Osteology (Relevant Features) - Upper Extremity

Question 1

Clavicle

Answer 1

Crank shaped/S-shaped long bone; convex medially and concave laterally

transmits forces from upper limb to axial skeleton (only bony articulation between UE and upper extremity - SC joint)

Fractures usually occur just before the lateral third where the joint goes from being convex to concave

SC joint - rarely dislocates
AC joint - frequently dislocates

Question 2

Scapula

Answer 2

Sits over ribs 2-7

About 5 cm lateral to spinous processes of vertebrae

Question 3

Humerus

Answer 3

Fracture tends to happen at the surgical neck

Question 4

Sternum

Answer 4

Elongated flat longbone in the anteromedial portion of the thoracic wall

Articulations:
Sternoclavicular joint (clavicle and manubrium)
Sternocostal joints (body and costal cartilages of ribs 1-7)

Question 5

Ribs

Answer 5

True Ribs - 1-7 (articulate with sternum at sternoclavicular joints via costal cartilages)

False Ribs - 8-10 (costal cartilages join up with the costal cartilages of the rib above

Floating Ribs - 11-12 - cartilages are rudimentary and end in the abdominal musculature

Articulations:
Costochondral joint
Sternocostal joints
Costovertebral joints