Search results
Results from the WOW.Com Content Network
The number of vertebrae in a region can vary but overall the number remains the same. In a human spinal column, there are normally 33 vertebrae. [3] The upper 24 pre-sacral vertebrae are articulating and separated from each other by intervertebral discs, and the lower nine are fused in adults, five in the sacrum and four in the coccyx, or tailbone.
The cervical spinal nerve 5 (C5) is a spinal nerve of the cervical segment. [1]It originates from the spinal column from above the cervical vertebra 5 (C5). It contributes to the phrenic nerve, long thoracic nerve, and dorsal scapular nerve before joining cervical spinal nerve 6 to form the upper trunk, a trunk of the brachial plexus, which then forms the lateral cord, and finally the ...
The spinal cord is an estimated 45 centimetres (18 inches) long in males and about 43 cm (17 in) in females. [citation needed] It is ovoid-shaped and is enlarged in the cervical and lumbar regions. The cervical enlargement, stretching from the C4 to T1 vertebrae, is where sensory input comes from and motor output goes to the arms and trunk.
The vertebral column is often used as a marker of human anatomy. This includes: At C1, base of the nose and the hard palate; At C2, the teeth of a closed mouth; At C3, the mandible and hyoid bone; At C4, the common carotid artery bifurcates. From C4–5, the thyroid cartilage [10] From C6–7, the cricoid cartilage [10]
Within the cervical spine, most joints are innervated by the medial branch nerve (a branch of the dorsal rami) from the same levels. In other words, the facet joint between C4 and C5 vertebral segments is innervated by the C4 and C5 medial branch nerves. However, there are two exceptions:
Cervical spinal nerve 4, also called C4, is a spinal nerve of the cervical segment. It originates from the spinal cord above the 4th cervical vertebra (C4). It contributes nerve fibers to the phrenic nerve , the motor nerve to the thoracoabdominal diaphragm .
Phrenic (C3-C5, but mostly C4) - innervates thoracic diaphragm and the pericardium. Segmental branches (C1-C4) - innervate anterior and middle scalene muscles Levator scapulae muscle (C3-C4) (also innervated by dorsal scapular nerve (C5) of the brachial plexus )
A tendon is a tough, flexible band of fibrous connective tissue that connects muscles to bones. [12] The extra-cellular connective tissue between muscle fibers binds to tendons at the distal and proximal ends, and the tendon binds to the periosteum of individual bones at the muscle's origin and insertion. As muscles contract, tendons transmit ...