1. Trauma: Shoulder - Impingement Flashcards
What are the two types of impingement?
External and Internal
impingement of the rotator cuff overlying the bursal surfaces (superficial surfaces) that are adjacent to the coracoacromial arch
External
The coracoacromial arch is made up of
coracoid process, acromion, and coracoacromial ligament
What are the Primary External Causes of impingment (Abnormal Coracoacromial Arch)
- Hooked acromion
- Subacrimial Osteophyte Formation
- Subcoracoid Imingement
Subacromial osteophyte formation or thickening of the coracoacromial ligament can impinge on what tendon?
Supraspinatus tendon
Impingement of the subscapularis between the coracoid process and lesser tuberosity (on axial look for a reduced coracohumeral distance). This can be secondary to congenital configuration, or a configuration developed post traumatically after fracture of the coracoid or lesser tuberosity.
Subcoracoid impingement:
typically seen in patients with generalizedjoint laxity
“Multidirectional Glenohumeral Instability”
This refers to impingement of the rotator cuff on the undersurface (deep surface) along the glenoid labrum and humeral head.
Internal
This is internal impingement that occurs when the arm is in horizontal adduction and internal rotation. In this position, the undersurface o f the biceps and subscapularis tendon may impinge against the anterior superior glenoid rim.
Anterior Superior
*Abnormal Coracoacromial Arch — Hook Shaped (B3)
— Osteophytes
—Post Traumatic
—Thickened Ligaments
External Primary
‘ Multidirectional Instability
—Labrum Often Normal
—“Increased Glenohumeral Volume” - with injection
External Secondary
*Throwers
—F’s with Infraspinatus (and posterior Supra)
—Posterior Superior Labrum Torn
—Cystic Change in Greater Tuberosity
Internal Posterior Superior
—Associated with Sub Scapular damage (Maybe the cause rather than the result)
—Anterior Superior Labrum Torn
Internal Anterior Superior
If the exam writers just say “Internal
Impingement” - this is the one they are talking about
Internal Posterior Superior
most common form
resulting from attrition of the coracoacromial arch.
Subacromial Impingement
Damages Supraspinatus
Lesser tuberosity and coracoid do the pinching.
Subcoracoid Impingement
Dmages Subscapularis
(remember the coracoid is anterior - and so is the subscapularis).
Athletes who make overhead movements. Greater tuberosity and posterior superior labrum do the pinching.
Posterior Superior “Internal” Imninsement
Damages Infraspinatus (and posterior fibers of the supraspinatus).
most common of the four muscles to tear is
the Supraspinatus
Most tears in the supraspinatus occur at
The critixal Zone 1-2 cm fromt the tendon footprint
the most common location for Calcium Hydroxyapatite (HADD) - or “calcific tendinitis.” in the supraspinatus?
Criical Zone (1-2 cm from the footprint
What tear extent warant surgical intervention
A partial tear > 50%
How do you know it’s afull thickness tear?
An inflammatory condition characterized by a global decrease in motion.
Adhesive Capsulitis “Frozen Shoulder”
Adhesive Capsulitis “Frozen Shoulder” commonly affects what structure
Rotator cuff interval
Adhesive Capsulitis “Frozen Shoulder”
Grey Smudgy Shit Instead of Clean Fat in the Rotator Cuff Interval
Labral tears favors =
Superor marign + anterior to posterior
SLAP tear involvement
Insterition = long head biceps
SLAP injury mechanism
Over-head movment (classic = swimmer)
A SLAP mimic = normal varint = incomplete attachment of the labrum at 12 o’clock’
Sublabral Recess
This is an unattached (but present) portion of the labrum - located at the anterior-superior labrum (1 o’clock to 3 o’clock).
Sublabral foramen
As a rule it should NOT extend below the equator (3 o’clock position).
absent anterior/superior labrum (1 o’clock to 3 o’clock), along with a thickened middle glenohumeral ligament.
Buford Complex
Superficial partial labral injury with cartilage defect
No instability
Glenolabral Articular Disruption
Avulsed anterior labrum (only minimally displaced).
Inferior
GH complex still attached to periosteum
Intact Periosteum (lifted up)
Perths
Medially displaced labroligamentous complex with absence of the labrum on the glenoid rim. Intactperiosteum. It scars down to glenoid.
Intact Periosteum
Anterior Labral Periosteal Sleeve Avulsion (ALPSA)
Torn labrum
Periosteum Disrupted
True Bankart
A fracture o f the posterior inferior rim ofthe glenoid.
Reverse Osseous Bankart
This is the bizarro version o f the ALPSA, where the posterior labrum and the posterior scapular periosteum (still intact) are stripped from the glenoid resulting in a recess that communicates with the joint space.
POLPSA
An extra-articular curvilinear calcification - associated with posterior labral tears (maybe the POLPSA).
It’s related to injury of the posterior band of the inferior glenohumeral ligament.
“Bennett Lesion”
An incompletely avulsed / flattened / mashed posterior- inferior labrum.
“glenoid cartilage and posterior labrum relationship is preserved.”
Kim’s Leison
anterior shoulder dislocation = Avulsion = Inferior glenohumeral ligament avulsion
HAGL (Humeral avulsion glenohumeral ligament)
HAGL (Humeral avulsion glenohumeral ligament).
The “J Sign” occurs when the normal U-shaped inferior glenohumeral recess is retracted away from the humerus, appearing as a J.
Axial MR - Showing the IGHL Tom at its Humeral Attachment
The subscapularis attachment =
It sends a few fibers across the bicipital groove to the greater tuberosity =
The subscapularis attaches to the lesser tuberosity. It sends a few fibers across the bicipital groove to the greater tuberosity , which is called the “transverse ligament”
Subscapularis Tear =
Medial Dislocation of the Long Head of the Biceps Tendon.
Subiuxation of the Biceps Tendon
Occurs with a Tear of the Subscapularis
A cyst at the level of the suprascapular notch will affect =
supraspinatus and the infraspinatus
A cyst at the level of teh spinoglenoid notch will only affect what?
infraspinatus
Cyst in the spinoglenoid notch causing fatty atrophy of the Infraspinatous
Compression of the Axillary Nerve in the Quadrilateral Space (usually from fibrotic bands)
Quadrilateral Space Syndrome
Quadrilateral Space Syndrome
- Atrophy of Teres Minor
This is an idiopathic involvement of the brachial plexus. Think about this when you see muscles affected by pathology in two or more nerve distributions (suprascapular and axillary etc..).
Parsonage-Turner Syndrome
