What is the Difference Between Tuberosity and Tubercle

The main difference between tuberosity and tubercle is that tuberosity refers to a slightly larger lump on bones, but tubercle refers to the smaller lump. Some of the examples of tuberosity are the greater tuberosity of the humerus and the ischial tuberosity of the hip bone. The examples of tubercles include the scalene tubercle on the first rib and the Chassaignac’s tubercle on the cervical vertebrae.  

In brief, tuberosity and tubercle are two types of protrusions or eminences in the bones of the human skeleton. And, their function is to serve as an attachment for skeletal muscles. Also, ‘apophysis‘ is another synonymous term for these protrusions.  

Key Areas Covered 

1. What is Tuberosity
     – Definition, Structure, Examples
2. What is Tubercle
     – Definition, Structure, Examples
3. What are the Similarities Between Tuberosity and Tubercle
     – Outline of Common Features
4. What is the Difference Between Tuberosity and Tubercle
     – Comparison of Key Differences

Key Terms 

Attachment of Muscles, Greater Tuberosity, Protrusions on Bones, Tubercle, Tuberosity

What is Tuberosity 

Typically, the tuberosity is a moderate prominence to which the muscles and connective tissues are attached. And, its function is similar to that of a trochanter. Basically, trochanter is a large prominence on the side of the bone to which the largest muscle groups and most dense connective tissues are attached. Examples of tuberosity include the greater tuberosity of the humerus, tibial tuberosity, deltoid tuberosity, and ischial tuberosity. 

Figure 1: The Greater Tuberosity of the Humerus

Discussing them further, the greater tuberosity of the humerus is a prominent area of the humerus at the top of the bone. It allows the attachment for two large, powerful rotator cuff muscles – supraspinatus and infraspinatus. Perhaps, it is known as the greater tubercle along with the lesser tubercle. 

What is Tubercle 

The tubercle is a small, rounded prominence to which the connective tissues are attached. Examples of tubercle include the lesser tubercle of the humerus. Here, the lesser tubercle is the more prominent protuberance than the greater tubercle and is situated in front, directed medially and anteriorly. 

Figure 2: Tubercles of the Rib

Moreover, some of the other examples of tubercles include the scalene tubercle on the first rib or Chassaignac’s tubercle on the cervical vertebrae. Usually, the tubercle is an eminence on the back surface of the ribs at the junction between the neck and the body. Its articular areas provide the articulation with the transverse processes as well as the ligaments. However, tubercles are much more prominent in the upper ribs than in the lower ribs. 

Similarities Between Tuberosity and Tubercle  

• Generally, tuberosity and tubercle are two types of protuberances on bones of the skeleton of many mammals.  
• Also, crests and trochanters are the other examples of such protrusions.  
• They are a result of traction forces of connective tissue and muscles.     
• Therefore, the main function of them is to provide sites for the attachment of muscles.  
• Also, they occur in various sizes and shapes, indicating the forces applied to the bone by these tissues.     
• Significantly, they serve as anatomic landmarks to the physicians and surgeons, giving information about the structures that surround them.     

Difference Between Tuberosity and Tubercle 

Definition 

Tuberosity refers to a moderate prominence where the muscles and connective tissues are attached. But, tubercle refers to a small, rounded prominence where the connective tissues are attached. 

Anatomy 

The tuberosity is a rough, elevated surface, but in contrast, tubercle is a small, rounded process.  

Size 

Generally, the tuberosity is a slightly larger lump on bones, but tubercle is a smaller lump.  

Examples 

Also, some of the examples of tuberosity include the greater tuberosity of the humerus and the ischial tuberosity of the hip bone. Meanwhile, the examples of tubercles include the scalene tubercle on the first rib and the Chassaignac’s tubercle on the cervical vertebrae.  

Conclusion 

In brief, the tuberosity is a type of slightly larger protrusions on the bones of the human skeleton. Also, the tuberosity of the humerus is an example of such tuberosity. In contrast, the tubercle is a small type of protrusion on bones. Basically, the scalene tubercle is an example of a tubercle. However, both tuberosity and tubercle are two types of protrusions on bones, serving as sites for the attachment of bones. Still, the main difference between tuberosity and tubercle is their size. 

References:

1. Bandovic I, Futterman B. Anatomy, Bone Markings. [Updated 2019 Feb 6]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available Here.

Image Courtesy:

1. “HumerusFron” By BDB (Public Domain) via Commons Wikimedia   
2. “732 Thoracic Vertebra and Rib” By OpenStax College – Anatomy & Physiology, Connexions Web site. (CC BY 3.0) via Commons Wikimedia