Musculoskeletal Flashcards
What is the anterior drawer sign? What does it mean? What is posterior drawer sign? What does is it mean? What is abnormal passive abduction? What does it mean? What is abnormal passive adduction ?What does it mean? What is the mcmurray test? What are some signs and what do they mean?
Pt supine, knee at 90 degree, incr. anterior gliding of tibia
ACL injury
Pt suping, knee at 90 degr., incr. posterior gliding of tibia
PCL inj
Pt. supine and knee either extended or at 30 degr. angle, lateral (valgus) fore leads to medial space widening of tibia.
MCL injury
Same as above, medial (varus) force leads to lateral space widening of tibia
LCL injury
With pt. supine, knee internally and extenally rotated during range of motion:
Pain, popping on external rotation=Medial meniscal tear
Pain, popping on internal rotation=lateral “ “
What is the unhappy triad? What causes it? Presentation?
What is prepatellar bursitis? Cause? What is a baker cyst? Association?
Contact sports; lasteral force applied to planted leg.
Classically, damage to ACL, MCL, and medial lemniscus (thought its usually the lateral one)
Acute knee pain and signs of joint injury/instability
Housemaids knee. Inflammation/liquid above patella.
Repeated trauma or pressure from extensive kneeling
Popliteal fluid collection
Chronic joint disease
What are the muscles that form the rotator cuff? Where are they located in relation to each other? What is the innervation of each? What is the function of each? What spinal levels primarily innervate them? Which is most commonly injured? Which is injured in pitching?
SItS
Supraspinatus superior to humerus suprascapular nerve Most common Abducts arm initially (before action of deltoid)
Infraspinatus Posterior superior to humerus Suprascapular Laterally rotates arm Pitching injury
Teres Minor
Posterioinferior to humerus
Axillary
Laterally rotates arm and adducts arm
Subscapularis
Anterior to humerus
Upper and lower subscap nerve
Adducts and medially rotates arm
C5-C6
What is medial epicondylitis? Another name? Cause? Presentation? Same Qs for lateral epicondylitis?
Golfers elbow
Repetitive flexion (forehand shots) or idiopathic
pain near medial epicondyle
Tennis elbow
Repetitive extension (backhand shots) or idiopathic
Pain near lateral epicondyle
What are the wrist carpal bones? Which is palpated in the anatomical snuff box? Which is most commonly fracture? Complications of fracture/mechanism? What can cause carpal tunnel syndrome? What can cause ulnar nerve injury?
So long to pinky, here comes the thumb
Scaphoid, lunate, triquetrium, pisiform, hamate, capitulum, trapezoid, trapezium (trapezithumb)
Scaphoid in snuff box
Scaphoid most common fracture=avascular necrosis due to retrograde blood supply
Dislocation of lunate–>carpal tunnel
FOOSH—>hook of hamate damage leading to ulnar nerve injury.
What is carpal tunnel syndrome? Causes/associations? Symptoms? Pathophys?
Entrapment of median nerve in carpal tunnel leading to nerve compression
paresthesia, pain, and numbness in distribution of median nerve
Pregnancy, RA, Hypothyroidism, repetitive use
What is guyon canal syndrome? Usually cause?
Compression of ulnar nerve at wrist or hand
Cyclists due to pressure from handlebars
Describe the anatomy of the brachial plexus including which nerves originate from where.
Randy Travis Drinks Cold Beer
Roots, trunks, divisions, cords, branches
Roots of C5, C6, and C7 give off long thoracic
C5 root gives off dorsal scap nerve
C5 and C6 roots make up the upper trunk
C7=middle trunk
C8/T1=lower trunk
Upper trunk gives off suprascapular nerve
All trunks give off anterior and posterior divisions
Anterior divisions of upper and middle trunk make up the lateral cord
All 3 posterior divisions make up posterior cord
Anterior division of Lower trunk make medial cord
Posterior cord gives off upper and lower subscapular nerves and thoracodorsal nerve
Lateral and medial cords give off lateral and medial pectoral nerves
Posterior cord gives off axillary nerve then becomes the radial nerve
Lateral cord and medial cord make up median nerve
Medial cord continues as ulnar nerve
Lateral cord continues as musculocutaneous nerve
What levels make up the axillary nerve? What will cause injury? What is the presentation?
C5-C6
Fractured surgical neck of humerus
Anterior dislocation of humerus
Flattened Deltoid
Loss of arm abduction at shoulder
Loss of sensation over deltoid muscle and lateral arm
What levels make up the musculocutaneous nerve? What will cause injury? Presentation?
C5-C7
Upper trunk compression
Loss of forearm flexion and supination
Loss of sensation over lateral forearm
What levels make up radial nerve? What will cause injury? Presentation?
C5-T1
Midshaft fracture of humerus
Compession of axilla due to crutches or arm over chair
Wrist drop: loss of elbow, wrist, and finger extension
Decr. grip strength (wrist extension necessary for max action of flexors)
Loss of sensation over post arm/forearm and dorsal hand
What levels make up median nerve? What will cause injury? Presentation?
C5-T1
Supracondylar fracture of humerus (proximal lesion)
Carpal tunnel and wrist laceration (distal)
DISTAL
Ape Hand and Popes Blessing
Loss of wrist flexion, flexion of lateral fingers, thumb opposition, lumbricals of 2nd/3rd digits
PROXIMAL Loss of sensation over thenar eminence and dorsal and palmar aspects of lateral 3 1/2 fingers Tinel sign (tingling on percussion) in carpal tunnel syndrome
What levels make up ulnar nerve? What will cause injury? Presentation?
C8-T1
Fracutre of medial epicondyle of humerus (funny bone) (proximal lesion)
Fracture hook of hamate (distal)
“Ulnar claw” on digit extension
Radial deviation of wrist upon flexion (proximal lesion)
Loss of wrist flexion, flexion of medial fingers, abductin and adduction of fingers (interossei), actions of medial 2 lumbrical muscles
Loss of sensation over medial 1 1/2 fingers including hypothenar eminence
What levels make up recurrent branch of median nerve? What will cause injury? Presentation?
C5-T1
Superficial laceration of palm
“Ape hand”
Loss of thenar muscle group: opposition, abduction, and flexion of thumb
No loss of sensation
Damage to these structures causes what?
Upper trunk: Lower trunk: Posterior Cord: Long thoracic nerve: Axillary nerve: Radial nerve: Musculocutaneous nerve: Median nerve: Ulnar Nerve:
Upper trunk: Erb Palsy (waiter’s tip)
Lower trunk: Claw hand (klumpke palsy)
Posterior Cord: Wrist drop
Long thoracic Nerve: Winged scapula
Axillary nerve: Deltoid paralysis
Radial nerve: Wrist drop
Musculocutaneous nerve: Difficulty flexing elbow, sensory loss
Median nerve: Decrease thumb function, Pope’s blessing
Ulnar Nerve: Intrinsic muscles of hand, claw hand
What is the injury in Erbs palsy? Causes? Muscle deficit? Functional deficit?
Tractin or tear of upper trunk
C5-C6
Infants-lateral traction on neck during delivery
Adults-trauma (head forcefully away from shoulder)
Deltoid, supraspinatus (abduction-arm at side)
Infraspinatus (lateral rotation-arm medially rotated)
Biceps (flexion, supination-arm extended and pronated)
What is the injury in Klumpke palsy? Causes? Muscle deficit? Functional deficit?
Traction of tear of lower trunk
C8-T1
Infants: upward force on arm during delivery
Adults: Trauma-forceful pulling up on arm
Intrinsic hand muscles: lumbrical, interossei, thenar, hypothenar
Total claw hand: Lumbrical normaly flex MCP joints and extend DIP and PIP joints
What is the injury in thoracic outlet syndrome? Causes? Muscle deficit? Functional deficit?
Compression of lower trunk and subclavian vessels
Cervical rib
pancoast tumor
Same as klumpke palsy
Atrophy of intrinsic hand msucles: ischemia, pain, and edema due to vascular compression
What is the injury in winged scapula? Causes? Muscle deficit? Functional deficit?
Long thoracic nerve
Axillary node dissectin after mastectomy
Stab wounds
Serratus anterior
Inability to anchor scapula to thoracic cage
Cannot abduct arm above horizontal position.
What is the function of the lumbricals? What is the deficit like in proximal lesions? In distal lesions? Why?
Flex at MCP, extend at DIP and PIP joints
Distal: clawing, loss of lumbrical leads to extend MCP, flex IPs
Proximal: deficits less pronounced; seen during voluntary flexion of digits
What muscles are i the thenar eminence? Innervation? Hypothenar eminence? Innervation? function of dorsal interossei? Palmar?
Thenar: median nerve=opponens pollicis, abductor pollicis brevis, flexor pollicis brevis
Hypothenar (ulnar): opponens digiti minimi, abductor digiti minimi, flexor digiti minimi
DAB (dorsals abduct)
PAD (palmar adduct)
What spinal levels make up the obturator nerve? Cause of injury? Presentation?
L2-L4
Pelvic surgery
Decr. thigh sensation (medial)
Decr. adduction
What spinal levels make up the femoral nerve? Cause of injury? Presentation?
L2-L4
Pelvic fracture
Decr. thigh flexion and leg extension
What spinal levels make up the common peroneal nerve? Cause of injury? Presentation?
L4-S2
Trauma or compression of lateral aspect of leg
fibular neck fracture
Foot drop-inverted and plantarflexed at rest
Loss of eversion and dorsiflexion
steppage gait
Loss of sensation on dorsum of foot
Foot dropPED=Peroneal everts and dorsiflexes
What spinal levels make up the tibial nerve? Cause of injury? Presentation?
L4-S3
Knee trauma
Baker cysts (proximal)
Tarsal tunnel syndrome (distal)
Inability to curl toes and loss of sensation on sole of foot
In proximal lesions, foot everted at rest with loss of inversion and plantar flexion
Can’t stand on TIPtoes=Tibial Inverts and Plantar flexes
What spinal levels make up the superior gluteal nerve? Cause of injury? Presentation? Muscles
L4-S1=gluteus medius and minimus
Iatrogenic injury during intramuscular injection to upper medial gluteal region
Trendelenburg sign/gait-pelvis tilts b/c weight bearing leg cannot maintain alignment of pelvis through hip abduction. Lesion is CL to side that drops, ipsilateral to extremity on which patients stands.
What spinal levels make up the inferior gluteal nerve? Cause of injury? Presentation? Muscles?
L5-S2=gluteus maximus
Posterior hip dislocation
Difficulty climbing stairs, rising from seated position
Loss of hip extension
What is the function of the sciatic nerve? Spinal levels?
Function of pudendal nerve? Spinal levels? What is a landmark for local anesthetic during childbirth?
L4-S3-Innervates posterior thigh, splits into common peroneal and tibial nerves
S2-S4-innervates perineum. Ischial spine.
What is a lumbosacral radiculopathy? pathophys? Which nerve is affected in the pathophys? Waht are the findings with disc level L3/L4, L4/L5, L5/S1
Paresthesias and weakness in distribution of specific lumbar or sacral spinal nerves
Intervertebral disc herniation
Nerve association with inferior vertebral body is impinged.
L3/L4=weakness of knee extension, decr. patellar reflex
L4/L5=weakness of dorsiflexion, difficulty in heel walking
L5/S1=weakness of plantar flexion, difficulty in toe walking, decr. achilles reflex
Describe the steps of muscle conduction and contraction.
AP leads presynaptic voltage gates Ca channels to open, which releases NT
NT binds causing muscle cell depol in the motor end plate
Depol travels along muscle cell and down the T tubule
Depol of voltage sens dihydropyridine receptor couple to ryanodine receptor on sarcoplasmic reticulum induces conformation change, releasing Ca from SR
Ca binds troponin C, which causes tropomyosin to move out of myosin binding groove on actin filaments
Myosin releases bound ADP and PO4 leading to displacement of myosin on the actin filament (power stroke)
Myosin binds new ATP molecule causing detachment of head.
ATP hydrolyzes causing myosin head to cock, ready for next cycle.
What are the different lines and bands in skeletal muscle? What happens to them during contraction? What are t tubules? How many T tubules and terminal cisternae in skeletal muscle? Cardiac?
Z line-separates sarcomeres, place to which actin binds (capZ) and myosin (through titin) binds
I band=Just actin filaments (thin filaments), no thick
A band=Myosin filaments, overlapping actin filaments
H band=zone of thick filaments, not superimposed by thin filaments
M line=middle of sarcomere
When they contract, actin moves in towards M line, thus making the H bands and the I bands smaller, as well as the space between the Z lines shorter.
A band stays constant
T-tubules-extensions of plasma membrane juxtaposed with terminal cisternae. They are part of SR
In SM=triad=2 cist. 1 tubule
In CM=dyad=1 cist 1 tub
What is type 1 muscle? Speed? Color? Why? Action? type 2?
TYPE 1
Slow twitch Sustained contraction Red fibers Incr mitochondria and myoglobin concentration Incr. oxidative phoshorylation
TYPE 2
Fast twitch
White fibers resulting from decr. mitochondra and myoglobin conc
Incr. anerobic
Weight training
Describe the contraction and relaxation of a smooth muscle cell.
CONTRACTION
Action potential causes depol which activates L type voltage gated Ca channel on plasma membrane
Ca enters cell, binds to calmodulin, which activates MLCK, which phosphorylates myosin, allowing it to bind acting leading to contraction.
RELAXATION
Nitric oxide activates guanylate cyclase which converts GTP into cGMP
cGMP activates myosin light chain phosphatase which dephosphorylates myosin leading to relaxation.
Describe endochondral ossification. Which bones? Which cells? When does woven bone occur in adults?
Bones of axial and appendicular skeleton and base of skull
Cartilaginous model of bone is first made by chondrocytes
Osteoclasts and blasts later relplace it with woven bone then remodel it to lamellar bone
Fractures and Pagets
Describe membranous ossification? Which bones?
Calvarium and facial
No cartilaginous, straight to woven bone then to lamellar
What is the function of osteoblasts? Origination? Osteoclasts? Origination?
blasts=build bone by secreting collagen and catalyzing mineralization.
Mesenchymal stem cells in periosteum
Clasts=multinucleated cells that dissolve bone by secreting acid and collegenases
Monocytes, macrophages
What does PTH do to bones at low intermittent levels? At high levels?
Low: anabolic effects on osteoblasts and osteoclasts (indirect)
High: catabolic effects
What does estrogen do to bones? Deficiency?
Inhibits apoptosis in bone forming osteoblasts and induces apoptosis in bone resorbing osteoclasts
Excess cycles of remodeling and bone resorption leading to osteoporosis.
What is the pathophys of achondroplasia? Mutation/genetics? Symtpoms? Epid?
Failure of longitudinal bone growth (endochondral ossification—>short limbs
Membranous ossification is not affected—large head relative to limbs
Activation of FGFR3 inhibits chondrocyte proliferation
85% is sporadic
homozygous is lethal
Most common cause of dwarfism
What is primary osteoporosis? Lab values? Diagnosis? Causes? Presentations? What is type I? pathophys? type II? Epid? How can you prevent it? Treat it?
Trabecular (spongy) bone loses masa nd interconnections despite normal bone mineralization and lab values (serum Ca and PO4).
Diagnosed by bone mineral density test (DEXA) with a t score of 70 y.o.
Prevent: regular weight bearing exercise and adequate Ca and vitamin D intake throughout adulthood
Treatment: Bisphosphonates, PTH analogs, SERMs, rarely calcitonin; denosumab (RANKL antibody—against it)
