Musculoskeletal Flashcards
What are the thenar (median) muscles of the hand and what are their functions?
Opponens pollicus
Abductor pollicis brevis
Flexor pollicis brevis
Superficial head (deep head by ulnar nerve)
Oppose, Abduct, Flex
What are the hypothenar (ulnar) muscles of the hand and what are their functions?
Opponens digiti minimi
Abductor digiti minimi
Flexor digiti minimi brevis
Oppose, Abduct, Flex
What is the function of the dorsal and palmar interossei?
Dorsal - abduct (DAB)
Palmar - adduct (PAD)
What is the function of the lumbricals?
Flex at the MCP joint, extend PIP and DIP joints
Hip abductors?
Gluteus medium, gluteus minimus
Hip adductors?
Adductor magnus, adductor longus, adductor brevis
Hip extensors?
Gluteus maximus, semitendinosus, semimembranosus
Hip flexors?
Iliopsoas, rectus femoris, tensor fascia lata, pectineus
Hip internal rotators?
Gluteus medius, gluteus minimus, tensor fascia latae
Hip external rotation?
Iliopsoas, gluteus maximus, piriformis, obturator
Nerves and arteries are frequently named together by the bones/regions with which they are associated. The following are exceptions. Name the nerve and artery associated with:
- Axilla/lateral thorax
- Surgical neck of humerus
- Midshaft of humerus
- Distal humerus/cubital fossa
- Popliteal fossa
- Posterior to medial malleolus
- Long thoracic nerve, lateral thoracic artery
- Axillary nerve, posterior circumflex artery
- Radial nerve, deep brachial artery
- Median nerve, brachial artery
- Tibila nerve, popliteal artery
- Tibial nerve, posterior tibial artery
2 common pediatric fractures?
- Greenstick fracture
2. Torus fracture
Compare the morphology and cause of a Greenstick vs. Torus fracutre.
Greenstick - binding stress causes incomplete fracture extending partway through the width of the bone
Torus - axial force leads to a simple buckle fracture of the cortex (subtle
Define the unhappy triad.
Classically - damage to the ACL, MCL, medial meniscus (note - lateral meniscus injury is more common)
Common cause of the unhappy triad?
Lateral force to a planted leg in contact sports
What is the “housemaid’s knee” and what causes it?
Prepatellar bursitis due to repeated trauma or pressure from excessive kneeling
What is a Baker cyst?
Popliteal fluid collection in the gastrocnemius-seminmembranosus bursa (communicates with synovial space, related to chronic joint disease)
BACK OF THE LEG
Compare medial and lateral epicondylitis (etiology and presentation).
Medial epicondylitis (golfer’s elbow) - repetitive wrist flexion with pain near the medial
Lateral epicondylitis (tennis elbow) - repetitive wrist extension
What is commonly fractured due to a fall on an outstretched hand and why?
Scaphoid bone fracture; direct axial compression or wrist hyperextension
How does a scaphoid bone fracture present?
Persistent wrist pain and TENDERNESS IN THE ANATOMIC SNUFFBOX - scaphoid and trapezius form the floor of the snuffbox
What is a potential complication of a scaphoid bone fracture?
Avascular necrosis
Compare the nerves affected in carpal tunnel vs. Guyon canal syndrome.
Carpal - median nerve
Guyon - ulnar nerve
What other bone may be injured following a fall on an outstretched hand? What disease may this cause?
Lunate; carpal tunnel syndrome (acute)
What are some important associations with carpal tunnel syndrome?
Hypothyroidism Acromegaly Rheumatoid arthritis, repetitive use Diabetes, dialysis-related amyloidosis, dislocation of lunate Pregnancy (edema)
HARDP
How does carpal tunnel syndrome present?
Paresthesia, pain, numbness in the distribution of the median nerve (palmar surface, fingers 1-4 + dorsal surface, upper 1/3 of fingers 2-part of 4) WITH SPARING OF THENAR SENSATION - palmar cutaneous branch enters the hand external to the carpal tunnel; thenar eminence atrophies
What are two clinical tests used to test for carpal tunnel syndrome?
Tinel sign (percussion of wrist causes tingling)
Phalen maneuver (90 degree flexion of wrist causes tingling)
List the important nerves of the arm and their nerve roots.
- Axillary (C5-6)
- Musculocutaneous (C5-7)
- Radial (C5-T1)
- Median (C5-T1)
- Ulnar (C8-61)
Name the nerve injury associated with the following presentation:
Flattened deltoid
Loss of arm abduction >15 degrees
Loss of sensation of deltoid muscle and lateral arm
Axillary nerve (C5-C6)
3 possible causes of axillary nerve (C5-C6) injury
- Fracture surgical neck of the humerus
- Anterior dislocation of the humerus
- Brachial plexus injury
Name the nerve injury associated with the following presentation:
Loss of forearm flexion and supination
Loss of sensation over the lateral forearm
Musculocutaneous nerve (C5-C7)
1 possible cause of musculocutaneous (C5-C7) injury
- Brachial plexus injury (upper trunk compression)
Name the nerve injury associated with the following presentation:
Wrist drop
Decreased grip strength
Loss of sensation over the posterior arm/forearm and dorsal hand
Radial (C5-T1) injury
3 possible causes of radial (C5-T1) nerve injury
- Midshaft fracture of the humerus
- Compression of the axilla (crutches)
- Brachial plexus lesion - posterior cord or at the radial nerve branch) - sleeping with arm over chair
Compare the presentation of a brachial plexus injury of the radial nerve at the posterior cord vs. at the radial nerve branch.
Posterior cord - wrist drop + Saturday night palsy
Branch - Saturday night palsy
Name the nerve injury associated with the following presentation:
“Ape hand”
“Pope’s blessing”
Loss of wrist flexion, flexion of the lateral fingers, thumb opposition, the lumbricals of 2 and 3
Loss of sensation over the thenar eminence and dorsal and palmar aspects of the lateral 3..5 fingers
Median (C5-T1) nerve
4 possible causes of median (C5-T1) nerve injury; specifiy if proximal or distal
- Supracondylar fracture of the humerus - proximal
- Carpal tunnel syndrome - distal
- Wrist laceration - distal
- Brachial plexus lesion
Cause of the “Pope’s blessing” presentation?
Median nerve injury (brachial plexus lesion)
Cause of Saturday night palsy presentation?
Radial nerve injury (brachial plexus lesion)
Cause of Ape hand presentation?
Median nerve injury or recurrent branch of the median nerve injury
Name the nerve injury associated with the following presentation:
Radial deviation of wrist upon flexion (proximal)
Loss of wrist flexion/adduction, flexion of the medial fingers, abduction and adduction of the fingers (interossei), actions of medial 2 lumbricals
Loss of sensation over the medial 1.5 fingers including the hypothenar eminence
Ulnar (C8-T1) nerve (also ulnar claw on digital extension)
3 possible causes of ulnar nerve injury; specify if proximal or distal
- Fracture of the medial epicondyle (proximal)
- Fractured hook of hamate (distal) - fall on an outstretched hand
- Brachial plexus injury of the ulnar nerve branch
(Elbow injury more common)