The transverse cervical artery is a branch of the thyrocervical trunk, which itself arises from the first part of the subclavian artery. This artery is responsible for supplying blood to the muscles of the neck and upper back, specifically the trapezius muscle. In some anatomical variations, it can also give rise to the dorsal scapular artery.
Location
The transverse cervical artery originates from the thyrocervical trunk, which branches off the subclavian artery. It courses laterally across the lower neck, running anterior to the scalene muscles and phrenic nerve. The artery travels towards the posterior aspect of the neck and upper back, passing deep to the sternocleidomastoid muscle. It divides into two main branches: the superficial branch, which supplies the trapezius, and the deep branch, which may supply the rhomboid muscles and scapular region, especially if the dorsal scapular artery arises from it. The artery often runs parallel to the spinal accessory nerve (CN XI) as it supplies the trapezius.
Structure and Anatomy
Origin
The transverse cervical artery typically arises from the thyrocervical trunk, which branches off the first part of the subclavian artery. The thyrocervical trunk usually gives rise to three branches: the inferior thyroid artery, the suprascapular artery, and the transverse cervical artery. However, variations in its origin exist, such as originating directly from the subclavian artery or other surrounding arteries. In cases where the dorsal scapular artery does not arise independently from the subclavian artery, it may originate as a deep branch of the transverse cervical artery.
Course
After originating from the thyrocervical trunk, the transverse cervical artery courses laterally across the neck. It travels anterior to the anterior scalene muscle, running over or near the phrenic nerve. As it moves towards the posterior part of the neck and upper back, it passes deep to the sternocleidomastoid muscle. Along its course, it approaches the posterior triangle of the neck, situated between the sternocleidomastoid and trapezius muscles.
Branches
The transverse cervical artery typically divides into two main branches:
- Superficial Branch (Superficial Cervical Artery): This branch continues its course posteriorly to supply the superficial muscles in the posterior neck and upper back, including the trapezius muscle. It often runs parallel to and accompanies the spinal accessory nerve (CN XI) as it innervates the trapezius.
- Deep Branch (Descending Scapular Artery): The deep branch, also known as the dorsal scapular artery in certain anatomical variations, travels toward the medial border of the scapula. It supplies the levator scapulae, rhomboid major, and rhomboid minor muscles. If the dorsal scapular artery does not arise directly from the subclavian artery, this deep branch functions in its place, following a similar course along the medial edge of the scapula.
Relations
- Anteriorly: The transverse cervical artery lies anterior to the anterior scalene muscle and may cross over or near the phrenic nerve.
- Posteriorly: It runs towards the posterior triangle of the neck, deep to the trapezius and sternocleidomastoid muscles, supplying the posterior neck and shoulder.
- Medially: The artery is situated medial to the lateral border of the trapezius and rhomboid muscles.
- Laterally: As it moves toward the scapular region, the artery runs in proximity to the scapula and its medial edge.
Termination
The superficial branch of the transverse cervical artery terminates by supplying the trapezius muscle, while the deep branch (if present as the dorsal scapular artery) descends along the medial border of the scapula, supplying the rhomboid muscles and terminating by anastomosing with other scapular arteries such as the suprascapular artery and circumflex scapular artery.
Anastomoses
The transverse cervical artery forms anastomoses with other nearby arteries that supply the scapular and shoulder regions. These include:
- Suprascapular artery: Originating from the thyrocervical trunk, it anastomoses with the deep branch of the transverse cervical artery near the scapula.
- Circumflex scapular artery: A branch of the subscapular artery, it anastomoses with the deep branch of the transverse cervical artery, ensuring collateral circulation to the scapular region.
Variations
Anatomical variations in the origin and branching pattern of the transverse cervical artery are common. In some individuals, the deep branch (or dorsal scapular artery) may arise directly from the subclavian artery, bypassing the transverse cervical artery entirely. In such cases, the transverse cervical artery may only provide a superficial branch to the trapezius and other superficial muscles of the neck and back.
Function
The transverse cervical artery plays a critical role in supplying blood to the muscles of the posterior neck and shoulder region, particularly those involved in scapular movement and stabilization. Its primary function is to provide vascular support to these muscles, allowing for proper mobility and strength in the shoulder and upper back. Depending on anatomical variations, the artery may also play a role in nourishing muscles along the medial scapular border.
Blood Supply to the Trapezius Muscle
One of the key functions of the transverse cervical artery is to provide blood to the trapezius muscle through its superficial branch (sometimes referred to as the superficial cervical artery). The trapezius muscle plays an important role in several movements of the scapula, including elevation, retraction, and rotation, which are critical for various shoulder and arm movements. By delivering oxygenated blood to the trapezius, the transverse cervical artery ensures the muscle has the necessary energy to maintain proper shoulder function, especially during activities that require shoulder and arm mobility, such as lifting and rotating the arm.
Blood Supply to the Rhomboid Muscles and Levator Scapulae
The deep branch of the transverse cervical artery (or the dorsal scapular artery, depending on the anatomical variation) supplies blood to the rhomboid major and rhomboid minor muscles, as well as the levator scapulae muscle. These muscles play a key role in scapular retraction, elevation, and stabilization:
- The rhomboid muscles retract the scapula, pulling it toward the vertebral column, which is important for proper posture and shoulder alignment.
- The levator scapulae elevates the scapula and contributes to neck movements by rotating or tilting the head.
Through the deep branch, the transverse cervical artery ensures that these muscles receive sufficient blood to perform their functions, which are crucial for stabilizing the shoulder girdle and enabling smooth movements of the shoulder blade during various upper body activities.
Collateral Circulation and Anastomoses
The transverse cervical artery, particularly its deep branch (if it functions as the dorsal scapular artery), plays a role in maintaining collateral circulation in the scapular and shoulder regions. This collateral network is essential for ensuring continued blood flow to these areas, even if one of the primary arteries is obstructed. The artery forms important anastomoses with other scapular arteries, such as the suprascapular artery and the circumflex scapular artery. This function is crucial in preserving muscle function and preventing ischemia in the scapular region in the event of trauma or occlusion of major arteries like the subclavian artery.
The collateral circulation also supports muscle recovery and helps maintain tissue viability, especially during surgical interventions or injuries that could potentially compromise the main arterial supply to the upper back and shoulder muscles.
Support for Shoulder and Scapular Movement
By supplying blood to the muscles that control scapular movements, such as the trapezius, rhomboids, and levator scapulae, the transverse cervical artery indirectly supports a wide range of shoulder and arm movements. These movements include:
- Elevation of the scapula (as when shrugging the shoulders).
- Retraction of the scapula (pulling the shoulder blades together).
- Rotation of the scapula, which is important for raising the arm above the head.
The muscles supported by the artery contribute to scapular stabilization, which is critical for maintaining proper shoulder mechanics during these movements. Without adequate blood flow from the transverse cervical artery, these muscles would become fatigued or impaired, leading to weakness, instability, and difficulty in performing upper body activities.
Nourishment of the Neck and Upper Back
In addition to supplying blood to the muscles of the scapular region, the transverse cervical artery also provides blood to other soft tissues in the posterior neck and upper back. These tissues include the fascia and skin that cover the muscles of the upper back. By ensuring these tissues remain healthy and well-oxygenated, the transverse cervical artery helps maintain the structural integrity and overall function of the neck and upper back region.
This vascular support is important for healing and tissue regeneration, particularly in cases of injury, surgery, or chronic strain in the neck and upper back. The artery’s role in supplying blood to these areas helps promote faster recovery and reduces the risk of tissue damage.
Clinical Significance
The transverse cervical artery holds clinical importance due to its role in supplying blood to key muscles of the neck, upper back, and scapular region, particularly the trapezius, rhomboids, and levator scapulae. Injury or compromise of this artery can lead to decreased blood flow to these muscles, resulting in muscle weakness, fatigue, or impaired scapular movements. This is especially relevant in cases of trauma, such as fractures involving the clavicle or scapula, or in surgeries affecting the posterior neck and shoulder region.
During surgical procedures like shoulder reconstructions or neck dissections, awareness of the transverse cervical artery’s course is crucial to avoid accidental injury, which could lead to excessive bleeding or postoperative complications. Additionally, the artery’s anastomoses with the suprascapular and circumflex scapular arteries provide collateral circulation, ensuring adequate blood supply to the scapular region in cases of arterial occlusion or injury. Anatomical variations, such as the origin of the dorsal scapular artery from the transverse cervical artery, are important considerations for surgeons and clinicians in planning interventions in the neck and upper back region.
