anatomy of the forearms, cubital fossa and hands Flashcards
what are the 2 parallel bones of the forearm?
the radius and ulna
what connects the 2 parallel bones of the forearm?
the interosseous membrane
which of the 2 bones of the forearm is the rotating one? which is the stabilising one?
ulna → stabilising
radius → pivoting
where does the radius and humorous articulate?
elbow joint
- radial head
- the capitulum of the humerus
where does the ulna and humorous articulate?
elbow joint
- trochlear notch of ulna
- trochlea of humerus
what movements happen at the elbow joint?
flexion and extension
where is the cubital fossa?
what shape is it?
triangular-shaped region anterior to the elbow joint
what are the borders of the cubital fossa?
superior - imaginary line between the epicondyles
lateral - brachioradialis muscle
medial - pronator teres muscle
what are the 3 key structures that cross vertically down through the cubital fossa?
TAN
- tendon (biceps brachii)
- artery (brachial)
- nerve (median)
name the muscles of the SUPERFICIAL anterior forearm
- pronator teres
- flexor carpi radialis
- palmaris longus
- flexor carpi ulnaris
what is the action of the pronator teres?
it pronates the forearm
- supinate is palms and forearm facing up holding (bowel of soup)
- pronate is face down
what are the 2 actions of the flexor carpi radialis
- flexes wrist
- lateral radial deviation (ie. abduction of hand and wrist)
palmaris longus - describe the shape and direction fo travel
- middle, long, big muscle belly - inserts into palmar fascia
what is the action of thepalmaris longus?
weak flexor of the wrist
not always present (30% dont have)
what is the action of the flexor carpi ulnaris?
- flexion
- medial ulnar deviation (ie. adduction of hand and wrist)
what nerves innervate the SUPERFICIAL muscles of the anterior forearm ?
median nerve -PT,FCR,PL
ulnar nerve - FCU
where do the SUPERFICIAL muscles of the anterior forearm originate from?
all originate from medial epicondyle
what is the muscle of the middle anterior forearm?
flexor digitorum superficialis
how many tendons does the flexor digitorum superficialishave?
where do they insert?
- 4
- each tendon splits into 2 and these slips insert on either side of the the middle phalanx of digits 2-5
what is the action of the flexor digitorum superficialis(FDS) ?
flexes digits 2-5 at MCP joints
(Metacarpophalangeal)
and PIP joints (proximal interphalangeal)
what nerve innervates FDS?
median nerve
name the muscles of the DEEP anterior forearm
- Flexor digitorium profundus
- flexor pollicis longus
- Pronator quadratus
Flexor digitorum profundus
- how many tendons arise from this muscle? where do these insert?
4 tendons
- travel into the hand
- onto digits 2-5
- pass through the slits in the FDS tendons
-to insert onto the palmar aspect of thedistalphalanx of digits 2-5.
(finger tip area)
what is the action of the Flexor digitorum profundus?
- flexes digits 2-5
- distal interphalangeal joints (DIPS)
what nerve innervates FDP?
dual innervation
lateral half - median
medial half - ulnar
what is the action of the Flexor policies longus?
flexes the IP joint of the thumb
Interphalangealjoint
what is the insertion of the Flexor pollicis longus (FPL)?
inserts onto thedistal phalanxof the thumb.
describe the location and shape of the pronator quadratus muscle?
deepest forearm muscle
square shaped
lies over the distal ends of the radius and ulnar
what is the action of the Pronator quadratus?
pronates the distal radioulnar joint.
what are the radial and ulnar arteries terminal branches of?
subclavian → axillary → brachial → radial and ulnar arteries
where do the superficial and deep veins of the upper limb drain?
axillary vein
what are the superficial veins of the upper limb?
- the cephalic vein
- the basilic vein
- the communicating median cubitalvein (connects the 2)
what are the deep veins of the upper limb?
radial and ulnar
what is the carpal tunnel?
- narrow passageway at the wrist
- entrance to the palm
what are the borders of the carpal tunnel?
Floor and sides (=carpal arch)
- the carpal bones
roof
- theflexor retinaculum
(fibrous band that’s attached to carpal bones)
what structures pass through the carpal tunnel?
- the 9 tendons of the anterior forearm
- the median nerve
what is carpal tunnel syndrome?
Compression of the median nerve
(very narrow)
weakness and atrophy of the muscles
what are the 8 carpal bones?
from lateral proximal row →
Scaphoid
Lunate
Triquatrum
Pisiform
Hamate
Capitate (central)
Trapezoid
Trapezium (thumb)
which carpal bones does the distal radius articulate with? what joint is this?
- the scaphoid
- the lunate
= the radio carpal joint
what are the 3 sets of bones in the hand?
the carpals
the metacarpals
the phalanges
what is the singular of phalanges?
a phalanx
how are the metacarpals labelled?
numbered 1-5
1 = thumb 5 = little finger
how many phalanges make up each digit?
digits 2-5 = a proximal, middle and distal phalanx (3)
digit 1 (thumb) = a proximal and distal phalanx (2)
what are the 3 different joint types in the hand?
- Carpometacarpal, CMC
- Metacarpophalangeal. MCP
- interphalangeal, IP
what are the interphalangeal joints of the thumb?
only 1 because only a proximal and distal phalanx
what are the interphalangeal joints of the digits 2-5?
PIP- proximal interphalangeal (between proximal and middle phalanges)
DIP- distal interphalangeal (between middle and distal phalanges)
what are the 3 grips the digits can make?
power grip (tight squeeze)
hook grip (eg. carrying bags)
precision grip (pads of thumb and index eg. pen holding)
what are the movements of the digits 2-5?
flexion (curl into fist)
extension (back to neural)
abduction (fingers apart)
adduction (fingers together)
what are the movements of digit 1?
flexion and extension
- thumb across palm, think knife hand
- thumb out to lateral side
abduction and adduction
- thumb away from palm vertically
- thumb back to in line with fingers
opposition
-across palm to touch little finger
what structure of the hand makes it so tough and protects the long flexor tendons, tendon sheaths and vessels in the central palm?
the palmar aponeurosis
where are the extrinsic and intrinsic muscles of the hand?
extrinsic - forearmand their tendons travel into the hand.
intrinsic -origins and insertions arewithinthe hand.
what 2 nerves innervate the intrinsic hand muscles?
ulnar and median
what are the 4 groups of intrinsic hand muscles?
- thenar eminence
- hypothenar eminence
- lumbricals
- interossei
where is the thenar eminence ?
- fleshy mass on the palm of the hand
- at the base of the thumb.