MSK, Skin and CT

Question 1

Arachidonic acid products

Answer 1

• Lipoxygenase pway- yields leukotrienes
  
  • LTB4 = neutrophil chemotactic agent (PMNs arrive B4 others)
  • LTC4, LTD4, LTE4 increase bronchial tone (inhibited by “-lukast” asthma drugs)
• COX pway
  
  • prostacyclins (PGI2) decrease platelet agg, vascular tone, bronchial tone and uterine tone (Platelet Gathering Inhibitors)
  • prostaglandins (PGE2, PGF2a) increase uterine tone, protect gastri mucosa, decrease bronchial tone
  • thromboxane (TXA2) increase platelet agg (“pro-thombotic”), increase vascular tone, increase bronchial tone

Question 2

1. Aspirin
2. Acetominophen

Answer 2

1. ASA: irreversibly inhibits COX1 and 2 –> increases bleeding time until new platelets are formed (TXA2)
   
   • low dose= antiplatelet; med dose = antipyretic and analgesic; high dose = anti-inflamm
   • gastric ulceration, tinnitus, ARF and interstitial nephritis, resp alkalosis
2. Tylenol: reversibly inhibits COX – acts in CNS (inactivated peripherally so it does not have anti-inflamm props)
   
   • OD = hepatic necrosis (tx with NAC)
   • component of Nyquil, excedrin, tylenol pm

Question 3

1. NSAIDs
2. COX-2 inhibitors
3. bisphosphonates

Answer 3

1. Ibuprofen, indomethacin, ketorolac (toradol): reversibly inhibit COX
   
   • antipyretic, analgesic, anti-inflamm; Indo used to close PDA
   • gastric ulcers, interstitial nephritis, renal ischemia (PGs vasodilate afferent arteriole)
2. Celecoxib(Celebrex): protects gastric mucosa
   
   • use in RA, OA, PTs with gastric ulcers
3. Alendronate: pyrophosphate analog (binds hydroxyapatite in bone) + inhibits OC activity
   
   1. use in osteoporosis, Paget
   2. corrosive esophagitis and poor GI absorption

Question 4

chronic gout drugs

Answer 4

• Allopurinol: inhibits XO –> decrease conversion of Xanthine to uric acid; increases concentrations of 6MP and azithioprine
• Febuxostat: inhibits XO
• Probenecid: inhibits reabsorption of uric acid in PT (competes with PCN)

Question 5

acute gout drugs

Answer 5

• Colchicine: inhibits MT polymerization – impairs leukocyte chemotaxis + degranulation
  
  • GI side effects (diarrhea)
• ​glucocorticoids
• NSAIDs (1st line)
• Etanercept: TNFalpha decoy receptor
• Infliximab and adalimumab: anti-TNF alpha mAb

Question 6

1. wrist bones
2. anterior shoulder dislocation
3. adhesive capsulitis

Answer 6

1. Scaphoid, Lunate, Triquetrum, Pisiform (1st row from thumb –> pinky); Trapezium, Trapezoid, Capitate, Hamate (2nd row from thumb –> pinky)
   
   • scaphoid palpated in anatomical snuff box – prone to avascular necrosis due to retrograde blood supply
   • Some Lovers Try Positions That They Can’t Handle
2. Hill-Saches lesion; damage to axillary nerve (test sensation over deltoid)
3. frozen shoulder due to trauma or immobilization

Question 7

1. tennis elbow
2. golf elbow
3. biceps tendon tear

Answer 7

1. lateral epicondylitis
2. medial “ “
3. muscle bulges in midpart of arm (FQs predispose)

Question 8

1. Erb’s Palsy
2. Klumpke Palsy
3. Winged scapula

Answer 8

1. upper trunk traction damage (C5, C6 roots) – “waiter’s tip” -> deltoid + supraspinatus (can’t abduct arm), infraspinatus (can’t laterally rotate arm), biceps brachi (can’t flex or supinate arm)
2. lower trunk traction damage (C8, T1) – total claw hand (intrinsic hand mm)
3. lesion of long thoracic nerve

Question 9

1. axillary nerve
2. musculocutaneous
3. Radial
4. median
5. ulnar

Answer 9

1. fractured surgical neck of humerus; ant dislocation of humerus –> flattened deltoid, can’t abduct arm, loss of sensation of deltoid
2. loss of forearm flexion and supination, loss of sensation of lateral forearm
   
   1. also supplies sensation to lateral forearm (“cutaneous”)
3. midshaft fracture (spiral groove) or compression of axilla (crutches) – Sat night palsy –> wrist drop (loss of extensors – elbow, wrist, fingers) + loss of sensation of posterior arm/forearm
4. Ape/Pope’s hand + loss of sensation over thenar eminence dorsal and palmar aspects of lateral 3.5 fingers
   
   1. carpal tunnel syndrome: Tinnel sign
5. fracture of medial epicondoyle of humerus (funny bone) or hook of hamate –> ulnar claw and loss of sensation of medial 1.5 fingers

Question 10

1. Obturator
2. Femoral
3. sciatic nerve

Answer 10

1. medial compartment of thigh: gracilis, adductor longus, adductor brevis, adductor magnus
   
   • sensation over medial thigh + adduction (“Obduction”)
2. anterior compartment of thigh: quadriceps, sartorius, pectineus
   
   • can’t flex thigh or extend leg
   • L2-L4
3. tibial n and common fibular/peroneal n travel together though gluteal region and thigh in common connective tissue (sciatic nerve)
   
   1. most commonly involves L5, S1
   2. can’t extend leg, pain down posterior aspect of leg, weakness of posterior mm below the knee; loss of ankle reflex

Question 11

arteries of the arm

Answer 11

• axillary a gives off posterior and anterior circumflex aa that anastamose at the surgical neck of the humerus (paired with axillary nerve)
• deep brachial a. branches off of axillary a and travels posteriorly with the radial nerve
• axillary a. becomes brachial a. which travels down anteriomedially –> divides into radial and ulnar aa –> ulnar aa give off common interosseus aa

Question 12

major hip flexors

Answer 12

• iliopsoas= psoas major + iliacus
  
  • strongest of the hip flexors
  • innervated by femoral n
• quadriceps= rectus femoris, vastus medialis, vastus lateralis and vastus intermedius (deep to rf)
  
  • all insert on patella
  • rectus femoris involved in hip flexion
  • innervated by femoral n
• sartorius

Question 13

major hip extensors

Answer 13

• gluteus maximus (innervated by inferior gluteal n)
• hamstrings
  
  • semitendinous
  • semimembranous
  • biceps femoris (long head)

Question 14

1. common peroneal nerve
2. tibial nerve
3. superior gluteal nerve
4. inferior gluteal nerve

Answer 14

1. trauma or compression to lateral aspect of leg
   
   1. superficial peroneal nerve- lateral compartment of leg (eversion)
   2. deep peroneal nerve - anterior compartment (dorsiflexion= tibialis anterior muscle)
2. baker cyst – posterior compartment of leg (gastrocnemius, soleus, flexor digitorum longus, etc)
   
   • inversion and plantar flexion (TIP and tip toes)
3. gluteus medius and minimus - thigh abduction
   
   • Trendelenburg sign (lesion on same side as the leg PT is standing on)
4. gluteus maximus
   
   • hip extension (climb stairs, rise from seat)