hand and wrist Flashcards
ACTIONS OF LUMBRICALS & INTEROSSEOUS MUSCLES
where do they insert?
The tendons of the lumbricals and interossei muscles insert on the lateral bands of the extensor expansions of the medial four digits.
their line of pull
Therefore, their line of pull is ventral to the MP joints, but dorsal to the PIP and DIP joints.
Thus these muscles can
Thus these muscles can all assist in flexion of the MP joints and extension of the DIP and PIP joints
BLOOD SUPPLY TO THE HAND
The ULNAR ARTERY enters
the hand anterior to the flexor retinaculum, just lateral to the pisiform bone. It gives off the deep palmar branch and continues onto the palm as the superficial palmar arterial arch
At the wrist, the RADIAL ARTERY gives off
a superficial palmar branch which completes the superficial palmar arterial arch. The radial artery then courses posteriorly, traveling in the floor of the anatomical snuffbox. It pierces the first dorsal interosseus muscle to enter the palm. When in the palm, the radial artery is the primary source of blood to the deep palmar arterial arch (completed by the the deep palmar branch of the ulnar artery).
Neurologic Evaluation
examine the patient’s sensation prior to instilling anesthesia.
Lacerated nerves are common
Median nerve: through carpal tunnel
Ulnar nerve: passing between hook of hamate
Radial nerve:
Superficial branch above radial styloid
THE RADIAL NERVE IN THE HAND supplies?
The radial nerve supplies NO MUSCLES in the hand
Superficial radial nerve supplies skin on the lateral side of the dorsum of the hand, and a small portion of the thenar eminence
where does it enter.
The median nerve enters the palm of the hand through the carpal tunnel
Once in the palm, it gives off:
the recurrent branch of the median n. supplies the muscles of the thenar eminence
THE ULNAR NERVE IN THE HAND
where does it enter?
what does it give off before it enters?
The ulnar nerve enters the palm of the hand through the ulnar canal (just lateral to the pisiform bone)
Prior to entering the ulnar canal, it gives off:
a palmar cutaneous branch which provides cutaneous innervation to the skin of the medial side of the palm
A dorsal cutaneous branch which provides cutaneous innervation to the skin of the medial side of the dorsum of the hand
In the palm of the hand, the ulnar nerve innervates all the intrinsic muscles of the hand not innervated by the median nerve
MC Hand and Finger Injuries
Most frequent body parts injured at work
Lacerations most frequent injury
Distal phalanx most commonly fractured
Little finger most common in US
what are crush injuries?
Dirty!!!
Documentation (for future reference)
Dominant hand Occupation Tetanus status Traumatized Ascertain hx of trauma Time elapsed since injury Environment of injury Mechanism of injury Nontraumatized When did sx begin What functional impairment What activities worsen sx
If there is decreased sweating at or around site of injury?
think nerve involvement.
Since the nerves follow vessels, never
ligate a hand vessel without directly visualizing the bleeding vessel and all surrounding structures.
Never blindly clamp a bleeding vessel:
trauma to nerve, tendon, or associated vessels
Nerve Injury Testing
Motor:
Motor:
Radial: extension at wrist and MP joint
Ulnar: forcible spread of fingers
Median: flexion of wrist and PIP of thumb and index against resistance
Range of Motion
Note that pain may
may also limit functional exam (false positive)
Flexor Examination
little trick
Test of Flexor Tendon function
Flexor Digitorum Profundus and Flexor Pollicis Longus
Have pt flex DIP while proximal joints are held in extension
Flexor Digitorum Superficialis
Test by holding all other fingers in extension and have the pt flex the finger to be tested
Testing Extension
If you suspect an extensor tendon laceration
Large f.b.’s tend to
(if pt adamant that FB but x-ry is clear=document that you told pt limitations to x-ray and to come back if sx’s worsen)
Patient position: hand palm-down on a table and extend the fingers off the table one at a time.
Test against resistance for partial lacerations
If you suspect an extensor tendon laceration but cannot visualize in the wound, try putting the hand in the position it was in when the injury occurred.
Moving the associated finger also increases the chances of seeing a tendon injury in the wound
Large f.b.’s tend to cause a fibrous rx and become symptomatic
Missed Foreign Bodies
1/3 of legal claims
retained FB
Xray neg but suspicion high = closer examination
Foreign Bodies IDENTIFICATION
Ultrasound
sensitive 95-100% < 1-4mm
CT most sensitive
mechanical and inflammatory effects
Small FB deeply imbedded best left
Hand Infections pathway
Infections that start in the fingers
Infections in the mid-palmar space
proceed through the flexor tendon sheath and enter the mid-palmar space.
extend rapidly into the thenar space.
devastating effects: may resist aggressive treatment with IV antibiotics
FELON= what is it, presents, MC organism
Subcutaneous pyogenic infection of the pulp space of the finger tip (tuft)
Presents with severe throbbing pain
Most common org = staph aureus
Requires I&D
Felon Treatment
Midline incision
Avoid neurovascular bundle
Most serious complication is acute tenosynovitis
Paronychia
what is it
predisposing factors
tx
Inflammation involving the lateral and posterior fingernail folds.
Predisposing factors:
overzealous manicuring
nail biting
thumbsucking
diabetes mellitus
occupations in which the hands are frequently immersed in water
also reported in association with antiretroviral therapy for HIV infection
TX=I&D: separate the nail plate from the lateral nail fold
Packing vs warm soaks
