Hand Flashcards
What’s the most frequently fractured carpal bone?
Scaphoid
What’s the most frequently dislocated carpal bone?
Lunate
Which wrist bone is found w/in the tendon of the flexor carpi ulnaris?
Pisiform
Which wrist bone has a hook-like process and what is it called?
Hamate, hamulus
Which carpal bone is the longest & 1st to ossify?
Capitate
Which carpal bone has a saddle-shaped facet for the 1st metacarpal and a tubercle for attachment to the flexor retinaculum?
Trapezium
What dermatome covers the thenar eminence?
C6
What dermatome covers the index and middle finger?
C7
What dermatome covers the ring and pinky finger?
C8
When the deep palmar fascia reaches the palm, it’s known as the _____. What tendon inserts into it?
- Palmar aponeurosis
- Palmaris longus tendon
What causes Dupuytren’s contracture? What are its sx?
- Progressive fibrosis from palmar aponeurosis to base of phalanges
- Pulls digits into flexion at the metacarpo-phalangeal joints (so they can’t be straightened)
Tendons of the fingers are surrounded by _________.
Synovial sheaths
What are the boundaries of the carpal tunnel?
- Anterior: flexor retinaculum
- Posterior: carpal bones
What lies w/in the carpal tunnel?
- 4 tendons of the flexor digitorum superficialis
- 4 tendons of the flexor digitorum profundus
- 1 tendon of flexor pollicis longus
- Median n.
What are some possible causes of carpal tunnel syndrome? What n. is affected? What are the sx?
- Fluid retention, infection, excessive exersize
- Median n.
- Wasting of the thenar mm. (can’t oppose thumb)
What mm. are in the thenar compartment of the hand and what are they innervated by?
- OAF:
1. Opponens pollicis m.
2. Abductor pollicis brevis m.
3. Flexor pollicis brevis m. - Median n. (recurrent branch)
What mm. are in the hypothenar compartment of the hand and what are they innervated by?
- OAF:
1. Opponens digiti minimi m.
2. Abductor digiti minimi m.
3. Flexor digiti minimi brevis m. - Ulnar n.
Adductor pollicis m. innervation and action?
- Ulnar nerve (deep branch)
- Adducts thumb
Abductor digiti minimi m. innervation and action?
- Ulnar nerve (deep branch)
- Adducts little finger
Flexor digiti minimi brevis m. innervation and action?
- Ulnar nerve (deep branch)
- Flexes proximal phalanx of little finger
Opponens digiti minimi m. innervation and action?
- Ulnar n. (deep branch)
- Draws 5th metacarpal anteriorly and rotates it to face thumb
Dorsal interosseous mm. (DABs) innervation and action?
How many are there?
- Ulnar n. (deep branch)
- Abducts digits from axial line of hand (3rd digit), flexes digits at metacarpo-phalangeal joints, extends interphalangeal joints
- There are 4 (2 on middle, pinky has it’s own abductor so none on pinky)
Palmar interosseous mm. (PADs) innervation and action?
How many are there?
- Ulnar n. (deep branch)
- Abducts digits from axial line of hand (3rd digit), flexes digits at metacarpo-phalangeal joints, extends interphalangeal joints
- There are 3 (none on middle finger)
Lumbrical mm. (1st and 2nd) innervation and action?
- Medial n. (digit branches)
- Extends digits at interphalangeal joints, flexes at metacarpo-phalangeal joints (can touch pulp of fingers)
Lumbrical mm. (3rd and 4th) innervation and action?
- Ulnar n. (deep branch)
- Extends digits at interphalangeal joints, flexes at metacarpo-phalangeal joints (can touch pulp of fingers)
Palmaris brevis m. innervation and action?
- Superficial palmar branch of ulnar n.
- Deepens hollow of hand, assists grip
Abductor pollicis brevis m. innervation and action?
- Medial n. (recurrent branch)
- Abducts thumb
Opponens pollicis m. innervation and action?
- Median n. (recurrent branch)
- Draws 1st metacarpal forward and rotates it medially
What is the basic arterial supply to the hand?
-USRD: Ulnar a. superficial, radial a. deep
What happens to the ulnar a. once it enters the hand?
- Divides into superficial branch and deep brach of ulnar a.
- Superficial branch then becomes superficial palmar arch (gives off common palmar digital and proper palmar digital aa. as it moves across hand)
Where are the common palmar aa.?
-Pass b/w metacarpals (comes from superficial branch of ulnar a.)
Where are the proper palmar digital aa.?
-Run on either side of digits 2-5 (comes from superficial branch of ulnar a.)
Where is the deep branch of ulnar a.?
- Passes b/w abductor digiti minimi and flexor digiti minimi mm.
- Anastomoses w/deep palmar arch
Describe radial a.’s path to the hand?
-Continues dorsally over lateral carpal bones, extends across the floor of the snuff box, and pierces the 1st dorsal interosseous m.
What aa. come off from the radial a. in the hand?
- Princeps pollicis a. (medial thumb supply)
- radialis incidis a. (lateral 2nd digit supply)
- Continue to deep palmar arch, which will anastomose w/deep branch of ulnar a.
- Superficial palmar branch (found at midpoint of metacarpal)
What nerves do the median n. branch into in the hand?
Common palmar digital and proper palmar digital branches
What nerves do the ulnar n. branch into in the hand?
- Palmar cutaneous branch (medial palm)
- Dorsal cutaneous branch
- Superficial branch (becomes common palmar digital nerves and then proper palmar digital nerves)
(- Deep branch, not highlighted)
What nerves do the radial n. branch into in the hand?
- Superficial branch
- Dorsal digital nerves
What causes claw hand/ulnar claw? What are the sx?
- Ulnar n. palsy causes unopposed activity of the extensor digitorum m.
- Intrinsic hand m. weakness; hyperextension of 4th and 5th metacarpophalangeal joints, flexion of DIPs and PIPs; loss of ability to spread fingers due to loss of interossei
What causes ape hand? What are the sx?
- Median n. palsy leads to wasting of thenar mm.
- Inability to oppose thumb, thumb is pulled posteriorly and lines up w/other digits
What causes Hand of Benediction/Pope’s blessing? What are the sx?
- Median n. palsy leads to deformity only while trying to make fist
- Inability to flex lateral 3.5 fingers
What causes wrist drop?
-Radial n. palsy: loss of motor innervation to wrist extensors (usually dmg proximal to elbow joint)
