The Hand Flashcards
How are the thumb and digits named?
Thumb (1st) Index Finger (2nd) Middle Finger (3rd) Ring Finger (4th) Little Finger (5th)
What bones other than the carpals make up the hand?
Metacarpals
Proximal, Middle and Distal Phalanges
How many radio-ulnar joints are there?
2 – proximal and distal
Describe the distal articulation of the radius and ulna with the carpal bones.
Radius – articulates with scaphoid and lunate
Ulna – doesn’t directly articulate with the carpal bones, it articulates with an articular disc
What separates the anterior and posterior compartments of the forearm?
Interosseous membrane
What are the four parts of the metacarpals?
Head (distal), tubercle, shaft and base
Which two carpal bones have bone protrusions?
Hook of Hamate
Tubercle of Trapezium
What type of skin do you get on the palms of your hands?
Palmar-plantar skin
Which muscle forms the palmar aponeurosis?
It is the distal end of palmaris longus
What is the palmar aponeurosis distally and proximally continuous with?
Distal – fibrous digital sheaths
Proximal – flexor retinaculum
What is contained within the fibrous digital sheaths?
Flexor tendons and their synovial sheaths
Which muscle tendons are found within the fibrous digital sheaths? Describe their attachments.
Flexor digitorum superficialis
Flexor digitorum profundus
FDS lies superficial to FDP and splits in two about midway up the proximal phalanx
FDP then runs between the two divisions of FDS
The two branches of FDS attach to the middle phalanx and FDP attaches to the distal phalanx
Which small quadrate muscle is found proximal to the hypothenar compartment?
Palmaris brevis
What is another name for the flexor retinaculum?
Transverse carpal ligament
Name the compartments of the hand.
Thenar
Hypothenar
Adductor
Central
What separates the compartments of the hand?
Fibrous septa
What are the two main spaces found within the hand?
Midpalmar
Thenar
What structures do the septa form within the hand?
Channels that contain various structures e.g. long flexors passing from the wrist into the digits
Which muscles have a proximal attachment along the ulna rather than the common extensor tendon?
Abductor pollicis longus (APL) Extensor pollicis longus (EPL) Extensor pollicis brevis (EPB) Extensor indicis (EI)
Describe the attachment of brachioradialis.
PA - Distal lateral side of the humerus
DA - lateral part of the styloid process of the radius
Name all the intrinsic muscles of the hand.
Thenar: Abductor pollicis brevis (APB), Flexor pollicis brevis (FPB), Opponens pollicis (OP)
Hypothenar:Abductor digiti minimi (ADM), Flexor digiti minimi (FDM), Opponens digiti minimi (ODM)
Adductor: Adductor pollicis (AP)
Interossei and Lumbricals: Palmar interossei
Dorsal interossei
Lumbricals
What movements are the lumbricals responsible for?
Flexion of metacarpophalangeal joint (MCP)
Extension of the interphalangeal joints (IPJs)
What movements are the palmar and dorsal interossei responsible for?
PAD & DAB
Palmar = ADduction of the fingers
Dorsal = ABduction of the fingers
Which muscles are responsible for the following thumb movements: Abduction Adduction Extension Flexion Opposition
Abduction: Abductor pollicis longus (APL), Abductor pollicis brevis (APB)
Adduction: Adductor pollicis (AP), First dorsal interosseus
Extension: Extensor pollicis longus (EPL), Extensor pollicis brevis (EPB), Abductor pollicis longus (APL)
Flexion: Flexor pollicis longus (FPL), Flexor pollicis brevis (FPB)
Opposition: Opponens pollicis
Why is adductor pollicis in a different compartment to the other pollicis muscles?
It is innervated by the ulnar nerve whereas the thenar muscles are all innervated by the median nerve
How many lumbricals, dorsal interossei and palmar interossei are there?
Lumbricals – 4
Dorsal interossei – 4
Palmar interossei - 3
Describe the attachments of the dorsal interossei and explain why they cause abduction of the fingers.
Dorsal interossei are attached proximally to adjacent metacarpals
They attach distally to the base of the proximal phalanx and extensor expansion towards the axial line (through the middle finger) of the hand
Dorsal interossei 2 and 3 are attached to opposite sides of the middle finger so it fixes the middle finger in the midline while dorsal interossei 1 and 4 cause abduction of the index and little fingers