Human Anatomy: Humerus Overview

Humerus Overview

• The humerus is a long bone located in the upper limb, connecting the shoulder to the elbow.
• It forms the glenohumeral joint by articulating with the scapula's glenoid fossa at the proximal end.
• At the distal end, it articulates with the radius and ulna at the elbow joint.

Proximal Humerus Structure

• Key features include the head, anatomical neck, surgical neck, greater and lesser tuberosities, and intertubercular sulcus.
• The head faces medially, upwards, and backwards, separating the greater and lesser tuberosities via the anatomical neck.

Tuberosities

• The greater tuberosity is located laterally and serves as the attachment site for three rotator cuff muscles:
  • Supraspinatus (superior facet)
  • Infraspinatus (middle facet)
  • Teres minor (inferior facet)
• The lesser tuberosity is smaller and found medially and anteriorly, providing attachment for the subscapularis muscle.

Intertubercular Sulcus

• A deep groove between the greater and lesser tuberosities.
• The tendon of the long head of the biceps brachii runs through this groove.
• The lips of the intertubercular sulcus are attachment sites for muscles:
  • Pectoralis major
  • Teres major
  • Latissimus dorsi

Surgical Neck and Shaft

• The surgical neck extends from below the tuberosities to the shaft and is adjacent to the axillary nerve and circumflex humeral vessels.
• The shaft of the humerus serves as an attachment site for several muscles:
  • Anteriorly: coracobrachialis, deltoid, brachialis, brachioradialis
  • Posteriorly: medial and lateral heads of the triceps (origins defined by the spiral groove)

Deltoid Tuberosity

• A roughened surface on the lateral side of the humeral shaft where the deltoid muscle attaches.

Radial Groove

• A shallow depression on the posterior surface that runs parallel to the deltoid tuberosity.
• Contains the radial nerve and profunda brachii artery.

Distal Region

• The capitulum, a rounded projection at the distal end, articulates with the head of the radius.