RADIOLOGY OF THE ELBOW JOINT
DR. SUMIT SHARMAPG RESIDENT
DEPT. OF RADIODIAGNOSISSLIMS, PUDUCHERRY
Normal Elbow AnatomyThe elbow is a complex synovial joint formed by the articulations of
the humerus , the radius and the ulna. Very important to be aware of pediatric growth centers
CRITOE
Osteology of Elbow
Articulations
• The elbow joint is made up of three articulations :
• radiohumeral: capitellum of the humerus with the radial head
• ulnohumeral: trochlea of the humerus with the trochlear notch (with separate olecranon and coronoid process articular facets) of the ulna
• radioulnar: radial head with the radial notch of the ulna (proximal radioulnar joint)
In full flexion, the coronoid process is received by the coronoid fossa and the radial head is received by the radial fossa on the anterior surface of the humerus and in full extension the olecranon process is received by the olecranon fossa on the posterior aspect of the humerus.
Articulations
Normal Alignment• Anterior humeral line- line drawn along
anterior surface of humeral cortex should pass through the middle third of the capitellum• Radiocapitellar line- Line drawn through the proximal radial shaft and neck should pass through to the articulating capitellum
Ligaments
• Medial (ulnar) collateral ligament complex• Lateral (radial) collateral ligament complex• Oblique cordinconstant thickening of supinator muscle
fascia and functionally insignificant runs from tuberosity of the ulna to just distal
to radial tuberosity
• Quadrate ligament (of Denuce)thickening of the inferior aspect of the joint
capsuleruns from just inferior to the radial notch of
the ulna to insert to the medial surface of the radial neck
• Anular (orbicular) ligamentEncircles the head and retains it in contact
with the radial notch of the ulna.
• Joint capsuleThe joint capsule has two layers, deep and
superficial, and attaches proximally to the radial, coronoid and olecranon fossae. Distally, it attaches to the annular ligament of the radius and coronoid process of the ulna . The volume of the joint capsule is 24-30 mL
Ligaments
Fat pads
• There are three fat pads of the elbow, which sit between the two layers of the joint capsule, making them extra-synovial:
• coronoid fossa fat pad (anterior)• radial fossa fat pad (anterior)• olecranon fossa fat pad (posterior)
Bursae
• superficial olecranon bursa: lies between the olecranon and the subcutaneous tissue
• subtendinous olecranon bursa: lies between olecranon and triceps brachii tendon
• intratendinous olecranon bursa: variably lies in the triceps brachii tendon
• bicipitoradial bursa: lies between biceps brachii distal tendon and ant. radial tuberosity
Fat Pads and Bursae
Relations
• anteriorly: biceps brachii tendon; brachialis muscle, median nerve, brachial artery
• posteriorly: olecranon bursae, triceps brachii tendon
• laterally: common extensor tendon; supinator muscle
• medially: ulna nerve
Blood & Nerve supply• Arterial supply is via
anastomotic (medial, lateral and posterior) arcades formed by branches of the radial, ulnar and brachial arteries.
• Articular branches of the radial, ulnar, median and musculocutaneous nerves.
Movements
• The elbow is a trochoginglymoid (combination hinge and pivot) joint :
• The hinge component (allowing flexion-extension) is formed by the ulnohumeral articulation
• The pivot component (allowing pronation-supination) is formed by the radiohumeral articulation and the proximal radioulnar joint
Variant anatomy• Synovial folds thin projections of synovial membrane (inner layer of
joint capsule) may be confused for intra-articular loose bodies on
MRI• Capitellar and Olecranon pseudodefects normal areas devoid of articular cartilage can be mistaken on MRI for impaction injuries or
osteochondral defects• Accessory ossicles os supratrochlear dorsale patella cubiti (very rare)
Elbow Trauma
• 6% of all fractures and dislocations involve elbow
• Most common fractures differ between adults and children – M.C. in adults- radial head and neck fxs.– M.C. in children- supracondylar fxs.
• Complex anatomy requires 4 views for adequate interpretation – AP in extension, medial oblique, lateral and axial
olecranon (Jones view)
Signs of Fracture
• Usual signs may not be readily visible– Fracture line, cortical disruption, etc.
• Soft tissue signs can indicate fracture– Fat pad sign
• On lateral, might see fat pad parallel to anterior humeral cortex, but should never see posterior fat pad
• With effusion, anterior may be displaced and will be shaped like a sail (sail sign)
Fat Pad Sign• Posterior fat pad is normally buried in olecranon fossa
and not visible– Becomes elevated and visible with joint effusion
• Effusion (acute capsular swelling) can be from any origin (hemorrhagic, inflammatory, infectious, traumatic, etc.)
• Ant. fat pad may be obliterated, so post. Fat pad is more reliable when visible
Distal humerus fractures
• 95% extend to articular surface• Classified according to relationship with
condyle and shape of fracture line– Supracondylar, intercondylar, condylar and
epicondylar
Supracondylar Fractures• Most common elbow fracture in children (60%)• Fracture line extends transversely or obliquely
through distal humerus above the condyles • Distal fragment usually displaces posteriorly
Normal
Intercondylar fracture
• Fracture line extends between medial and lateral condyles and extends to supracondylar region– Results in T or Y shaped configuration for fracture
• Called trans-condylar if it extends through both condyles
Epicondylar fracture• Usually avulsion from traction of respective
common flexor (medial) or extensor (lateral) tendons
• Medial epicondyle avulsion common in sports with strong throwing motion (little leaguer’s elbow)
Fractures of Proximal Ulna• Olecranon fx.- direct trauma or avulsion by
triceps tendon• Coronoid process fx.- avulsion by brachialis or
impaction into trochlear fossa– Rarely isolated; usually associated with post. elbow dislocation
Fractures of Proximal Radius• M.C. adult elbow fx. (50%)• FOOSH transmits force causing impaction of
radial head into capitellum• Chisel fracture- incomplete fracture of radial
head that extends to center of articular surface• Usual rad. signs (fx. Line, articular disruption) may not be visible
– May be occult; fat pad sign is good indicator of occult fx.
Fractures of the forearm
• Isolated ulnar fractures• Isolated radial fractures• Bony rings usually can't be fractured in one
place without disruption somewhere else in the ring
• 60% or forearm fractures involve both bones (BB fractures)
• These fractures usually have associated displacement with angulation and rotation
Isolated Ulnar Fractures• Distal shaft (Nightstick fx.)- direct trauma
• Proximal shaft (Monteggia’s fx.)- fx. of proximal ulna with dislocation of radius
Isolated Radial Fractures• Most frequent is a Galeazzi’s fx. (reverse
Monteggia’s fx.) – Fracture of distal radial shaft with dislocation of distal radioulnar joint– Rare, but serious injury
Dislocations of Elbow
• 3rd m.c. dislocation in adults behind shoulder and interphalangeal joints– More common in children
• Classified according to displacement of radius and ulna relative to humerus– Posterior, posterolateral, anterior, medial and
anteromedial
• Posterior and posterolateral - more common– 85-90% of all elbow locations– 50% have associated fractures
Pulled Elbow
• AKA nursemaid’s elbow• Occurs when child’s hand is pulled, traction of arm
causes radial head to slip out from under annular ligament and traps the ligament in the radiohumeral articulation
• Immediate pain; stuck in mid-pronation due to pain• No radiographic pain• Supination reduces the dislocation and ends pain,
usually during positioning of lateral radiograph
Case Study
Case of Mrs. X
• Here is a case of a female patient with acute trauma of the right elbow joint.
• Lets have a look at her Right Elbow X-ray AP and lateral view.
AP
LAT
• Lets also have a look at her right elbow CT images…..
Mason classification• The Mason classification is used to classify radial head fractures
and is useful when assessing further treatment options .• type I: non-displaced radial head fractures (or small marginal
fractures), also known as a "chisel" fracture• type II: partial articular fractures with displacement (>2mm)• type III: comminuted fractures involving the entire radial head
– IIIa: fracture of the entire radial neck, with the head completely displaced from the shaft
– IIIb: articular fracture involving the entire head, consisting of more than two large fragments
– IIIc: fracture with a tilted and impacted articular segment
• type IV: fracture of the radial head with dislocation of the elbow joint
What is your diagnosis?
My Diagnosis
Marginal rim fracture of the head of the Radius with intra-articular dispensation of fractured fragments(Mason’s Type IIIb) in the Right Elbow.
Treatment
• In general type I injuries can be treated conservatively whereas type II injuries require open reduction and internal fixation (ORIF). Type III injuries often require early complete excision of the radial head .
Thank You