Anatomy of the Shoulder Flashcards
What are the greater and lesser tubercles of the humerus?
Greater = lateral Lesser = medial
What is the socket part of the ball and socket joint of the shoulder?
Glenoid cavity
What spinal level is the spine of the scapula level with?
T3
What spinal level is the inferior angle of the scapula level with?
T7
What are the 4 joints of the shoulder? Which is a “false” joint?
- Sternoclavicular
- Acromioclavicular
- Glenohumeral
- Scapulothoracic (false)
What is the only bony connection of the UE to the axial skeleton?
Sternoclavicular joint
What type of joint is the sternoclavicular joint?
Cartilaginous disc joint
What are the four ligaments that surround the sternoclavicular joint?
- Sternoclavicular (ant/post)
- Costoclavicular ligament
- Interclavicular ligaments
What are the ligaments that surround the AC joint? (3)
- Acromioclavicular
- Coracoclavicular
- Coracoacromial
What are the two components of the coracoclavicular ligament? Which is medial and which is lateral?
Trapezoid (lateral)
Conoid (medial)
What is the most mobile joint in the body?
Glenohumeral joint
What are the motions of the glenohumeral joint?
- Flexion/extension
- Abduction/adduction
- Medial/lateral rotation
Why is the glenohumeral joint relatively unstable?
Only holds about 1/3 of the humerus
Where is the glenoid labrum weakest?
Anteriorly and inferiorly
What primarily provides stability to the glenohumeral joint: muscles or ligaments?
Muscles
What are the three components of the glenohumeral ligament? Is this on the anterior or posterior part of the glenohumeral joint?
Superior
Middle
Inferior
Anterior part
What is the ligament that sits just above the glenohumeral ligament?
Coracohumeral ligament
What is the ligament that sits on the superior aspect of the glenohumeral joint?
Transverse humeral ligament
What is the function of the glenoid labrum?
Deepens the glenoid fossa
What is the muscle that sits atop the glenohumeral joint?
Supraspinatus
What is the muscle that sits posterior along the glenohumeral joint?
Infraspinatus
What is the muscle that sits posteriorly along the glenohumeral joint, but inferior to the infraspinatus?
Teres minor
What is the muscles that sits anterior to the glenohumeral fossa?
Subscapularis
What are the four muscles that comprise the rotator cuff?
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
What are the spinal levels that comprise the brachial plexus?
C5-T1
What is scalenus anticus syndrome?
Compression of the brachial plexus/axillary artery between the scalenes
What is the Adson’s sign, and what does it assess for?
Adson’s sign is the loss of the radial pulse in the arm by rotating head to the ipsilateral side with extended neck following deep inspiration.
What is costoclavicular syndrome?
Downward movement of the clavicle against the first rib, with a resultant tendency to shearing of the neurovascular bundle
What is the costoclavicular test?
The examiner palpates the radial pulse and then draws the patient’s shoulder down and back as the patient lifts their chest in an exaggerated “at attention” posture. A positive test is indicated by an absence or decrease in vigor of the pulse and implies possible costoclavicular syndrome.
What is pec minor syndrome?
Pec minor compression of the brachial plexus
What is the Wright’s test?
Abduction of the arms bilaterally. Loss of radial pulse may indicate pec minor compression of the neurovascular bundle
What are the three main bursae of the shoulder?
- Subdeltoid
- Subacromial
- Subscapularis
What is the most common cause of bursitis?
Repetitive use
What is the innervation of the serratus anterior? What is significant about this?
Long thoracic nerve (SALT)
Sits superficial to the muscle, and is thus easily damaged
Injury to the long thoracic nerve causes what classic physical exam finding? Why?
Winged scapular d/t loss of innervation to the serratus anterior
What is the origin and insertion of the lat dorsi?
Spinous process of T6 to sacrum
Medial lip of the the intertubercular groove
What is the major muscle of shoulder flexion?
Deltoid
What is the major muscle of shoulder extension?
Deltoid
What are the muscles that are involved with medial rotation of the shoulder? (4)
Subscapularis
Teres major
Pectoralis major
Lat dorsi
What are the muscles that are involved with lateral rotation of the shoulder? (2)
Infraspinatus
Teres minor
What are the two muscles that are involved in abduction of the shoulder? Which initiates movement, and which carries it into full abduction?
Supraspinatus (initiates)
Deltoid (full abduction)
What are the two major muscles that are involved in adduction of the shoulder?
Pec major
Lat dorsi
What are the muscles that cause scapular elevation? (3)
Trap
Levator scap
Rhomboids
What are the two major muscles that cause scapular depression?
Pec minor
Trap
What is protraction of the scapula?
Sticking out the scapula (like hugging oneself)
What is retraction of the scapula?
Bringing the scapula back toward the thoracic cage
What is adhesive capsulitis?
Glenohumeral capsule becomes stiff and inflamed, restricting motion
What are the classic characteristics of a patient with adhesive capsulitis?
Female greater than 50 y/o, with a h/o DM and rotator cuff injury
Which should is usually affected with adhesive capsulitis: the dominant, or the non-dominant?
Non-dominant
What happens to postural muscles with strain? Phasic?
Postural = tight Phasic = Loose
