The Brachial Plexus- Animated Review [HD]

The Brachial Plexus- Animated Review [HD]


in this video we will discuss the
typical anatomy of the brachial plexus the brachial plexus supplies motor
innervation to muscles of the shoulder, arm, forearm, and hand the brachial plexus also provides
sensory innervation to the bones, skin muscles, and connective tissue of the
shoulder and upper extermity. let’s begin by defining what a nerve
plexus is a nerve plexus is formed when nerve
fibers from two or more spinal segments intermingle and then segregate in order
to travel together to a common anatomical region for example, fibers from two or three
spinal segments that are all going to the biceps brachii muscle may join
together to form a single nerve bundle the travels to the biceps other fibers from the same spinal
segments maybe destined for the triceps brachii muscle and they will join together to form a
separate nerve bundle the travels to the triceps specifically, the brachial plexus contains
motor and sensory fibers for spinal segments C5 to T1 fibers from the spinal segments mix
together and then segregate as they form first roots, then trunks, then divisions then cords, and finally terminal branches. let’s look at how these different parts
of the brachial plexus are formed ventral rami from C5 to T1
form the roots there is one root from each spinal
segment and they’re named according to the
spinal segment they represent example “the C5 root” more distally the roots form the trunks the C5 and C6 roots join together
to form the upper or superior trunk likewise the C8 and T1 roots
join to form the lower or inferior trunk. finally the C7 root continues by
itself to become the middle trunk next each trunk divides into an anterior
division and a poster division this is the most important functional
segregation that takes place in the brachial plexus because all of the
fibers in the anterior division will innervate anterior compartment muscles all of the fibers in the posterior
division innervate posterior compartment muscles. let’s look at what this means in the anatomical position, the arm can
be divided by a midaxillary line into an anterior compartment and a posterior compartment these are also called preaxillary and
post axillary compartments or flexor and extensor compartments you can now understand why the anterior and
posterior divisions of the brachial plexus are formed and how they are segregated to
serve different anatomical regions returning to the brachial plexus we
can see that the poster divisions of each of the three trunks join together
to form the posterior cord anterior division of the upper trunk and
the anterior division of the middle trunk join together to form the lateral cord finally, the anterior division of the
lower trunk continues by itself to form the medial cord. note that these cords, medial, lateral, and
posterior, are named according to their position
relative to the axillary artery in the anatomical position the medial cord lies medial to the artery, the lateral cord lies lateral to the artery and the posterior cord lies posterior
to the artery it’s just a coincidence that the posterior cord is also formed by the posterior divisions of the three trunks finally the brachial plexus will form
it’s five terminal branches these are the axillary nerve, radial nerve, musculocutaneous nerve,
ulnar nerve, and to median nerve. the posterior cord divides into two
terminal branches: the axillary nerve and the radial nerve the lateral cord divides into the
musculocutaneous nerve and contributes to the median nerve by
giving off the lateral root of the median nerve the medial cord divides into the ulnar nerve and also contributes to the median nerve by giving the medial root of the median
nerve, which joins with the lateral root of the median nerve to form the
median nerve proper the terminal branches of the lateral and medial cords form the characteristic “M” shape anterior to the axillary artery,
which is usually the most distinctive feature of the brachial plexus and serves as a reference point for
locating and identifying the other components of the plexus now that we understand the major
structural features of the brachial plexus, it’s time to add in important
smaller nerves that arise from the roots, trunk,s and chords. note that no nerves arise directly from
the divisions two nerves arise from the roots: the dorsal scapular nerve which is a branch of the C5 root and the long thoracic nerve, which is
formed by branches from C5, C6, and C7 roots. two nerves also arise from the trunks: both the suprascapular nerve and the nerve to subclavius are branches from the upper trunk remember: the divisions do not give rise
to any nerves finally, the cords give rise to seven
nerves in addition to their terminal branches: the lateral cord gives off the lateral
pectoral nerve, the posterior cord gives off the upper, middle, and lower subscapular nerves note that the middle subscapular nerve is also called the thoracodorsal nerve. the medial cord gives off the medial
pectoral nerve, medial the medial brachial cutaneous nerve, and the medial antebrachial cutaneous nerve. let’s conclude by briefly discussing
some clinical aspects of the brachial plexus because the brachial plexus innervates
all the muscles of the upper extremity injuries to it could have devastating
effects on arm and hand function that are critical for activities of daily
living the brachial plexus can be injured in
many ways, of course, including penetrating knife or bullet wounds, shoulder injuries, fractures of the humerus, and surgical
procedures however two of the most common types of
injuries are upper brachial plexus injury and lower brachial plexus injury upper brachial plexus injury occurs
during extreme or violent lateral flexion of the head especially if the shoulder is
simultaneously depressed this is typified by a difficult delivery
in which the baby’s head is pulled out of the birth canal while his shoulders are trapped within
the mother’s pelvis Upper brachial plexus injuries can also occur in adults when an oblique
force pushes the head and shoulder in opposite directions such as might occur during a fall from a
motorcycle such injuries put enormous stretch on
the C5 and C6 nerve roots and/or the upper trunk itself injury to these structures results in
characteristic deficits known as Erb-Duchenne paralysis In erb duchenne paralysis, the arm hangs limply at the side and is
internally rotated, the forearm is also pronated which slightly flexes the wrist this produces the characteristic “waiters
tip position” lower brachial plexus injury occurs
during extreme or violent abduction of the arm, such as occurs when a person
falling from a ladder or tree attempts to stop himself by reaching overhead for
something to hang on to additionally, this type of injury can
also occur during delivery when the baby is pulled by the arm from the birth
canal lower brachial plexus injury occurs
from extreme stretch placed upon the C8 root, the the T1 root, the lower trunk or a combination of
these damage to these structures compromises
muscles in the forearm and hand resulting in Klumke’s paralysis Klumke’s paralasis is typified by “claw hand,” in which the fingers are flexed

Only registered users can comment.

  1. very very very helpful! I couldn't find lumbar plexus if someone can help me to attach a link to this that ll be appreciated! Thank you

  2. Origin of "Roots" described right, but drawn wrong. What is shown as the Roots is the Spinal Nerve which originates from Dorsal Root and Ventral root. Anyway a brilliant effort.

  3. very concise and informative. best video for brachial plexus anatomy. Hope to see more uploaded anatomy videos.

  4. Brilliant video! Very clear and easy to understand since you provide visuals for everything that you are saying. Thank you!

  5. Still waiting for your video of the lumbrosacral plexus, your videos are the best for this topic! Keep going!

  6. Great video. Very conceptual as compared to the "shortcut" videos that others have taught about drawing mathematical signs, etc. Good if it worked for them but that is not conceptual knowledge.

    IMPORTANT:
    I think it is quite important to not omit and show the smallish "posterior rami" branching off the spinal nerve after its formation from fusion of ventral and dorsal roots.
    Experienced clinicians know that the spinal nerve divides into an anterior ramus and a posterior ramus, but the novices students dont and that create a massive opportunity for them to take the wrong message home

  7. thanks though there's a careful Mistake on ground concerning the naming of both anterior Roots and posterior root of T1….

  8. The best brachial plexus video I have seen. Thank you very much for performing such a great job in explaining BP.

  9. Why is the brachial plexus only formed by the ventral rami?
    Shouldn't it be "ventral rami + dorsal ganglia form the roots"?

Leave a Reply

Your email address will not be published. Required fields are marked *