The hand Flashcards
Dorsal Interossei
Origin:
1: 1st metacarpal (medially) and 2nd metacarpal laterally
2: 2nd metacarpal (medially) and 3rd metacarpal laterally
3: 3rd metacarpal medially and 4th metacarpal laterally
4: 4th metacarpal medially and 5th metacarpal lateral
Insertion:
1. proximal phalanges of 2-4 (2nd=lateral, 3=medial and lateral, 4-medial)
Action:
1. MCP abduction of fingers 2,3,4 (dab)
Innervation:
1. ulnar nerve C8,T1
Palmar Interossei
Origin:
1. Medial 1st metacarpal
2. Medial 2nd metacarpal
3. Lateral 4th metacarpal
4. lateral 5th metacarpal
Insertion:
1. Medial 1st proximal phalanx
2. medial 2nd proximal phalanx
3. Lateral 4th proximal phalanx
4. Lateral 5th proximal phalanx
action:
1. adduct fingers 1,2,4,5
Innervation:
1. ulnar nerve C8,T1
Opponens Pollicis
origin:
1. tubercle of trapezium and flexor retinaculum
Insertion:
1. 1st metacarpal
Action:
1. medially rotates thumb
Innervation:
1. recurrent branch median nerve C8,T1
Abductor Pollicis Brevis
origin:
1. tubercle of scaphoid and trapezium, flexor retinaculum
Insertion:
1. proximal phalanx, extensor hood of thumb
Action:
1. abduct the thumb MCP joint
Innervation:
1. recurrent branch median nerve C8,T1
Flexor Pollicis Brevis
origin:
1. tubercule of trapezium, flexor retinaculum
Insertion:
proximal phalanx of thumb
Action:
1. flexes thumb MCP joint
Innervation:
1. recurrent branch median nerve C8,T1
abductor Digiti Minimi
Origin:
1. pisiform, pisohamate ligament, tendon of FCU
Insertion:
1. proximal phalanx of little finger
Action:
1. abducts 5th finger MCP joint
innervation:
1. deep branch ulnar nerve C8,T1
Flexor Digiti Minimi Brevis
Origin:
1. hook of hamate, flexor retinaculum
Insertion:
1. proximal phalanx of little finger
Action:
1. flexes 5th finger MCP joint
innervation:
1. deep branch ulnar nerve C8,T1
Opponens Digiti Minimi
Origin:
1. hook of hamate, flexor retinaculum
Insertion:
1. 5th metacarpal
Action:
1. laterally rotates 5th metacarpal
innervation:
1. deep branch ulnar nerve C8,T1
Lumbricals of the hand
origin:
1. tendons of flexor digitorum profundus
Insertion:
1. extensor hood
Action:
1. flex MCP joints
2. extend IP joint lumbrical position
Innervation:
1. 1st and 2nd (laterally) = median nerve
2. 3rd and 4th (medially) =deep branch ulnar
Adductor Pollicis
origin:
1. transverse head: 3rd metacarpal
2. oblique head: capitate and bases of 2nd and 3d metacarpals
Insertion:
1. base of proximal phalanx of thumb
action:
1. adducts the thumb
Innervation:
1. ulnar never (deep branch) C8,T1
Blood supply into the hand
- radial artery
- ulnar artery
Radial artery
- enters deep into palm to form deep palmar arch
- supplies thumb and lateral index finger
Ulnar Artery
- forms superficial palmar arch
- supplies medial index finger and fingers 3-5
Nerves of the hand
- Median nerve
- radial nerve
- ulnar nerve
What does the median nerve supply
- motor- thenar muscles and lateral 2 lumbricals
- sensory: thumb, index, middle and 1/2 ringfinger
Median nerve entrapment
location, cases, clinical findings
- Location: in the carpal tunnel under transverse carpal ligament
Causes:
- sprains
- wrist fx
- arthritis
- ganglion cysts
Clinical findings:
- numbness or pain in wrist/hands/fingers
- tingling, difficulty with fine motor movements
Radial Nerve (superficial branch)
supplies
- sensory only
- dorsal lateral palm, dorsal aspect of finges 1-3 and the lateral 1/2 of the ring finger
Radial nerve entrapment at the hand
location, causes, clinical findings
Location:
- wartenberg’s syndrome
- between brachioradialis and ECRL
Clinical findings:
- pain over distal radial forearm and paresthesia over dorsal radial hand
Causes:
- trauma
- stretch injury
Ulnar Nerve Supplies
Sensory:
- medial dorsal and palmar aspect of the hand, 5th digit and medial half of 4th digit
Motor:
- all intrinscis EXCEPT 2 lateral lumbricals and thenar muscles
Ulnar nerve Entrapment
location, causes, clinical findings
Location
- tunnel of Guyon
Causes
- ganglion cysts
- trauma
- repetitive wrist movements
- arthritis
- wrist fx
Clinical findings
- wrist pain
- numbeness/tingling in pinky and ring fingers
- weakness in pal of hand and thumb
- difficulty with grip
Review Laceration zones
review picture
MRI medical imaging in the hand
- MRI is the most important imaging that takes place when lacerations of the hand occur, due to the ability to view the integrity of the tendons within the hand.
X-ray at the hand
- Depending on how a laceration occurs,
- possible through a crushing accident,
- an Xray may be required to assess bone integrity and see if there are any loose bodies within the hand.
Ultrasound at the hand
- bedside US in ED
- takes less time to preform than traditional wound exploration techniques or MRI
Wrist radial deviation
Ulnar subluxation of carpals
Ulnar drift
- Radial collateral ligament breakdown of the MCP joints
- Swelling causes flexor tendons to migrate ulnarly causing deviation at MCP
Swan neck
- Hyperextension or PIP and flexion at DIP
- Lateral bands at PIP drift dorsally and bowstring causes hyperextension at PIP
- Taut FDP causes flexion at DIP
- May have rupture of PIP volar plate
Boutonniere
Flex of PIP, hyperextension of DIP
Rupture of the central slip
Lateral bands volarly to PIP
Mallet finger
Flexed DIP
Rupture of lateral bands at or near DIP insertion
No active DIP extension
Palmar dislocation at MCP
Due to collateral ligament tear and force of FDP and FDS
Steps for Differential Diagnosis at the hand
medical hx:
- co-morbities
Physical exam:
- deformities, swelling, strength etc
labs:
- blood tests
imaging:
- Can see similar inflammation and pattern of joint involvement in lupus and psoriatic arthritis
MSUS - Spot RA early in those who are seronegative (lack antibodies to confirm disease)
- Convenient (during physical exam)
- Less than MRI but more than X-ray
