PBL 40 Flashcards
The radius articulates in 4 places, where?
- Elbow joint
- Proximal radio ulnar joint
- Distal radio-ulnar joint
- Wrist joint
What are the 3 bony landmarks of the proximal radius?
- Head
- Neck
- Radial tuberosity
Which muscle inserts onto the radial tuberosity?
Biceps brachii
Which muscle inserts onto the shaft of the radius?
Pronator teres
The lateral side of the distal radius projects distally as the…
Styloid process
In the medial surface of the distal radius, there is a concavity called the…
Ulnar notch
What makes up the distal radio-ulnar joint?
The ulnar notch from the radius and the head of the ulna
What are the important landmarks of the proximal ulna?
- Olecranon
- Coronoid process
- Trochlear notch
- Radial notch
- Tuberosity of the ulnar
Which muscle attaches onto the olecranon?
Triceps brachii
What are the muscles of the superficial layer of the anterior forearm?
- Flexor carpi ulnaris
- Flexor carpi radialis
- Palmaris longus
- Pronator teres
What are the muscles of the intermediate layer of the forearm?
Flexor digitorum superficialis
What are the muscles of the deep layer of the forearm?
- Flexor pollicis longus
- Flexor digitorum profundus
- Pronator quadratus
The anterior/flexor aspect of the forearm is most innervated by which nerve?
- Median nerve
- FCU and medial half of FDP is ulnar nerve!
Where do the muscles of the superficial layer of the forearm originate?
The medial epicondyle of the humerus
What is the action of the flexor carpi ulnaris & nerve supply?
- Flexion and adduction at the wrist
- Ulnar nerve
Where does the flexor carpi ulnaris originate and attach?
Originate: humeral head = the medial epicondyle of humerus, and the ulnar head = olecranon of the ulnar
Attach: The pisiform bone, hook of hamate and base of the 5th metacarpal
Where does the palmaris longus attach?
The flexor retinaculum
What is the action of the palmaris longus & nerve supply?
Flexion at the wrist
Median nerve
Where does the flexor carpi radialis attach?
The base of metacarpals 2 and 3
What is the action and nerve supply of flexor carpi radialis?
Action: Flexion and abduction at the wrist
Nerve supply: median nerve
Where does the pronator teres originate?
1st origin: Medial border of the antecubital fossa
2nd origin: Coronoid process of the ulna
Where does the pronator teres attach?
The shaft of the radius
What is the action of the pronator teres muscles and nerve supply?
Action: Pronation of the forearm
Nerve supply: median nerve
What passes through the two heads of the flexor digitorum superficialis?
Median nerve and ulnar artery
Where does the flexor digitorum superficialis originate
1st origin: medial epicondyle of humerus
2nd origin: radius
What happens to the flexor digitorum superficialis at the wrist? Where does it attach?
It splits into four tendons which travel through the carpal tunnel and attaches to the MIDDLE phalanges of the four fingers
What is the action and nerve supply of the flexor digitorum superficialis?
Action: flexion of the MCP joins and the PIP joints at the 4 fingers, and flexes the wrist
Nerve supply: median nerve
Where does the flexor digitorum profundus originate?
The ulna
What happens to the flexor digitorum profundus at the wrist?
It splits into four tendons that pass through the carpal tunnel and attach to the DISTAL phalanges of the four fingers
What is the action and nerve supply of the flexor digitorum profundus?
Action: Flexion of the DIP joints, MCP joints and at wrist
Nerve supply: Medial half that acts on little and half of ring fingers is ulnar nerve and the lateral half which acts on the middle and index fingers is median nerve.
Where does the flexor pollicis longus attach?
To the base of the distal phalanx of the thumb
What is the action and innervation of the flexor pollicis longus?
Flexion of the IP and MCP joint of the thumb
Median nerve
Where does the pronator quadratus originate and attach?
Origin: anterior surface of ulna and attaches to the anterior surface of radius
What is the action and nerve supply of the pronator quadratus?
Action: pronates the forearm
Nerve supply: Median nerve
Which nerve innervates all muscles in the posterior/extensor aspect of the forearm?
Radial nerve
Which nerve innervates all muscles in the posterior forearm?
Radial nerve
What is the general function of the posterior forearm muscles?
Produce extension at the wrist and fingers
What are the layers of the posterior forearm?
Superficial
Deep
Where do the majority of posterior forearm muscles originate?
Lateral epicondyle of the humerus
What are the superficial muscles of the posterior forearm?
Extensor carpi ulnaris
Extensor carpi radialis brevis
Extensor digitorum
Extensor digiti minimi
What are the deep muscles of the posterior forearm?
Supinator Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indicis proprius
Where does the brachioradialis originate and attach?
Origin: lateral epidondyle of humerus
Attach: distal end of radius just before the radial styloid process
What is the action and nerve supply of the brachioradialis?
Flexion of the elbow
Radial nerve
Where do extensor carpi radialis longus and brevis attach?
The metacarpal bones 2 and 3
What is the action and nerve supply to extensor carpi radialis longus and brevis?
Action: extension and abduction at the wrist
Nerve supply: Radial nerve
What is the role of extensor digitorum communis?
The main extensor of the fingers
Where does the extensor digitorum originate and attach?
Origin: lateral epicondyle of the humerus
Attach: the extensor hood of each finger
What is the action and nerve supply of the extensor digitorum?
Action: Extends the four fingers at the MCP and IP joints
Nerve supply: radial nerve
Where does the extensor digiti minimi originate and attach?
Origin: lateral epicondyle of humerus
Attach: the extensor hood of the little finger
What is the action and nerve supply to the extensor digiti minimi?
Extension of the little finger
Radial nerve
Where does the extensor carpi ulnaris originate and attach
Origin: lateral epicondyle of humerus
Attach: base of the 5th metacarpal
Action and nerve supply of the extensor carpi ulnaris?
Extension and ADDuction of the wrist
Radial nerve
Where does the supinator originate and insert?
Origin: lateral epicondyle of humerus and posterior surface of ulna
Attach: insert into the posterior surface of the radius
What is the action and nerve supply of the supinator?
Action: Supination of the forearm
Nerve supply: Radial nerve
What are the borders of the anatomical snuff box? (brevis sandwich)
Lateral: abductor pollicis longus
Medial: extensor pollicis longus
Between: extensor pollicis brevis
Where does the abductor pollicis longus originate and attach?
Origin: interosseous membrane and posterior surfaces of radius and ulna
Attach: Lateral side of the base of metacarpal 1
What is the action and nerve supply of abductor pollicis longus?
Abduct the thumb
Radial nerve
Where does the extensor pollicis brevis originate and attach?
Originates from the posterior surface of the radius and attaches to the proximal phalanx of thumb
What is the action and nerve supply of the extensor pollicis brevis?
Action: extension at the MCP and CMC joints of the thumb
Nerve: Radial nerve
Where does the extensor pollicis longus originate and attach?
Origin: posterior surface of the ulna and interosseous
Attachment: distal phalanx of the thumb
What is the action and nerve supply of extensor pollicis longus?
Action: extension of all joints of the thumb: CMC, MCP and IP
Nerve: radial nerve
Where does the extensor indicis proprius originate and attach?
Origin: posterior surface of ulna
Attach: Extensor hood of the index
What is the action and nerve supply of the extensor indicis proprius?
Action: extension of the index finger
Nerve supply: radial nerve
What are the carpal bones in the proximal row from lateral to medial?
Scaphoid
Lunate
Triquetrum
Pisiform
What are the carpal bones in the distal row from lateral to medial?
Trapezium
Trapezoid
Capitate
Hamate
Which tendons travel through the carpal tunnel?
The tendon of the flexor pollicis longus
The four tendons of flexor digitorum profundus
The four tendons of flexor digitorum superficialis
What are the four ligaments of the wrist joint?
- Palmar radiocarpal
- Dorsal radiocarpal
- Ulnar collateral
- Radial collateral
Contents of the anatomical snuff box?
Radial artery
Superficial branch of radial nerve
Cephalic vein
Which nerve innervates all thenar muscles?
Median nerve
What are the thenar muscles responsible for?
Fine movements of the thumb
What are the 3 thenar muscles? OAF
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
What is the action and innervation of opponens pollicis?
Oppose the thumb
Median nerve
Where does opponens pollicis originate and attach?
Origin: tubercle of trapezium
Attach: lateral margin of thumb metacarpal
Where does abductor pollicis brevis originate and attach?
Origin: Tubercles of scaphoid and trapezium
Attach: lateral side of proximal phalanx of thumb
What is the action and nerve supply of abductor pollicis brevis?
Action: abducts the thumb
Nerve supply: median nerve
Where does flexor pollicis brevis originate and attach?
Origin: tubercle of trapezium
Attach: base of proximal phalanx of thumb
What is the action and nerve supply to flexor pollicis brevis?
Flexes the MCP joint of thumb
Median nerve, the deep head is ulnar nerve innervated
Where are the hypothenar muscles situated?
The medial side of the palm at the base of the little finger
Which nerve supplies the hypothenar muscles?
Ulnar nerve
What are the 3 hypothenar muscles?
Opponens digiti minimi
Abductor digiti minimi
Flexor digiti minimi brevis
What is the origin and attachment of the opponens digiti minimi?
Origin: hook of hamate
Attach: inserts into the medial margin of metacarpal 5
What is the action and nerve supply of opponens digiti minimi?
Opposes the little finger, rotates the metacarpal towards the palm
Ulnar nerve
What is the origin and attachment of abductor digiti minimi?
Origin: Pisiform
Attach: base of proximal phalanx of little finger
What is the action and nerve supply to abductor digiti minimi?
Abducts the little finger
Ulnar nerve
What is the origin and attachment site of flexor digiti minimi brevis?
Origin: hook of hamate
Attach: base of proximal phalanx of middle finger
What is the action and nerve supply to flexor digiti minimi brevis?
Action: flexes the MCP joint of the little finger
Nerve supply: ulnar nerve
How many lumbrical muscles does each hand have?
4 - each associated with a finger
What does denervation of the lumbricals lead to?
Ulnar claw and hand of benediction
What is the origin and attachment of the lumbricals?
Each lumbrical originates from a tendon of the flexor digitorum profundus, passing dorsally and laterally around each finger to insert into the extensor hood
What is the action and nerve supply to the lumbrical muscles?
Action: flexion at the MCP joint and extension at the IP joints of each digit
Nerve supply: index and middle finger = median nerve, little and ring finger = ulnar nerve
Where are the interossei muscles located?
Between the metacarpals
What are the two groups of interossei muscles?
Palmar and dorsal
Where do the dorsal interossei originate and attach?
Origin: lateral and medial surfaces of the metacarpals
Attach: extensor hood and proximal phalanx of each finger
What is the action and nerve supply of the dorsal interossei?
Action: DAB: abduct the fingers at the MCP joint
Innervation: Ulnar nerve
How many dorsal interossei muscles are there?
4
How many palmar interossei muscles are there?
3
Where do the palmar interossei muscles originate and attach?
Origin: medial or lateral surface of metacarpal
Attach: extensor hood and proximal phalanx of same finger
What is the action and nerve supply to the palmar interossei?
Action: PAD: Adducts the fingers at the MCP joint
Nerve: Ulnar nerve
What is the action and nerve supply of adductor pollicis?
Action: adduct the thumb
Nerve supply: ulnar nerve
What is the arterial supply to the hand?
Ulnar artery –> deep palmar branch –> superficial palmar arch
Radial artery –> branches to the thumb, index and superficial palmar arch –> continues as the deep palmar arch
What are the 5 degrees of nerve injury?
- Neuropraxia
- Axonotmesis (2,3,4)
- Neurotmesis
What is the consequence of neuropraxia?
Focal segmental demyelination
What is the consequence of axonotmesis (G2)?
Damaged axon with intact endoneurium
What is the consequence of axonotmesis (G3)?
Damaged axon and endoneurium with intact perineurium
What is the consequence of axonotmesis (G4)?
Damaged axon, endoneurium, and perineurium with intact epineurium
What is the consequence of neurotmesis?
Complete nerve transection
Characteristic of ulnar hand
Ulnar nerve damage at forearm/elbow
Hyperextension at the MCP joints and flexion of the PIP and DIP joints of the 4th and 5th fingers
- Can make a full fist but when they extend their fingers, the hand posture is referred to as claw hand
Characteristic of hand of benediction
Median nerve damage at the forearm/elbow
- When a patient is asked to make a fist, the ring finger and little finger flex but the index and middle fingers cannot flex at the MCP, PIP and DIP joints