The cervical spine is an important part of the human body, located below the head and above the thoracic spine. The cervical spine has seven components and is the smallest segment of the vertebrae in the spine, but with the greatest flexibility, the highest frequency of activity, and the greater weight bearing. Each cervical vertebra is composed of a vertebral body, a vertebral arch and seven protrusions (a pair of spinous processes, a pair of transverse processes, and two pairs of articular processes), which are connected by ligaments and intervertebral discs to form the cervical vertebrae.
Characteristics of the first cervical vertebra The first cervical vertebra is also called the atlas vertebrae, which has no vertebral body and spinous process, and is composed of anterior and posterior arches and lateral blocks. Among them, the anterior and posterior arches are enclosed into vertebral foramina, and the two sides are connected to the transverse foramen, which is the access of the vertebral artery and vertebral vein. The second cervical vertebra is also called the pivotal vertebrae. It is similar to the normal cervical vertebrae, but there is a dentate process above the vertebral body called the odontoid process, which can be regarded as the vertebral body of the atlas vertebrae.
The seventh cervical vertebra, also known as the carina, is the lowest one of the cervical vertebrae, except for the spinous process that extends to the back of the longest, the rest of the structure is the same as the ordinary pyramid, it is subcutaneous and rotates with the rotation of the neck, which is clinically used as a landmark to identify the ordinal number of vertebrae.
The third, fourth, fifth, and sixth are ordinary cervical vertebrae, with a smaller, oval-shaped, upper transverse diameter depression, and the upper cervical vertebrae are located in the depression of the lower cervical vertebrae, which are embedded with each other to increase the stability of the cervical vertebrae. These cervical vertebrae play an important role in the human body, not only supporting the key structures of the head and neck, but also providing access to nerves, blood vessels, and other tissues. At the same time, the flexibility and stability of the cervical spine are also important guarantees for human movement and balance.
Sensory innervation of the cervical nerve root plays an important role in the human body, which is described here:
1.The dermatomeous innervation of the 3 nerve roots of the neck is mainly located in the upper posterior part of the neck to the level of the occipital bone and ear. Sensory transmission in this area is essential for maintaining balance and comfort in the head and neck.
2.The 4 nerve roots of the neck involve the base of the neck, outward to the inner edge of the shoulder, and down to the level of the scapula. It has an important impact on the movement and sensation of the shoulder, and it is inseparable from its normal function for many activities in daily life, such as raising arms and dressing.
3.The 5 cervical nerve root mainly innervates the base of the neck to the acromion and continues to the ** region on the lateral aspect of the upper arm. In addition, the deltoid muscle is also innervated primarily by cervical 5 nerve roots. This means that when the 5 nerve roots in the neck are damaged, sensory and motor function on the lateral side of the upper arm may be affected.
4.The six cervical nerve roots radiate from the base of the neck along the biceps brachii and the radial side of the forearm to the dorsal side of the hand and the thumb. The biceps reflex is mainly innervated by the 6 cervical nerve roots, so the weakening of this reflex has the significance of localizing the damage of the 6 cervical nerve roots. When the 6 cervical nerve root is damaged, patients often complain of lateral upper arm pain with numbness of the radial fingers of the hand.
5.The seven nerve roots of the neck run along the back of the shoulder, the deltoid muscle, and the lateral aspect of the forearm, to the index and middle fingers. Decreased triceps reflex is a localized sign of cervical 7 nerve root damage.
6.The 8 nerve roots of the neck innervate the ulnar side of the hand, mainly the ring and little fingers and the ulnar side of the forearm. The 8 nerve roots of the neck innervate mainly the small muscle groups of the hand.
Overall, the distribution and function of these nerve roots in the human body is essential for maintaining normal motor and sensory function. Knowing this information can help doctors diagnose and alike conditions more accurately.