06: MSK Flashcards
List two common pediatric bone fractures.
- Greenstick (bending stress; incomplete extension through bone width)
- Torus (axial force; simple buckle fracture of cortex)
Knee: Unhappy triad involves damage to which structures?
- MCL
- ACL
- Medial meniscus
Nerve supply to “SITS” muscles
- Supraspinatus (suprascapular n)
- Infraspinatus (suprascapular n)
- Teres minor (axillary n)
- Subscapularis (upper and lower subscap nn)
Which muscles play pivotal roles in arm abduction below 90 degrees?
Supraspinatus (0-15o) then deltoid (15-100o)
Which muscles play pivotal roles in arm abduction above 90 degrees?
- Deltoid (15-100o)
- Traps
- Serratus anterior
Most commonly fractured carpal bone
Scaphoid (typically due to fall of outstretched hand)
Acute carpal tunnel syndrome may be a result of (X) carpal bone dislocation
X = lunate
Which carpal bone is palpable in anatomical snuff box?
Scaphoid
Humerus surgical neck fracture: (X) muscle will become flattened and (Y) movements will be compromised.
X = deltoid Y = abduction over 15o
(Axillary n injury)
Humerus surgical neck fracture: sensation is lost in which areas?
Over deltoid and lateral aspect of upper arm (axillary n injury)
Pitcher presents with shoulder pain and loss of sensation over lateral forearm. What movements would you expect to be compromised?
Forearm flexion and supination (musculocutaneous n injury)
Humerus fractures: surgical neck injures (X) n, midshaft injures (Y) nerve, supracondylar injures (Z) n.
X = Axillary Y = Radial Z = Median (if anteromedial displacement of proximal humerus)
(“ARM” from proximal to distal fractures); if humerus displaced anterolateral in supracodylar fracture, RADIAL N injured
67 yo M presents with finger drop on R hand. He denies history of trauma, is a retired police officer, and spends his days doing work around the house/yard. Sensation intact, and both elbow and wrist flexion/extension intact. Likely diagnosis/mechanism of injury?
Injury to posterior interosseous nerve (deep branch of radial) in supinator canal
(potentially due to repetitive pronation/supination such as excessive screwdriver use)
Use of crutches may compress (X) nerve.
X = radial
Which nerve travels with brachial artery between (X) upper arm muscles?
X = biceps and brachialis
Median n
Median nerve enters forearm and travels between which muscles?
- Two heads of pronator teres
2. Then between FDS and FDP
(X) nerve passes in Guyon’s canal, between which bones?
X = ulnar
Hook of hamate and pisiform
A superficial palm laceration will likely compromise which sensation/muscle movements?
Recurrent branch of median nerve damage most likely;
Sensation intact
“OAF” (from 1/2 LOAF) will be compromised (loss of thenar muscle group - opposition, abduction, flexion of thumb; ape hand)
“Waiter’s tip”, aka (X) palsy, is due to which injury?
X = Erb's Upper trunk (C5-6) of brachial plexus
“Total claw hand”, aka (X) palsy, is due to which injury?
X = Klumpke Lower trunk (C8-T1) of brachial plexus
Lumbricals have which actions and which joints?
Flex at MCP
Extend at PIP, DIP
Clawing of hand (median or ulnar claws) is more prominent with (proximal/distal) nerve lesions.
Distal (clawing of fingers evident at rest)
Housemaid’s knee: (X) is affected
X = pre-patellar bursa (bursitis due to repetitive kneeling)
Carpal tunnel: excision of (X) improves symptoms.
X = transverse carpal ligament (aka flexor retinaculum)