Conditions

Erb’s Palsy

Injury to upper trunk C5-C6

Birth trauma or Fall “waiter Tip”

arm adducted internally rotated, elbow extended, wrist fixed

Klumpke’s palsy

Injury to lower trunk C8-T1

falls where the arm is pulled Overhead

results “Claw Hand” posture with loss of intrinsic hand muscle function

Thoracic Outlet Syndrome “TOS”

compression of the neurovascular bundle as it passes through thoracic outlet, commonly at the space between the clavicle and first rib

causes: pain, numbness, and tingling in the shoulder/ Arm

Axillary nerve palsy

damage to the axillary nerve

often from shoulder dislocation or humeral neck fracture.

Impairs deltoid function, reading to weak shoulder abduction and sensory loss over the “regimental Badge” area of lateral shoulder

Mallet Finger

Rupture or avulsion of the terminal (END) extensor tendon at the DIP Joint, usually from a direct blow to an extended fingertip.

the DIP joint Droops into flextion and can not actively extend

lateral epicondylitis

“ Tennis Elbow”

overuse injury/ inflammation of the common extensor tendon origin at the lateral epicondyle

aggrivated by wrist extension and gripping

Boutonniere’s Deformity

rupture of the central slip of the extensor mechanism at the PIP joint

PIP= flexion DIP=hyperextension

Swan Neck Deformity

PIP= hyperextends

DIP= Flexion

A Lax PIP volar plate or damage to the terminal tendon can cause this

Claw Hand

ulnear nerve damage causing loss of intrinsic muscle function in the ring+ pinky fingers, resulting in MCP hyperextension with IP flexion in these Digits

Carpal Tunnel syndrom

compression of the median nerve as it passes under the flexor retinaculum at the wrist. Casuse numbess/ tingling in the thumb, index, middle, and half the ring finger often worse at night

trigger finger

a size mismatch between the flexor tendon and the A1 pulley, causing the finger to catch or lock in flexion before snapping straight

Dupuytren’s contracture

progressive thickening and tightening of the palmer fascia, pulling fingers (typicall ring and pinky finger) into fixed flexion.

De Quervain’s syndrome

inflammation of the abductor pollicis longus and extensor pollicis brevis tendons at the first dorsal compartment of the wrist, causing pain at the thumb/wrist base

Brachial Plexus

Network of nerve roots (C5-T1) that reorganizes into trucks ( Upper, Middle, lower) -division- cords ( lateral, posterior, medial)- terminal branches ( musculocutaneous, axillary, radial, median, ulnar)

Each nerve innervates specific muscle groups and skin region, so damage at different points produces distinct patters

Radial Nerve

powers the posterior/ extensors caompartment of the arm, forearm, and hand

tracks down the posterior humerus, then continues into the forearm. Damage causes wrist drop and loss of fingers/ thumb extension

extensor mechanism of the fingers

the complex hood of tendon and ligaments structures on the dorsal finger that extends the PIP and DIP joints. made up of the central a slip ( inserts at middle phalanx base) and lateral bands ( which join distally to from the terminal tendon inserting at the distal phalanx).

disruption at different points causes boutonniere or mallet deformities

Muscles of the arm, forearm, and hand

known attachment sites( origin/insertion) primary action, and innervation for each.

best artery for pulse

radial artery, at the wrist ( Lateral to the flexor capri radialis tendon)

Bursa

fluid filled sacs that reduce friction between tendons, muscles , and bone

central slip

inserts at the middle phalanx

extends PIP

terminal slip/Tendon

inserts at the distal phalanx

extends DIP

PAD (Palmar interosseus performs finger ADDuction)

palm side of the metacarpals and pull the fingers toward the middle finger

the axis of adduction/ abduction is the middle finger

DAB Dorsal interosseus performs finger abductions

sits on the back side and spread the fingers away from the middle finger