Difference between Tendon and Ligaments

To know the difference between tendon and ligament, we must be familiar with what they actually are and what their functions are in the human body. Let’s explore.

Tendons and Ligaments

A tendon is a hard band of fibrous connective tissue which is high in strength and joins the muscle to the bone. It is very efficient in transmitting the mechanical forces of contraction of muscles to the skeletal system without giving up its ability to maintain an important amount of tension. 

Tendons and ligaments have one similar thing, that is, they both are made of collagen. 

Tendons and ligaments are part of the skeletal and muscular systems of the human body. These are connective tissue as they connect different parts of the body. The tendons are cord-like, strong and inelastic structures that connect bone to muscle and the ligaments are elastic structures that connect bones to other bones in our body. Both tendons and ligaments are composed of living cells and contain numerous collagen fibers and are seen as dense-granular connective tissues that function as connecting and anchoring various organs.

Difference between Tendon and Ligament Presented Diagrammatically.

(Image will be Updated soon)

Structure of Tendons 

Tendon cells (Tenocytes) are the most important cellular components of tendons that specialize in fibroblasts. The extracellular matrix of tendons, in densely packed collagen fibers, gets synthesized by tenocytes. These collagen fibers are parallel to each other and are organized in tendon fascicles. 

Endotendineum, a loose connective tissue that is delicate in nature contains elastic fibers and thin collagen fibrils, binds Individual fascicles. 

Epitenon, a sheath of irregular dense connective tissue, bounds the group of fascicles. Fascia encloses the full tendon. The space that is between the tendon tissue and the fascia gets filled with paratenon, which is fatty areolar tissue. Tendons that are healthy are anchored to the bone with the help of Sharpey's fibers. 

Tenocytes 

The collagen molecules are produced by Tenocytes, which further produces collagen fibrils. Fibril bundles are set in an order to form fiber with the tenocytes that are closely packed between them. 

A network that is three dimensional of cell processes is present in the tendon with collagen. Gap junctions help the cells to communicate with each other and these signals provide them with the ability to determine and respond to mechanical loading. 

Endotendon runs parallel to collagen fibers and helps in visualizing the blood vessels with anastomosis that is an occasional branching transverse. 

Length of the tendon 

The length of the tendon depends on all the major groups and from person to person. It acts as a deciding factor between actual and potential muscle size. For instance, every other biological factor being equal, a man who has a shorter tendon and longer biceps has a greater potential mass in comparison to a man who has a longer tendon and shorter muscle. The bodybuilders who are successful in their respective fields have shorter tendons. 

The length of the tendon depends on the genetic predisposition and is not based on the response of the environment but the muscles can be shortened by any trauma, imbalanced use and recovery don’t occur. 

Culinary Uses of Tendons 

Some Asian cuisines use tendons in their food. One of the many popular dishes is suan bao niu Jin in which they marinate the tendon with garlic. It’s also found in the noodle dish of Vietnam.

Ligament Anatomy 

Ligaments help in connecting the bones, joints and organs and keep them intact in their original place in the body. In a body, there are more than 900 ligaments present inside, mostly in your arms and legs. The size and shapes in which ligaments are created are very different to each other. Most of them are like the shape of ropes, bands or cords. Few are thin in nature like a string and some are wider in size. Some are shaped like an arch. They are yellow, pink and white in color. 

Types of Ligaments 

Desmology is the study of ligaments. Different types of ligaments are: 

• Articular ligaments - the movement of articulation or stopping some activity are limited by some ligaments. Capsular ligaments are those ligaments that are surrounded by synovial joints and are a part of an articular capsule. They work as mechanical reinforcements. Ligaments that join other ligaments to provide stability are Extracapsular ligaments. The not so common ligaments which also provide stability with a larger range of motion are Intracapsular ligaments. Ligaments that are in pairs and their shape is of a cross are Cruciate ligaments. 

• Artificial ligaments - (ACL) Anterior cruciate ligaments are the most commonly broken ligament in a body. It is very crucial in the stability of the knee and when someone's ACL gets torn, that results in reconstructive surgery that is done by using many techniques and materials. Replacing the torn ligament with an artificial material is one of the many techniques. An artificial ligament is a material that is reinforced to use in replacing a torn ligament as ACL. It is a synthetic material made of polymer, like polyacrylonitrile fiber or PET. 

• Peritoneal ligaments - particular folds peritoneum are known as ligaments. A few examples are: the uterus’s broad ligament is a fold of the peritoneum. The hepatic portal vein and other vessels are surrounded by the hepatoduodenal ligament. They travel from the duodenum to the liver.

• Fetal remnant ligaments - some tubular structures from the fetal period are known as ligaments after they close up and change into cord-like structures. 

Functions and Problems Associated

Tendons and ligaments are known to provide skeletal and muscular support to the body. How do they perform it? 

Tendon- Tendons transfer force by the muscle to the bone so they play an important part in the movement of our body. Tendons are present throughout the body, from the head to the neck and all the way down to the feet. Sometimes, the force applied by a tendon is even 5 times our body weight. Sometimes, the overuse and repetitive motion of our body parts such as hands, biceps, shoulders, ankles and knees cause problems like tendonitis. It is a condition developed with sudden force and strained or torn tendon fibers. It can be caused due to different activities like cleaning, golfing, throwing balls, bad posture, exercising carelessly, etc. 

Ligament- Now, talking about ligaments, ligaments are also musculoskeletal systems present as criss-cross bands that attach bone to another bone. For example, a knee consists of femur and tibia/fibula bones that have patella or kneecap in between. Different ligaments connect these two bones together and if it is damaged, it hurts and we look for strengthening the ligaments of our knees. Ligaments are not like bones as they cannot attach and heal themselves. Ligaments are long collagen fibers that form a band of tough fibrous connective tissue and are elastic in nature. So, these can stretch and provide flexibility but if they are stretched beyond a certain point, ligaments become overstretched and compromise the integrity; it may cause problems like ligament tears that cause inflammation, swelling, pain and bruising. The recovery of a torn ligament takes several weeks as they don’t regenerate themselves.

Both tendon and ligament are extra strong and dense tissues and both are located near joints. The point where one bone meets up with another bone is called a joint. It takes a long time to heal a tendon or a ligament if it is damaged as both are made up of collagen fibers which are avascular, meaning it's hard to get nutrients due to lack of blood vessels. Despite various functional similarities, we can differentiate tendon and ligament depending on various aspects. We will distinguish and compare tendons and ligaments further.

Distinguish between Tendon and Ligament

Tendon Vs Ligament can be better understood with the following tabular characteristics.

Tangent vs Ligament