What is an Axial Muscle?

Axial muscle is one of the skeletal muscles that are found in the trunk and the head regions of the human body. They include the muscles of the tail and eyeball too. Axial muscles are originated from the axial skeleton that composes the bones in the neck and head. The bones in the skeletal system are arranged in this manner only. The axial muscles are grouped based on their function and location. 

How do Muscles Create Facial Expressions? 

The muscles contain fibers that are intertwined with the connective tissue and the skin dermis; as they are inserted into the skin. When these muscles contract, the skin could move and facial expressions occur. 

Orbicularis oris controls the movement of the lips whereas orbicularis oculi close the eyes. Both are circular muscles. Buccinator is a muscle that occupies the face, which helps in the compression of cheeks, to blow or to suck; this contributes to the action of chewing. Corrugator supercilii is a small facial muscle that has a role in moving the eyebrows.  

Note: The origins of the muscles are always present on the skull that does not move.

Which Muscle takes part in the Movement of the Eyes?

Extrinsic eye muscles originate from the outside of the eye to the outer white surface of the eye and control the eyeball movement. 

Note: The muscles are located inside the eye socket and can’t be seen. 

How do Muscles Move in the Lower Jaw?

The lower jaw elevates due to mastication. The masseter muscle helps in chewing and closing the jaw.  

What are the Muscles in the Anterior Neck?

Suprahyoid muscles and infrahyoid muscles are present superior and inferior to the neck respectively. These muscles are categorized based on the position relative to the hyoid bone. They assist in swallowing the food by controlling the position of the larynx and hyoid bone. They rise and depress the hyoid bone relevant to the movement of the food.

Which Muscle Moves the Head?

The sternocleidomastoid is the muscle that flexes laterally to rotate the head; when the muscles flex bilaterally the head extends.   

The Muscles in the Abdomen 

The muscle in the abdomen helps in maintaining the posture of the body. The brain sends signals or impulses to the muscles to control the posture by contracting and relaxing. In the anterolateral wall of the abdomen, there are three flat skeletal muscles namely the external oblique (present close to the surface and extends inferiorly), vertically the internal oblique (extends superiorly), and the transversus abdominis that is arranged transversely around the abdomen. 

The function of these three layers is to protect the internal organs and for the different variations in the movements of the body.  

The posterior abdominal wall also has different parts namely the parts of the ilia of the hip bone and iliac muscles and quadrates lumborum muscle. These are formed by the lumbar vertebrae. They help in stabilizing the body and maintain posture. 

The Muscle in the Thorax Region 

During breathing, the chest rises because of the expansion of the thoracic cavity. The thoracic cavity increases and decreases in size due to the contraction and relaxation of the diaphragm respectively. The thoracic and abdominal cavities are separated from each other. 

Note: The curved roof or the end of the abdominal cavity is because the diaphragm’s superior surface is convex, and the interior is concave. 

Three passages act as the opening of the inferior vena cava, the esophagus, and the aorta thoracic duct. These are the caval opening, esophagus hiatus, and aorta hiatus respectively. Breathing is done by the change in the dimensions of the rib cage with a set of three intercostal muscles. Eleven pairs of ribs help in the inspiration through the contraction of the muscles. 

What is an Appendicular Muscle?

Appendicular muscle is another type of skeletal muscle found on the bones or skeletal system which makes the limbs of the body. These muscles are categorized based on the part of the skeleton in movement. These muscles support the movement and stabilize the pelvic girdle; as that is the foundation for the lower limbs. There is not much movement observed in the pelvic girdle.  

What are the Thigh Muscles which move the Femur, Tibia, and Fibula? 

he anterior compartments of the thigh consist of four muscles that help in the extension and stabilization of the knee. These muscles are the rectus femoris (present on the anterior part of the thigh), the vastus lateralis (lateral side of the thigh), vastus medialis (medial side of the thigh), and the vastus intermedius (in between the lateral and the medial side). All these muscles have a common tendon named quadriceps tendon that is continued into the patella and called the patellar ligament. A flexible band-like muscle called sartorius flexes the knee and rotates the leg laterally. This muscle enables a person to sit with crossed legs. 

The posterior compartments of the thigh and the back of the knee have three long muscles, the biceps femoris, semitendinosus, and the semimembranosus that give the space at the back of the knee. 

Note: The femur is the longest bone in the body. It is present in the thigh from the hip to the knee. 

The tibia is present in the lower leg from the knee to the ankle. 

The fibula is the calf bone present on the lateral side of the tibia. 

What are the Muscles that Move the Feet and Toes? 

The lower limb has three parts: anterior, lateral, and posterior. The anterior part of the leg helps to lift the foot. The muscle involved is the tibialis anterior, a long and thick muscle. Second, comes the extensor hallucis longus muscle located next to the digitorium longus. The superior and inferior extensor retinaculum holds the tendons in place.  

The lateral compartment comprises two muscles namely fibularis longus and fibularis Brevis. 

The posterior compartment of the leg insects all to the tendon. In both lateral and posterior, the muscles are long and strong to withstand the body weight and keep up the posture. 

The foot contains innate muscles that provide support to the foot and helps in the movement of the toes. The deep fascia named plantar aponeurosis gives the main support.

Importance of Axial and Appendicular Muscles 

The axial muscles are concerned with providing mechanical support to the axial skeleton in the body, whereas the appendicular muscles mediate the mechanical support to the appendicular skeleton. The structures including the head and the vertebral column are being supported by the axial muscles, where they are grouped based on their location and function. The muscles attached to the arms and legs are found to be appendicular. This attachment of muscles to their respective bones together coordinates the movement of the body.  

Content and Applications   

This topic is significant in the professional exams for both undergraduate and graduate courses, especially for 

• Bachelor of Science in Zoology 
• Bachelor of Science in General Physiology 
• Master of Science in Human Physiology    
• Master of Science in Anatomy and Physiology 

Related Concepts

• The muscular system of human 
• Skeletal muscles  

Practice Problem

What are suprahyoid muscles and infrahyoid muscles? 

Both the muscles' role is to assist the movement of the tongue, swallowing the food, and the overall movement of the mouth. Suprahyoid muscles are the muscles present on the upper part of the hyoid bone of the neck, and they have four muscles: digastric, geniohyoid, mylohyoid, and stylohyoid. The main role of the infrahyoid is to help in swallowing food. The four muscles grouped under the infrahyoid muscles are sternohyoid, sternothyroid, thyrohyoid, and omohyoid muscles.