2. MSK (Soft Tissue Injury/Acquired - Upper limb) Flashcards
Wrist extensor tendon compartments
There are 6 of them.
First compartment (APL, EPB) are affected in De Quervain’s
Third compartment has EPL, which courses beside Lister’s tubercle.
Sixth compartment (ECU) can get early tenosynovitis in RA.
Carpal tunnel anatomy (6)
Lies deep to palmaris longus.
Defined by 4 bony prominences
- Pisiform
- Scaphoid tubercle
- Hook of hamate
- Trapezium tubercle
Transverse carpal ligament wraps contents in fibrous sheath
Carpal tunnel contents (7)
10 things:
- 4 flexor profundus
- 4 flexor superficialis
- 1 flexor pollicis longus
- 1 median nerve
Does NOT contain
- Flexor carpi radialis or ulnaris
- palmaris longus
- flexor pollicis brevis
Which synovial spaces usually communicate
Pisiform recess and Radiocarpal joint (wither space can be used for wrist arthrography)
Which synovial spaces should NOT usually communicate (3)
GH joint and subacromial bursa - implies full thickness rotator cuff tear
Ankle joint and common (lateral) peroneal tendon sheath - implies tear of calcaneofibular ligament
Achilles tendon and posterior subtalar joint - Achilles tendon does not have a true tendon sheath
Triangular fibrocartilage tears (4)
Acute or chronic
Acute: young person with tear on ulnar side
Chronic: Ulnar abutment syndrome (positive ulnar variance with cystic change in lunate)
Degeneration of this cartilage is common (50% at age 60)
Scapholunate ligament tear (4)
Terry Thomas sign (increased SL distance on plain film).
3 parts to the SL ligament, volar, dorsal, middle.
Dorsal most important for carpal stability.
Predisposition for DISI deformity.
Keinbocks (3)
AVN of lunate, seen in 20s-40s.
Associated with negative ulnar variance.
Signal drop out on T1
De Quervain’s tenosynovitis (5)
“Washer woman’s sprain” or “Mommy thumb” due to repetitive activity/overuse.
Classically new mum holding a baby. Much more common in women.
First extensor compartment (EPB and APL) affected.
Imaging:
- US: Increased fluid within the first extensor compartment.
- MRI: Increased T2 signal in the tendon sheath
Intersection syndrome (3)
Repetitive use issue, classic in rowers.
1st extensor compartment cross over 2nd extensor compartment.
Results in extensor carpi radialis brevis and longus tenosynovitis.
Tenosynovitis (2)
Inflammation of tendon with increased fluid around the tendon.
Can be diffuse or focal
Diffuse tenosynovitis (5)
Nontuberculous mycobacterial infection:
- Hand and wrist commonly affected.
- Diffuse exuberant tenosynovitis sparing the muscles.
- Usually occurs in immunocompromised
Rheumatoid arthritis
- Multiple flexor tendons or extensor carpi ulnaris affected.
- Tenosynovitis can present as an early RA (before bone findings)
Focal tenosynovitis (4)
Overuse:
- Will be in classic locations, like 1st extensor compartment for DeQuervains
Infection
- Tenosynovitis of any flexor tendon is a surgical emergency, infection can spread rapidly to common flexors of wrist.
- Increased pressures and necrosis of tendons
- Delayed treatment tend to do terribly.
Dupuytren contracture (4)
Most common fibromatosis.
Classically white person with alcoholic liver disease.
Nodular mass on palmar aspect of aponeurosis, progressing to cord like thickening and contracture. Usually involves 4th finger.
50% are bilateral.
Finger tumours (9)
Scalloping on plain film. MRI needed for a specific diagnosis
Glomus tumour
- Benign vascular tumour seen at tips of fingers (75% in hands).
- T1 dark, T2 bright, avid enhancement.
Giant Cell Tumour of Tendon Sheath
- basically PVNS of tendon.
- Usually palmar tendons of hand.
- Can erode underlying bone.
- Soft tissue density, T1 and T2 dark, blooming on gradient.
Fibroma
- Benign overgrowth of tendon collagen.
- Low T1 and T2, will NOT bloom like GCT.
Cubital Tunnel Syndrome (3)
Result of repetitive valgus stress.
Ulnar nerve passes beneath cubital tunnel retinaculum, aka epicondylo-olecranon ligament or Osborne band.
Due to compression by any pathology (tumour, haematoma, accessory muscle (classically anconeus epitrochlearis)
Partial Ulnar Collateral Ligament Tear (3)
Throwers (valgus overload) hurt their ulnar collateral ligament (attaches to medial coronoid - sublime tubercle).
UCL has 3 bundles, anterior bundle is most important.
Partial UCL tear demonstrates T sign, with contrast extending medially to the tubercle.