Wrist and hand anatomy Flashcards
What forms the roof of the anatomical snuffbox?
Skin
What forms the floor of the anatomical snuffbox?
Scaphoid and trapezium.
What forms the proximal border of the anatomical snuffbox?
Styloid process of radius
What forms the radial border of the anatomical snuffbox?
Tendons of the extensor pollicis brevis and abductor pollicis longus
What forms the ulnar border of the anatomical snuffbox?
Tendon of the extensor pollicis longus
What is included in the contents of the anatomical snuff box?
Radial artery
Superficial branch of radial nerve
Cephalic vein
Pain and tenderness in the anatomical snuffbox suggests what?
Scaphoid fracture
What is the scaphoid bone at risk of when fractured?
Avascular necrosis
Why is the scaphoid bone at risk of avascular necrosis when fractured?
Due to retrograde blood supply that enters at the distal end
Fractures of which aspect of the scaphoid are most at risk of causing avascular necrosis?
Fractures to the middle/ ‘waist’ if the scaphoid.
What is the extensor retinaculum?
A thickened, fibrous band that holds the extensor tendons at the dorsum of the wrist.
What is De Quervain’s tenosynovitis?
Inflammation of the tendons in the first extensor compartment of the wrist.
What are the attachments of the extensor retinaculum of the wrist?
Lateral surface of distal radius proximally and pisoform + traquetal bones distally.
What type of joint is the wrist?
Ellipsoidal (condyloid) type synovial joint.
Which muscles allow for flexion of the wrist?
Flexor carpi ulnas
Flexor carpi radialis
Flexor digitorum superficialis (assistance)
Which muscles allow for extension of the wrist?
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor carpi ulnaris
Extensor digitorum (assistance)
Which muscles allow for adduction at the wrist?
Extensor carpi ulnaris
Flexor carpi ulnaris
Which muscles allow for abduction at the wrist?
Abductor pollicis longus
Flexor carpi radials
Extensor carpi radialis longus
Extensor carpi radialis brevis
What structures form the carpal tunnel?
Flexor retinaciulum superficially
Carpal bones posteriorly
Scaphoid and trapezium laterally
Hook of the hamate and pisiform medially
Where does the flexor retinaculum span between?
Hook of hamate and pisiform + scaphoid and trapezius
What does the carpal tunnel contain?
9 tendons surrounded by synovial sheaths and the median nerve
What aspect of the median nerve is not found within the carpal tunnel?
Palmar cutaneous branch (is given off prior to median nerve entering carpal tunnel)
Where does the palmar cutaneous branch of the median nerve travel with regards to the flexor retinaculum?
Superficially to it.
Which tendons are found in the carpal tunnel?
Tendon of flexor pollicis longus
4 tendons of flexor digitorum profundus
4 tendons of flexor digitorum superficialis
Which tendon is located within the flexor retinaculum?
Flexor carpi radialis tendon
Which muscles make up the thenar eminence?
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
What are the thenar muscles responsible for?
Fine movements of the thumb
Which nerve innervates the muscles of the thenar eminence?
Median nerve (recurrent branch)
What is the function of the opponent pollicis?
Opposition of the thumb
(medially rotates and flexes the metacarpal on the trapezium)
What is the function of the abductor pollicis brevis?
Abducts the thumb.
What is the function of the flexor pollicis brevis?
Flexes the MCP joint of the thumb.
What are the muscle components of the hypothenar eminence?
Opponens digiti minimi
Abductor digiti minimi
Flexor digiti minimi brevis
What is the innervation of muscles in the hypothenar eminence?
Ulnar nerve
What is the function of the opponents digiti minimi?
Opposition of little finger
What is the function of the abductor digiti minimi?
Abducts the little finger
What is the function of the flexor digiti minimi?
Flexes MCP joint of little finger
What structures do the lumbricals link together?
The extensor tendons and flexor tendons.
What are the functions of the lumbricals?
Flexion at the MCP joints
Extension at IP joints
What is the innervation of the lumbricals?
Lateral 2 lumbricals = median nerve
Medial 2 lumbricals = ulnar nerve
Where are the interoessei located?
Between metacarpal bones of the hand (there are dorsal and palmar groups)
What is a common function of the interossei?
Assist lumbricals in flexion of MCP joints and extension of IP joints.
What is the function of the dorsal interossei?
Finger abduction
What is the function of the palmar interossei?
Finger adduction
What is the innervation of the interossei?
Ulnar nerve
Which 2 muscles of the hand do not fit into a common group?
Palmaris brevis
Adductor pollicis
What is the innervation of the palmaris brevis?
Ulnar nerve
What is the innervation of the adductor pollicis?
Ulnar nerve
What is the function of the palmaris brevis?
Wrinkles the skin of the hypothenar eminence + deepens the curvature of the hand (improves grip)
What is the function of the adductor pollicis?
Adducts the thumb
Where do the lumbricals originate from?
A tendon of the flexor digirotum profundus
Where do the lumbricals insert to?
Pass dorsally and laterally around each finger and insert into the extensor hood.
What is the function of the flexor pulley system of the hand?
To hold the flexor tendons against the phalanges, preventing them from pulling away and bowstringing.
Where do the tendons of the flexor digitorum superficialis attach to?
The base of the middle phalanx.
Where do the tendons of the flexor digitorum profundus attach to?
The base of the distal phalanx.
Which tendons of the hand flex the IP joints?
Flexor digitorum profundus and the flexor digitorum superficialis
Which tendons of the hand flex the DIP joints?
Flexor digitorum profundus.
The flexor retinaculum is attached medially to which carpal bones?
Hamate and pisiform
What are the lateral attachments of the flexor retinaculum?
Scaphoid and trapezium
What is the function of the palmar interossei?
Adduct the fingers towards middle finger
