What is the humerus and what is its main function?

The humerus is the longest and strongest bone in the upper arm, extending from the shoulder to the elbow. Its primary functions include serving as a lever for muscle action to enable arm movement and forming major articulations at the shoulder and elbow joints.

What are the key bony landmarks of the humerus?

Key landmarks include the head for shoulder articulation, greater and lesser tubercles for muscle attachments, the surgical neck (a common fracture site), the spiral groove for the radial nerve, and the capitulum and trochlea at the distal end for elbow articulation.

Which muscles attach to the humerus?

Important muscle attachments include the greater tubercle for supraspinatus, infraspinatus, and teres minor; the lesser tubercle for subscapularis; the intertubercular groove for pectoralis major, teres major, and latissimus dorsi; and the deltoid tuberosity for the deltoid muscle.

Why is the surgical neck of the humerus clinically significant?

The surgical neck is a common site for fractures due to its anatomical location. It has neurovascular significance because the axillary nerve is closely related, making injuries here potentially damaging to nerve function.

How do you determine the side of a humerus bone?

To determine the side, hold the bone vertically with the head facing medially, backwards, and upwards. The lesser tubercle and intertubercular groove should face anteriorly, and the olecranon fossa must point posteriorly.

What structures pass through the spiral groove of the humerus?

The spiral groove on the posterior surface houses the radial nerve and the profunda brachii artery. This groove is a key landmark for these neurovascular structures as they course along the humerus.

What joints does the humerus form?

The humerus forms two major joints: the glenohumeral joint at the shoulder, where its head articulates with the scapula, and the elbow joint at the distal end, where the capitulum and trochlea articulate with the radius and ulna.

Humerus Anatomy – Proximal, Shaft & Distal Features

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