Cervical Plexus (EASY Scheme) | Anatomy

Summary

In this video, Taim Talks Med provides a detailed yet accessible overview of the cervical plexus, a network of nerves crucial for sensation and motor control in the neck, head, and diaphragm. The video explores the topography of the plexus, its sensory and motor branches, and their roles in innervating muscles like the scalene and infrahyoid muscles. Special focus is given to the phrenic nerve, vital for breathing, and its connection to the cervical plexus. The video also touches on the relationship between the cervical plexus and the accessory nerve, emphasizing its importance in neck and upper body function.

Takeaways

• 😀 The cervical plexus is crucial for innervating many structures in the head, neck, and some muscles, forming a key component of the peripheral nervous system.
• 😀 The cervical plexus is formed by the anterior branches of spinal nerves C1, C2, C3, and C4, which come together to form various nerve branches.
• 😀 The cervical plexus gives rise to several somatosensory branches including the transverse cervical nerve, greater auricular nerve, and lesser occipital nerve, which are responsible for sensations in areas like the neck, ear, and occiput.
• 😀 The supraclavicular nerves (C3 and C4) provide sensation to regions like the skin over the sternum, infraclavicular area, and acromial region.
• 😀 The motor branches of the cervical plexus, including the muscular branches from C1-C4, innervate muscles of the neck, such as the scalenus and longus capitis muscles.
• 😀 The Ansa Cervicalis, formed by roots from C1, C2, and C3, supplies the infrahyoid muscles, which control movements of the hyoid bone and larynx.
• 😀 The hypoglossal nerve (Cranial nerve 12) travels alongside C1 to innervate the tongue's intrinsic and extrinsic muscles.
• 😀 The phrenic nerve, arising from C3-C5, is critical for diaphragm movement and breathing. Any damage to these nerve roots can lead to respiratory failure.
• 😀 The phrenic nerve has a mixed function, containing motor, sensory, and sympathetic fibers to support various structures like the pericardium, pleura, and abdominal region.
• 😀 The accessory nerve (Cranial nerve 11) has both cranial and spinal parts. It works closely with the cervical plexus to innervate muscles like the trapezius and sternocleidomastoid.

Q & A

What is the main function of the cervical plexus?

The cervical plexus is responsible for supplying many structures in the head, neck, and some other muscles. It plays a crucial role in innervating both sensory and motor functions in these regions.

Which spinal nerves form the cervical plexus?

The cervical plexus is formed by the anterior branches of spinal nerves C1, C2, C3, and C4.

How are the sensory branches of the cervical plexus organized?

The sensory branches of the cervical plexus include the transverse cervical nerve, greater auricular nerve, lesser occipital nerve, and supraclavicular nerves. These nerves provide sensory innervation to the skin of the neck, ear, and parts of the upper chest.

What does the transverse cervical nerve innervate?

The transverse cervical nerve innervates the skin on the anterior and lateral aspects of the neck, with its branches supplying the skin over the suprahyoid and infrahyoid regions.

What muscles are innervated by the cervical plexus motor branches?

The cervical plexus motor branches innervate muscles such as the rectus capitis lateralis, rectus capitis anterior, longus capitis, longus coli, and the scalenus anterior and scalenus medius muscles.

What is the significance of the ansa cervicalis?

The ansa cervicalis is a loop formed by the superior and inferior roots from C1 to C3. It is essential for innervating the infrahyoid muscles, which help in functions such as depressing the hyoid bone and thyroid cartilage.

How does the phrenic nerve relate to the cervical plexus?

The phrenic nerve is a mixed nerve formed primarily from C3, C4, and C5. It plays a critical role in motor innervation of the diaphragm, which is crucial for respiration.

What are the consequences of damage to the phrenic nerve?

Damage to the phrenic nerve can result in respiratory failure or arrest, as the diaphragm would no longer function properly, impairing the ability to inhale.

What is the relationship between the accessory nerve and the cervical plexus?

The accessory nerve (cranial nerve XI) is associated with the cervical plexus. The anterior rami of C2, C3, and C4 contribute branches to the accessory nerve, which then innervates muscles like the trapezius and sternocleidomastoid.

Why is the accessory nerve considered to have both cranial and spinal components?

The accessory nerve has both cranial and spinal parts. The cranial part emerges from the medulla and travels with the vagus nerve, while the spinal part originates from the cervical spinal cord segments (C1-C5) and innervates muscles of the neck and upper back.