Humerus

• Humerus


  the humerus is the sole bone of the arm

  a typical long bone

  articulates w the scapula at the shoulder + w the radius + ulna (forearm bones) at the elbow

  
• Head of the Humerus

  at the proximal end of the humerus is its smooth, hemispherical head, which fits into the glenoid cavity of the scapular in a manner that allows the arm to hang freely at one's side

  
• Anatomical Neck & Tubercles

  immediately inferior to the head is a slight constriction, the anatomical neck

  just inferior to this r the lateral greater tubercle + the more medial lesser tubercle, separated by the intertubercular sulcus

  
• Functions of the Tubercles

  these tubercles r sites of attachment of the rotator cuff muscles

  the intertubercular sulcus guides a tendon of the biceps muscle of the arm to its attacment point at the rim of the glenoid cavity
• Deltoid Tuberositu


  about midway down the shaft on its lateral side is the V-shaped deltoid tuberosity

  = a roughened attachment site of the deltoid muscle of the shoulder

  
• Humerus' Condyles


  at the distal end of the humerus r 2 condyles:

  a medial trochlea

  lateral ball-like capitulum

  these condyles articulate w the ulna + the radius, respectively

  
• Humerus' Epicondyles


  the condyle pair is flanked by the medial + lateral epicondyles (muscle attachment sites)

  
• Coronoid Fossa & Olecranon Fossa

  superior to the torchlea on the anterior surface is the coronoid fossa

  on the posterior surface is the deeper olecranon fossa

  these 2 depressions allow the corresponding process of the ulna to move freely when the elbow is flexed + extended

  
• Radial Fossa


  a small radial fossa, lateral to the coronoid fossa, receives the head of the readius when the elbow is flexed