ANATOMY OF THE FOREARM Flashcards
What are the basic proximal and distal anatomical landmarks of the forearm?
- proximal = elbow
- distal = radio-ulnar joint at the wrist
The radius is the lateral bone of the foreman that runs down to the thumb. Using the labels below, label the major parts of the radius bone:
Radial Styloid Head Oblique line Radial Tuberosity Anterior Border Neck Interosseous Border
1 - Head 2 - Neck 3 - Radial Tuberosity 4 - Oblique line 5 - Interosseous Border 6 - Anterior Border 7 - Radial Styloid
The radius bone has a radial tuberosity which allows for the attachment of muscle of the upper arm. Which muscle of the upper arm attaches here?
1 - brachoradialis
2 - biceps brachii
3 - triceps brachii
4 - brachialis
2 - biceps brachii
The brachioradialis is a flexor of the elbow muscle. Is it predominantly located on the anterior or posterior part of the forearm?
- posterior forearm
- thats why its surprising that it is a flexor or the elbow
The brachioradialis is a flexor of the elbow muscle, that is predominantly located on the posterior part of the forearm, but it acts to flex the elbow. What are the origin and insertions of the brachioradialis?
- originates = proximal aspect of the lateral supracondylar ridge of humerus
- insertion = radial styloid process of radius
The radius articulates with 2 of the carpal bones of the hand, and therefore has 2 unique articulation surfaces at the proximal end of the bone. What 2 carpal bones does the radius articulate with at the hand?
1 - scaphoid and lunate
2 - triquetrum and lunate
3 - scaphoid and hamate
4 - lunate and trapezoid
1 - scaphoid and lunate
The radius and ulnar are almost triangular bones. Where does the apex of each bone point towards?
- radius = medially towards the ulnar bone and interosseus membrane
- ulnar = laterally towards the radial bone and interosseus membrane
The ulnar is the medial bone of the foreman that runs down towards the little finger. Using the labels below, label the major parts of the radius bone:
Radial Notch Trochlear Notch Olecranon Coronoid Process Ulnar Tuberosity Anterior Border Styloid process of ulnar Interosseous Border
1 - Trochlear Notch 2 - Coronoid Process 3 - Radial Notch 4 - Interosseous Border 5 - Olecranon 6 - Ulnar Tuberosity 7 - Anterior Border 8 - styloid process of ulnar
The brachialis is a muscle of the upper arm that flexes the elbow and lies deep to the biceps brachii. What is the insertion and origin of this muscle?
- origin = medial and lateral surfaces of the humeral shaft
- insertion = ulnar tuberosity and coronoid process
Is the head of the ulnar distal or proximal?
- distal at wrist
The ulnar bone of the forearm does not come into direct contact with the carpal bones of the hand. How does it connect to the hands?
- through a fibrocartilaginous disc
What is the name of the membrane that can be seen between the radius and ulnar in the image below?
- interosseus membrane
The interosseus membrane has an upper and lower area where there are gaps/apertures. What is the purpose of these?
- allows vessels to flow from anterior to posterior
The radius attaches the ulnar at the radial head via what ligament?
1 - ulnar collateral ligament
2 - radial collateral ligament
3 - annular ligament
4 - radial ligament
3 - annular ligament
What type of joint is the elbow joint and how many points of articulations does it have?
- a synovial hinge joint
- 3 points of articulation
The elbow joint is a synovial hinge joint with 3 points of articulation. Label the points of articulation in the image below using the labels here:
head of radius radial notch on ulnar capitulum trochlea trochlea notch
1 - trochlea 2 - capitulum 3 - trochlea notch 4 - head of radius 5 - radial notch on ulnar
The elbow joint is a synovial hinge joint with 3 points of articulation. Using the labels below, where does the humerus connect to the radius?
head of radius radial notch on ulnar capitulum trochlea trochlea notch
- head of radius and capitulum
- CRazy = C = capitulum and R = radius
The elbow joint is a synovial hinge joint with 3 points of articulation. Using the labels below, where does the humerus connect to the ulnar?
head of radius radial notch on ulnar capitulum trochlea trochlea notch
- trochlea and trochlea notch
- TULips = T = Trochea and UL = ulnar
The elbow joint is a synovial hinge joint with 3 points of articulation. Using the labels below, where do the radius and ulnar articulate forming the proximal radioulnar joint?
head of radius radial notch on ulnar capitulum trochlea trochlea notch
- head of radius and radial notch on ulnar
There are the 2 important ligaments of the elbow that aid with stability of the joint. One is connected to the radius and the other the ulna, both attach to the humerus. What are these 2 ligaments called?
1 - ulnar and radial collateral ligament
2 - radial and annular collateral ligament
3 - annular and scaphoid ligament
4 - radial and humeral ligament
1 - ulnar and radial collateral ligament
The radioulnar joint has a proximal and distal joint. What articulations make up the distal joint?
- ulnar head with ulnar notch of radius
What 2 movements are able to occur at the distal and proximal ends of the radioulnar joint?
- pronation and supination
During pronation of the wrist, what happens to the radial and ulnar bones?
- the radial bone rotates over the ulnar bone
- ulnar does not really change position
During pronation of the wrist the radial bone rotates over the ulnar bone, but the ulnar does not really change position. Which 2 muscles facilitate pronation of the wrist?
1 - pronator teres and supinator
2 - brachioradialis and pronator quadratus
3 - pronator quadratus and pronator teres
4 - pronator teres and brachialis
3 - pronator quadratus and pronator teres
Which 2 muscles of the forearm facilitate supination?
1 - supinator and biceps brachii tendon
2 - supinator and brachioradialis
3 - supinator and brachialis
4 - supinator and corachobrachialis
1 - supinator and biceps brachii muscle
What is the name given to the area of transition between the anatomical arm and the forearm on the anterior surface of the elbow that acts as a gateway for nerves and blood vessels?
1 - carpal tunner
2 - anticubital space
3 - cubital fossa
4 - anatomical snuff box
3 - cubital fossa
What are the 3 muscles that make up the medial, lateral and floor of the cubital fossa?
1 - brachioradialis, bicep brachii, triceps
2 - pronator teres, brachioradialis, brachialis
3 - pronator teres, brachioradialis, bicep brachii
4 - bicep brachii, pronator teres, brachialis
2 - pronator teres, brachioradialis, brachialis
- medial = pronator teres
- lateral = brachioradialis
- floor = brachialis
Which part of the humerus can an imaginary line be drawn to signify the base of the cubital fossa?
- between lateral and medial epicondyles
What structure forms the roof of the cubital fossa?
1 - aponeurosis of bicep brachii
2 - aponeurosis of supinator
3 - interosseus membrane
4 - aponeurosis of pronator teres
1 - aponeurosis of bicep brachii
There are 3 main sites for venepuncture that are superior to the cubital fossa. Use the labels below to label the image:
basilic vein
cephalic vein
median cubital vein
1 - cephalic vein
2 - median cubital vein
3 - basilic vein
The cubital fossa is the name of the area of transition between the anatomical arm and the forearm on the anterior surface of the elbow that acts as a gateway for nerves and blood vessels. The mnemonic Really Need - Beer To - Be At - My Nicest can be used to identify the contents of the cubital fossa. Using the mnemonic, what are the contents?
Laterally to medial 1 - Really Need = radial nerve 2 - Beer To = biceps tendon 3 - Be At = brachial artery 4 - My Nicest = median nerve
The forearm can be subdivided into an anterior (flexor) and posterior (extensor) compartment. What divides the anterior and posterior compartments?
- interosseus membrane between radius and ulna
What direction to the wrist and digits move in for flexion and extension if the arm is in a neutral position with palms facing forward?
- flexion = wrist and digits bend forward
- extension = wrist and digits move backwards
What movements of the wrist, fingers, thumb and forearm are facilitated by the muscles located in the posterior compartment of the forearm?
- extension of the wrist, fingers and thumb
- supination of forearm
The posterior compartment is mainly innervated by one key nerve and its main branch. What are these called?
1 - ulnar nerve and deep posterior interosseous branch
2 - radial nerve and deep posterior interosseous branch
3 - ulnar nerve and deep anterior interosseous branch
4 - radial nerve and deep anterior interosseous branch
2 - radial nerve and deep posterior interosseous branch
The posterior compartment is mainly supplied by one key artery and 2 of its main branches, what are these called?
1 - ulnar artery and deep posterior and anterior interosseous arteries
2 - radial artery and deep posterior and anterior interosseous arteries
3 - brachial artery and deep anterior and posterior interosseous arteries
4 - brachialis artery and deep anterior and posterior interosseous arteries
2 - radial artery and deep posterior and anterior interosseous arteries
Using the mnemonic Big Chocolate Chips, Double Dip Cherries from medial to lateral, what are the superficial muscles of the posterior compartment of the forearm?
- Big = Brachioradialis
- Chocolate = extensor Carpi Radialis Longus
- Chips = extensor Carpi Radialis Brevis
- Double = extensor Digitorum superficialis
- Dip = Digiti Minimi Extensor
- Cherries = Carpi Ulnaris Extensor
All superficial muscles of posterior compartment of the forearm cross what joint?
- elbow
The 2 muscles below belong to the superficial posterior compartment of the forearm. Where do both of these muscles originate from?
Extensor Carpi Radialis Longus
Brachioradialis
- lateral supracondylar ridge of the humerus
All the muscles below originate at what bony point of the humerus?
Extensor Carpi Radialis Brevis
Extensor Digitorum
Extensor Digiti Minimi
Extensor Carpi Ulnaris
- lateral epicondyle of humerus
The Extensor Carpi Radialis Longus and Extensor Carpi Radialis Brevis are located in the superficial posterior compartment of the forearm. Their origins are as follows:
- Extensor Carpi Radialis Longus = supracondylar ridge of humerus
- Extensor Carpi Radialis Brevis = lateral epicondyle
Where do these 2 muscles insert?
- Extensor Carpi Radialis Longus = base of 2nd metacarpal
- Extensor Carpi Radialis Brevis = base of 3rd metacarpal
The Extensor Carpi Radialis Longus and Extensor Carpi Radialis Brevis are located in the superficial posterior compartment of the forearm. The muscles originate and insert as follows:
1 - Extensor Carpi Radialis Longus
- origin at supracondylar ridge of humerus
- insert at base of 2nd metacarpal
2 - Extensor Carpi Radialis Brevis = base of 3rd metacarpal
- origin at lateral epicondyle of humerus
- insert at base of 3rd metacarpal
What movement do these muscles facilitate at the wrist?
- extension of wrist
- abduction/radia déviation
Where does the extensor digitorum originate and insert?
- origin = lateral epicondyle of humerus
- insertion = each of the 4 extensor hood of each finger
The extensor digitorum originate and inserts as follows:
- origin = lateral epicondyle of humerus
- insertion = each of the 4 extensor hood of each finger
What movements does this allow?
- extends medial four fingers at the MCP and IP joints.
Where does the extensor digiti minimi originate and insert?
- origin = lateral epicondyle of the humerus
- insertion = extensor digitorum tendon, into the extensor hood of the little finger
The extensor digiti minimi and inserts as follows:
- origin = lateral epicondyle of the humerus
- insertion = extensor digitorum tendon, into the extensor hood of the little finger
What movement does this allow?
- extension of the little finger
- contributes to extension at the wrist
Where does the Extensor Carpi Ulnaris originate and and insert?
- origin = lateral epicondyle of the humerus
- insertion = base of metacarpal V.
The brachioradialis muscle is located in the superficial posterior section of the forearm, but is involved in flexion of the elbow. Where does this muscle originate and insert?
- lateral supracondylar ridge of humerus
- inserts = radial styloid process of radius
The anconeus muscle is located in the superficial posterior compartment of the forearm. Where does this muscle originate and insert?
- origin = lateral epicondyle
- inserts = posterior and lateral part of the olecranon of ulnar
‘Some People Prefer Punching It’ is the mnemonic to help remember the deep muscles of the posterior compartment of the forearm. What are the 5 muscles using the mnemonic?
- Some = Supinator
- People = abductor Pollicis longus
- Prefer = extensor Pollicis brevis
- Punching = extensor Pollicis longus
- It = extensor Indicis
‘Some People Prefer Punching It’ is the mnemonic to help remember the deep muscles of the posterior compartment of the forearm. Using the labels below, label the muscles on the image:
- Some = Supinator
- People = abductor Pollicis longus
- Prefer = extensor Pollicis brevis
- Punching = extensor Pollicis longus
- It = extensor Indicis
- 1 = supinator
- 2 = Extensor Pollicis Longus
- 3 = Abductor Pollicis Longus
- 4 = Extensor Pollicis Brevis
- 5 = Extensor Indicis
‘Some People Prefer Punching It’ is the mnemonic to help remember the deep muscles of the posterior compartment of the forearm. Of the muscles below, which is the only muscle that crosses the elbow?
- Some = Supinator
- People = abductor Pollicis longus
- Prefer = extensor Pollicis brevis
- Punching = extensor Pollicis longus
- It = extensor Indicis
- supinator
The supinator is one of the deep muscles of the posterior compartment of the forearm. What is the origin and insertion of this muscle?
- origin: lateral epicondyle and supinator crest (dorsolateral ulna)
- insertion: lateral surface and posterior border of radius
The abductor pollicis longus name can be broken down into:
- abductor = movement it contributes to and abducts the thumb
- pollicis = latin for thumb
- longus = muscle with long tendon
Where does this muscle originate and insert?
- origin = proximal dorsal radius, ulna and interosseous membrane
- insertion = lateral aspect of 1st metacarpal
The extensor pollicis brevis name can be broken down into:
- extensor = movement it contributes to extension of the thumb
- pollicis = latin for thumb
- brevis = muscle with short tendon
Where does this muscle originate and insert?
- origin = dorsal radius, ulna and interosseous membrane
- insertion = dorsal surface of the proximal phalanx of digit I
The extensor pollicis longus name can be broken down into:
- extensor = movement it contributes to extension of the thumb
- pollicis = latin for thumb
- brevis = muscle with long tendon
Where does this muscle originate and insert?
- origin = dorsal ulna and interosseous membrane
- insertion = dorsal surface of the distal phalanx of digit I
The extensor indices name can be broken down into:
- extensor = movement it contributes to extension of the index finger
- indices = latin for index finger
Where does this muscle originate and insert?
- origin = posterior surface of ulna
- insertion = extensor expansion of digit II (index finger)
‘Some People Prefer Punching It’ is the mnemonic to help remember the deep muscles of the posterior compartment of the forearm. Of the muscles below, which 3 muscles form the snuff box, given the name as this is where people inhaled tobacco from, at the wrist?
- Some = Supinator
- People = abductor Pollicis longus
- Prefer = extensor Pollicis brevis
- Punching = extensor Pollicis longus
- It = extensor Indicis
- Abductor Pollicis Longus
- Extensor Pollicis Brevis
- Extensor Pollicis Longus
The anatomical snuff box, given the name as this is where people inhaled tobacco from, is formed by the 3 muscles below.
- Abductor Pollicis Longus
- Extensor Pollicis Brevis
- Extensor Pollicis Longus
What is the clinical relevance of the snuff box?
- during a fall, the scaphoid bone is commonly broken
- pain is felt in the snuff box
The anterior compartment of the forearm contains muscles involved in flexion of the elbow. What other movements does the anterior compartment of the forearm contribute to?
- flexion of the wrist, fingers and thumb
- pronation of the forearm
The anterior compartment of the forearm contains muscles involved in flexion of the elbow. There are 2 key nerves, and a branch from a key nerve in the posterior compartment of the forearm. What are these nerves?
1 - radial and median nerve, superficial branch of radial (sensory)
2 - ulnar and median nerve, superficial branch of ulnar (sensory)
3 - ulnar and median nerve, superficial branch of radial (sensory)
4 - ulnar and radial nerve, superficial branch of radial (sensory)
3 - ulnar and median nerve, superficial branch of radial (sensory)
The anterior compartment of the forearm contains muscles involved in flexion of the elbow. There are 2 key arteries contained within. What are these blood vessels?
1 - ulnar and median artery
2 - ulnar and brachial artery
3 - radial and brachial artery
4 - ulnar and radial artery
4 - ulnar and radial artery
- branches of brachial artery that brach at cubital fossa
There are 3 layers of muscles contained within the anterior forearm, the superficial, intermediate and deep layers. Using the mnemonic Pass Fail Pass Fail what are the 4 muscles moving laterally to medially of the superficial layer?
- Pass = Pronator Teres
- Fail = Flexor Carpi radialis
- Pass = Palmer Longus
- Fail = Flexor Carpi ulnaris
All muscles of the superficial layer of the anterior layer of the forearm cross what and originate from what?
- cross the elbow
- originate from medial epicondyle
There are 3 layers of muscles contained within the anterior forearm, the superficial, intermediate and deep layers. Using the mnemonic ‘Today Colin Loves Cats’ what are the 4 muscles moving laterally to medially of the superficial layer are:
- Today = pronator Teres
- Colin = flexor Carpi radialis
- Loves = palmer Longus
- Cats = flexor Carpi ulnaris
Where does the pronator teres originate and insert and what action does this facilitate?
- origin = 2 heads: one is the medial epicondyle and the 2nd is the coronoid process of the ulna
- insertion = lateral mid-shaft of the radius
- pronation of the forearm
There are 3 layers of muscles contained within the anterior forearm, the superficial, intermediate and deep layers. Using the mnemonic ‘Today Colin Loves Cats’ what are the 4 muscles moving laterally to medially of the superficial layer are:
- Today = pronator Teres
- Colin = flexor Carpi radialis
- Loves = palmer Longus
- Cats = flexor Carpi ulnaris
Where does the flexor carpi radialis originate and insert and what action does this facilitate?
- origin = medial epicondyle
- inserts = attaches to the base of metacarpals II and III
- movement = flexion and abduction (radial deviation) at the wrist
There are 3 layers of muscles contained within the anterior forearm, the superficial, intermediate and deep layers. Using the mnemonic ‘Today Colin Loves Cats’ what are the 4 muscles moving laterally to medially of the superficial layer are:
- Today = pronator Teres
- Colin = flexor Carpi radialis
- Loves = palmer Longus
- Cats = flexor Carpi ulnaris
Where does the palmer longus originate and insert and what action does this facilitate?
- originates = medial epicondyle
- flexor retinaculum of the wrist
- movement = flexion at the wrist
There are 3 layers of muscles contained within the anterior forearm, the superficial, intermediate and deep layers. Using the mnemonic ‘Today Colin Loves Cats’ what are the 4 muscles moving laterally to medially of the superficial layer are:
- Today = pronator Teres
- Colin = flexor Carpi radialis
- Loves = palmer Longus
- Cats = flexor Carpi ulnaris
Where does the flexor carpi ulnaris originate and insert and what action does this facilitate?
- origin 1 = medial epicondyle of the humerus
- origin 2 = olecranon of the ulnar
- insertion = pisiform bone, hook of hamate, and base of the 5th metacarpal
- movement = flexion and adduction (ulnar deviation) at the wrist
There are 3 layers of muscles contained within the anterior forearm, the superficial, intermediate and deep layers. In the intermediate layer there is only one muscles with 2 heads. What is this muscle called?
- flexor diegitorum superficialis
There are 3 layers of muscles contained within the anterior forearm, the superficial, intermediate and deep layers. In the intermediate layer there is only one muscles called the flexor digitorum superficialis. What are the 2 origins and insertions of this muscle?
- origin 1 = medial epicondyle of the humerus (humeral-ulnar head)
- origin 2 = radial head
- insertion = four tendons at the wrist, which travel through the carpal tunnel, and attaches to the middle phalanges of the four fingers (slightly off medial)
There are 3 layers of muscles contained within the anterior forearm, the superficial, intermediate and deep layers. In the intermediate layer there is only one muscles called the flexor digitorum superficialis. What movement does this muscle facilitate?
- flexion of the metacarpophalangeal joints and proximal interphalangeal joints at the 4 fingers
- flexion at the wrist
There are 3 layers of muscles contained within the anterior forearm, the superficial, intermediate and deep layers. There are 3 muscles in the deep layer of the anterior forearm. Using the mnemonic ‘David Polices Queeny’ what are the 3 muscles called?
- David = flexor Digitorum profundus
- Polices = flexor Pollicis longus
- Queeny = pronator Quadratus
There are 3 layers of muscles contained within the anterior forearm, the superficial, intermediate and deep layers. There are 3 muscles in the deep layer of the anterior forearm. The 3 muscles are called:
- David = flexor Digitorum profundus
- Polices = flexor Pollicis longus
- Queeny = pronator Quadratus
What is the origin and insertion and movement facilitated by the flexor Digitorum profundus muscle?
- origin = ulna and associated interosseous membrane
- insertion = splits into four tendons, that pass through the carpal tunnel and attach to the distal phalanges of the four fingers
- movement = flex the distal interphalangeal joints of the fingers and flexes the metacarpophalangeal joints and at the wrist
There are 3 layers of muscles contained within the anterior forearm, the superficial, intermediate and deep layers. There are 3 muscles in the deep layer of the anterior forearm. The 3 muscles are called:
- David = flexor Digitorum profundus
- Polices = flexor Pollicis longus
- Queeny = pronator Quadratus
What is the origin and insertion and movement facilitated by the flexor Pollicis longus muscle?
- origin = anterior surface of the radius and surrounding interosseous membrane - insertion = distal phalanx of the thumb
- movements = flexes the interphalangeal joint and metacarpophalangeal joint of the thumb
There are 3 layers of muscles contained within the anterior forearm, the superficial, intermediate and deep layers. There are 3 muscles in the deep layer of the anterior forearm. The 3 muscles are called:
- David = flexor Digitorum profundus
- Polices = flexor Pollicis longus
- Queeny = pronator Quadratus
What is the origin and insertion and movement facilitated by the pronator Quadratus muscle?
- origin = anterior surface of the ulna
- insertion = anterior surface of the radius
- movements = pronates the forearm
The radial artery is a key artery of the forearm. What important anatomical landmark does it pass through as it enters the wrist?
- snuff box
Is the radial artery located in the anterior or posterior compartment and what key muscle is it located beneath?
- located in anterior forearm and passes through cubital fossa
- below brachioradialis
There are 3 key nerves of the forearm, what are they?
- median
- radial
- ulnar
Which 2 key nerves supply the anterior compartment of the forearm?
- median all muscles except 2 below
- ulnar nerve = medial head of flexor digitorum profundus (medial 1/2 of digit IV and all of digit V) and flexor carpi ulnaris
By placing your left hand (without including the thumb) onto your right forearm with the wrist over the medial epicondyle of the humerus you can use your fingers and the mnemonic Pass Fail Pass Fail to remember the 4 superficial forearm muscles. Remembering the orientation of your fingers can help:
- Pass = finger is on radius bone
- Fail = finger is on the radius bone
- Pass = finger is in middle of ulnar and radius
- Fail = finger is on the ulnar bone
What are the 4 anterior muscles of the forearm?
- Pass = Pronator tere
- Fail = Flexor carpi radiali
- Pass = Palmer longus
- Fail = Flexor carpi ulnaris
By placing your left hand (without including the thumb) onto your right forearm with the wrist over the medial epicondyle of the humerus you can use your fingers and the mnemonic Pass Fail Pass Fail to remember the 4 superficial forearm muscles. The first finger reaches over grabbing the radius bone. If this muscle begins with P and contracts it will pull the radius over. This helps identify the muscle, what is the name?
- pronator teres
- pulling radius over from supine position is called pronation
By placing your left hand (without including the thumb) onto your right forearm with the wrist over the medial epicondyle of the humerus you can use your fingers and the mnemonic Pass Fail Pass Fail to remember the 4 superficial forearm muscles. The second finger reaches over and is on the radius. It begins with F and is on the radial side, what muscle is this?
- flexor carpi radialis
- it flexes the wrist at the carpal joints
- it abducts the wrist called radial deviation as hand deviates towards the radius
By placing your left hand (without including the thumb) onto your right forearm with the wrist over the medial epicondyle of the humerus you can use your fingers and the mnemonic Pass Fail Pass Fail to remember the 4 superficial forearm muscles. The 3rd finger is in the middle of the forearm. It begins with P and is, what muscle is this?
- palmaris longus
- attaches to flexor retinaculum of the wrist
- only tendon that does not pass through carpal tunnel
By placing your left hand (without including the thumb) onto your right forearm with the wrist over the medial epicondyle of the humerus you can use your fingers and the mnemonic Pass Fail Pass Fail to remember the 4 superficial forearm muscles. The 4th finger is on the ulnar bone. It begins with F and is, what muscle is this?
- flexor carpi ulnaris
- on forearm so it is a flexor
- carpi so it flexes the wrist
- ulnaris so it causes ulnar deviation (adduction)
We have 8 muscles in the anterior compartment of the forearm and 3 layers. Using 4 - 1 = 3 we can see the following:
- superficial = 4 muscles
- intermediate = 1 muscle
- deep = 3 muscles
What is the 1 muscle located in the intermediate compartment?
1 = Pronator teres
2 - Flexor digitorum superficial
3 - Extensor digitorum superficial
4 - Flexor carpi ulnaris
2 - Flexor digitorum superficial
- flexes the finger at the metacarpophalangeal and PIP joint (knuckles)
- we can make a girly fist without the thumb as it attaches to digits II-V (2-5) but not the thumb
- IT CANNOT FLEX THE DIP
We have 8 muscles in the anterior compartment of the forearm and 3 layers. Using 4 - 1 = 3 we can see the following:
- superficial = 4 muscles
- intermediate = 1 muscle
- deep = 3 muscles
There are 3 muscles in the anterior deep compartment. They are the:
- Flexor Digitorum Profundus
- Flexor Pollicis Longus
- Pronator Quadratus
How do we know what the Flexor Digitorum Profundus does and attaches to?
- flexor so we know it flexes the proximal interphalangeal joints (PIP)
- digitorum so we know it attaches to the distal phalanx
- profundus so we know this muscle is deep
We have 8 muscles in the anterior compartment of the forearm and 3 layers. Using 4 - 1 = 3 we can see the following:
- superficial = 4 muscles
- intermediate = 1 muscle
- deep = 3 muscles
There are 3 muscles in the anterior deep compartment. They are the:
- Flexor Digitorum Profundus
- Flexor Pollicis Longus
- Pronator Quadratus
How do we know what the Flexor Pollicis Longus does and attaches to?
- flexor so we know it flexes the interphalangeal and MCT joint
- pollicis (latin for thumb) so we know it attaches to the thumb
- longus
We have 8 muscles in the anterior compartment of the forearm and 3 layers. Using 4 - 1 = 3 we can see the following:
- superficial = 4 muscles
- intermediate = 1 muscle
- deep = 3 muscles
There are 3 muscles in the anterior deep compartment. They are the:
- Flexor Digitorum Profundus
- Flexor Pollicis Longus
- Pronator Quadratus
How do we know what the Pronator Quadratus does and attaches to?
- pronator so it pronates the forearm
- quadratus is due to the shape of the muscle
- origin is on ulnar so when it contracts it pulls the radial on top like pulling a duvet and pronating the wrist
The 8 muscles of the anterior forearm are innervated by 2 nerves, the median or ulnar nerve. Only 2 of these 8 muscles are innervated by the ulnar nerve. The 2 muscles of the anterior forearm that are innervated actually trap the ulnar nerve. Using the acronyms FDP and FCU what are these 2 muscles called?
- FDP = flexor digitorum profundus (medial head, 1/2 of digit 4 (medial) and all of digit 5)
- FCU = flexor carpi ulnaris
The posterior forearm has 12 muscles in total, 6 superficial and 6 deep. The 1st muscle from lateral to medial is the brachioradialis. What is the function of this muscle and what does it attach?
- lateral supracondylar ridge of humerus, and attaches to the styloid process of the radius
- flexes the elbow and pronates the wrist (try to contract the bicep but then pronate and supinate the wrist)
The posterior forearm has 12 muscles in total, 6 superficial and 6 deep. The 2nd muscle from lateral to medial is the Extensor Carpi Radialis Longus. What is the function of this muscle and what does it attach?
- originates from the supracondylar ridge, attaching to the posterior aspect of base of metacarpal bone 2
- extensor means it extends
- carpi means carpal joint (wrist)
- radialis means it causes radial deviation (abduction) at the wrist
The posterior forearm has 12 muscles in total, 6 superficial and 6 deep. The 3rd muscle from lateral to medial is the Extensor Carpi Radialis brevis. What is the function of this muscle and what does it attach?
- originates from the lateral epicondyle, attaching to metacarpal bones III
- extensor so it extends
- carpi is carpal joint (wrist)
- radialis so it causes radial deviation (abduction)
The posterior forearm has 12 muscles in total, 6 superficial and 6 deep. The 4th muscle from lateral to medial is the Extensor digitorum. What is the function of this muscle and what does it attach?
- originates from the lateral epicondyle and inserts into the extensor hood of each finger
- extensor so it extends
- digitorum so it extends the 4 digits at the MCP and IP joints
The posterior forearm has 12 muscles in total, 6 superficial and 6 deep. The 5th muscle from lateral to medial is the Extensor Digiti Minimi. What is the function of this muscle and what does it attach?
- originates from the lateral epicondyle, attaching to the extensor digitorum tendon, on the extensor hood of the little finger
- extensor = extends
- digit = finger
- minimi = little finger
- extends the little finger
The posterior forearm has 12 muscles in total, 6 superficial and 6 deep. The 5th muscle from lateral to medial is the Extensor Carpi Ulnaris. What is the function of this muscle and what does it attach?
- originates from the lateral epicondyle, attaching to the base of metacarpal V (little finger)
- extensor = extends
- carpi =carpal bone joint
- ulnaris = ulnar deviation (adduction) of wrist.
The posterior forearm has 12 muscles in total, 6 superficial and 6 deep. The order of these is how the muscles run proximally to distally down the arm. The 1st muscle is the anconeus. What is the function of this muscle and what does it attach?
- lateral epicondyle of humerus and inserts onto the lateral surface of olecranon
- due to its location it extends the elbow joint
The posterior forearm has 12 muscles in total, 6 superficial and 6 deep. The order of these is how the muscles run proximally to distally down the arm. The 2nd muscle is the supinator. What is the function of this muscle and what does it attach?
- it has two heads of origin, one originates from the lateral epicondyle and the 2nd from the posterior surface of the ulna.
- they insert together into the posterior surface of the radius
- facilitate supination by pulling on the radius, like pulling a cover over in bed
The posterior forearm has 12 muscles in total, 6 superficial and 6 deep. The order of these is how the muscles run proximally to distally down the arm. The 3rd muscle is the Abductor Pollicis Longus. What is the function of this muscle and what does it attach?
- originates from the interosseous membrane and the adjacent posterior surfaces of the radius and ulna, attaching to the lateral side of the base of metacarpal I (thumb)
- abductor so we know it abducts
- pollicis so we know it abducts the thumb
The posterior forearm has 12 muscles in total, 6 superficial and 6 deep. The order of these is how the muscles run proximally to distally down the arm. The 4th muscle is the Extensor Pollicis Brevis. What is the function of this muscle and what does it attach?
- originates at the posterior surface of the radius and interosseous membrane, attaching to the base of the proximal phalanx of the thumb
- extensor so we know it extends
- pollicis so we know it extends the thumb
- brevis is shorter than longus for attachment
- extends at the metacarpophalangeal and carpometacarpal joints of the thumb.
The posterior forearm has 12 muscles in total, 6 superficial and 6 deep. The order of these is how the muscles run proximally to distally down the arm. The 5th muscle is the Extensor Pollicis longus. What is the function of this muscle and what does it attach?
- originates from the posterior surface of the ulna and interosseous membrane, attaching to the distal phalanx of the thumb
- extensor so we know it extends
- pollicis so we know it extends the thumb
- longus so we know it attaches further along the thumb
- extends anywhere on the thumb
The posterior forearm has 12 muscles in total, 6 superficial and 6 deep. The order of these is how the muscles run proximally to distally down the arm. The 6th muscle is the Extensor Indicis
What is the function of this muscle and what does it attach?
- originates from the posterior surface of the ulna and interosseous membrane, attaching to the extensor hood of the index finger
- extensor so we know it extends
- indices so we know it extends the index finger
The anatomical snuffbox is formed from 3 of the muscles from the deep layer of the posterior compartment of the forearm. Using the mnemonic Brevis between 2 Longus AEE (from median to lateral) can help remember this. What are the muscles?
- A = Abductor pollicis brevis
- E = Extensor pollicis brevis
- E = Extensor pollicis longus
The flexor digitorum profundus (FDP) and superficialis (FDS) are both flexor muscles contained within the anterior compartment of the forearm. The FDP has its insertion at the distal phalanx of the digits II-V. However, to each this it must pass through the FDS. What is the name of the structure that is created by this?
1 - carpal tunnel
2- politeal fossa
3 - axilla fossa
4 - campers chiasm
4 - campers chiasm
