MSK 15 - Upper Limb-I Flashcards
How can you tell which end of the clavicle is which?
The flat end is the acromial end and the quatdrangular end is the sternal end
Where do most fractures of the proximal humerus occur and what else can be injured with these fractures?
List all of the joints of the shoulder complex.
- Sternoclavicular (sternum and clavicle)
- Acromioclavicular (scapula and clavicle)
- Glenohumeral (humerus and scapula)
- Scapulothoracic (scapula and thorax)
What are the synovial joints of the shoulder complex?
Sternoclavicular
Acromioclavicular
Glenohumeral
What is impingement syndrome?
A clinical syndrome which occurs when the tendons of the rotator cuff muscles become irritated and inflamed as they pass through the subacromial space
What type of movement does the sternoclavicular joint do?
What ligaments form/reinforce the sternoclavicular joint?
- Anterior sternoclavicular ligament (forms most of the joint)
- Interclavicular ligament
- Costoclavicular ligament
What type of movement does the acromioclavicular joint allow for and what ligaments reinforce this joint?
What is the glenoid labrum and what is its primary purpose?
The glenoid labrum (glenoid ligament) is a fibrocartilaginous rim attached around the margin of the glenoid cavity in the shoulder blade. It serves to deepen and strengthen the glenohumeral joint
Where does the synovial membrane of the glenohumeral joint attach?
To the margins of the articular suface
What ligaments serve to thicken the joint capsule of the glenohumeral joint?
The superior, middle, and inferior glenohumeral ligaments
The coracohumeral ligament
The transverse humeral ligament
When a clavicle is broken, how are the fragments usually displaced and why?
What are some injuries typically associated with a clavicle fracture?
Pneumothorax
Damage to subclavian vein and artery
What are the varying degrees of shoulder separation injuries?
List the muscles that act on the shoulder joint and what they do.
- Deltoid - abducts arm from 15-90 degrees
- Pectoralis major - flexion, adduction and medial rotation of arm
- Serratus anterior - rotates scapula upward for abduction of arm above 90 degrees
- Trapezius - helps rotate scapula during abduction of arm >90 degrees, elevation of scapula
- Teres major - extension, adduction, medial rotation of the arm
- Latissimus dorsi - extends, adducts and medially rotates arm
- Supraspinatus - abduction of arm from 0-15 degrees
- Infraspinatus - lateral rotation of arm
- Subscapularis - medial rotation of arm
- Teres minor - lateral rotator of arm
List the muscles that act on the shoulder joint and the nerves that innervate them.
- Deltoid - axillary nerve
- Pectoralis major - medial and lateral pectoral nerves
- Serratus anterior - long thoracic nerve (C5-C7)
- Trapezius - spinal accessory nerve
- Teres major - lower subscapular nerve
- Latissimus dorsi - thoracodorsal nerve
- Supraspinatus - suprascapular nerve
- Infraspinatus - suprascapular nerve
- Subscapularis - upper and lower subscapular nerves
- Teres minor - axillary nerve
What is the mnemonic to remember the rotator cuff muscles?
SITSS
S - Supraspinatus
I - Infraspinatus
T - Teres minor
SS - subscapularis
Discuss the most common rotator cuff injury.
What is Hilton’s law?
Any nerve that provides motor innervation to the muscles acting on a joint will also carry sensation from the joint
List the vessels that innervate and supply blood to the shoulder joint.
Innervation - posterior cord of the brachial plexus, terminal branches of the brachial plexus, suprascapular nerve, axillary nerve, and the lateral pectoral nerves
Blood Supply - branches of the antreior and posterior circumflex humeral and suprascapular arteries
Why are many shoulder dislocations in the anterior-inferior direction?
Typically the subscapularis is the muscle of the rotator cuff that gives out first. Because of this most should dislocations occur toward that muscle which is anteriorly and inferiorly
What neurovascular structures are often damaged in shoulder dislocation injuries? What sensory and motor deficits could this lead to?
Axiallary nerve and posterior humeral circumflex artery
This could lead to a decreased ability to laterally rotate the arm (teres minor), abduct the arm from 15-90 degrees (deltoid), and could lead to a sensory deficit in the upper lateral part of the arm.
