Anatomy chap 2 from clinical snells

1. Anatomy
Chapter no 2
Anatomy

2. 01. Deep Fascia
02. Back blood supply
03. Lymph Drainage
04. Spinal Cord
05. Dura Mater
CONTENTS

3. DEEP
FASCIA
01

4. DEEP FASCIA :
The deep fascia, also known as the thoracolumbar fascia, is a tough, fibrous sheet of connective tissue that covers
the muscles of the back and abdomen. It serves as a stabilizing structure for the spine, providing support to the back
muscles and helping to maintain posture.
The deep fascia is composed of several layers of connective tissue, including collagen and elastin fibers, which give it
strength and flexibility. It is divided into three parts: the anterior layer, the middle layer, and the posterior layer.
The anterior layer covers the abdominal muscles and attaches to the lower part of the rib cage. The middle layer
covers the erector spinae muscles and attaches to the spinous processes of the vertebrae. The posterior layer covers
the deep muscles of the back and attaches to the iliac crest and the sacrum.
The deep fascia also plays an important role in the transmission of forces generated by the muscles during
movement. It helps to distribute these forces evenly throughout the back and abdomen, which reduces the risk of
injury.
Overall, the deep fascia is a vital component of the musculoskeletal system, providing structural support and helping
to maintain stability and mobility in the back and abdomen.

5. Back blood
supply
02

6. BACK BLOOD SUPPLY:
The back is supplied with blood by a network of arteries and veins that provide oxygen and nutrients to the
muscles, bones, and other tissues in this region. The major arteries that supply blood to the back include:
ARTERIES :
Thoracic aorta:The thoracic aorta is a large artery that originates from the heart and supplies blood to
the upper part of the back.
Lumbar arteries: The lumbar arteries branch off from the abdominal aorta and supply blood to the
lower back.
Posterior intercostal arteries: These arteries arise from the thoracic aorta and supply blood to the
back muscles and skin.
Subclavian artery: The subclavian artery is a large artery that supplies blood to the upper extremities
as well as the upper part of the back.

7. Back blood supply
Veins:
The back is also drained by a network of veins that carry deoxygenated blood back to the heart. These
include:
Inferior vena cava: The inferior vena cava is a large vein that collects blood from the lower part of the
body, including the back, and returns it to the heart.
Lumbar veins: The lumbar veins drain the lower back and join with the inferior vena cava.
Intercostal veins: The intercostal veins drain the back muscles and skin and join with the azygos vein,
which then empties into the superior vena cava.
Overall, the back is supplied with blood by a complex network of arteries and veins that work together to
provide the oxygen and nutrients needed for the proper functioning of the muscles and other tissues in
this region.

8. Lymph
Drainage
03

9. Lymph drainage
The lymphatic system is responsible for the drainage of lymph, a clear fluid that contains immune cells
and waste products, from the tissues of the body. The lymphatic system in the back is composed of
lymphatic vessels, lymph nodes, and lymphoid tissues. The lymphatic vessels in the back run parallel to
the veins and arteries and drain into the lymph nodes located in the axillary, cervical, and inguinal
regions.
The lymph nodes that receive lymphatic drainage from the back include:
Axillary lymph nodes: The axillary lymph nodes are located in the armpit region and receive lymphatic
drainage from the upper back.
Cervical lymph nodes: The cervical lymph nodes are located in the neck region and receive lymphatic
drainage from the upper and mid-back.
Inguinal lymph nodes: The inguinal lymph nodes are located in the groin region and receive lymphatic
drainage from the lower back.

10. The lymph nodes filter the lymphatic fluid and remove any harmful substances, such as bacteria and
cancer cells, before the fluid is returned to the bloodstream. The lymphatic vessels in the back also
connect to the thoracic duct, which is the largest lymphatic vessel in the body and empties into the left
subclavian vein, where the lymphatic fluid re-enters the bloodstream.
In summary, lymphatic drainage in the back involves the lymphatic vessels, lymph nodes, and lymphoid
tissues that work together to filter lymphatic fluid and remove harmful substances from the body.

11. Spinal
cord
04

12. Spinal cord :
The spinal cord is a long, cylindrical structure that extends from the base of the brain down to the lower
back. It is part of the central nervous system (CNS) and serves as a communication pathway between the
brain and the rest of the body.
The spinal cord is surrounded and protected by the vertebral column, which consists of 33 vertebrae in
adults. The spinal cord is divided into five regions: the cervical, thoracic, lumbar, sacral, and coccygeal
regions. Each region is composed of a specific number of spinal cord segments, which are named based
on their corresponding vertebral level.
The spinal cord is composed of both gray and white matter. The gray matter is located in the center of the
spinal cord and contains cell bodies, dendrites, and axon terminals of neurons. The white matter is located
on the outer part of the spinal cord and contains myelinated axons that carry sensory and motor
information between the brain and the peripheral nervous system.

13. The spinal cord is responsible for relaying sensory information from the peripheral nervous system to the
brain and for transmitting motor signals from the brain to the muscles and glands. It also plays a role in
reflexes, which are rapid, automatic responses to a stimulus that occur without conscious thought.
Damage to the spinal cord can result in a variety of neurological problems, including paralysis, loss of
sensation, and loss of reflexes, depending on the location and extent of the damage.

14. Spinal nerves:
Spinal nerves are the nerves that emerge from the spinal cord and transmit sensory, motor, and
autonomic signals between the spinal cord and the rest of the body. There are 31 pairs of spinal nerves,
each pair emerging from a specific level of the spinal cord.
The spinal nerves are named based on their corresponding vertebral level, with the exception of the first
pair of spinal nerves which emerge from the space between the skull and the first cervical vertebra. Each
spinal nerve is composed of two roots: a dorsal (posterior) root, which contains sensory fibers that carry
information from the periphery to the spinal cord, and a ventral (anterior) root, which contains motor fibers
that carry information from the spinal cord to the periphery.
After exiting the spinal cord, the dorsal and ventral roots of each spinal nerve join together to form a mixed
spinal nerve. The mixed spinal nerve then divides into branches that innervate different parts of the body.
The branches include:

15. Dorsal ramus: The dorsal ramus supplies the muscles and skin of the back.
Ventral ramus: The ventral ramus supplies the anterior and lateral parts of the body, including the limbs,
chest, and abdomen.
Communicating rami: The communicating rami connect the spinal nerves to the sympathetic chain
ganglia, which are involved in the autonomic nervous system.
Spinal nerves play a crucial role in the functioning of the peripheral nervous system, as they are
responsible for transmitting information between the spinal cord and the rest of the body. Damage to spinal
nerves can result in a variety of neurological problems, including loss of sensation, loss of motor function,
and loss of autonomic function, depending on the location and extent of the damage.

16. Spinal cord nerve supply:
The spinal cord is supplied by a network of arteries that provide oxygenated blood to the neural tissue.
The main arteries that supply blood to the spinal cord are the anterior spinal artery, the two posterior spinal
arteries, and the radicular arteries.
The anterior spinal artery is the largest of the spinal cord arteries and runs along the anterior (front)
surface of the spinal cord. It supplies the anterior two-thirds of the spinal cord with oxygenated blood.
The posterior spinal arteries are two smaller arteries that run along the posterior (back) surface of the
spinal cord. They supply the posterior one-third of the spinal cord with oxygenated blood.
The radicular arteries are smaller arteries that branch off from other arteries and supply the nerve roots
and the meninges (the protective coverings of the spinal cord) with oxygenated blood.

17. The spinal cord also receives blood supply from the segmental arteries, which are branches of the aorta
that supply blood to the vertebral column. These arteries provide collateral circulation to the spinal cord
and can compensate for decreased blood flow through the anterior or posterior spinal arteries.
Disruption of the blood supply to the spinal cord, such as from a blocked or ruptured artery, can lead to
spinal cord ischemia (lack of oxygenated blood flow to the spinal cord) and subsequent neurological
damage. Spinal cord ischemia can result in a variety of neurological symptoms, including weakness,
numbness, and loss of function in the areas of the body that are supplied by the affected segment of the
spinal cord.

18. Spinal cord menings
The spinal cord is surrounded and protected by three layers of membranes called meninges. The
meninges are continuous with the meninges that surround the brain and provide protection and support to
the spinal cord.
The three layers of meninges that surround the spinal cord, from outermost to innermost, are:
Dura mater: The outermost and thickest layer of the meninges, composed of tough, fibrous tissue that
provides protection to the spinal cord.
Arachnoid mater: The middle layer of the meninges, composed of delicate, web-like tissue that is loosely
attached to the dura mater. The space between the arachnoid mater and the pia mater is filled with
cerebrospinal fluid (CSF), which helps to cushion and protect the spinal cord.

19. Pia mater: The innermost layer of the meninges, composed of thin, delicate tissue that is closely adhered
to the surface of the spinal cord. It contains blood vessels that supply nutrients to the spinal cord.
The meninges provide several important functions to the spinal cord, including:
Protection: The meninges provide a physical barrier that protects the spinal cord from injury.
Cushioning: The CSF that surrounds the spinal cord in the subarachnoid space provides a cushioning
effect that protects the spinal cord from mechanical shock.
Nutrient supply: The pia mater contains blood vessels that supply oxygen and nutrients to the spinal
cord.
CSF circulation: The meninges play a role in the circulation of CSF, which helps to remove waste
products from the spinal cord and regulate the chemical environment surrounding the spinal cord.
Damage or infection to the meninges can result in a variety of neurological problems, including meningitis
(infection of the meninges), spinal cord compression, and spinal cord injury.

20. Dura meter
05

21. Dura meter:
The dura mater is one of the three layers of the meninges, which are the protective membranes that
surround and cushion the brain and spinal cord. It is the outermost layer, closest to the skull or vertebral
column, and is made up of tough, fibrous tissue. The dura mater helps protect the brain and spinal cord
from physical injury and trauma, and also helps to contain cerebrospinal fluid (CSF) that cushions the brain
and spinal cord. Additionally, the dura mater contains blood vessels that supply blood to the brain and
spinal cord.