Week 3 The Spine - Grp 2 answers

Question 1

Cervical spine

Describe the five segments of the spinal column

Answer 1

Cervical spine- These vertebrae are the top section of the spine with seven vertebrae in total (C1-C7 with C1 being the highest in the spine). The cervical spine vertebrae are smaller since they are not responsible for having to support heavy weight. Within the transverse processes there is an opening (Transverse foramina) , of the upper six cervical vertebrae, that allows the vertebral artery and vein to pass through. This section of the spin has a lordotic curve.

Question 2

Thoracic spine

Describe the five segments of the spinal column

Answer 2

Thoracic spine- The 12 vertebrae (T1–T12) in the middle back, where your ribs attach. Each vertebrae has six costal facets.This section of the spin has a kyphotic curve

Question 3

Sacrum-

Describe the five segments of the spinal column

Answer 3

Sacrum- Is a large, concave, triangular-shaped bone at the base of the spine, which connects to the pelvis. It is formed by the fusion of the five sacral vertebrae. This section of the spin has a kyphotic curve

Question 3

Lumbar spine-

Describe the five segments of the spinal column

Answer 3

Lumbar spine- There are five vertebrae (L1–L5) in the lower back, which support the upper parts of the spine. The vertebrae have a large vertebral body. The vertebrae also has short thick spinous process This section of the spin has a lordotic curve

Question 4

Coccyx-

Describe the five segments of the spinal column

Answer 4

Coccyx- The are three to five (usually 4) fused vertebrae at the bottom of the spine, which make up the tailbone. The coccyx does not have pedicles, laminae and spinous process.This section of the spin has a kyphotic curve

Question 5

Dura mater

Describe the layers of spinal meninges

Answer 5

Dura mater: creates the thecal sac with its tough outer layer extending to S2 creating a dural nerve root sleeve for each spinal nerve.

Question 6

Arachnoid:

Describe the layers of spinal meninges

Answer 6

-Arachnoid: is a thin transparent membrane attached to the inner surface of the dura mater. It also attaches to the pia mater with delicate spider like strands.

Question 7

Pia mater:

Describe the layers of spinal meninges

Answer 7

-Pia mater: highly vascular layer that closely adheres to the spinal cord.

Question 8

Filum terminale

Describe the layers of spinal meninges

Answer 8

-Filum terminale: anchors the spinal cord at L1 to the coccyx.

Question 9

Describe the position and reasoning for this positioning of the gray and white matter within the spinal cord.

Answer 9

The gray and white matter within the spinal cord acts opposite of the white and gray matter in the brain.

White Matter is on the outside of spinal cord. The white matter in the spinal cord eases the transition of the stimulus going from one region in the body to another. The white matter brings the processed information and stimulus down to the gray matter in the spinal cord.

Gray Matter is on the inside of spinal cord. It carries the stimulus from other regions through the white matter. It then goes into the gray matters processing area within the spinal cord. It sends the signal and stimulus up to the cerebrum/ cerebellum for processing.

Question 10

Nerve Plexuses

describe the various nerve plexuses – names, number of nerves involved a

Answer 10

Nerve Plexuses:They serve to distribute the spinal nerve fibers to various regions of the body, this allows there to be more efficient innervation. The four major nerve plexuses are the cervical, brachial, lumbar, and sacral.

Question 10

Discuss the number of spinal nerves

Answer 10

Number of Spinal Nerves: The ventral and dorsal roots unite to form the 31 pairs of spinal nerves. 8 correspond to the cervical region (C1-C8), 12 ar part of the thoracic section( T1-T12), 5 correspond to the lumbar region(L1-L5), 5 correspond to the sacrum(S1-S5), and 1 belongs to the coccyx.

Question 11

Cervical Plexus:

describe the various nerve plexuses – names, number of nerves involved a

Answer 11

Cervical Plexus: Arises from the upper four ventral rami of C1–C4 so there are 8 nerves involved. It innervates the neck, the lower part of the face and ear, the side of the scalp, and the upper thoracic area. It is also important to note that the phrenic nerve is a major motor branch of this nerve, formed by motor fibers of C3-C5.

Question 12

Brachial Plexus:

describe the various nerve plexuses – names, number of nerves involved a

Answer 12

Brachial Plexus: The Brachial plexus is a network of nerves arising from the five ventral rami of C5–C8 and T1, so there are five nerves involved. These nerves provide innervation for the muscles of the upper extremity and shoulder, but exclude the trapezius and levator scapula muscles.

Question 13

Lumbar Plexus:

describe the various nerve plexuses – names, number of nerves involved a

Answer 13

Lumbar Plexus:The lumbar plexus consists of six nerves from the ventral rami of T12 and L1–L4. It serves the lower abdominopelvic region and anterior and medial muscles of the thigh. It is also important to note that the femoral nerve is the largest branch of the lumbar plexus that divides into several branches, one including the saphenous nerve that innervates the anterior lower leg, some of the ankle, and part of the foot.

Question 14

Sacral Plexus:

describe the various nerve plexuses – names, number of nerves involved a

Answer 14

Sacral Plexus: Nerves involved are L4–L5 and S1–S4, so five nerves in total. These nerves innervate the buttocks, posterior thigh, and feet.

Question 15

Discuss the arterial vascular structures found within the cervical region of the spinal column

Answer 15

Arterial Vasculature:
Aortic Arch: The aortic arch gives rise to several major arteries, including the brachiocephalic trunk (brachiocephalic artery), left common carotid artery, and left subclavian artery.
Brachiocephalic Trunk (Brachiocephalic Artery): The brachiocephalic trunk is a short artery that divides into the right common carotid artery and the right subclavian artery.
Common Carotid Arteries: There are two common carotid arteries, one on each side of the neck. The right common carotid artery arises directly from the brachiocephalic trunk, while the left common carotid artery arises directly from the aortic arch.
Internal Carotid Arteries: Each common carotid artery divides into the internal and external carotid arteries. The internal carotid artery is one of the major arteries supplying blood to the brain. It travels through the neck and enters the skull via the carotid canal.
Vertebral Arteries: These arteries arise from the subclavian arteries bilaterally. They ascend through the cervical vertebrae, enter the skull through the foramen magnum, and join to form the basilar artery, which is a critical component of the Circle of Willis.

Question 16

Discuss the venous vascular structures found within the cervical region of the spinal column

Answer 16

Venous Vascular Structures:
1. Internal Jugular Vein: The internal jugular veins run alongside the common carotid arteries within the neck. They drain blood from the brain, face, and neck and merge with the subclavian veins to form the brachiocephalic veins.
2. Brachiocephalic Veins (Right and Left): These veins are formed by the confluence of the internal jugular vein and subclavian vein on each side of the body. The right and left brachiocephalic veins join to form the superior vena cava, which delivers deoxygenated blood from the upper body to the right atrium of the heart.
The Circle of Willis: The Circle of Willis is a circulatory anastomosis that supplies blood to the brain and surrounding structures. It is formed by the convergence of several arteries at the base of the brain. The major arteries contributing to the Circle of Willis include:
- Anterior cerebral arteries (paired): These arteries arise from the internal carotid arteries and supply blood to the frontal lobes and medial aspects of the brain hemispheres.
- Middle cerebral arteries (paired): Arising from the internal carotid arteries, these arteries supply blood to the lateral surfaces of the brain hemispheres.
- Posterior cerebral arteries (paired): These arteries arise from the basilar artery, a continuation of the vertebral arteries, and supply blood to the occipital lobes and the inferior and medial parts of the temporal lobes.

Question 17

blood from the aortic arch reaches the cervical region

Answer 17

So, blood from the aortic arch reaches the cervical region via the common carotid arteries and the subclavian arteries. Venous blood from the cervical region drains into the internal jugular veins, which merge with the subclavian veins to form the brachiocephalic veins, eventually returning to the heart via the superior vena cava. From there, oxygenated blood is pumped into the systemic circulation, including the arteries that contribute to the Circle of Willis, ensuring adequate blood supply to the brain.