Steve Tyler's Screaming Skin MS Stuff Flashcards
Name the Epidermis layers from outer layer to inner layer
Stratum Corneum (keratin), Stratum Lecidum, Stratum Granulosum, Stratum Spinosum (spines=desmosomes), Stratum Basale (Stem cell site); Californians Like Girls in String Bikinis
Tight junction
Zona Occludens: prevent paracellular movement of solutes; composed of claudins and occludins
Adherens Junction
Zona adherens; below tight junction forms belt connection actin cytoskeletans of adjacent cells with CADherins (Ca dependent ADhesion proteins) Loss of E cadherin promotes metastasis
Desmosome
Macula adherens; structural support via keratin interactions. Autoantibodies against desmosomes lead to pemphigus Vulgaris;
Gap Junctions
Channel proteins call connexons permit electrical and chemical communication between cells.
Integrins
Membrane proteins that maintain the integrity of basolateral membrane by binding to collagen and laminin in basement membrane;
Hemidesmosome
Connects keratin in basal cells to underlying basement membrane. Autoantibodies against hemidesmosomes leads to bullos pemphigoid (hemidesmosomes are down bullow)
Knee Injury exam methods and what they mean
Anterior drawer sign is ACL injury;
Posterior drawer sign is PCL injury;
Abnormal passive abduction (Valgus stress) is MCL injury;
Abnormal passive adduction (Varus stress) is LCL;
McMurray test: pain on external rotation is medial meniscus and pain on internal rotation is lateral meniscus
Unhappy triad
Common injury in contact sports due to lateral force applied to a planted leg. Classically consists of damage to the ACL, MCL, and medial meniscus (Attached to MCL); However, lateral meniscus injury is more common
What landmark do you look for when doing a Pudendal nerve block (relieve pain of delivery)
ischial spine
Where do you palpate for the appendix
2/3 distance between the umbilicus and the anterior superior iliac spine (ASIS), just proximal to the ASIS (McBurney point)
If you want to do a lumbar puncture what landmark do you look for
Iliac crests
Rotator Cuff muscles, their nerves, and function
SITS;
supraspinatus (suprascapular nerve): abducts the arm initially, most common rotator cuff injury;
Infraspinatus (suprascapular nerve): laterally/external rotates arm, common pitching injury;
Teres Minor (axillary nerve): adducts and laterally/external rotates arm;
Subscapularis (subscapular nerve): medially/internally rotates and adducts arm;
SITS are mostly innervated by C5 and C6
Name the wrist bones
Scaphoid, Lunate, Triquetrum, Pisiform, Hamate, Capitate, Trapezoid, Trapezium;
So Long To Pinky, Here Comes The Thumb
Special stuff about the scaphoid
Palpated in anatomical snuff box;
Is the most commonly fractured carpal bone and is prone to avascular necrosis owing to retrograde blood supply
Dislocation of Lunate can cause what acute symptoms
can cause acute carpal tunnel syndrome
A fall on an outstretched hand that damages the hook of the hamate can cause what
ulnar nerve injury
Carpal Tunnel Syndrome
Entrapment of median nerve in carpal tunnel: nerve compression leading to paresthesia, pain, and numbness in distribution of median nerve; more common in pregnant women
Guyon Canal Syndrome
Compression of the ulnar nerve at the wrist or hand, classically seen in cyclists due to pressure form handlebars
What supplies the cells that differentiate into osteoblasts after a fracture?
Periosteum
Erb’s Palsy
Waiter’s tip;
Injury: traction or tear of the upper (Erber) trunk (C5, 6 roots);
Caused by: infants due to lateral traction on neck during delivery and adults get it form trauma;
Causes deficits in deltoid (abduction), Infraspinatus (lateral rotation), Biceps brachii (flexion and supination)
Klumpke Palsy
Traction of tear of Lower trunk: C8-T1 root;
Caused by: infants get it from upward force on arm during delivery, Adults form trauma;
Causes deficits in intrinsic hand muscles, lumbricals, interossei, thenar, hypothenar (get claw hand, lumbricals normally flex MCP joints and extend DIP and PIP joints)
Thoracic outlet syndrome
Compression of the lower trunk and subclavian vessels;
Caused by cervical rib injury or pancoast tumor;
Causes deficits in intrinsic hand muscles, lumbricals, interossei, thenar, hypothenar (with atrophy of hand muscles, edema, pain, and ischemia due to vascular compression);
Treat with incision of anterior scalene muscle
Winged scapula
Lesion of the long thoracic nerve;
Caused by axillary node dissection after mastectomy, stab wounds;
Deficit in Serratus anterior causing the inability to anchor scapula to thoracic cage so you cannot abduct arm above horizontal position
Injury to the axillary nerve
C4-C6;
Can be caused by fractured surgical neck of humerus or anterior dislocation of humerus;
Presents as Flattened deltiod, loss of arm abduction at shoulder (>15 degrees), loss of sensation over deltoid muscle and lateral arm
Injury to Musculocutaneous nerve
C5-C7;
Caused by upper trunk compression;
Presents as loss of forearm flexion and supination, loss of sensation over lateral forearm
Injury to Radial Nerve
C5-T1;
Caused by Midshaft fracture of humerus, compression of axilla (due to crutches or sleeping with arm over chair);
Presents as wrist drop (loss of elbow, wrist, and finger extension, Decreased grip strength (wrist extension necessary for maximal action of flexors), Loss of sensation over posterior arm/forearm and dorsal hand
Injury to Median Nerve
C5-T1;
Caused by supracondylar fracture of humerus (proximal lesion), carpal tunnel and wrist laceration (distal lesion);
Presents as “Ape hand” and “Pope’s blessing,” Loss of wrist and lateral finger flexion, thumb opposition, lumbricals of 2nd and 3rd digits, Proximal lesion causes loss of sensation over thenar eminence and dorsal and palmar aspects of lateral 3 1/2 fingers (but not with carpal tunnel)
injury to Ulnar
C8-T1;
Caused by fracture of medial epicondyle of humerus “funny bone” (proximal lesion), fractured hook of hamate (Distal);
Presents as ulnar claw on digit extension, proximal lesion shows radial deviation of wrist upon flexion, loss of flexion of wrist and medial fingers, abduction and adduction of fingers (interossei will waste), actions of medial 2 lumbrical muscles, loss of sensation over medial 1 1/2 fingers including hypothenar eminence.
Recurrent branch of median nerve
C5-T1;
Caused by superficial laceration of palm;
Get Ape Hand, loss of thenar muscle group (opposition, abduction, and flexion of thumb), no loss of sensation
What are the thenar muscles
By the thumb Opponens pollicis (Opposes), Abductor pollicis brevis (abducts), Flexor pollicis brevis (Flexes)
What are the hypothenar muscles
By the pinky;
Opponens digiti minimi (opposes), Abductor digiti minimi (abducts), Flexor digiti minimi brevis (flexes)
Dorsal interosseous muscles do what
Abduct the fingers (DAB=Dorsal ABduct)
Palmar interosseous muscles do what
Adducts the fingers (PAD=Palmars ADducts
Lumbrical muscles do what
Flex at the MCP joint, extend PIP and DIP joints
Injury to Obturator nerve
L2-L4;
Cause of injury: pelvic surgery;
Presents as: decreased sensation of medial thigh and decreased abduction (adductor longus, adductor brevis, adductor magnus, gracilis)
Injury to Femoral nerve
L2-L4;
Cause of the injury is likely pelvic fracture;
Presents as decreased thigh flexion and leg extension
Injury to Common peroneal nerve
L4-S2;
Cause of injury is trauma or compression of lateral aspect of leg, fibular neck fracture;
Presents as foot drop (inverted and plantarflexed at rest, loss of eversion and dorsiflexion. “steppage gate.” loss of sensation on dorsum of foot;
PED=Peroneal Everts and Dorsiflexes foot (injury causes foot to be dropPED)
Injury to tibial nerve
L4-S3;
Caused by knee trauma, baker cyst (proximal lesion), tarsal tunnel syndrome (distal lesion);
Presents as inability to curl toes and loss of sensation on sole of foot. In proximal lesions, foot everted at rest with loss of inversion and plantarflexion;
TIP=Tibial Inverts and Plantarflexes (injury means you can’t stand on your TIP toes)
Injury to Superior gluteal nerve
L4-S1;
Posterior hip dislocation or polio are common causes;
Presents as Trendelenburg gait
What is trendelenburg gait
Common in superior gluteal nerve damage;
Pelvis tilts because weight bearing leg cannot maintain aligment of pelvis through hip abduction (superior nerve innverates medius and minimus). Lesion is contralateral to the side of the hip that drops, ipsilateral to extremity on which the patient stands
Inferior gluteal nerve damage
L5-S2;
Posterior Hip Dislocation is common cause;
Presents as difficulty climbing stairs, rising from seated position, loss of hip extension (inferior nerve innervated maximus)
What nerve and artery run in the axilla and lateral thorax
Long thoracic nerve and lateral throracic artery
What nerve and artery run by the surgical neck of humerus
Axillary nerve, posterior circumflex artery
What nerve and artery run in the midshaft of humerus
Radial nerve, deep brachial artery
What nerve and artery run in the distal humerus and cubital fossa
Median nerve and the popliteal artery
What nerve and artery run in the Posterior to medial malleolus
Tibial nerve and Posterior tibial artery
What bands get smaller and which ones stay the same during muscle contraction
Contraction results in shortening of H and I bands, and Z lines come closer together (HIZ shrinkage); but the A band stays the same (A is Always the same)
Type 1 muscle fibers
Slow twitch; red fibers resulting from increased mitochondria and myoglobin concentration (increased oxidative phosphorylation) leading to sustained contraction (1 slow red ox);
Decreased amount of glycogen
Type 2 Muscle fibers
Fast twitch;
white fibers resulting from decreased mitochondria and myoglobin concentrations (increased anaerobic glycolysis); weight training results in hypertrophy of fast twitch muscles.;
increased amount of glycogen
Endochondral ossification
bones of axial and appendicular skeleton, and base of the skull. Cartilaginous model of bone is first made by chondrocytes. Osteoclasts and osteoblasts later replace with woven bone and then remodel to lamellar bone. In adults, woven bone occurs after fractures and in Paget disease.
Membranous ossification
Bone of calvarium and facial bones. Woven bone formed directly without cartilage. Later remodeled to lamellar bone.
Osteoblasts
Build Bone by secreting collagen and catalyzing mineralization. Differentiate from mesenchymal stem cells in periosteum.
Osteoclasts
Multinucleated cells that dissolve bone by secreting acid and collagenases. Differentiate from monocytes/macrophages.
Parathyroid and its effect on bones
at low and intermittent levels it exerts anabolic effects (builds bones) on osteoblasts (directly) and osteoclasts (indirectly). Chronic high PTH levels cause catabolic effects (osteitis fibrosa cystica)
Estrogen and its effect on bones
Estrogen inhibits apoptosis in osteoblasts and induces apoptosis in osteoclasts. When estrogen deficient, excess remodeling cycles and bone resorption lead to osteoporosis.
Achondroplasia
Failure of longitudinal bone growth (endochondral ossification) causing short limbs. Membranous ossification is not affected leading to large head relative to limbs. Constitutive action of fibroblast growth factor receptor (FGFR3) actually inhibits chondrocyte proliferation. >85% of mutations occur sporadically and are associated with increased paternal age, but there is some autosomal dominant inheritance. Common cause of dwarfism. Normal life span and fertility.
Osteoporosis
Trabecular (spongy) bone loses mass and interconnections despite normal bone mineralization and lab values (Ca and PO) Diagnosis by a bone mineral density test (DEXA) with a T score of
Type 1 osteoporosis
Postmenopausal; increased bone resorption due to decreased estrogen levels. Commonly get a femoral neck fracture, distal radius (Colles) fracture
Type 2 osteoporosis
Senile osteporosis; affects men and women >70 years old. Prophylaxis: regular weight bearing exercise and adequate calcium and vitamin D intake throughout adulthood.
Treat with Bisphosphonates, PTH, SERMs, rarely calcitonin; denosumab (antibody against RANKL)
Osteopetrosis
AKA marble bone disease;
Failure of normal bone resorption due to defective osteoclasts leading to thickened, dense bones that are prone to fracture. Bone fills marrow space leading to pancytopenia, extramedullary hematopoiesis. Mutations (e.g. carbonic anhydrase II) impair ability of osteoclasts to create an acidic environment necessary for bone resorption. X rays show bone in bone appearance. Can result in CN impingement and palsies as a result of narrowing foramina. Bone marrow transplant is potentially curative as osteoclasts are derived from monocytes.
Osteomalacia/rickets
Vitamin D deficiency. Osteomalacia in adults, rickets in kids. Due to defective mineralization/calcification of osteoid leading to soft bones that bow out. Decreased Vit D leads to decreased Ca leads to increased PTH secretion leading to decreased PO4. Hyperactivity of osteoblasts leads to increased ALP (osteoblasts need alkaline environment);
Look for vegan diet low in vitamin D
Paget disease of bone (osteitis deformans)
Common, localized disorder of bone remodeling caused by increase in both osteoblastic and osteoclastic activity. Serum Calcium, phosphorus, and PTH levels are normal. Increase ALP. Mosaic pattern of woven and lamellar bone, long bone chalk-stick fractures. Increased blood flow from increased arteriovenous shunts may cause high output cardiac failure. Increased risk of osteogenic sarcoma. Hat size will be increased. Hearing loss common due to narrowing foramen. Associated with paramyxovirus infection
Stages of Paget
Lytic stage-osteoclasts;
Mixed stage-osteoclasts and osteoblasts;
Sclerotic stage-osteoblasts;
Quiescent stage- minimal osteoclast/osteoblast activity
Osteonecrosis
AKA avascular necrosis;
Infarction of bone and marrow, usually very painful. Caused by trauma, high dose corticosteroids, alcoholism, sickle cell. Most common site is femoral head (due to insufficiency of medial circumflex femoral artery)
What will labs look like in osteoporosis
Everything is normal here, just decreased bone mass
What will labs look like in Osteoporosis
usually normal calcium unless severe malignant disease, dense brittle bones
What will labs look like in Paget Disease
Increased ALP and abnormal mosaic bone architecture, everything else is normal
What will labs look like in Osteomalacia/Rickets
decreased serum Ca, decreased PO4, Increased ALP, Increased PTH; See soft bones that bow out
What will labs look like in Hypervitaminosis D
Increased serum Ca, increased PO4, normal ALP, decreased PTH; Caused by over supplementation or granulomatous disease (e.g. sarcoidosis)
What will labs look like in Osteitis Fibrosa Cystica due to primary hyperparathyroidism
Increased serum Ca, Decreased PO4, Increased ALP, Increased PTH
What will labs look like in osteitis fibrosa cystica due to secondary hyperparathyroidism
decreaed serum Ca, Increased PO4, Increased ALP, Increased PTH
Giant Cell tumor
20-40 year olds get it; In the epiphyseal end of long bones; locally aggressive benign tumor around the knee; Soap bubble appearance on X ray; Multinucleated giant cells
Osteochondroma
Most common benign tumor;
Males
Osteosarcoma (osteogenic sarcoma)
2nd most common primary malignant bone tumor after multiple myeloma;
Bimodal distribution of 10-20year olds and >65 year olds;
Predisposing factors are Paget disease, bone infarcts, radiation, familial retinoblastoma, Li-Fraumeni syndrome (germline p53 mutation);
Usually in the metaphysis of long bones often around knee;
Codman triangle (from elevation of periosteum) or sunburst pattern on x ray;
Aggressive and treated with surgical en bloc resection and chemo
Ewing Sarcoma
Think boys less than 15;
Commonly appears in diaphysis of long bones, pelvis, scapula, and ribs;
anaplastic small blue cell malignant tumors (histology looks like a crap load of blue cells);
Extremely aggressive with early metastases, but responsive to chemo;
onion appearance in bone;
Associated with 11;22 translocation