Musculoskeletal - Skin - Connective Tissue_1 Flashcards
What are the epidermis layers from surface to base?
Stratum Corneum (keratin • Stratum Lucidum • Stratum Granulosum • Stratum Spinosum • Stratum Basale
what are the spines in the stratum spinosum?
desmosomes
which epidermal layer is the stem cell site?
Stratum Basale
what are the 3 epidermal appendages?
Sebaceous gland • Eccrine gland • Apocrine gland
mechanism of sebaceous gland secretion?
holocrine secretion of sebum
sebaceous gland associated with what?
hair follicle
eccrine gland secretes what?
sweat
eccrine glands are found where?
throughout the body • Eccrine glands are every where
apocrine glands secrete what?
milky viscous fluid
apocrine glands are found where?
axillae, genitalia, areolae
when are apocrine glands functional?
do not become functional until puberty
why are apocrine glands malodorous?
because of bacterial action
functions of tight junctions?
zona occludens: • prevents paracellular movement of solutes
tight junctions are composed of what?
claudins and occludins
where are adherens junctions?
zonula adherins: below tight junctions
adherens junctions form what?
belt connecting actin cytoskeletons of adjacent cells with Cadherins
what are Cadherins?
Ca++ dependent adhesion proteins
loss of E-cadherin does what?
promotes metastasis
what is the function of desmosomes?
structural support via keratin interactions
atoantibodies to desmosomes cause what?
pemphigus vulgaris
components of desmosomes?
keratin • desmoplakin
what happens in gap junctions?
channel proteins called connexons permit electrical and chemical communication between cells
function of a hemidesmosome?
connects keratin in basal cells to underlying basement membrane
autoantibodies to hemidesmosomes cause what?
bullous pemphigoid
what are integrins?
membrane proteins that maintain integrity of basement membrane by binding to laminin in BM
how does unhappy triad happen?
common injury in contact sportsL lateral force applied to a planted leg
unhappy triad includes which injuries?
tear of ACL, MCL and meniscus (classically medial, but lateral more common)
treatment for unhappy triad?
often requires surgical reconstruction
A and P in ACL and PCL refer to what?
sites of tibial attachment
positive anterior drawer test means what?
ACL tear
abnormal passive abduction at the knee means what?
MCL tear
what is the important landmark for pudendal nerve block?
ischial spine
what is the important landmark in finding the appendix?
2/3 of the way from the umbilicus to the anterior superior iliac spine (McBurney’s point)
what is the important landmark in lumbar puncture?
iliac crest
what are the shoulder muscles that form the rotator cuff?
Supraspinatus • Infraspinatus • teres minor • Subscapularis • SItS (small t is for teres minor)
what is the most common rotator cuff injury?
Supraspinatus
action of supraspinatus?
abducts arm initially (before deltoid)
which rotator cuff muscle is a common pitching injury?
Infraspinatus
action of infraspinatus?
laterally rotates arm
action of teres minor?
adducts and laterally rotates arm
action of subscapularis?
medially rotates and adducts arm
rotator cuff muscles are innervated by what?
C5-C6
what are the bones of the wrist?
Scaphoid • Lunate • Triquetrum • Pisiform • Trapezium • Trapezoid • Capitate • Hamate • Some Lovers Try Positions That They Can’t Handle
what is the most commonly fractured carpal bone?
scaphoid
scaphoid is prone to which complication?
avascular necrosis owing to retrograde blood supply
dislocation of which wrist bone may cause acute carpal tunnel syndrome?
lunate
what is carpal tunnel syndrome?
entrapment of median nerve in carpal tunnel
what is the pathogenesis of carpal tunnel syndrome?
nerve compression → paresthesia, pain, and numbness in distribution of median nerve
cause of lesion in upper trunk of brachial plexus?
trauma
cause of lesion in C7 root of brachial plexus?
compressed by cervical disk lesion
cause of lesion in axillary nerve?
fracture of surgical neck of humerus • dislocation of humerus • intramuscular injections
cause of lesion to lower trunk of brachial plexus?
compressed by cervical rib or by pancoast tumor of lung
lesion of lower trunk of brachial plexus leads to what?
Klumpke’s palsy
cause of lesion to radial nerve in spiral groove?
lesioned by midshaft fracture of the humerus
cause of radial nerve compression in the axilla?
incorrect use of a crutch
cause of lesion in proximal median nerve?
compressed by supracondylar fracture of humerus • pronator teres syndrome
cause of lesion to deep branch of radial nerve?
stretched by subluxation of radius
cause of proximal ulnar nerve lesion?
lesioned by repeat minor trauma • fracture of medial epicondyle of humerus
caused of lesion to anterior interosseous nerve?
compressed in deep forearm
cause of lesion in distal median nerve?
compressed in carpal tunnel syndrome and by dislocated lunate
cause of distal ulnar nerve lesion?
lesioned by trauma to heel of the hand • fracture of hook of hamate
cause of lesion to recurrent branch of median nerve?
lesioned by superficial laceration
nerve root of top of shoulder dermatome?
C4
nerve root of lateral humerus dermatome?
C5
nerve root of medial arm → lateral forearm→ thumb and index finger dermatome?
C6
nerve root of middle finger and middle palm dermatome?
C7
Nerve root of ring/little finger and medial palm dermatome?
C8
Nerve root of medial forearm and distal medial arm dermatome?
T1
nerve root of medial proximal arm and inferior shoulder dermatome?
T2
cutaneous sensory nerve distribution on hand of the ulnar nerve?
little + 1/2 ring finger on palmar and dorsal surface of hand
cutaneous sensory nerve distribution on hand of median nerve?
thumb → half of ring finger on palmar surface • inner half of thumb, distal half of index to 1/2 ring finger on doral surface
cutaneous sensory nerve distribution on hand of radial nerve?
proximal edge of palmar thenar eminence on palmar and whole dorsum of thenar eminence
lesion to long thoracic nerve causes what?
winged scapula
lesion to upper trunk of the brachial plexus causes what?
Waiter’s tip (Erbs palsy)
lesion to lower trunk of brachial plexus causes what?
Claw hand (Klumpke palsy)
lesion to posterior cord of the brachial plexus causes what?
wrist drop
damage to the axillary branch of the brachial plexus causes what?
deltoid paralysis
damage to radial branch of the brachial plexus causes what?
Saturday night palsy (wrist drop)
damage to musculocutaneous branch of brachial plexus causes what?
Difficulty flexing elbow, variable sensory loss
damage to the median branch of the brachial plexus causes what?
decreased thumb function (pope’s blessing)
damage to the ulnar branch of the brachial plexus causes what?
intrinsic muscles of the hand, claw hand
roots that contribute to the long thoracic nerve?
C5, 6, 7
roots that contribute to upper trunk of the brachial plexus?
C5-6
roots that give rise to middle trunk of brachial plexus?
C7
roots that give rise to lower trunk of brachial plexus?
C8-T1
how many divisions in the brachial plexus?
6
trunks that contribute to the lateral cord of the brachial plexus?
upper • middle
trunks that give rise to posterior cord of the brachial plexus?
upper • middle • lower
trunks that give rise to medial cord of the brachial plexus?
lower
nerve roots that give rise to lateral cord of brachial plexus?
C5, 6, 7
nerve roots that give rise to posterior cord of brachial plexus?
C5, 6, 7, 8, T1,
nerve roots that give rise to medial cord of brachial plexus?
C8, T1
trunks that give rise to axillary branch of brachial plexus?
upper • middle • lower
trunks that give rise to radial branch of brachial plexus?
upper • middle • lower
trunks that give rise to musculocutaneous branch of brachial plexus?
upper • middle
trunks that give rise to median branch of brachial plexus?
upper • middle • lower
trunks that give rise to ulnar branch of brachial plexus?
lower
cords of brachial plexus that innervate flexors of forearm?
lateral • medial
cords of brachial plexus that innervates extensors of forearm?
posterior
nerve roots that contribute to axillary nerve?
C5-C6
nerve roots that contribute to radial nerve?
C5-T1
nerve roots that contribute to musculocutaneous nerve?
C5-C7
nerve roots that contribute to median nerve?
C5-T1
nerve roots that contribute to ulnar nerve?
C8-T1
brachial plexus is protected from clavicle fracture by what?
subclavius muscle
typically injury of axillary nerve?
fractured surgical neck of humerus • dislocation of humeral head
motor deficit in axillary nerve injury?
Deltoid- arm abduction at shoulder
sensory deficit in axillary nerve injury?
over deltoid muscle
sign associated with axillary nerve injury?
atrophied deltoid
what is the typical injury of the radial nerve?
fracture at midshaft of humerus • extended compression of axilla by back of chair or crutches
motor deficit seen in radial nerve injury?
BEST extensors • Brachioradialis • Extensors of wrist and fingers • Supinator • Triceps
sensory deficit seen in radial nerve injury?
posterior arm and dorsal hand and thumb
sign seen in radial nerve injury?
wrist drop
typical injury to the median nerve?
fracture of supracondylar humerus
motor deficit in proximal lesion to median nerve?
opposition of thumb • lateral finger flexion • wrist flexion
sensory deficit in proximal lesion to median nerve?
dorsal and palmar aspects of lateral 3 1/2 fingers • thenar eminence
sign seen in median nerve lesion?
ape hand • popes blessing
typical injury to ulnar nerve?
fracture of medial epicondyle of humerus • funny bone
motor deficit in proximal ulnar nerve injury?
medial finger flexion • wrist flexion
sensory deficit in proximal ulnar nerve lesion?
medial 1 1/2 fingers • hypothenar eminence
sign seen in proximal ulnar nerve lesion?
radial deviation of wrist upon wrist flexion
typical injury to musculocutaneous nerve?
upper trunk compression
motor deficit in musculocutaneous nerve injury?
biceps • brachialis • coracobrachialis • flexion of forearm at elbow
sensory deficit in musculocutaneous nerve injury?
lateral forearm
what causes erb-duchenne palsy ‘waiters tip’?
traction or tear of the upper trunk of the brachial plexus (C5-C6)
erb duchenne palsy ‘waiters tip’ seen in who?
infants following trauma during delivery
findings in erb-duchenne palsy ‘waiters tip’?
limb hangs by side (paralysis of abductors) • medially rotated (paralysis of lateral rotators) • forearm is pronated ( loss of biceps)
what are the causes of Klumpke palsy and thoracic outlet syndrome?
an embryologic or childbirth defect affecting inferior trunk of brachial plexus (C8-T1) • cervical rib can compress subclavian artery and inferior trunk, resulting in thoracic outlet syndrome
findings in klumpke palsy/thoracic outlet syndrome?
atrophy of thenar and hypothenar eminences • atrophy of interosseous muscles • sensory deficits on the medial side of the forearm and hand • disappearance of the radial pulse upon moving the head toward the ipsilateral side
clawing of the hand is conceptualized how?
as loss of the lumbricals, which flex the MCP joints and extend both the DIP and PIP joints
ulnar claw can be caused by what?
long-standing injury to ulnar nerve at hook of hamate (falling onto outstretched hand)
pathogenesis of ulnar claw?
distal ulnar nerve lesion → loss of medial lumbrical function→ inability to extend 4th and 5th digits when trying to open hand
median claw can be caused by what?
carpal tunnel syndrome or dislocated lunate
pathogenesis of median claw?
distal (after branches containing C5-C7 branches off to feed forearm flexors) median nerve lesion→ loss of lateral lumbrical function→ 2nd and 3rd digit are clawed upon attempted finger extension
what causes pope’s blessing?
proximal median nerve lesion causes loss of lateral finger extension and thumb opposition
finding in pope’s blessing?
when asked to make a fist, 2nd and 3rd digits remain extended and thumb remains unopposed, which looks like the hand of benediction
pathogenesis of ape hand?
proximal median nerve lesion → loss of opponens pollicus muscle function → unopposable thumb
pathogenesis of klumpke’s total claw?
lesion of lower trunk (C8-T1) of brachial plexus → loss of function of all lumbricals; • forearm finger flexors (fed by part of median nerve with C5-C7) and finger extensors (fed by radial nerve) are unopposed→ clawing of all digits
muscle innervated by LTN?
serratus anterior
action of serratus anterior?
anchors scapula to thoracic cage • used for abduction above horizontal position