ANATOMY
Upper Extremities
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Axillary nerve injury results in -?-deltoid
paralysis with total inability to abduct the arm and severe impairment of
flexion & extension at the glenohumeral joint.
Mid hemeral fracture may involve the deep brachial artery and
the radial nerve as they wind about the -?-posterior aspect of the
humerus. Arterial injury produces -?-ischemic contracture; nerve
injury paralyzes the -?-wrist extensors and extrinsic extensors
of the hand.
Except on the ulnar side, the forearm
-?-flexor compartment is innervated by the median nerve.
Scaphoid fracture is most common because it transmits forces
from the abducted hand directly to the -?-radius. Since the
blood supply enters distally, the scaphoid is especially prone to
-?-avascular necrosis.
Lunate dislocation is most common in falls on the
out-stretched hand, compressing the -?-median nerve within the
carpal tunnel and producing carpal tunnel syndrome.
Extension of the proximal phalanges is accomplished by the
extensor digitorium in the forearm, innervated by the -?-radial
nerve. Digital extension at the interphalangeal joints is primarily by dorsal
and ventral interossei, both innervated by the -?-ulnar nerve.
Proximal phalangeal flexion is by the
-?-interossei and lumbricales (median and ulnar nerves); middle
phalangeal flexion is by the -?-extensor digitorum superficialis
(median nerve); distal phalangeal flexion is by the -?-flexor.
Digital abduction is a function of the
-?-dorsal interossei; digital adduction is a function of
-?-palmar interossei.
The ulnar artery is the principal supply to the superficial
palmar -?-arch in the hand.
Lymphaatic drainage from the palmar hand and digits is toward
the dorsal subcutaneous space of the hand, explaining the extreme
-?-swelling of this region that accompanies infections of the
digits or volar surface.
Radial sensory function is tested in the
-?-web space of the thumb; ulnar sensory function is tested
along the -?-fifth digit. The digital brances of the median
and ulnar nerves lie along the sides of the fingers where they may be
-?-anesthetized.
| Nerve | Muscle Group | Reflex Test | Sign or Functional Deficit |
|---|---|---|---|
| Long thoracic | Serratus anterior | -- | -?-Wing scapula |
| Suprascapular | -?-supraspinatus -?-infraspinatus |
-- | Difficulty initiating arm abduction |
| Axillary | deltoid | -- | Inability to fully abduct arm |
| Musculocutaneous | Flexors of arm, forearm | -?-Triceps & wrist extension reflexes | Weak arm flexion, weak forearm flexion, weak forearm supination |
| Median | -?-Wrist & hand flexors | Wrist flexion reflex | Paralysis of flexor, pronator, and thenar muscles; inability to fully flex the index & middle fingers (sign of benediction) |
| -?-Ulnar | Wrist and hand flexors, phalangeal extensors | -- | Inability to extend the distal & middle phalanges (clawhand); loss of thumb adduction |