The anatomy of the hand Flashcards
Where do all fingers point when they’re flexed?
Scaphoid tubercle
What do ligaments in the hand do?
Join bones to other bones
Characteristics of ligaments in hands
Co-axial or co-lateral
Features of hand
- Creases
- Thenar/hypothenar eminence
- Hills and valleys
- Web spaces
- Sesamoids
- Lister’s tubercle - extensor polices longus
- DIP - distal interphalangeal joint
- PIP - proximal interphalangeal joint
- MCP - metacarpophalangeal joint
How many bones are in the hand?
31
Where are the 31 bones in the hand?
- Phalanges: 14
- Sesamoids: 2
- Metacarpals: 5
- Carpals (proximal row): 4
- Carpals (distal row): 4
- Radius
- Ulna
What are the 8 bones in the hand?
- Scaphoid
- Lunate
- Triquetrum
- Pisiform
- Trapezium
- Trapezoid
- Capitate
- Hamate
How do you assess the hand?
To assess the hand, palpate for swelling/tenderness. The following areas should be palpated:
- Radial styloid
- Scaphoid
- 1st MC/trapezium joint
- Lunate
- Lister’s tubercle
Then assess for symmetry and look for any visible fractures and any phalangeal rotation. Normally, everything in the hand should form a line from fingertip to wrist
What does FOOSH stand for?
Fall on outstretched hand
Symptoms of FOOSH injury
- Tender snuffbox
- Painful/swollen wrist
- High frequency of non-union and avascular necrosis
Which parts of the hand can be palpated on the central and ulnar sides?
- Metacarpals
- Ulnar styloid
- Triquetrum
- Pisiform
- Hook of hamate
Characteristics of injured pisiform/hamate
- Frequently misdiagnosed as tendonitis/spasm
- Pain/swelling over hypothenar eminence
- Painful gripping and swinging
Range of wrist motion
- Flexion (make fist)
- Extension (extend fingertips)
- Radial deviation
- Ulnar deviation (typically greater than radial deviation)
Range of finger motion:
- Flexion/extension at MCP, PIP, DIP
- Tight wrist and open to test grip
- Abduction/adduction at MCP (spread fingers apart then back together)
Where are proximal phalanges frequently injured?
Shaft/base
When are metacarpals frequently injured?
Boxing
What are intrinsic hand muscles?
Start in metacarpals and finish at fingertips
What are extrinsic hand muscles?
Start in wrists and finish at fingertips
How many extensor muscles are there?
12
How many flexor muscles are there?
8
How many intrinsics are there?
2 sets of 4
Which nerve supplies extensor muscles?
Radial nerve
What is the common extensor origin?
Lateral epicondyle
Which condition affects the common extensor origin?
Tennis elbow
What are the 12 extensor muscles?
- Brachioradialis - from brachium to radius
- Extensor carpi radialis longus
- Extensor carpus radius brevis
- Abductor pollicis longus
- Extensor pollicis brevis
- Extensor pollicis longus
- Extensor indices proprius
- Extensor digitorum communis
- Extensor digitorum minimi
- Supinator
- Anconeus
- Extensor carpi ulnaris
What are the two types of flexors?
Superficialis and deepus
Which nerves supply the flexor muscles?
Median and ulnar
Which arteries supply the flexor muscles?
Radial and ulnar
Which joint do the superficial flexor muscles bend?
The PIP joint
Which joint do the deep flexor muscles bend?
DIP joint
What is the common flexor origin?
Medial epicondyle
Which condition affects the common flexor origin?
Golfer’s elbow
Are the 8 flexor muscles posterior or anterior?
Anterior
What is the name of the vessel that transports nerves/arteries/flexor tendons into the hand?
Palmar tunnels
How many palmar tunnels are there?
2
What are the 8 flexor muscles?
- Flexor digitorum superficialis (middle finger)
- Flexor digitorum profundus
- Palmaris longus
- Flexor pollicis longus (thumb)
- Flexor carpi radialis (index fingers)
- Flexor carpi ulnaris
- Pronator teres (in thumb)
- Pronator quadratus
How to test the FDS?
Flex the finger at the PIP joint - FDS is the only tendon functioning here
How to test the FDP?
Flex the DIP joint - FDP is the only tendon functioning here
Function of transport extensor tendons?
Reduce bowstringing in transition from forearm into hand
How many compartments does the extensor retinaculum form?
6
Why are tendons bathed in synovial fluid?
Blood flow
What are vinaculae?
Blood vessels supplying tendons
What are palmar spaces involved in?
Infection
Which two spaces are known for collecting bacteria and pus?
Thenar and midpalmar
What is the palmar aponeurosis?
A sheet of tissue under the skin of the palm that helps to form ridges
What 4 deep spaces are involved in hand infections?
Subfascial palmar
Dorsal subaponeurotic
Thenar
Midpalmar
What are the two eminences in the finger?
Thenar and hypothenar
Characteristics of the thenar eminence
3 muscles of the thumb, atrophy seen in carpal tunnel syndrome median nerve
Characteristics of hypothenar eminence
3 muscles of little finger, atrophy with ulnar nerve compression
What are the three muscles found in an eminence?
Opponens (helps thumb oppose)
Abductor (lift away from palm)
Flexor (flex thumb down)
What is Dupuytren’s contracture?
Contracture under skin but above tendons
Which tunnel holds the median nerve?
Carpal tunnel
Which vessel holds the ulnar nerve and artery?
Guyon’s canal
Test for radial nerve
Thumb up/ little and index fingers up
Test for ulnar nerve
Cross fingers
Test for median nerve
Okay sign
What happens when ulnar nerve is damaged?
Flattening of hypothenar eminence and loss of intrinsics (can’t PAD or DAB)
What does DAB stand for?
Dorsal abducts
What does PAD stand for?
Palm adducts
Where are interossei found?
Between metacarpals, there are two layers (one on dorsal and one on palmar side)
Which nerve causes adduction and abduction of fingers?
Ulnar nerve
What connects flexors to fingers?
Flexor retinaculum
Characteristics of carpal tunnel
U-shaped bones with lid, joining scaphoid/pisiform/hamate
Opposition of thumb
Touch tip to tip of each finger
Flexion of thumb
Moves towards palm
Extension of thumb
Away from palm
Where does most movement in the digits occur?
Carpometacarpal joint
Where does flexion/extension of the thumb occur?
MCP and IP
