Which of the following nerves originates from the cervical plexus?
A Radial
B Mediam
C Phrenic
D Axillary
E Femoral
The correct answer and explanation is:
The correct answer is C) Phrenic.
The phrenic nerve originates from the cervical plexus, which is formed by the anterior rami of the first four cervical nerves (C1 to C4). The cervical plexus is responsible for supplying sensory and motor innervation to parts of the neck, shoulder, and upper chest. One of its most important branches is the phrenic nerve.
The phrenic nerve plays a crucial role in breathing, as it innervates the diaphragm, which is the primary muscle involved in respiration. The nerve carries motor impulses that stimulate the diaphragm to contract, allowing for the inhalation of air into the lungs. Additionally, it carries sensory information from the diaphragm and the pleura (lining of the lungs and chest cavity), which helps in the detection of pain or other sensations from these areas.
Other nerves listed in the question—radial, median, axillary, and femoral—do not originate from the cervical plexus. The radial and axillary nerves are branches of the brachial plexus, which arises from the cervical and upper thoracic spinal nerves. The median nerve is also a branch of the brachial plexus, and the femoral nerve originates from the lumbar plexus.
In summary, the phrenic nerve is the only one of the listed options that comes from the cervical plexus. It is vital for the function of respiration by controlling the diaphragm, and its role highlights the importance of the cervical plexus in both sensory and motor functions related to breathing.