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.