The human skeletal system is made up of many different bones that provide support, protect vital organs, and help us move. One of the bones that make up the human skeletal system is the humerus. This bone is found in the upper arm and is the longest and largest bone of the arm. In this quick guide, we will cover everything you need to know about the humerus bone.
Anatomy of the Humerus Bone
The humerus bone is a long bone that extends from the shoulder to the elbow. It is divided into three parts: the proximal end, the diaphysis, and the distal end.
The proximal end of the humerus is the uppermost part of the bone, which connects with the scapula bone to form the shoulder joint. The proximal end is made up of the head, the greater tubercle, the lesser tubercle, and the anatomical neck.
- The head of the humerus is spherical and articulates with the glenoid cavity of the scapula bone to form the shoulder joint.
- The greater tubercle is a bony prominence on the lateral side of the proximal end of the humerus. It serves as an attachment site for the rotator cuff muscles.
- The lesser tubercle is a smaller bony prominence on the anterior side of the proximal end of the humerus. It also serves as an attachment site for the rotator cuff muscles.
- The anatomical neck is a groove that separates the proximal end of the humerus from the shaft of the bone.
The diaphysis is the long, straight, and cylindrical part of the humerus bone that connects the proximal end to the distal end. It is the thickest part of the bone and provides the attachment for the arm muscles.
The distal end of the humerus is the lowermost part of the bone, which connects with the radius and ulna bones to form the elbow joint. The distal end is made up of the capitulum, the trochlea, and the medial and lateral epicondyles.
- The capitulum is a rounded eminence on the lateral side of the distal end of the humerus. It articulates with the head of the radius bone to form the radial humeral joint.
- The trochlea is a spool-shaped eminence on the medial side of the distal end of the humerus. It articulates with the trochlear notch of the ulna bone to form the humeroulnar joint.
- The medial and lateral epicondyles are bony projections on the distal end of the humerus. They serve as attachment sites for the forearm muscles and ligaments.
Function of the Humerus Bone
The humerus bone plays a vital role in the proper functioning of the upper body. It is responsible for the movement of the arm and is involved in many daily activities such as reaching, lifting, and throwing.
The humerus bone also provides attachment points for numerous muscles, including the rotator cuff muscles, which help to stabilize the shoulder joint, and the biceps and triceps muscles, which help to flex and extend the arm.
Common Injuries to the Humerus Bone
The humerus bone is a strong bone, but it can be injured in many ways. Some of the most common injuries to the humerus bone include:
- Fractures: Fractures of the humerus bone can occur in different parts of the bone and can range from minor cracks to severe breaks. These fractures can be caused by direct trauma or by repetitive stress.
- Dislocations: A dislocated humerus occurs when the bone is displaced from its normal position in the shoulder joint. This can cause pain, swelling, and limited mobility.
- Tendonitis: Tendonitis is the inflammation of the tendons that attach muscles to bones. Tendonitis in the shoulder can cause pain, weakness, and limited mobility.
- Rotator cuff tears: The rotator cuff is a group of muscles and tendons that surround the shoulder joint. Tears in the rotator cuff can cause pain and weakness in the shoulder.
Prevention and Treatment of Humerus Injuries
Prevention of humerus injuries includes proper conditioning, stretching, and warm-up before any physical activity. It is also important to use proper technique and equipment to minimize the risk of injury.
Treatment for humerus injuries depends on the type and severity of the injury. Mild injuries can be treated with rest, ice, compression, and elevation (RICE). More severe injuries may require surgery, physical therapy, or a combination of both.
The humerus bone is an essential part of the human skeletal system. Its structure and function are responsible for the proper functioning of the upper body, and injuries to this bone can cause significant pain and mobility issues.
- ‘Humerus Bone.’ Encyclopædia Britannica, Encyclopædia Britannica, Inc., 14 Aug. 2018, www.britannica.com/science/humerus.
- ‘Humerus Fracture.’ Mayo Clinic, Mayo Foundation for Medical Education and Research, 11 Feb. 2020, www.mayoclinic.org/diseases-conditions/humerus-fracture/symptoms-causes/syc-20372419.
- ‘Shoulder Dislocation.’ Mayo Clinic, Mayo Foundation for Medical Education and Research, 29 May 2020, www.mayoclinic.org/diseases-conditions/shoulder-dislocation/symptoms-causes/syc-20373864.
- Seibert, F J, et al. ‘Reconstruction of the humerus in diaphyseal deficiency.’ Journal of pediatric orthopedics, U.S. National Library of Medicine, Jan. 2007, pubmed.ncbi.nlm.nih.gov/17195870/.