Humerus

The humerus (plural: humeri) is a tubular bone of the arm that articulates proximally at the shoulder with the glenoid of the scapula, and distally at the elbow, with the radius and ulna.

The humerus begins proximally as a rounded head and joins the greater and lesser tubercles via the anatomical neck of the humerus. The surgical neck is found just inferior to the tubercles where the shaft begins. The surgical neck is a common site for fractures (hence its name), while fractures of the anatomical neck are rare.

The shaft of the humerus has a cylindrical shape proximally then flattens to produce more distinct surfaces. There are three surfaces (antero-lateral, antero-medial and posterior surfaces) and three borders (anterior, lateral and medial borders).

The condyle of the humerus articulates with the radius and ulna. It is composed of the trochlea, capitulum, and medial and lateral epicondyles.

The supracondylar process is a variant that is found ~5 cm above the medial epicondyle and can be 2 to 22 mm in length. It can be continuous with the ligament of Struthers, beneath which the median nerve and brachial artery pass.

The proximal and distal ends of the humerus are cancellous bone with a superficial layer of compact bone. The shaft is comprised of compact bone containing a medullary canal traversing its length.

  • proximal (refer to shoulder joint article for more details):
  • distal (refer to elbow joint article for more detail):
    • condyle of the humerus:
      • trochlea: articulates with the trochlear notch of the ulna
      • radial fossa: receives the anterior border of the radial head in forearm flexion
      • capitulum: articulates with the head of the radius
      • olecranon fossa: receives the olecranon process of the ulna with forearm extension
      • coronoid fossa: receives the coronoid process of the ulna with forearm flexion

There are eight ossification centers that begin ossification in the following order:
body (8th week of fetal life), head (1 year of age), capitulum (1 year), greater tubercle (3 years), lesser tubercle (5 years), medial epicondyle (5 years), trochlea (10 years), and lateral epicondyle (10 years).

See also: ossification centers of the pectoral girdleelbow ossification

It may be fractured by excessive torsion or by a direct blow. The humeral neck is frequently fractured in elderly patients following a fall on the shoulder.

The humeral head may be dislocated from the glenoid fossa anteriorly or, much less frequently, posteriorly or inferiorly.

The humeral neck is also a common location for simple bone cysts.

Anatomy: Upper limb
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Article information

rID: 24562
Section: Anatomy
Synonyms or Alternate Spellings:
  • Humeri

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Cases and figures

  • Humerus. Image so...
    Figure 1
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  • Figure 2: humerus radiographs
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