Forearm Flashcards
What is the common origin of the flexor muscles of the forearm?
Medial epicondyle
How many layers of muscles are there in the anterior compartment of the forearm?
3 - superficial, intermediate & deep
What are the superficial muscles of the anterior compartment of the forearm?
Med to lat;
- FCU
- Palmaris longus
- FCR
- Pronator teres
What characterises palmaris longus?
Small muscle with long tendon
Which muscle makes up the intermediate layer of the anterior compartment?
Flexor digitorum superficialis
How many tendons does flexor digitorum superficialis form, and where do they pass?
4 tendons
-through the carpal tunnel
What lies on the underside of flexor digitorum superficialis?
Median nerve
Which muscles make up the deep layer of the anterior compartment?
Flexor digitorum profundus
Flexor pollicis longus
Pronator quadratus
How many tendons does flexor digitorum profundus split into and where do they pass?
4 tendons
-through the carpal tunnel
Which muscle lies deepest in the deep layer of the anterior compartment of the forearm and where does it run from and to?
Pronator quadratus
- runs from radius to ulnar
What is the common origin of the extensor muscles of the forearm?
Lateral epicodyle
Which muscle is most lateral/radial in the superficial layer of the posterior compartment of the forearm?
Brachioradialis
What is unusual about brachioradialis?
Part of posterior compartment, but acts as a flexor of the arm
How many layers of muscles make up the posterior compartment of the forearm?
2 - superficial and deep layers
Which muscles make up the superficial layer of the posterior compartment of the forearm?
Lateral to medial;
- Brachioradialis
- Extensor carpi radialis longus
- Extensor carpi radialis brevis
- Extensor digitorum (lies in the midline)
- Extensor digiti minimi
- Extensor carpi ulnaris
How many tendons does extensor digitorum split into where do they pass?
4 - deep to extensor retinaculum
Which 4 muscles make up the deep layer of the posterior compartment of the forearm?
Medial to lateral;
- Extensor indicis
- Extensor pollicis longus
- Extensor pollicis brevis
- Abductor pollicis longus
What does abductor pollicis longus wrap around?
Radius
Which tendons form the medial and lateral boundaries of the anatomical snuff box?
Medial - extensor pollicis longus
Lateral - extensor pollicis brevis and abductor pollicis longus
What is the role of supinator muscle and what compartment is it found in?
Wraps around radius and works with biceps to supinate forearm
- deep layer of post compartment
What are the boundaries of the cubital fossa?
Lateral = brachioradialis Medial = pronator teres Superior = imaginary line between epicondyles
What muscle forms the floor of the cubital fossa?
Brachialis
What forms the roof of the cubital fossa?
Deep fascia and bicipital aponeurosis
What is the bicipital aponeurosis?
Thickening of deep fascia running medially from bicipital tendon
What are the contents of the cubital fossa?
Lat to med;
Biceps brachii tendon
Brachial artery
Median nerve
Which superficial veins lie laterally and medially to the cubital fossa?
Lat = Cephalic vein Med = Basilic vein
Which vein joins the cephalic and basilic vein?
Median cubital vein
Which ligament holds the radius in place at the superior radioulnar joint and what are its attachments?
Annular ligament
- PROX: ant margin of radial notch (ulnar)
- DIST: post margin of radial notch
Which carpal bones articulate with the radius at the radiocarpal joint?
Lunate and scaphoid
How can a FOOSH result in compression of the median nerve?
Dislocation of lunate bone»_space; median nerve compression
What effect would median nerve damage from dislocation of the lunate bone have on movements of the digits?
Supplies 1st and 2nd lumbricals; lose flexion at MCP joint and extension at IP joint.
Suplies thenar muscles; wouldn’t be able to abduct, flex or oppose thumb
What effect would damage to the median nerve in the cubital fossa have on the movements of the upper limb?
Difficulty flexing wrist, and flexing/extending MCP/IP joints
Where does the ulnar nerve run past the elbow joint?
Behind medial epicondyle
Other than pronating the arm what else does pronator teres do?
Weak flexor of forearm
Palmaris longus is present in approximately what percentage of individuals?
85%
Brachioradialis is particularly important in what action?
Returning arm to midprone position
What is the nerve supply of brachioradialis?
Radial nerve
To which phalanges does flexor digitorum superficialis attach?
Mid phalanges of II-V
Where does the median nerve lie in relation to flexor digitorum superficialis?
Deep to the muscle
Which neurovascular bundle lies median to flexor digitorum superficialis?
Ulnar nerve and artery
Where do the tendons of flexor digitorum profundus insert?
Palmar surfaces on distal phalanges of II-V
In which direction do the collagen fibres run in the interosseous membrane?
Mainly inferior from radius to ulna (transfers forces from radius to ulna)
Which 4 structures run through the carpal tunnel?
- Flexor pollicis longus tendon
- Flexor digitorum superficialis tendons (4)
- Flexor digitorum profundus tendons (4)
- Median nerve
Which structures pass deep to the extensor retinaculum?
Tendons of extensor digitorum and digiti minimi
Which compartment is anconeus muscle part of?
Superficial posterior compartment
Where does anconeus insert and what is its function?
Into olecranon and prox post ulna.
Function: abduction of ulna and accessory flexor at elbow
Where do the deep extensors generally arise?
Shaft of radius and ulna, and interosseous membrane
Which vein runs over the anatomical snuff box?
Cephalic vein
What bony elements can be palpated in the floor of the anatomical snuff box?
Scaphoid and trapezium
Which 2 muscles are responsible for pronation of the forearm?
Pronator teres
Pronator quadratus
