radius- general features

0:00 hello everyone let us learn today bony features of the radius now this is radius it is a lateral bone of the forearm and it is homologous with the tibia of the lower limb as it's a typical long bone it has got 2 ends upper and lower end and intervening shaft the shaft has got three borders and three surfaces with a nutrient foramen Now let us see first the upper end bony features it builds a head which is disc shaped and it is covered with hyaline cartilage okay now it will take part in two joints the superior surface which is concave okay that will articulate with the capitulum of the humerus

0:49 and that will form part of the elbow joint let me show you this is humerus and this is called as capitulum right and this is trochlea so this can be capitulum will be in contact with superior concave surface of the radius so this will form the humero-radial part of the elbow joint the circumference of the head is also articular and it fits into socket formed by a radial notch of the ulna

1:36 and the annular ligament and together form superior radioulnar joint which is a part of radio synovial joint let me show you ulna see this this is right ulna and it has got a radial notch okay so here this is how the radius fits into it okay and remaining socket is from by annular ligament like this Right! it rotates within the socket which is partly bony and partly ligamentous Right! so that circumference of the head forms the superior radioulnar joint whereas

2:25 the superior concave surface forms support of the elbow joint okay now next is a constricted neck you can see over here and that is also partly enclosed by the lower margin of the annular ligament right next to the neck is a tuberosity that is called as a radial tuberosity which is rough posteriorly and smooth anteriorly right so this is about four end of the radius shaft of the radius as you know it is a typical long bone so it has got three borders and three surfaces right let us see first the borders first is the anterior border now you know the side of this bone

3:15 this is right radius so this is anterior aspect and here lies the anterior border okay the anterior border extends from anterior margin of radial tuberosity okay to the styloid process now here is a styloid process so this is the extent of the anterior border the upper half of the anterior border is oblique and it is called as anterior oblique line the lower half of the anterior border is vertical and it is crest like okay see this it is sharp is is crest like

4:02 but this one is called as anterior oblique line okay now the posterior border this is tubercle of Lister so this is posterior aspect of the radius and the posterior border is a mirror image of the entire border right and it is clearly seen particularly in the middle third right but again it has got in the upper half a posterior oblique line okay so as it is a mirror image again it is oblique in upper half and vertical in lower half the upper oblique part of the posterior border is called as posterior oblique line

4:52 right the third border is medial border which is sharpest it is also called interosseous border because part of it provides attachment to interosseous membrane and it extends from the radial tuberosity above you can see over here right to the posterior margin of ulnar notch below, up to this point now this is ulna notch and head of the ulna accomodates here Let me show you Like this, this is head of ulna and it articulates like this with ulnar notch at the lower end

5:37 and together forms inferior radio ulnar joint which is again part of radio-synovial joint okay so that is about medial border or interosseous border now the surface is there are three surfaces anterior surface it lies between the anterior border okay and the interosseous border or medial border right there lies a nutrient foramen along the course okay and the direction of nutrient foramen is upward so the lower end is going in for the radius right the branch of the anterior interosseous artery gives nutrient artery

6:29 right to supply it now the posterior surface lies between the posterior border and the medial border right or interosseous border similarly third surface is lateral surface which is situated between anterior border and posterior border okay specifically in the middle third it is rough you can see over here, right so that is about the shaft now the lower end, lower end is expanded and it has got five surfaces, anterior surface, medial surface, lateral surface posterior surface and inferior surface

7:17 right so the anterior surface it is continuation of the anterior surface of the shaft and it is crest like and the radial artery is perforated against it right so that is anterior surface but it is comparatively smoother as compared with the posterior surface if you see it bears three to four grooves right and a tubercle which is called as tubercle of lister right which lies lateral to an oblique group okay So, here is the oblique groove and you can see laterally there lies tubercle of Lister this oblique groove is lodging

8:03 tendon of extensor pollicis longus right the medial surface is occupied by ulnar notch for the head of the ulna that we have discussed right the lateral surface is prolong and it forms the styloid process, okay the inferior surface see this it is an articular it is smooth it is covered by hyaline cartilage and laterally it has got a triangular articular surface right which accommodates with the scaphoid wall and medially there is quadrangular articular surface for the lunate bone right together these three bones and the articular disc will form wrist joint or radiocarpal joint

8:48 okay so this is about bony features of the radius Hope you understood well thanks for watching (●'◡'●)