locomotor system lesson 6

Question 1

rotation (pronation and supination) involves 2 joints:

Answer 1

-superior radio ulnar joint
-inferior radio ulnar joint

Question 2

how are the radius and the ulna positioned during supination?

Answer 2

they are parallel to each other

Question 3

how are the radius and the ulna positioned during pronation?

Answer 3

the radius is lateral to the ulna on the proximal part and it becomes medial at the level of the wrist. It can cross over the ulna thanks to the radial tuberosity

Question 4

superior radio ulnar joint

Answer 4

-trochoid joint
-it is a joint between the head of the radius (convex) and the radial notch of the ulna (concave)
-it is stabilized by the anular ligament that sorrounds the head of the radius and attaches by its ends posteriorly and anteriorly the radial notch of the ulna.
-the angular ligament surrounds the head of the radius, the radius rotate inside this ligament–>the annular ligament keeps in place the head of the radius and allows its rotation.
-this joint is also stabilized by the quadrate ligaments which attaches on the inferior part of the radial notch (so its inferior respect to the annular ligament) and right below the head of the radius

Question 5

is pronation allowed when the head of the radius slips out from the annular ligament?

Answer 5

when the head of the radius slips out of the annular ligament—a condition known as radial head subluxation or nursemaid’s elbow—pronation (and supination) of the forearm becomes very difficult or even impossible. This is because the annular ligament normally holds the head of the radius snugly against the ulna, stabilizing the proximal radioulnar joint and allowing smooth rotation of the radius over the ulna during these movements.

Question 6

pronation and supination also require the inferior radio ulnar joint

Answer 6

-not part of the wrist joint
-comprehend the head of the ulna and the ulnar notch of the radius

Question 7

is the superior radio ulnar join part of the elbow joint?

Answer 7

yes

Question 8

is the inferior radio ulnar joint part of the wrist joint?

Answer 8

no

Question 9

In summary, during pronation

Answer 9

The head of the radius rotates within the proximal radioulnar joint.
The distal radius moves around the ulna at the distal radioulnar joint, allowing the forearm and hand to rotate into a palm-down position.

Question 10

supination occurs thanks to 2 muscles

Answer 10

-biceps brachii
-supinator

Question 11

when does the biceps Brachii obtain maximal efficiency?

Answer 11

when flexed at 90 degrees. that’s the reason why people screw by supinating the forearm having the elbow flexed at 90 degrees

Question 12

pronation occurs thanks to 2 muscles as well

Answer 12

-pronator quadratus
the deepest muscle of the forearm
it is wrapped around the radius and the ulnar distal ends to allow the radius to cross the ulna
-pronator teres
pronator teres
-origin: medial epicondyle
insertion: apex of the pronator bend of the radius
its weak
NB: pronator muscles are more weak than supinator ones

Question 13

what is the range of true rotation of the forearm? (pronation, supination)

Answer 13

180 degrees

Question 14

the wrist

Answer 14

the distal joint of the upper limb and allows the hand to reach the optimal position for prehension.
it allows flexion-extension, abduction and adduction

Question 15

2 joints that compose the wrist

Answer 15

-radio carpal joint: a joint between the distal surface of the radius and the first row of carpal bones
-mid carpal joint: between the first and the second row of carpal bones.
NB: the ulna is not part of the wrist joint

Question 16

transverse concavity of the radial carpal joint for which movements

Answer 16

adduction and abduction

Question 17

antero posterior concavity of radio carpal joint for which movements

Answer 17

flexion and extension

Question 18

first row of carpal bones

Answer 18

scaphoid
lunate
triquetrum

Question 19

pisiform bone

Answer 19

it is connected to the triquetrum on its medial palmar side
it can be considered as a first row carpal bone but its not part of the radial carpal joint cause is not attached to the radius

Question 20

bones of second row of carpal bones (from styloid process of radius to medial)

Answer 20

trapezium
trapezoid
capitate –>biggest one, center of the wrist
hamate

Question 21

scaphoid articulates with 3 bones

Answer 21

trapezium
trapezoid
capitate

Question 22

lunate articulates with

Answer 22

capitate (mostly) and hamate

Question 23

triquetrum articulates with

Answer 23

hamate only

Question 24

lateral or radial collateral ligament

Answer 24

goes from the styloid process of the radius till the scaphoid bone

Question 25

medial or ulnar collateral ligament

Answer 25

goes from the styloid process of the ulna till the triquetrum

Question 26

triangular fibrocartilage complex

Answer 26

stabilizes the wrist at the distal radioulnar joint. it is made of -ulnolunate ligament -radioulnar ligament -ulnotriquentral ligament -articular disc -meniscus

Question 27

palmar radio carpal ligament

Answer 27

-anterior divided in -radio capitate band, laterally -radio-triquetral band, medially connects radius with carpal bones

Question 28

planar uno-carpal ligament

Answer 28

anterior divided in -ulnolunate band (connecting the ulna and the lunate) -ulno triquetral band (connecting the ulna and the triquetrum) -->ligament that connect the ulna with the carpal bones

Question 29

dorsal radiocarpal ligament

Answer 29

-stabilize the wrist on the dorsal side -posterior divided in -radio-lunate band -radio-triquetral band

Question 30

dorsal inter carpa ligament

Answer 30

dorsal side, posterior

Question 31

the lateral collateral ligament is stretched during? and why?

Answer 31

adduction, to limit the range of motion

Question 32

the medial collateral ligament is stretched when? and why?

Answer 32

during abduction, to limit the range of motion

Question 33

the posterior ligament is stretched during?

Answer 33

flexion

Question 34

the anterior ligament is stretched during?

Answer 34

extension

Question 35

on the mid carpal joint we have

Answer 35

radio capitate ligament triquetro capitate ligament scapho trapezium ligament scapho lunate ligament triquetro hamate ligament piso hamate ligament

Question 36

anterior (palmar) compartment

Answer 36

flexor muscles

Question 37

posterior (dorsal compartment)

Answer 37

extensor muscles

Question 38

flexor muscles

Answer 38

-located in the anterior surface of the wrist -held in place by the palmar carpal ligament and the flexor retinaculum