MSK Flashcards
Erb Palsy
Which injury?
What causes the injury?
What is the muscular deficit?
How does it present?
Which injury?
- Traction or tear of upper (“Erb-er”) trunk: C5-C6 roots
What causes the injury?
Infants—lateral traction on neck during delivery
Adults—trauma
What is the muscular deficit?
Deltoid, supraspinatus, Infraspinatus, Biceps brachii
How does it present?
Waiter’s tip
What are the bones of the wrist?
Scaphoid, Lunate, Triquetrum, Pisiform, Hamate, Capitate, Trapezoid, Trapezium
What are the rotator cuff muscles and what are their actions?
Supraspinatus - abduction
Infraspinatus - externally rotates
Teres minor - adducts and externally rotates
Subscapularis - internally rotates and adducts arm
Which nerve innervates the hypothenar eminence?
ulnar nerve
Musculocutaneous
What is the nerve root?
What is the cause of injury?
How does injury present?
What is the nerve root?
(C5-C7)
What is the cause of injury?
Upper trunk compression
How does injury present?
Loss of forearm flexion and supination
Loss of sensation over lateral forearm
Recurrent branch of median nerve
What is the nerve root?
What is the cause of injury?
How does injury present?
What is the nerve root?
C5-T1
What is the cause of injury?
Superficial laceration of palm
How does injury present?
- “Ape hand”
- Loss of thenar muscle group: opposition, abduction, and flexion of thumb
- No loss of sensation
What is carpal tunnel syndrome?
Entrapment of median nerve in carpal tunnel
Thenar eminence atrophies but sensation spared, because palmar cutaneous branch enters hand external to carpal tunnel.
What is a Baker cyst?
Popliteal fluid collection
Median
What is the nerve root?
What is the cause of injury?
How does injury present?
What is the nerve root?
C5-T1
What is the cause of injury?
- Supracondylar fracture of humerus (proximal lesion)
- Carpal tunnel syndrome and wrist laceration
How does injury present?
- “Ape hand” and “Pope’s blessing”
- Loss of wrist flexion, flexion of lateral fingers, thumb opposition, lumbricals of 2nd and 3rd digits
- Loss of sensation over thenar eminence
What are the muscles of the hypothenar eminence?
Opponens digiti minimi
Abductor digiti minimi
Flexor digiti minimi brevis
Obturator
What is the nerve root?
What does it innervate?
How is it commonly injured?
How does the injury present?
What is the nerve root?
L2-L4
What does it innervate?
Sensory—medial thigh
Motor—obturator externus, adductor longus, adductor brevis, gracilis, pectineus, adductor magnus
How is it commonly injured?
Pelvic surgery
How does the injury present?
decreased thigh sensation (medial) and adduction
Ulnar
What is the nerve root?
What is the cause of injury?
How does injury present?
What is the nerve root?
C8-T1
What is the cause of injury?
- Fracture of medial epicondyle of humerus “funny bone” (proximal lesion)
- Fractured hook of hamate (distal lesion) from fall on outstretched hand
How does injury present?
- “Ulnar claw” on digit extension
- Radial deviation of wrist upon flexion (proximal lesion)
- Loss of wrist flexion, flexion of medial fingers abduction and adduction of fingers (interossei),
- Loss of sensation over medial 11/2 fingers including hypothenar eminence
Extensors of the hip
Gluteus maximus
Semitendinosus
Semimembranosus
Lateral femoral cutaneous
What is the nerve root?
What does it innervate?
How is it commonly injured?
How does the injury present?
What is the nerve root?
L2-L3
What does it innervate?
Sensory—anterior and lateral thigh
How is it commonly injured?
Tight clothing, obesity, pregnancy, pelvic procedures
How does the injury present?
decreased thigh sensation (anterior and lateral)
Thoracic outlet syndrome
Which injury?
What causes the injury?
What is the muscular deficit?
How does it present?
Which injury?
Compression of lower trunk and subclavian vessels
What causes the injury?
Cervical rib fracture, Pancoast tumor
What is the muscular deficit?
Same as Klumpke
How does it present?
Atrophy of intrinsic hand muscles; ischemia, pain, and edema due to vascular compression
Tibial
What is the nerve root?
What does it innervate?
How is it commonly injured?
How does the injury present?
What is the nerve root?
L4-S3
What does it innervate?
Sensory—sole of foot Motor—biceps femoris (long head), triceps surae, plantaris, popliteus, flexor muscles of foot
How is it commonly injured?
Knee trauma, Baker cyst
How does the injury present?
TIP = Tibial Inverts and Plantarflexes; if injured, can’t stand on TIPtoes Inability to curl toes and loss of
Abductors of the hip
Gluteus medius
Gluteus minimus
What causes abnormal passive adduction of the knee?
Knee either extended or at ~ 30° angle, medial (varus) force lateral space widening of tibia
LCL injury.
Genitofemoral nerve
What is the nerve root?
What does it innervate?
How is it commonly injured?
How does the injury present?
What is the nerve root?
(L1-L2)
What does it innervate?
Sensory—scrotum/labia majora, medial thigh
Motor—cremaster
How is it commonly injured?
Laparoscopic surgery
How does the injury present?
- decreased anterior thigh sensation
- absent cremasteric reflex
Which nerve innervates the thenar eminence?
median nerve
Adductors of the hip
Adductor magnus
Adductor longus
Adductor brevis
What is the posterior drawer sign?
Bending knee at 90° angle, posterior gliding of tibia due to PCL injury.
What is cauda equina syndrome?
- Compression of spinal roots L2 and below, often due to intervertebral disc herniation or tumor.
- Unilateral radicular pain, absent knee and ankle reflex, loss of bladder and anal sphincter control, saddle anesthesia.
Common peroneal
What is the nerve root?
What does it innervate?
How is it commonly injured?
How does the injury present?
What is the nerve root?
L4-S2
What does it innervate?
Sensory - dorsum of foot
Motor—peroneus longus
How is it commonly injured?
Trauma or compression of lateral aspect of leg, fibular neck fracture
How does the injury present?
PED = Peroneal Everts and Dorsiflexes; if injured, foot dropPED
Loss of sensation on dorsum of foot
Foot drop—inverted and plantarflexed at rest, loss of eversion and dorsiflexion; “steppage gait”
Iliohypogastric nerve
What is the nerve root?
What does it innervate?
How is it commonly injured?
How does the injury present?
What is the nerve root?
T12-L1
What does it innervate?
Sensory—suprapubic region
Motor—transversus abdominis
How is it commonly injured?
Abdominal surgery
How does the injury present?
Burning or tingling pain in surgical incision site radiating to the inguinal and suprapubic region
Flexors of the hip
Iliopsoas
Rectus femoris
Tensor fascia lata
Pectineus
Sartorius
What do the ACL and PCL tendons connect?
Lateral femoral condyle to anterior tibia: ACL.
Medial femoral condyle to posterior tibia: PCL.
LAMP.
Superior gluteal
What is the nerve root?
What does it innervate?
How is it commonly injured?
How does the injury present?
What is the nerve root?
L4-S1
What does it innervate?
Motor—gluteus medius, gluteus minimus, tensor fascia latae
How is it commonly injured?
Iatrogenic injury during intramuscular injection to superomedial gluteal region (prevent by choosing superolateral quadrant, preferably anterolateral region)
How does the injury present?
- Trendelenburg sign/gait— pelvis tilts because weight-bearing leg cannot maintain alignment of pelvis through hip abduction
- Lesion is contralateral to the side of the hip that drops, ipsilateral to extremity on which the patient stands
What causes abnormal passive abduction of the knee?
- Knee either extended or at ∼ 30° angle, lateral (valgus) force
- medial space widening of tibia
- MCL injury.
Inferior gluteal
What is the nerve root?
What does it innervate?
How is it commonly injured?
How does the injury present?
What is the nerve root?
L5-S2
What does it innervate?
Motor—gluteus maximus
How is it commonly injured?
Posterior hip dislocation
How does the injury present?
Difficulty climbing stairs, rising from a seated position; loss of hip extension
Femoral
What is the nerve root?
What does it innervate?
How is it commonly injured?
How does the injury present?
What is the nerve root?
L2-L4
What does it innervate?
Sensory—anterior thigh medial leg
Motor—quadriceps, iliacus,
How is it commonly injured?
Pelvic fracture
How does the injury present?
decreased thigh flexion and leg extension
Which muscles are responsible for the abduction of the arm and what are their nerves
Supraspinatus - Suprascapular
Deltoid - Axillary
Trapezius - Accessory
Serratus Anterior - Long Thoracic
Axillary nerve
What is the nerve root?
What is the cause of injury?
How does injury present?
What is the nerve root?
(C5-C6)
What is the cause of injury?
Fractured surgical neck of humerus
Anterior dislocation of humerus
How does injury present?
Flattened deltoid
Loss of arm abduction at shoulder (> 15°)
Loss of sensation over deltoid muscle and lateral
What is a Trochanteric bursitis?
Inflammation of the gluteal tendon and bursa lateral to greater trochanter of femur.
Sciatic
What is the nerve root?
What does it innervate?
How is it commonly injured?
How does the injury present?
What is the nerve root?
L4-S3
What does it innervate?
Motor—semitendinosus, semimembranosus, biceps femoris, adductor magnus
How is it commonly injured?
Herniated disc, posterior hip dislocation
How does the injury present?
Splits into common peroneal and tibial nerves
What are the tests for carpal tunnel syndrome?
Tinel’s test
Phalen maneuver
Radial
What is the nerve root?
What is the cause of injury?
How does injury present?
What is the nerve root?
C5-T1
What is the cause of injury?
- Compression of axilla, eg, due to crutches or sleeping with arm over chair (“Saturday night palsy”)
- Midshaft fracture of humerus
- Repetitive pronation/supination of forearm due to screwdriver use (“finger drop”)
How does injury present?
- Wrist drop: loss of elbow, wrist, and finger extension, decreased grip strength
- Loss of sensation over posterior arm/forearm and dorsal hand
Pudendal
What is the nerve root?
What does it innervate?
How is it commonly injured?
How does the injury present?
What is the nerve root?
(S2-S4)
What does it innervate?
Sensory—perineum
Motor—external urethral and anal sphincters
How is it commonly injured?
Stretch injury during childbirth
How does the injury present?
- decreased sensation in perineum and genital area; can cause fecal or urinary incontinence
- Can be blocked with local anesthetic during childbirth using ischial spine as a landmark for injection
Klumpke palsy
Which injury?
What causes the injury?
What is the muscular deficit?
How does it present?
Which injury?
Traction or tear of lower trunk: C8-T1 root
What causes the injury?
Infants—upward force on arm during delivery
Adults—trauma
What is the muscular deficit?
Intrinsic hand muscles: lumbricals, interossei, thenar, hypothenar
How does it present?
Total claw hand: lumbricals normally flex MCP joints and extend DIP and PIP joints
What are the muscles of the thenar eminence?
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
Which ligament is most commonly damaged in an ankle sprain?
Anterior TaloFibular ligament—most common ankle sprain overall, classified as a low ankle sprain.
Due to overinversion/supination of foot. Always Tears First.
Anterior inferior tibiofibular ligament—most common high ankle sprain.
Winged scapula
Which injury?
What causes the injury?
What is the muscular deficit?
How does it present?
Which injury?
Lesion of long thoracic nerve, roots C5-C7 (“wings of heaven”)
What causes the injury?
Axillary node dissection after mastectomy, stab wounds
What is the muscular deficit?
Serratus anterior
How does it present?
Inability to anchor scapula to thoracic cage - cannot abduct arm above horizontal position
Which muscles abduct and adduct the fingers?
Dorsal interossei (ulnar)—abduct the fingers.
Palmar interossei (ulnar)—adduct the fingers.
Internal rotation of the hip
Gluteus medius
Gluteus minimus
Tensor fascia latae
What does the McMurray test diagnose?
Pain, “popping” on external rotation - medial meniscal tear (external rotation)
Pain, “popping” on internal rotation - lateral meniscal tear (internal rotation stresses lateral meniscus)
What is the anterior drawer sign?
- Bending knee at 90° angle, anterior gliding of tibia (relative to femur) due to ACL injury.
