The rhomboid major is a muscle located in the back that connects the scapula (shoulder blade) to the vertebrae of the spine. Along with the rhomboid minor muscle, it works to keep the scapula pressed against the thoracic wall (the back of the chest) and to move the scapula towards the spine. This muscle plays an important role in maintaining proper shoulder and back posture and stability.
Structure
The rhomboid major muscle is a long, thin muscle that originates from the spinous processes (bony protuberances) of the thoracic vertebrae (T2-T5). It runs upwards and outwards, attaching to the medial border (inner edge) of the scapula at a point called the scapular spine.
The rhomboid major muscle is innervated (supplied with nerves) by the dorsal scapular nerve, a branch of the brachial plexus. This nerve provides the muscle with the necessary signals to contract and relax, enabling it to perform its various functions.
There are a few variations in the structure of the rhomboid major muscle that can occur. For example, some people may have a double-headed rhomboid major muscle, meaning that it has two separate muscle bellies that merge into a single tendon at the scapular spine. This variation is relatively rare and does not typically cause any functional problems.
Location
As mentioned earlier, the rhomboid major muscle is located in the upper back and shoulder region, specifically within the posterior (back) aspect of the thoracic cage. It is situated between the scapula and the vertebral column, running from the spinous processes of the thoracic vertebrae to the scapular spine.
Function
The main function of the rhomboid major muscle is to control the position and movement of the scapula. When the muscle contracts, it pulls the scapula towards the midline of the body, a movement called scapular adduction. This action helps to stabilize the scapula, keeping it in the correct position relative to the spine and chest.
The rhomboid major muscle also plays a role in shoulder movement. When the arm is raised, the muscle helps to elevate the scapula, allowing the shoulder joint to move freely. In addition, the rhomboid major muscle works in conjunction with other muscles in the shoulder and back to provide support and stability to the spine.
Clinical Significance
Like any muscle, the rhomboid major muscle can become strained or injured due to overuse or trauma. This can lead to muscle pain and weakness, which can make it difficult to perform everyday activities such as lifting or carrying objects.
In some cases, the rhomboid major muscle may be weakened or damaged due to other underlying health conditions, such as nerve damage or spinal stenosis (narrowing of the spinal canal). In these instances, treatment may involve physical therapy, medications, or other forms of supportive care to manage symptoms and improve muscle function.
