Anatomy of the forearm Flashcards
Which bony structures for anatomical landmarks of the two bones in the forearm?
What lies between these two bones?
ULNA tuberosity and styloid process of ulna
RADIAL tuberosity and styloid process of ulna
Interosseus membrane
Consider the elbow joint
What kind of joint is this?
Which range of movement does this facilitate?
There is also a proximal radioulnar joint. What kind of joint is this and which range of movement does it facilitate?
Synovial hinge joint- flexion/extension
Proximal raadioulnar joint is a PIVOT joint for supination and pronation
Consider the elbow joint
Which bony structures of the bones involved for this joint?
Capitulum and trochlea (forms trochlea notch) of humerus (anteriorly)
Olecranon of humerus posteriorly
Head of radius, and radial notch
What is the function of a ligament?
State the three ligaments in the elbow?
Ligaments stabilise/strengthen joint
Radial collateral ligament
Annular ligament
Ulnar collateral ligament
What is the cubital fossa?
Borders, structures passing through
Triangle region over anterior elbow
Its borders include the lateral and medial epicondyle, brachioradialis and pronator teres
The brachialis muscle Lateral cutaneous nerve to forearm Median nerve Brachial artery Biceps tendon
What is the clinical relevance of the median cubital vein?
Important for venopuncture
The forearm can be divided into compartments. The flexor compartment is found anteriorly.
State the four muscles found in the superficial layer
Where do they originate?
Pronator teres- pronator
Flexor carpi radialis- flexor
Palmaris longus- flexor
Flexor carpi ulnaris- flexor
Common flexor origin (medial epicondyle)
The forearm can be divided into compartments. The flexor compartment is found anteriorly.
State the muscle found in the intermediate layer
Where does it originate and insert? Function
Flexor digitorum superficialis
Origin: medial epicondyle
Insertion: middle phalanges
Function: flexor of digits 2-5
The forearm can be divided into compartments. The flexor compartment is found anteriorly.
State the three muscles found in the deep layer
Where do they originate and insert? Function?
Flexor digitorum profundus- flexor of digits 2-5
Flexor pollicis longus - flexor of thumb
Pronator quadratus - pronator
Origin: medial epicondyle
Insert: distal phalanges
The forearm can be divided into compartments. The extensor compartment is found posteriorly.
State the names and functions of the muscles in the superficial layer
(excluding brachioradialis and anconeus)
EXTENSORS OF WRIST
Extensor carpi radialis longus/brevis-
Extensor carpi ulnaris
EXTENSOR OF DIGITS 2-5
Extensor digitorum
ACCESSORY EXTENSORY TO DIGIT 5
Extensor digiti minimi
State the orgin, insertion and function of the brachioradialis m
Origin: Lateral supracondylar ridge
Insertion: Styloid process of the radius
Function: flexion of elbow
State the orgin, insertion and function of the Anconeus m
Origin: dorsal side of the lateral epicondyle of the humerus
Insertion: olecranon of the ulna
Function: extension of elbow and rotation of forearm
The forearm can be divided into compartments. The extensor compartment is found posteriorly.
State the names and functions of the muscles in the deep layer
Supinator
ANATOMICAL SNUFF BOX - Extensor of thumb Abductor pollicis longus Extensor pollicis longus - Abductor of thumb Extensor pollicis brevis-
Accessory extensor to digit 2
Extensor indicis
Which muscles are responsible for wrist abduction?
Which muscles are responsible for wrist adduction?
Flexor carpi radialis
Extensor carpi radialis (longus+brevis)
Flexor carpi ulnaris
Extensor carpi ulnaris
Together muscles splint the wrist to allow fine movements of the hand
Which muscles are involved in supination?
What happens to the bones of the forearm during pronation?
Biceps brachii
Supinator
The radius rotates over the ulna facilitated by the proximal and distal radioulnar joints
Which muscles are involved in pronation?
Pronator teres
Pronator quadratus
What is the carpal tunnel?
What does it contain?
What surrounds it?
Tunnel for flexor tendons to digits and median nerve
- Median nerve
- Flexor policis longus
- Flexor digitorum superficialis
- Flexor digitorum profundus
Synovial sheaths
Which structure lies anteriorly to the carpal tunnel?
What is its function?
Flexor retinaculum- the transverse carpal ligament
Prevents bowing of tendons
What is carpal tunnel syndrome?
Median nerve compression due to increased pressure in carpal tunnel- associated with trauma, obesity and pregnancy
What is Golfers elbow?
Epicondylitis at CFO
Tendon inflammation due to overuse/excessive rippig
What is Tennis elbow?
Epicondylitis at CEO (tendon inflammation due to overuse/forceful extension
What is the function of the extensor retinaculum?
- Prevents bowing of tendons
- Separates tendons into compartments
State the name and insertions of the long tendons (digits 2-5)
Flexor digitorum profundus- into distal phalanx
Extensor digitorum- into middle and distal phalanx
Flexor digitorum superficialis- into middle phalanx
Describe the arterial supply of the forearm
At the cubital fossa the brachial artery divides into:
Radial artery - under bracioradialis
Ulnar artery- under flexor carpi ulnaris, gives off common interosseous
Anastomosis around elbow joint ( by recurrent branches of radial and ulnar artery)
State the branches of the ulnar artery
Common interosseous artery
Posterior interosseous artery
Anterior interosseous artery
Which nerves supply the forearm?
Median nerve
Radial nerve
Ulnar nerve
Describe the location of the median nerve and its passage
Lies mid forarm between FDS and FDP
- Gives off anterior interosseous nerve to deep flexor muscles
Passes through carpal tunnel
Function:
- Motor supply to anterior compartment except FCU/medial aspect of FDP
- Sensory to lateral palm + d1-3 + 1/2 d4
Describe the motor and sensory supply provided by the ulnar nerve
- Motor supply to FCU and medial part FDP
- Sensory supply to medial hand including 1/2 d4 + d5
Describe the location and branches of the radial nerve
Enters forearm on lateral side under brachioradialis
- Superficial branch (sensory)
- under brachioradialis
- winds round to dorsum of hand - Deep branch - posterior interosseus nerve (motor)
- passes through supinator muscle
- Enters extensor (posterior) compartment
Which disorder is caused by radial nerve palsy?
Wrist drop
Consider the cutaneous innervation of the forearm
In the anatomical position, state the nerves that supply the anterior skin
Lateral side- lateral cutaneous nerve of forearm (musculocutaneous)
Medial side- medial cutaneous nerve of forearm
Lateral palm + thumb + d2+d3+1/2 d4 = median nerve
Medial palm + 1/2 d4 + d5= ulnar nerve
Consider the cutaneous innervation of the forearm
In the anatomical position, state the nerves that supply the posterior skin
Lateral side- musculocutaneous nerve
Medial side- medial cutaneous nerve of forearm
Middle forearm - radial nerve( branches from arm)
