The course i used to go to (unwillingly at first) had an amazing teacher who made it sound so interesting. 

Sean

These parts don’t work differently from each other, the divisions just help us describe where the nerves are as they move through the body.

Roots

• The roots are the anterior rami (front branches) of spinal nerves C5–T1.

• At each level of the spine, nerves leave the spinal cord through small openings called intervertebral foramina.

• Each spinal nerve splits into a front (anterior) and back (posterior) branch.

• The front branches form the brachial plexus and supply the arm, while the back branches serve the back muscles.
  
  

After forming, these roots pass between two neck muscles (the anterior and middle scalene muscles) to enter the base of the neck.

Trunks

At the base of the neck, the roots join together to form three trunks:

• Superior trunk – made from C5 and C6

• Middle trunk – continuation of C7

• Inferior trunk – made from C8 and T1

These trunks travel sideways (laterally) through the back part of the neck.

Divisions

Each trunk then splits into two parts:

• An anterior division (toward the front of the body)

• A posterior division (toward the back of the body)

This gives us three anterior and three posterior divisions. These then move into the armpit area, where they reorganize into cords.

Cords

In the axilla (armpit), the divisions join to form three cords, named by their position relative to the axillary artery (a major blood vessel in the arm):

• Lateral cord – formed from the anterior divisions of the superior and middle trunks

• Posterior cord – formed from all three posterior divisions (superior, middle, and inferior trunks)

• Medial cord – formed from the anterior division of the inferior trunk

Major Branches

From these cords come five major nerves that travel down the arm to supply muscles and skin:

1. Musculocutaneous nerve

2. Axillary nerve

3. Radial nerve

4. Median nerve

5. Ulnar nerve

These nerves allow you to move and feel your shoulder, arm, hand, and fingers.

Anatomy Insight

There are three main groups of bone markings:

• Parts of a Bone

• Bone Projections and Parts

• Bone Openings and Depressions

Parts of a Bone

Long bones (like the femur or humerus) have four main parts:

1. Head (Epiphysis) – The rounded end of the bone, usually forms a joint with another bone.

2. Neck (Metaphysis) – The area between the head and the main body of the bone.

3. Body (Diaphysis) – The long, middle part (shaft) of the bone.

4. Articular Surface – The smooth surface where one bone meets another to form a joint.

Bone Projections and Parts

Projections are areas where the bone sticks out from the main structure. These raised parts are important because they are where muscles, tendons, and ligaments attach. The size and shape of these projections often show how much force or movement happens there.

Here are the main types:

• Condyle - A smooth, rounded bump that forms a joint with another bone.

• Epicondyle - A smaller bump located above a condyle; used for muscle attachment.

• Process - A bony projection or outgrowth.

• Protuberance - A swelling or bump on a bone.

• Tubercle - A small, rounded bump for muscle or ligament attachment.

• Tuberosity - A larger, rougher bump than a tubercle.

• Trochanter - A very large, rough bump found only on the femur. It attaches strong muscles.

• Spine - A sharp, slender projection.

• Linea (Line) - A narrow ridge or raised line on a bone.

• Facet - A flat, smooth surface where bones meet.

• Crest / Ridge - A long, raised edge or border of a bone.

Bone Openings and Depressions

Depressions and openings are holes, grooves, or shallow areas in bones. They allow nerves, blood vessels, and tendons to pass through or fit into the bone.

There are: 

Foramen - A round hole in a bone for nerves and blood vessels.

Fissure - A long, narrow slit in a bone.

Meatus - A short, tube-like passage.

Fossa - A broad, shallow depression.

Fovea - A small pit or depression.

Notch (Incisure) - A small cut or indentation on the edge of a bone.

Sulcus (Groove) - A narrow channel that holds a nerve or blood vessel.

Sinus - A hollow cavity inside a bone.

Anatomy Insight

When you blush, the inside of your stomach "blushes" too.

Liv, United Kingdom

Flashcards. You can make some or look them up on quizzlet.  

Spencer, Canada