Page 492 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat

448 section iii Musculoskeletal, skin, and connective tissue ` anatomy and physiology Musculoskeletal, skin, and connective tissue ` anatomy and physiology

Brachial plexus lesions
Erb palsy (“waiter’s tip”) C5 Upper Lateral Randy
Klumpke palsy (claw hand) Musculocutaneous Travis
Wrist drop C6 Drinks
Winged scapula Middle Posterior Axillary Cold
Deltoid paralysis C7 (Extensors) Median (flexors) Beer
“Saturday night palsy” (wrist drop)
Di‡culty flexing elbow, variable Radial
sensory loss C8 Lower Medial
Decreased thumb function, Ulnar
“Pope’s blessing” T1
Trunks Divisions Cords Branches
Intrinsic muscles of hand,
claw hand
Long thoracic

Roots
pREsEntation
Condition inJURy CaUsEs mUsClE dEFiCit FUnCtional dEFiCit Erb-Duchenne palsy
(”waiter’s tip”)
Erb palsy (“waiter’s Traction or tear Infants—lateral Deltoid, Abduction (arm
tip”) of upper trunk: traction on neck supraspinatus hangs by side)
C5-C6 roots during delivery Infraspinatus Lateral rotation (arm
Adults—trauma medially rotated)
Biceps brachii Flexion, supination
Herb gets DIBs (arm extended and
on tips pronated)
Klumpke palsy Traction or tear Infants—upward Intrinsic hand Total claw hand:
of lower trunk: force on arm muscles: lumbricals normally
C8-T1 roots during delivery lumbricals, flex MCP joints and
Adults—trauma interossei, extend DIP and PIP
(eg, grabbing a thenar, joints
tree branch to hypothenar
break a fall)
Thoracic outlet Compression Cervical rib Same as Klumpke Atrophy of intrinsic A
syndrome of lower trunk (arrows in A , palsy hand muscles; C5
and subclavian Pancoast tumor ischemia, pain, C6
vessels, most and edema C7
T1
commonly due to vascular
within the compression
scalene triangle
Winged scapula Lesion of long Axillary node Serratus anterior Inability to anchor B
thoracic nerve, dissection after scapula to thoracic
roots C5-C7 mastectomy, cage Ž cannot
(“wings of stab wounds abduct arm
heaven”) above horizontal
position B

FAS1_2019_11-Musculo.indd 448 11/7/19 5:23 PM