Anatomy of Limbs 3 - Elbow, forearm and wrist Flashcards
List the bones of the elbow, forearm and wrist
- Humerus
- Radius
- Ulna
- Carpal bones
List the carpal bones
Proximal row (lateral to medial)
- Scaphoid
- Lunate
- Triquetum
- Pisiform
Distal row (lateral to medial)
- Trapezium
- Trapezoid
- Capitate
- Hamate
List the muscles in the superficial anterior compartment of the forearm
- Pronator teres
- Flexor carpi radialis
- Palmaris longus
- Flexor carpi ulnaris
- Flexor digitorum superficialis
First 4 represented by the fingers when you hold the thumb to the medial epicondyle and spread the fingers
List the muscles in the deep anterior compartment of the forearm
- Flexor digitorum profundus
- Flexor pollicis longus
- Pronator quadratus
List the muscles in the extensor compartment of the forearm
Muscles that move the wrist joint
- Extensor carpi radialis longus (ECRL)
- Extensor carpi radialis brevis (ECRB)
- Extensor carpi ulnaris (ECU)
Muscles that move the digits
- Extensor digitorum (ED)
- Extensor indicis (EI)
- Extensor digiti minimi (EDM)
Muscles that move the thumb
- Abductor pollicis longus (APL)
- Extensor pollicis brevis (EPB)
- Extensor pollicis longus (EPL)
Other Muscles of the Forearm
- Brachioradialis
- Supinator
List the joints in this region
- Elbow joint
- Proximal radio-ulnar joint
- Distal radioulnar joint
- Wrist joint
What kind of joint is the elbow joint?
- Synovial hinge
- Between the humerus, radius and ulna
- Humerus articulates with the ulna via the trochlea
- Humerus articulates with the radius via the capitulum, only when in full flexion
Which ligaments are important in the elbow joint?
- Medial collateral ligaments (ulnar)
- Lateral collateral ligaments (radial)
- Annular ligament
List the movements of the elbow joint. Which muscles are involved?
Flexion - Brachialis - Biceps (- Brachioradialis - Pronator teres)
Extension
- Triceps
(- Aconeus)
What is the carrying angle?
- The deviation of the long axis of the radius and ulna from that of the humerus when you put your arm by the side
- Greater in women than men
What type of joint is the proximal radio-ulnar joint?
- Uni-axial pivot-type synovial joint
- Allows the head of the radius to rotate within the annular ligament
What type of joint is the distal radio-ulnar joint?
- Pivot type synovial joint that allows the radius to rotate around the distal ulna and the articular surfaces are held together by a articular disk
Which movements take place at the radio-ulnar joints? Which muscles are involved?
Supination
- Supinator
- Biceps brachii
- (EPL, ECRL)
Pronation
- Pronator quadratus
- Pronator teres
- (FCR, PL, Brachioradialis)
What is the interosseus membrane of the forearm?
- Fibrous sheet connecting the radius and the ulna
- Forms a fibrous joint between the two bones
- Divides forearm to posterior and anterior compartments
What type of joint is the wrist joint?
- Elipsoid synovial joint between the distal radius and its associated triangular fibrocartilage articular disc, with the proximal carpal bones
- The ulna does not directly articulate with the carpal bones, there is an articular disc between them (unlike the radius)
List the ligaments stabilising the wrist joint
- Ulnar collateral ligament
- Radial collateral ligament
- Palmar radio-capral ligament
- Palmar ulnocarpal ligament
- Dorsal radiocarpal ligament
- Intercarpal ligament
List the important muscles for flexion and extension of the wrist
Flexion
- FCR (flexor carpi radialis)
- FCU (flexor carpi ulnaris)
- Long flexors of thumb and fingers
- Palmaris longus
- APL (abductor pollicis longus)
Extension
- ECRL (extensor capri radialis longus)
- ECRB (extensor carpi radialis brevis)
- ECU (extensor carpi ulnaris)
- Long extensors of the thumb and fingers
List the muscles used in radial deviation
- FCR (flexor carpi radialis)
- ECRL (Extensor carpi radialis longus)
- ECRB (extensor carpi radialis brevis)
- APL (abductor policis longus)
- Extensor pollicis brevis
List the muscles used in ulnar deviation
- Extensor carpi ulnaris
- Flecor carpi ulnaris
List the attachments, innervation and function of the flexor carpi ulnaris
- Proximal attachments humeral head (medial epicondyle), ulnar head, olecranon and posterior border of ulna
- Distal attachment to pisiform bone, via pisohamate and pisometacarpal ligaments into the hamate and metacarpal V
- Innervated by the ulnar nerve
- Flexes and adducts the wrist
List the attachments, innervation and function of the palmaris longus
- Medial epicondyle of humerus to Palmar aponeurosis of hand
- Innervated by median nerve
- Flexes joint
List the attachments, innervation and function of the flexor carpi radialis
- Medial epicondyle of humerus to base of metacarpals II and III
- Innervated by the median nerve
- Flexes and abducts the wrist
List the attachments, innervation and function of the pronator teres
- Humeral head (medial epicondyle and adjacent supra-epicondylar ridge) and ulnar head (medial side of coronoid process) to the roughening on the lateral surface midshaft of radius
- Innervated by the median nerve
- Pronation
List the attachments, innervation and function of the flexor digitorum superficialis
- Origin is the humero-ulnar head (median epicondyle of humerus and margin of coronoid) and radial head (oblique line) to 4 tendons which attach to palmar surfaces of the index middle ring nd little fingers
- Innervated by the median nerve
- Flexes fingers and wrist joint
List the attachments, innervation and function of the flexor digitorum profundus
- Anterior and medial surfaces of ulnal, anterior medial half of interossus membrane to index middle ring and little finders
- Lateral half median nerve, middle half ulnar nerve
- Flexes distal interphalangial joints, and metacarpiphalangial joints
List the attachments, innervation and function of the flexor pollicis longus
- Anterior surface of radius and radial half of interosseous membrane to palmar surface of distal phalanx of thumb
- Median nerve
- Flexes thumb
List the attachments, innervation and function of the pronator quadratus
- Linear ridge on distal anterior surface of ulna to the distal anterior surface of radius
- Median nerve
- Pronation
List the attachments, innervation and function of the brachioradialis
- Proximal part of lateral supraepicondylar ridge of humerus and adjacent intermuscular septum to the lateral surface of distal end of radius
- Radial nerve
- Flexor of elbow joint (when forearm midpronated)
List the attachments, innervation and function of the extensor carpi radialis longi
- Distal part of lateral supraepicondylar ridge of humerus and adjacent septum to dorsal surface of metacarpal II
- Radial nerve
- Extends and abducts the wrist
List the attachments, innervation and function of the extensor carpi radialis brevis
- Lateral epicondyle of humerus and adjacent intermuscular septum to dorsal surface of base of metacarpals II and III
- Deep branch of radial nerve
- Extends and abducts the wrist
List the attachments, innervation and function of the extensor digitorum
- Lateral epicondyle of humerus and adjacent intermuscular septum and deep fascia to middle and distal phalanges of index, middle, ring and little fingers
- Posterior interosseous nerve
- Extends fingers and wrist
List the attachments, innervation and function of the extensor digiti minimi
- Lateral epicondule of humerus to extensor hood of little finger
- Posterior interosseous nerve
- Extends little finger
List the attachments, innervation and function of the extensor carpi ulnaris
- Lateral epicondyle of humerus and posterior border of ulna to tubercle on base of metacarpal V
- Posterior interosseous nerve
- Extends and adducts the wrist
List the attachments, innervation and function of the aconeous
- Lateral epicondyle of humerus to the olecranon and proximal posterior surface of ulna
- Radial nerve
- Abduction of the ulna in pronation, accessory extensor of the elbow joint
List the attachments, innervation and function of the supinator
- Lateral epicondyle of humerus and supinator crest of ulna to the lateral surface of radius superior to the anterior oblique line
- Posterior interosseous nerve
- Supination
List the attachments, innervation and function of the abductor pollicis longus
- Posterior surfaces of ulna and radius, and interosseous membrane to base of metacarpal I
- Posterior interosseous nerve
- Abducts carpometacarpal joint of thumb, acessory extensor of thumb
List the attachments, innervation and function of the extensor pollicis brevis
- Posterior surface of radius to dorsal surface of proximal phalanx of thumb
- Posteiror interosseous nerve
- Extends thumb
List the attachments, innervation and function of the extensor indicis
- Posterior surface of ulna to extensor hood of index finger
- Posterior interosseous nerve
- Extends index finger
List the attachments, innervation and function of the extensor pollicis longus
- Posterior surface of ulna to dorsal surface of base of distal phalanx of thumb
- Posterior interosseous nerve
- Extends interphalangeal joint of thumb, as well as carpometacarpal and metacarpophalangeal
Describe the arterial supply of the region
- Brachial artery divides at the elbow (radial neck) to the ulnar and radial arteries
- Ulnar artery passes into the hand anteriorly. Forms common interosseous artery which splits into the anterior and posterior interosseous arteries, and finally forms the palmar arches in the hand with the radial artery
- Radial artery descends in lateral aspect of the forearm.
Describe the venous supply of the region
Superficial
- Cephalic (lateral) and basilic (medial)
- Median cubital vein connects them
Deep
- Accompany radial and ulnar arteries, flow into brachial vein of the arm
List the three main nerves of the forearm
- Ulnar
- Median
- Radial
What is a sesamoid bone?
- A bone embedded in a tendon or a bit of muscle
- Eg. pisiform bone
Where does the biceps attach distally?
- Radial tuberosity via tendon
- Aponeurosis merges with the fascia of the region
Where does the branchialis attach distally?
Coronoid process of the ulna
Where does the triceps attach distally?
Olecranon process of the ulna
What is the proximal attachment of the superficial anterior compartment of the arm
- Common flexor tendon
- Pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris and the flexor digitorum superficialis
What is the flexor retinaculum?
Band of connective tissue which binds the tendons so when you flex and extend they do not bow
How can muscles in the forearm be worked out?
- Flexors are anterior, extensors are posterior
- Muscles with movement on the wrist are carpi, they either act on radial or ulnar aspects of the forearm (radialis or ulnaris)
- Movers of the digits are called digitorum, or have specific action (pollicus=thumb, indicis=index, digiti minimi=little finger)
Where is the anatomical snuff box?
- Between the extensor pollicis longus and the extensor pollicis brevis tendon
- This is important in determining if the scaphoid might be fractured
- Avascular necrosis has potential for disability in action of the wrist
- Contains the scaphoid bone and radial artery
What is supplied by the musculocutaneous nerve in the forearm?
- Sensory to lateral forearm
- As the lateral cutaneous nerve of the forearm
What is supplied by the median nerve in the forearm? Describe its course.
- Courses through the anterior compartment of the arm (no significant branches) and lies anterior to the elbow, lateral to the brachial artery in proximal arm, medial at the elbow joint (easily damaged!)
- Main nerve to the muscles of the forearm
Describe the course and function of the ulnar nerve
- Courses via the posterior compartment of the upper arm
- No significant branches in the upper arm
- Lies behind the medial epicondyle at the elbow (easily damaged - funny bone)
- The main nerve of the hand
- Supplies the flexor carpi ulnaris and flexor digitorum profundus (ulnar half)
Describe the course and function of the radial nerve
- Supplies all the muscles of the posterior compartments of the upper arm and forearm
- Passes around the body of the humerus at its mid-shaft in the radial groove (easily damaged!)
- Supplies triceps in the arm
- Courses via the anterior compartment of the upper arm more distally
- Divides just above the level of the elbow into;
Deep branch – the posterior interosseous nerve (motor)
Superficial branch – the superficial radial nerve (sensory)
What are the borders of the cubital fossa?
- Brachioradialis muscle (lateral)
- Pronator teres muscle (medial)
- Line between the humeral epicondyles (superior)
List the muscles in the deep posterior compartment of the forearm
- Supinator
- Abductor pollicus longus
- Extensor pollicis brevis
- Extensor pollicis longus
- Extensor indicis
List the muscles in the superficial posterior compartment of the forearm
- Brachioradialis
- Extensor carpi radialis longus
- Extensor carpi radialis brevis
- Extensor digitorum
- Extensor digiti minimi
- Extensor carpi ulnaris
- Anconeous
SCRB, ED, EDM, EDU all attach to the lateral epicondyle of the humerus via a common tendon
