Week 1 Flashcards
Proximal
Nearer to the attachment of an extremity (limb) to the trunk or a structure; nearer to the point of origin
Distal
Farther from attachment of an extremity (limb) to the trunk or structure, farther from point of origin
Sagittal plane
vertical plane that divides body into left & right sides
Coronal (frontal) plane
Vertical plane that divides body into anterior and posterior portions
Horizontal (transverse) plane
plane that divides body into superior and inferior portions
Where is the X-ray image less distorted?
For portion of body closer to the detector - the farther away a tissue is, the larger it will appear (ex: heart in AP projection is much larger than in standard PA projection of chest)
PA projection - goes from posterior to anterior - standard
AP projection - goes from anterior to posterior - not standard, heart looks larger
What are air filled structures?
Stomach & colon - air has atoms far apart, radio-lucent
How lucent are body fluids (blood) and tissues?
Similar density, with fat slightly more lucent (more dense than air, less dense than bone)
CT Scans
Multiple X-rays of the body are performed very rapidly- amt of radiation atleast 100 fold X-rays - more details than X-rays, but use should be minimal
How does ultrasound work?
High freq. sound waves (sonar) are differentially reflected by surfaces separating structures of different densities
-Safe for pregnancy, can be performed at bedside
How does MRI work?
- Use magnetic fields to produce images - patient is pulse with radiofrequency waves in a powerful magnetic field that causes nuclei of atoms to emit a radiosignal that can be detected, stored and reproduced as an image
- NOT DAMAGING (Ionizing radiation of X-rays)
- Better images of soft tissues than CT
- Expensive & cannot be used with patients who have metal in body
How does nuclear medicine imaging work?
- Radioactive material that is injected is taken up selectively by different body organs
- Used to evaluate the physiological function of organ or structure
What is a colles fracture? What causes it?
It is usually caused by a fall onto a hard surface and the patient catching themselves with their wrist.
-Fracture of distal radius - diagnosed in osteoporosis often and post menopausal women
Extension
an increase in the angle between two bones
What innervates the Trapezius?
What innervates the Lat. dorsi?
Accessory nerve (CNXI) & cranial nerves C3 & C4 Thoracodorsal nerve
What innervates the rhomboid muscles?
Dorsal Scapular nerve
What is the function of the trapezius? What does damage to the Accessory nerve cause?
Elevation, retraction & depression of the scapula
-Damage causes trapezius muscle not to function - “Droopy Shoulder”
What is the function of the latissimus dorsi?
Extends, adducts, medially rotates the humerus at the shoulder joint
What muscle of the back connects the upper limb to the thoracic wall? What is its nerve supply?
Serratus anterior, long thoracic nerve, injury to it produces ‘winged scapula’
-Allows anteversion (bent elbow and twisting it) of the arm & pulls scapula forward
What is the function of the deltoid? What innervates it?
- Roundness of shoulder, anterior fibers flex & medially rotate it, middle fibers are chief abductor of humerus, posterior fibers extend laterally and rotate the humerus
- Supplied by the axillary nerve
When is the axillary nerve usually damaged?
Improper use of crutches, fracture to humerus
How to test deltoid muscle?
Abduct the arm starting from 15 degrees.
What muscles form the armpit? What are the innervations?
Latissimus dorsi & teres major!
Long thoracic nerve
Lower subscapular nerve - teres major
What muscle form the rotator cuff?
SITs
Supraspinatus, Infraspinatus, Teres minor, Subscapularis
-stabilizes shoulder joint during abduction and rotation of the upper limb (also involved in adduction)
What vessels are involved in establishing collateral circulation in the shoulder region?
Anastomosis of arteries - located on the dorsum of the scapula
Where does the omohyoid muscle attach? What innervates it?
Inferior attachment of the muscle is to superior boarder of the scapula - on the suprascapular notch. Superior attachment is on the hyoid bone.
It is innervated by cranial nerves I, II and III. It’s function is to depress, retract & steady the hyoid bone.
What does the dorsal scapular nerve innervate?
rhomboid muscles, levator scapulae
What originates on the acromion?
Deltoid!
In which direction does dislocation of the glenohumeral joint usually occur?
Anterior
What does the dorsal horn contain?
Sensory information/sensory neurons - sensory neuron cell bodies lie here!
What innervates the teres minor?
Axillary nerve
What does the supraspinatus do?
Abducts the arm!! and stabilizes the humerus
What muscle/nerve is involved in chin ups/arm adduction?
Latisssimus dorsi & thoracodorsal nerve
What is a pseudounipolar neuron & where are they usually located?
Dorsal horn - usually sensory - have short, apparently single process extending from the body
- Conductions from receptor organ to a cell body in the CNS
- Located outside the CNS in sensory ganglia & part of PNS
What is a mutlipolar neuron?
Usually motor - has two or more dendrites & a single axon
-Most common type of neuron in CNS & PNS
What type of neurons are all motor neurons that control skeletal muscle & those comprising the ANS?
Multipolar neurons
What is the difference between a nucleus & a ganglion?
A nucleus is a collection of nerve cell bodies in the CNS while a ganglion is a collection of nerve cell bodies within the PNS.
How is a peripheral nerve different than a tract?
A peripheral nerve is part of the PNS, not the CNS. Peripheral nerve fibers travel in bundles. A bund of nerve fibers (axons) in the CNS connecting nuclei of the cerebral cortex is a tract.
What are afferent and efferent nerves?
Afferent (sensory) fibers - convey neural impulses to the CNS from the sense organs and from sensory receptors
Efferent (motor) fibers - convey neural impulses from the CNS to effector organs
Anterior (ventral) nerve root
motor (efferent) fibers passing from nerve cell bodies in the anterior horn of the spinal cord gray matter to effector organs
Posterior (dorsal) nerve root
Sensory (afferent) fibers from cell bodies in spinal sensory or posterior root ganglion that extend to sensory endings & centrally to the posterior horn of the spinal cord gray matter
What are the two rami and what do they innervate?
The large ramus is the anterior primary ramus (anterior & lateral trunk along with extremities) while the smaller branch is the posterior primary ramus that goes toward the back (muscles of back, vertebral column, overlying skin)
What are somatic sensory & motor fibers?
Sensory - transmit sensations from body to CNS
Motor - transmit impulses to the skeletal (voluntary muscles)
Where do visceral motor fibers go?
They transmit impulses to smooth (involuntary) muscle and glandular tissues. [pre and post synaptic muscles work together to conduct impulses from the CNS to the smooth muscle or glands]
What does the somatic nervous system control?
Voluntary muscle control
What does the autonomic nervous system control?
[Motor/Visceral areas] It is made up of the sympathetic & parasympathetic ganglia
What is the gray matter of the spinal cord?
Made up of dorsal/posterior horn, lateral horn & ventral horn. It contains nerve cell bodies & synapses
What forms the white matter of the spinal cord?
Contains the axons of nerves which form tracts (from dorsal, lateral & ventral columns
How does the shape of the spinal cord change as you move down the back?
At the top, cervical segments are large, oval while lumbar and sacral segments are smaller and rounder.
Where is the lateral horn present?
At T1-L2 segmental levels - it contains cell bodies of preganglionic sympathetic neurons
(also called intermediolateral cell column)
Describe the white & gray matter in the spinal cord as you move down:
The cord gets smaller caudally.
White matter decreases at lower levels because the number of nerve fibers decreases caudally as descending tracts gradually terminate and ascending tracts aren’t yet complete
Where is gray matter larger?
At cervical (C4-T1) and lumbosacral (L2-S3) levels - due to large number of nerve cells associated with innervation of the limbs
What is the difference between upper and lower motor neurons?
Upper means the cell body starts in the CNS and ends in the CNS (can terminate on a lower neuron)
Meanwhile, lower means the neuron (cell body) starts in the CNS and terminates in the PNS (peripheral motor neurons are always lower neurons)
How many neurons in the somatic and autonomic nervous system?
Somatic - voluntary - one neuron
Autonomic or visceral (involuntary) - two neurons before reaching target
What does the dorsal (posterior) root hold?
Sensory nerve cell bodies (somatic & visceral)
Pseudounipolar neurons
What does the ventral root contain?
Motor or efferent nerves - it joins the dorsal root to make the spinal nerve
What are first, second & third order neurons?
First - cell body in ganglia - located in dorsal root ganglion (sensory)
Second - always starts in CNS & ends up in thalamus
Third - goes from thalamus to cerebral cortex
Where are sensory nerve cell bodies located?
Sensory ganglia - dorsal - located outside the CNS
Where do multipolar neurons of the dorsal horn send their axons?
- higher levels in the CNS
OR - Ventral or anterior horn (interneurons)
What makes up the lateral horn?
Preganglionic cell bodies (multipolar neurons) of Autonomic nervous system (ANS) - found only in thoracic & upper lumbar spinal cord segments
What are alpha motor neurons?
They are present in the ventral horn (motor horn) and send their axons to innervate extrafusal skeletal muscle fibers - “lower motor neurons”
Where are autonomic (motor) nerve cell bodies located?
In motor or visceral ganglia found outside the CNS - Autonomic or Motor ganglia
What muscles - C5?
Upper extremity abductors (deltoid, biceps brachii)
What muscles - C5/C6?
Forearm flexors (biceps brachii, brachioradialis) forearm pronators
What muscles C7?
Forearm extensor (triceps brachii), wrist extensors, finger extensors
What muscles L3/L4?
Leg extension - quadriceps - knee jerk reflex
What muscle L4/L5?
Foot dorsiflexors and toe extensors (anterior tibial muscles)
What muscles S1/S2?
Foot plantarflexors and toe flexors (posterior tibial muscles) (Achilles tendon reflex)
What spinal cord segments supply the intrinsic hand muscles?
C7/T1
What are synarthrotic joints?
together joints, fibrous (sutures in brain), cartilaginous (intervertebral discs & femurs), bony (replaced by bone)
What are diarthrotic joints?
Moveable or synovial joints - has fibrous capsul, synovial membrane (composed of cell making the synovial fluid) & articular surface or hyaline cartilage
What are the 3 synarthrodial joints?
Syndesmosis, Synchondrosis, Synostosis
What are syndesmosis joints?
Fibrous joints, suture in skull, interosseous membrane
What are synchondrosis joint?
Cartilaginous joints
Primary - temporary joint - hyaline cartilage (disappears with age)
Secondary - permanent joints - fibrocartilage in intervertebral discs
[symphysis - secondary cartilaginous joint composed of fibrocartilage found between 2 pubic bones}
What is a synostosis joint?
Bony joint - in the skull - may have existed in development as a fibrous or cartilaginous joint but was replaced by bone upon cessation of growth (ex: epiphyseal plate or frontal bones)
What are the features of a diarthrodial joint?
Moveable/Synovial joint - two bones separated from one another with synovial space (joint cavity) containing synovial fluid
-the fibrous capsule covers the synovial membrane
What are arthritis, synovitis, bursitis?
inflammation of the joint, synovial membrane of a joint & bursa
What is Albinism?
Inability to produce melanin - lack of tyrosinase activity (99% of cases)
What is vitiligo?
An autoimmune disorder in which melanocytes are destroyed - secondary to autoimmune dysfunction, leading to depigmentation
What are the four layers of the epidermis?
Stratum Germinativum, Stratum Spinosum, Stratum Granulosum, Stratum Corneum
What is the stratum germinativum (stratum basal)?
Basal layer, mitotically active, hemidesmosomes, desmosomes - form intermediate filaments
What are the anchoring elements in hemidesmosomes?
Lamins!
What is the stratum spinosum?
2nd layer - ‘prickle’ cell layer (spiny cells), mitotically active, MANY DESMOSOMES, MAKES LAMINAR BODIES
What is the stratum granulosum?
No mitotic activity, keratohyalin cells dying, discharges lamellar bodies, keratohyalin granules
What is the stratum corneum?
Outermost layer, cells are dead & flat, completely ‘keratinized’
What’s the difference between secretory portions and ducts of eccrine glands? Where are eccrine glands located?
Secretory portions of eccrine glands look pink, mushy & filled in. Meanwhile, ducts of eccrine glands look open and empty.
-All over the body
Where are apocrine glands found? What do their glands/secretory units look like?
They are ‘stinky’ sweating glands found in the groin, axilla, around nipple, etc.
-Very large, open
What cells line apocrine and eccrine sweat glands?
Myoepithelial cells
What are the outer layers of the finger under the nail plate?
hyponychium
What do sebaceous glands look like?
Clumps of fat!
Where are pyramidal cells located?
The cerebral cortex
What is the blue staining substance in nerve cells?
RER - Nissl Substance
What surrounds peripheral nerve cells?
epineurium
What is in the middle (inner part) of the cerebellum?
Nerve fiber tracts (white matter)
Macule
flat, circumscribed region of skin with different color or texture
What causes Melasma (cheeks, forehead, temples, facial hyperpigmentation)?
Pregnancy, oral contraceptives, hydantoin
What is Lentigo simplex?
-Localized hyperplasia of melanocytes, not sun releated, small brown macules
What is a benign neoplasm?
Can be destructive or symtomatic - this does not define malignancy. (neoplasm with no capacity for metastasis)
What is a malignant neoplasia?
Neoplasm with potential for metastasis and subsequently growth/proliferation at distant site - often locally destructive but may not be
What’s a spitz nevi?
Red, dome shaped papule (benign but should be removed bc its unpredictable)
-Starts in melanocytes
How do you determine if a skin lesion is a melanoma?
ABCDEs!
A- symmetry
B- normal, nice circumscribed boarder
C - Color - color is variegated/uneven
D - Dimension (larger than 1 cm >10 mm - greater than pencil eraser)
E - Elevation, Evolution, Enlargement - changes in size, growth of mole - EVOLUTION IS MOST IMP!
What does melanoma diagnosis rely on?
Depth of biopsy (needs to go through the lower skin layers)
What is spinal stenosis?
Narrowing of the spinal column that causes pressure on the spinal cord or narrowing of openings where the spinal nerves leave the spinal column
What do meissner’s corpuscles sense?
Touch (high numbers in very sensitive areas)
What do pacinian corpuscles sense?
Pressure (in deeper dermis)
What do free nerve endings sense?
Touch, tactile, pain - peritrichial nerve endings - non-encapsulated
What are the 3 different types of burns?
First - involves epidermal damage, occasional blistering but you usually don’t get any blistering
Second - blistering, epidermal & dermal damage, typically not permanent
Third - destruction of the dermis & epidermis, severe chemical burns = electrical burns
What is Breslow depth?
An important prognostic parameter in evaluating a primary tumor - It is the size of specimen that is adequate to determine the histologic depth of lesion penetration
What happens if the Breslow depth is 1.0 mm or greater?
Usually the patient receives a sentinel node biopsy (first node where cancer is likely to spread from primary tumor)
What are 3 critical features related to staging & ultimate prognosis of a patient’s disease?
Breslow depth, ulceration & mitotic rate
Why should non-excisional (shave/punch) biopsies be avoided?
They underestimate the final Breslow depth.
Multipolar cell bodies of somatic motor neurons innervating skeletal muscle are located. . .
. . .in the gray matter of the spinal cord & brainstem
Where do upper motor neurons originate?
cerebral cortex or brainstem
What does ACh cause in the body?
Excessive sweating, flushing, activation of eccrine glands (great sweating), causes dilation of blood vessels
When should you use a punch biopsy?
Rashes or blisters involving the dermis layer of skin (pemphigoid, pemphigus, lupus erythematosus, erythema multiforme - circular red lesions (itchy blotches of unknown cause possibly mediated by immune complex (mostly IgM)
What is ET-B?
An exfoliating toxin associated with SSSS in young children. (ET-A is associated with bullous impetigo)
What organism causes lyme’s disease and how does the rash present?
Red, erythematous periphery
Borrelia Burgdorferi
What are the properties of pseudomonas auruginosa?
Gram -, bacilli, oxidase +, hot tubs, red, round bumpy itch/blister
What are Lamellar granules?
They are membrane-coating granules (MCGs) filled with lipid
What is a precursor to cutaneous squamous cell carcinoma?
Actinic Keratosis
What is the most common skin cancer?
Basal Cell Carcinoma
What can CT IV contrast material cause?
Transient decrease in renal function
What is ultrasound commonly used for?
To assess abdominal pain in females & gallbladder disease
What has intense tyrosinase activity?
Melanocytes
What is the shoulder muscle over the humerus shown in the MRI?
Supraspinatus
How is blood flow decreased to the hands?
Norepinephrine is released around cutaneous blood vessels and causes constriction.
What types of channels are nicotinic receptors?
ACh from preganglionic neurons binds here.
-They are Na+ channels/depolarizing channels
How does Botulinum toxin work?
It prevents ACh release from nerves to suppress sweating
What catalase?
- Staph aureus
- Strep pyogenes
- Catalase +
2. Catalase -
What is cellulitis and what causes it?
Fast spreading - pain, tenderness, warmth, almost any organism can cause this in immunocompromised patients
-Strep. pyogenese or Staph. aureus
What happens in a catalase test?
Catalase converts hydrogen peroxide to water and oxygen - if catalase +, bubbles form
What happens in a coagulase test?
Can be used to diff. between Strep (+) and Staph (-). Coagulase is bound to the wall & reacts with fibrinogen, resulting in clumping/precip.
Pseudomonas aeruginosa
Bacterial skin infections - “hot tube folliculitis” - usually burn wound infection - organism inhabits soil, water & large intestine
Clostridium perfringens
- Non-motile, found in soil, skin, intestine & vagina
- Cellulitis, gas gangrene, food poisoning
- Can cause crepitus infections (gas production)
What is the cause of and treatment for gas gangrene?
Clostridium perfringens - pick up spores from soil where they get into deep lacerations
- Black fluid can leak, shock is possible
- Surgical removal of infected areas, hyperbaric oxygen to kill anaerobic organisms
- Usually not blood flow to site to deliver antibiotic
Propionibacterium acnes - How does it cause inflammation?
Gram (+) rod, releases lipases to digest the surplus of trapped oil. The presence of bacterial metabolism in the clogged pore results in local inflammation.
What are the bacterial properties of Staph aureus?
Catalase +, Coagulase +, gram (+), cocci - most common skin infection
What are the virulence factors of Staph aureus?
Protein A, Coagulase, Hemolysins & leukocidins
