Shoulder Flashcards
What is the primary restraint to inferior translation of the shoulder at 0° degrees of abduction (neutral rotation)?
SGHL
What resists anterior and posterior translation in the midrange of abduction (~45°) in ER of the shoulder?
MGHL
In the shoulder, what is the primary restraint to anterior/inferior translation 90° abduction and maximum ER (late cocking phase of throwing)
anterior band IGHL
What is the most important static stabilizer of the shoulder joint?
superior band IGHL
What is the function of the superior band IGHL?
the most important static stabilizer about the shoulder joint
What is the composition of the glenoid labrum?
fibrocartilagineous tissue
What is a Buford complex?
A normal variant of the shoulder labrum; there is absence of the anterosuperior labrum with a cord-like MGHL that attaches to the long head of the biceps tendon
What happens if a Buford complex is attached?
Painful and limited ER and elevation
What is the approximate retroversion of the humeral head?
20 degrees
What is the average version of the glenoid?
average version is 5° of retroversion in relation to the axis of the scapular body and varies from 7° of retroversion to 10° of anteversion
What are the muscle attachments to the coracoid?
- coracobrachialis
- pectoralis minor
- short head of the biceps
What is the average acromiohumeral interval?
acromiohumeral interval is 7-8mm
What provides the blood supply to the humeral head?
The ascending branch of the anterior humeral circumflex artery and the posterior humeral circumflex artery (most current literature supports this as the main blood supply to the humeral head)
The rotator cuff experiences the greatest stress at which phase of throwing?
deceleration phase; eccentrically slowing the arm
Hornblower’s sign is indicative of what?
Teres minor injury
Anterior shoulder dislocations in patients older than 40 years may result in rotator cuff tears; what is the most commonly affected rotator cuff tendon?
Supraspinatus
What patient is the optimal candidate for a latissimus dorsi transfer?
young laborer with massive posterior/superior RCT, atrophy and fatty infiltration
What nerve is most at risk during pectoralis major tendon transfer?
Musculocutaneous
What nerve is most at risk during latissimus dorsi tendon transfer?
Radial nerve
What is the most common finding during arthroscopic surgery for traumatic anterior shoulder instability?
anteroinferior labral tear
What is the blood supply to the serratus anterior?
Long thoracic artery (superiorly); thoracodorsal artery (inferiorly)
What is the innervation of the trapezius?
Spinal accessory nerve (cranial nerve XI)
What is the innervation of the rhomboid muscles?
Dorsal scapular nerve
What are the contents of the quadrilateral space?
axillary nerve (C5) and posterior humeral circumflex artery
What is the innervation of teres minor?
axillary nerve
Suprascapular notch entrapment of the suprascapular nerve causes weakness in what muscle(s)?
supraspinatus and infraspinatus
Spinoglenoid notch entrapment of the suprascapular nerve causes weakness in what muscle(s)?
infraspinatus ONLY
What genetic mutation is associated with Parsonage-Turner syndrome?
gene septin 9 on chromosome 17q24
What are the soft tissue adaptations to glenohumeral internal rotation deficit (GIRD)?
increased sulcus sign, humeral head and glenoid retroversion, SLAP tears and articular sided partial RCTs; will see increased shoulder ER and a deficit in IR
What are the properties of C. acnes?
gram positive, facultative, aerotolerant, anaerobic rod that ferments lactose to propionic acid
What nerve roots supply the long thoracic nerve?
C5, C6, C7
The long thoracic nerve supplies which muscle?
Serratus anterior
Injury to the serratus anterior or long thoracic nerve causes what type of scapular winging?
Inferomedial scapular winging (the inferior and medial border to wing out as the serratus is not able to hold it lateral/anterior)
What is the innervation of the rhomboids?
Dorsal scapular nerve
The latissimus dorsi muscle is innervated by what nerve?
thoracodorsal nerve
What nerve innervates teres major?
lower subscapular nerve
Which nerve roots supply the dorsal scapular nerve?
C4 and C5 (mostly C5)
What nerve roots supply the thoracodorsal nerve?
C6-C8
Which nerve roots supply the suprascapular nerve?
C5 and C6
What are the anatomic boundaries of the rotator interval?
Superior: anterior border of the Supraspinatus tendon
Inferior: the superior border of the subscapularis
Medial: coracoid
Lateral: transverse humeral ligament
What are the contents within the rotator interval?
Long head of the biceps tendon; superior Glenohumeral ligament; coracohumeral ligaments
Which nerve could be injured during a latissimus dorsi transfer due to its proximity?
Radial nerve; it runs immediately deep (anterior) to LD tendon 3 cm medial to its insertion on the humerus
If someone has an internal rotation contracture of the shoulder, they can not abduct beyond […] degrees
120 degrees
What prevents anteroinferior translation of long head of biceps (biceps pulley)?
SGHL
In the shoulder, what is the most important restraint to posterior subluxation at 90° flexion and IR?
Posterior band of the IGHL
Tightness in the […] leads to internal impingement and increased shear forces on superior labrum in the shoulder
posterior band of the IGHL
Which band of the IGHL anchors into anterior labrum?
anterior
What is the origin and insertion of the coracohumeral ligament?
coracoid to rotator cable
The coracohumeral ligament limits […] translation with shoulder in flexion, adduction, and internal rotation
posterior
The glenoid labrum creates […] percent of the glenoid socket depth
50
Which region of the glenoid labrum has the poorest blood supply?
anterior-superior labrum
What is the medial boundary of the rotator interval?
coracoid
What is the superior boundary of the rotator interval?
Supraspinatus
What is the inferior boundary of the rotator interval?
Subscapularis
What is the lateral boundary to the rotator interval?
transverse humeral ligament
What is the average diameter of the humeral head?
43mm
The humeral head has an approximate retroversion of […] degrees from transepicondylar axis of the distal humerus
20
The humeral head articular surface inclined upward […] degrees from the shaft
130
The glenoid has an average upward tilt of […] degrees
5
What is the average version of the glenoid?
5° of retroversion
The ascending branch of anterior humeral circumflex artery runs along the […] aspect of the long head of the biceps in the bicipital groove
lateral
A sulcus sign of […] has a specificity of up to 97% for multidirectional instability
2 cm
What exam finding is most commonly associated with multidirectional instability?
Sulcus sign (great than 2 cm is very specific)
