Elbow, Posterior Forearm, and Wrist Flashcards
what makes up the elbow joint
the elbow joint is actually made from 3 separate joints
- humeroulnar joint
- humeroradial joint
- proximal radioulnar joint
humeroulnar joint
this is the joint between the humerus and the ulna within the elbow
-the junction between the trochlear notch of ulna and the trochlea of humerus
humeroradial joint
this is the joint between the humerus and the radius within the elbow
the joint between the head of the radius and the capitulum of the humerus
proximal radioulnar joint
a synovial joint that connects the proximal ends of the radius and ulna.
- In this joint, the circumferent head of radius is placed within the ring formed by the radial notch of ulna and the annular ligament –> makes this joint a pivot joint
annular ligament
this is a ligament that surrounds the radius, holding it tight to the ulna which still allowing it to rotate on the ulna with pronation and supination
-this is within the proximal radioulnar joint
radial collateral ligament
- this is a short and narrow fibrous band that is less distinct that the ulnar collateral ligament
- this is on the radial side of the humeroulnar joint
- works with the ulnar collateral ligament to prevent abduction and adduction at the joint
ulnar collateral ligament
- runs along the inner side of the elbow
- this is on the ulnar side of the humeroulnar joint
- works with the radial collateral ligament to prevent abduction and adduction at the joint
distal radioulnar joint
the distal articulation between the radius and ulna.
The ulna is smaller distally while the radius is larger
radiocarpal joint
between the radius and carpal bones. The ulna does not articulate directly with the first row of carpal bones in the lower hand
midcarpal joint
synovial gliding joints between the proximal and distal rows of carpal bones
intercarpal joint
synovial plane joints that connect the carpal bones
carpometacarpal joints
between the distal carpals and the metacarpals
extensor carpi radialis longus
- On the radial side of the forearm
- deep to the brachioradialis
- has a longer tendon and is just superficial and lateral to the extensor carpi radialis brevis
Action:Extends wrist, abducts hand
origin: Lateral distal humerus
insertion: Base of 2nd metacarpal
innervation: Radial nerve
extensor carpi radialis brevis
- On the radial side of the forearm
- deep to the brachioradialis
- has a shorter tendon and is just deep to the extensor carpi radialis longus
action:Extends wrist, abducts hand
origin:Lateral epicondyle of humerus
insertion:Base of metacarpal III
Innervation: Radial nerve
radial deviation
abduction of the wrist
extensor carpi ulnaris
action: Extends wrist, adducts hand
origin: Lateral epicondyle of humerus
insertion: Base of 5th metacarpal
Innervation: Radial nerve
ulnar deviation
adduction of the wrist
extensor digitorum
Note that there is only one extensor digitorum muscle, so there is no other descriptor in the name
action: Extends wrist, 2nd–5th MP joints, PIP joints, & DIP joints
origin: Lateral epicondyle of humerus
insertion: Distal & middle phalanges of digits 2–5
Innervation: Radial nerve
juncturae tendinae.
angled dense connective tissue connecting the tendons of the extensor digitorum in the hand
- functions to coordinate and distribute force across the extensor tendons
extensor digiti minimi
just medial to the extensor digitorum and is lateral to the extensor carpi ulnaris
allows you to you can extend your 5th digit much farther while the others are flexed
action: Extends wrist, MP, and PIP joints of finger 5
origin:Lateral epicondyle of humerus
insertion:Proximal phalanx of finger 5
Innervation: Radial nerve
extensor indicis
deep to the extensor digitorum
medial to the extensor pollicis longus
allows you to extend your 2nd digit (pointer finger) while flexing your other digits
action: Extends MP, PIP, and DIP joints of finger 2
origin: Posterior ulna
insertion: 2nd finger
Innervation:Radial nerve
supinator
- this is a deep muscle in the posterior arm
- is deep and more difficult to find, but it can be observed running from the lateral epicondyle to the shaft of the radius.
- this is just distal to the elbow
action:Supinates forearm
origin:Lateral epicondyle of humerus & proximal ulna
insertion: Anterolateral radius
Innervation: Radial nerve
abductor pollicis longus
- a deep muscle in the forearm
- this is on the lateral side and wraps around the tendons of the extensor carpi radialis longus and brevis
- this is lateral to the extensor pollicis brevis
action:Abducts thumb
origin:Proximal radius and ulna
insertion:Lateral 1st metacarpal
Innervation:Radial nerve
extensor pollicis brevis
- a deep muscle of the forearm
- it’s tendon sits between the abductor pollicis longus and extensor pollicis longus tendons
- this is on the lateral side and wraps around the tendons of the extensor carpi radialis longus and brevis
- this is just medial to the abductor pollicis longus
action:Extends MP joints of thumb
origin:Posterior radius
insertion: thumb
Innervation:Radial nerve
extensor pollicis longus
- a deep muscle of the forearm
- just lateral to the extensor indicis muscle
action:Extends MP and IP joints of thumb
origin:Posterior ulna
insertion: thumb
Innervation:Radial nerve
extensor retinaculum
this is the dense connective tissue running over the extensor tendons
- this holds the extensor tendons in place and provided a mechanical advantage with extension
