shaft o Greater tubercle o Lesser tubercle o Intertubercular groove o Radial groove o Deltoid tuberosity o Trochlea o Capitulum o Coronoid fossa o Olecranon fossa o Medial epicondyle o Lateral epicondyle o Radial fossa  What is the difference between the anatomical neck and the surgical neck of the humerus?

The Upper extremity I 6 o Name three static stabilizers for the shoulder and explain the overall function of these muscles. o Dynamic stabilizers are muscles that surround the joint and when they contract produce movement. A specific group of muscles under this classification are the rotator cuff muscles. They compress the head of the humerus into the glenoid fossa and stabilize movements in all directions. Name the four muscles of the rotator cuff. Activity 2: Rotator Cuff Anatomy and Function  Using the right arrow, navigate to slide 3 of 3 entitled “Normal Anatomy.”  In the view, select each muscle and bone to learn its name. Then, identify the structures indicated by each letter on the image below, and fill in their names in the corresponding spaces beneath the image. Can you identify any of these muscles on your shoulder joint model? A. A. B. B. C. D. E. F.  Select each muscle, then select the icon to learn their actions. List their actions, attachments and innervation in the table below. Rotator Cuff Muscles Muscle Origin Insertion Action Innervation Infraspinatus

The Upper extremity I 7 Supraspinatus Subscapularis Teres minor Activity 3: Rotator Cuff Tear  In Muscle Premium App navigate to Pathologies, then find Rotator Cuff Tear under Shoulder.  Select the icon and read the description of rotator cuff tears. Then answer the following questions in 1-2 sentences. o Gradual degeneration or a sudden traumatic event can tear what structures of the rotator cuff? o What are the symptoms of this injury? o Where is the common location of rotator cuff tears? o Tears are usually categorized in two ways. Explain the two categories. o Which muscle of the rotator cuff is most commonly torn? Activity 4: Partial Tear of the Supraspinatus  Using the right arrow, navigate to slide 2 of 3 entitled “Partially Torn Supraspinatus.” o Note the tear in the tendon of the supraspinatus. Describe the location of the tear and why it’s a partial tear in 1-2 sentences. o Select the icon to learn more about the partially torn supraspinatus. What is the function of the supraspinatus? o The supraspinatus tendon can begin to fray from overuse, poor posture, or the wear and tear of aging. It can also fray due to excessive strain. Based on what you’ve read, list two examples of actions that may involve excessive strain and cause a tear.  Fill in the blanks: A traumatic event such as ______ can also cause tears of the supraspinatus tendon. Fraying and degenerative tears can also be caused by chronic ______ . Activity 5: Arm Synergists / Fixators  Open the Visible Body Anatomy and Physiology App.  View Module 16.34 (Arm: Synergists / Fixators) and Module 16.35 (Arm: Rotator Cuff).  These muscles primarily act to stabilize the scapula and move the arm and four of them are part of the rotator cuff muscles previously mentioned.

The Upper extremity I 9 Arm: Prime Movers Muscle Origin Insertion Action Innervation Pectoralis major Deltoid Latissimus dorsi Review your answers with your group mates and your TAs.

The Upper extremity I 10 Section: Muscles of the Elbow Joint Resources to use:  Visible Body Human Anatomy Atlas App or Visible Body Muscle Premium App  Visible Body Physiology and Anatomy App  Upper Limb Models in the lab Activity 1: Elbow Flexors  View Module 16.36 Forearm: Elbow Flexors  These muscles are all located on the anterior side of the humerus and cross the elbow to insert on the radius or ulna (we will study these bones in the next lab). o Biceps brachii is named for its “two heads;” note the two different origins of this muscle.  Complete the following table. You need to understand each muscle’s action and innervation. Forearm: Elbow Flexors Muscle Origin Insertion Action Innervation Biceps brachii (long and short heads) Brachialis

The Upper extremity I 12 Review your answers with your group mates and your TAs. Section: Review of the Muscles of the Shoulder and Elbow *TA talking point.  Using the biceps muscle, we will describe its various actions at the shoulder and elbow joints. This is an example of a muscle that passes more than one joint and has multiple actions at these joints.  Major Muscles of the Shoulder (glenohumeral) joint o Flexion: Anterior Deltoid, Biceps, Coracobrachialis, Pectoralis major (Clavicular head). o Extension: Posterior Deltoid, Triceps (long head), Latissimus dorsi (from the flexed position), Teres major. o Abduction: Lateral Deltoid, Supraspinatus. o Adduction: Pectoralis major, Teres major, Latissimus dorsi, coracobrachialis. o Medial rotation: Pectoralis major, Latissimus dorsi, Teres major, Subscapularis, anterior deltoid. o Lateral rotation: Infraspinatus, Deltoid (spiral part), Teres minor.  Focus on the muscles listed above and disregard the minor muscles you may see while working on the modules. You need to be able to identify the muscles on the models in the lab. **Remember, that sometimes a joint must be placed in hyperextension or flexion for that muscle to work as described. Activity 1: Review Questions/Nerve Damage  Which muscles are part of the rotator cuff muscles and what is their main function as a whole?  Which muscles are used when performing the following actions? o Raising your hand high over your head during class o Rowing a boat o Reaching behind you, arm extended and pronated o Reaching in front of you, arm extended and supinated o Bringing your hand to your heart  What would happen if the musculocutaneous nerve is cut off of the brachial plexus? o Is there another muscle(s) with a different innervation that can still allow for flexion? YES or NO o Can the same be said for the other actions at the shoulder? Note, this is very important in physical therapy  What muscles can flex at the elbow? Biceps Y / N, Brachialis Y / N, Pronator teres (look it up in Human Anatomy Atlas) Y / N, Brachioradialis Y / N o Would you need the entire biceps muscle fibers to flex at the elbow? Y / N o Would you need the entire biceps muscle to flex at the elbow with a 10 lb weight in your hand? Y / N / maybe

The Upper extremity I 13 o What muscle might you use to help if you cannot? Brachialis Y / N o Now, I am trying to pick up a 50 lb weight and flex at the elbow. Other than the biceps and brachialis muscles, what other muscles might I recruit to help? Pronator teres Y / N, brachioradialis Y / N  Because the pronator teres and the brachioradialis do other actions at the elbow, if you want to recruit them, you cannot ask them to do their other actions at the same time.  What are their other actions?  Now, what happens with flexion if you cut the musculocutaneous nerve? o You have lost the use of what muscles?  Can you still flex at the elbow? Y / N, if yes, why? o What is the innervation to the other muscles? Review your answers with your group mates and your TAs. Section: Joint Range of Motion (ROM)  Health care professionals commonly test different joints in the body for their range of motion (ROM) . A joint’s range of motion is usually measured by the number of degrees from the starting position of a body segment to its position at the end of its full range of motion. The starting position is the zero position (or zero degrees) which is in the anatomical position.  We use a double-armed goniometer to measure ROM, which has a stationary body segment and a moveable arm that moves along a moveable body segment. The axis of the goniometer, also known as a pin, is placed over the joint and the armed follow the movement of the two bones that create the joint. o When anatomical landmarks are well defined, the accuracy of measurement is greater. If there is more soft tissue surrounding the joint area, measurement error can be more frequent. Activity: Upper limb ROM  For this exercise, we will use a goniometer to make measurements. Get the TAs to assist you with the use of the goniometer.  Shoulder abduction o Using figure 1 below, stand behind a subject and palpate the scapula o Have the subject slowly abduct his/her arm at the shoulder joint. o Record the number of degrees of shoulder joint abduction at the point the scapula starts moving. _____

The Upper extremity I 15 Figure 3. Medial and Lateral Rotation of the Shoulder Joint or segment Movement Average ROM (multiple sources) Forearm Pronation 80-90 Supination 80-90 Shoulder Flexion 170-180 Hyperextension 30, 50, 60, 80, depending on source Abduction 170-180 Adduction 50

The Upper extremity I 16 Section: Case Study  A 15-year-old male comes to the emergency department complaining of severe pain over his right collarbone. He uses his left hand to hold his right arm close to and across the front of his body. He explains while playing baseball, he collides with the pitcher when running to first base. The impact knocked him off his feet and he fell on his right shoulder. His mother, and others nearby, reported hearing a loud snap. When he stood up, he was slouched and complained of extreme pain on the impact area.  Radiography of his right shoulder revealed a _______ fracture. See figure below: Figure 1 Physical Examination The following findings were noted on physical examination:  Prominence, ecchymosis 1 , and tenderness over the right midclavicular region  Diffuse swelling over the right clavicle, shoulder, and arm  Right upper limb depressed (i.e., lower than left)  Mild numbness over right upper limb  Right radial pulse weaker than left  Lung sounds normal  Which muscles act on the clavicle? You can use Visible Body Human Atlas and find the clavicle. Click on the bone, then click on the details icon, then muscle attachment to find these muscles.  With logical reasoning and help from Human Anatomy Atlas app explain the position of shoulder and arm (motor deficit) and clavicle due to the type and location of the injury (think of the muscles you listed in the previous question and how they are oriented relative to the clavicle and the glenohumeral joint). 1 Ecchymosis Hemorrhage into skin (bruising)