Humerus (Viva-related)

Q.1 How will you determine the side to which the humerus belongs?

• The upper end is rounded and forms the head. The lower end is flattened from before backward.
• Head is directed medially and backward.
• Lesser tubercle projects from the front of the upper end.
• The anterior aspect of the upper end shows a vertical groove called the intertubercular sulcus.
  
  

Q.2 What is the anatomical position of the humerus in the body?

• Head is directed medially, upwards and backward.
• The medial epicondyle is directed medially and slightly backward.
  
  

Q.3 What are the contents of the intertubercular sulcus (Bicipital groove)?

• The tendon of the long head of biceps.
• Synovial sheath of the tendon.
• Ascending branch of anterior circumflex humeral artery.
  
  

Q.4 What are the structures attached to intertubercular sulcus?

• To medial lip: Teres major, insertion.
• To floor: Latissimus dorsi, insertion.
• To lateral lip: Pectoralis major, insertion.

Q.5 How the tendon of the pectoralis major is inserted?

• It is inserted by a bilaminar tendon on the lateral lip of the bicipital groove, the two laminae are continuous with each other inferiorly.
  
  

Q.6 What are the muscles inserting on greater tubercle?

• Supraspinatus: On upper impression.
• Infraspinatus: On middle impression.
• Teres minor: On lower impression.
  
  

Q.7 Which muscle is inserted into lesser tubercle?

•  Subscapularis
  
  

Q.8 What is the ‘anatomical neck’ and ‘surgical neck’ of the humerus?

• Anatomical neck: Surrounds the margin of head. Provides attachment to the capsular ligament which is deficient inferiorly on the medial side.
• Surgical neck: Lies at the upper end of the shaft, below the epiphyseal line. It is a common site for fracture.
  
  

Q.9 What are the structures related to the surgical neck of the humerus?

• Axillary nerve • Anterior and posterior circumflex humeral vessels
  
  

Q.10 Name the structures related to the radial groove of shaft of humerus.

• Radial nerve and
• Profunda brachii vessels
  
  

Q.11 Which muscle originates from medial supracondylar ridge?

• Pronator teres, from the lower end of the medial supracondylar ridge
  
  

Q.12 Which muscle originates from lateral supracondylar ridge?

• Brachioradialis: From upper two-thirds.
• Extensor carpi radialis longus: From lower one-third.
  
  

Q.13 Which muscles arise from the lateral epicondyle of the humerus (common extensor origin)?

• Extensor carpi radialis brevis
• Extensor digitorum
• Extensor digiti minimi
• Extensor carpi ulnaris
  
  

Q.14 Which muscles also arise from the lateral epicondyle of humerus except from common extensor origin?

• Anconeus
• Supinator
  
  

Q.15 What is the angle of ‘Humeral torsion’?

• It is an angle formed by the superimposition of long axes of upper and low articular surfaces of the humerus.
• It is about 164 degrees.
• It is greater in men and in adults.
  
  

Q.16 What are fossae present in the lower end of the humerus?

• Olecranon fossa: Posteriorly, just above trochlea. Accommodates the olecranon process in extended elbow.
• Radial fossa: Anteriorly, above capitulum. Accommodates radial head in flexed elbow.
• Coronoid fossa: Anteriorly, above trochlea. Accommodates coronoid process of ulna in flexed elbow.
  
  

 Q.17 Why the fracture of the humerus at the junction of the upper and middle third leads to delayed union?

• Because of poor blood supply at the junction.
  
  

Q.18 Which nerve is most commonly involved in the supracondylar fracture of the humerus?

• Median nerve
  
  

Q.19 What are the ossification centers for the lower end of the humerus and at what age they appear?

• Capitulum: First year
• Medial epicondyle: Fifth year
• Medial part of trochlea: Ninth year
• Lateral epicondyle: Twelfth-year Medial epicondyle fuses with the shaft at 20th year and others fuse together to form a single epiphysis, which fuses with the shaft at 15 years of age.