welcome to a brief talk on the anatomy and Neurology of the cervical spine and so uh in order to appreciate all the various pathologies that can happen to the spine particularly the cervical spine I think it's very appropriate that we understand the anatomy and so first off the cervical spine is a normal lordotic curve so the facets are angulated inferiorly one vertebrae on top of another and if you're thinking kind of like a structural engineer right the way that the cervical spine is designed it's naturally in relative extension so the c-spine likes to handle extension and compression loads it's uh less likely to be able to handle a straight axial load when the cervical spine becomes straight and so we're going to talk about what potentially catastrophic injuries that could lead to in the axial loaded flexed spine and so um as we're looking at these facet joints of course the um cervical spine facets are prone to uh overuse degeneration and we're going to talk about in the pathology section the other video we're going to talk about um spondy losis and instability so a bird's eye view here you're looking at the fan um and which houses the spinal cord and then nerve Roots exiting bilaterally out of the cord this is is posterior right so the spinus process and so this must be the dis cut in half here so you've got the nucleus and the annulus and then blood supply coming through these vertual forment and so um we've said this before in class I think but whereas in the lumbar spine the nerve Roots exit below the vertebral body for which they're named so L2 nerve root goes below the lumbar spine uh the second lumbar spine the cervical spine is the opposite and so if this is the C3 vertebrae the C3 nerve root is the yellow nerve root so and then if this is C4 the vertebral body that's the C4 nerve root and then where do you think that changes well it changes where we've got eight nerve Roots but only seven vertebrae so an extra nerve root there so after the seventh cervical vertebrae the eighth nerve root exits below and then from there on out T1 the nerve root exits below and so here's a really good pictures of the anatomy right in between each vertebrae we've got a dis discs don't start until below C2 so c0 and one where the where the uh occipital bone fits onto the first vertebrae that does not have a disc and then between one and two does not have a disc but underneath that C2 the discs start and of course nerve Roots exit out of each of these vertebrae through these intervertebral foramina here's a nice angulation of the facet joints of the cervical spine and you can see where the spinus processes start to angle at a sharper and sharper angle downward as we go down the cervical spine and of course all of us can easily palpate our C7 spinus process go ahead and slide down the back of your own neck all the way from the base of your skull your head all the way down and where you feel the most prominent spinus process you're on C7 okay so um kind of a three-dimensional uh anatomic model here so the occipital bone rests on C1 atlanto occipital joint is what we call it that has a little bit of flexion and extension about 15 or 20 degrees and then right below that we get all well a lot of the rotation through the cervical spine through that atlanto axial joint C1 and two remember that Atlas has no vertebral body and then the atlas below it has that odontoid tooth around which the atlas rotates very important here uh for you to remember that the cervical joints uh facet joints are sovial joints and so they can refer pain uh like any other joint here you see the neurology uh with without respect to there are no vertebrae here right and so any injury of the cervical spine be um above C4 here so C3 C1 2 or three if you've got damaged to the cord at that level this is the patient that is is at risk for um you know discontinuing to breathe so stopping to breathe so this is a medical emergency um okay and so we're going to talk about the myotomes and the dermatome supplied by all of the levels below uh C4 uh as we move on forward not a whole lot else here to talk about other than this vertebral Arch obviously is a bony protection of the spinal cord itself and then the spinus process is an attachment for muscle and ligament as as are the transverse processes and then you've got anterior and posterior longitudinal ligaments that limit extension and flexion respectively okay we're going to talk a little bit uh actually a lot about the bracho plexus so what is the bracho plexus it's a group of nerves that's what a plexus is or a network of nerves originating in the cervical spine that starts at C5 sorry about my pointer there C5 and it includes 5 6 7 8 and T1 so five uh nerve roots that then go and and become eventually peripheral nerves that Supply uh muscles throughout the upper extremity so let's break this down a little bit okay uh if we think about a tree a tree has roots Trunks and branches right working up from the ground to the branches and so in the same way the bracho plexus has roots and it has trunks three of them you see here the superior middle and inferior so Roots trunks that then become cords and then finally those terminate in branches and each of these uh branches are peripheral nerves that Supply muscle okay so I mentioned Roots uh trunks branches but then um those uh also divide further into cords and so where are are where are our cords okay so trunks then become cords and so we have lateral posterior and medial cords and the lateral cord supplies the muscul cutaneous and the median nerve so you see muscul cutaneous and median nerves the big claim to fame of the musculocutaneous nerve is that it's going to supply our biceps so our large oval flexor and then you've got the medial cord and that supplies then and terminates in the olar and the medial aspect of the median nerve so you get the median nerve supplied by two cords and then the posterior cord right here goes behind so think of the back of your arm by your triceps it dips um around your armpit and goes posteriorly and that supplies the axi axillary nerve which is going to supply right here by the shoulder and then the radial nerve the radial nerve is going to dive back behind your elbow and Supply well what muscles live back behind there it's the wrist and elbow extensors right okay so a good way I'm going to take away the branches cords divisions Trunks and Roots uh in a second um actually let me do that now because I want to show you something there This Acronym really tired drink coffee buddy really tired drink coffee buddy some of you just need to memorize that as you go to PT and OT school so I'm trying to help you out there but let's go back um where we were so really tired drink coffee buddy a nice acronym let's say you just needed to really know the bracho plexus and you wanted to draw it well let's start with the roots and let's end with the branches so think of the uh letters VI IV so if you draw VI i v you've drawn essentially C5 to T1 nerve roots and then way over here we're going to draw an M do you see that M there m those are three of the five peripher nerves and then you connect each one of the vivs with the m and you've essentially got most of the bracho plexus uh drawn there so if you can remember that um great more power to you this dotted line is that that posterior cord that we just talked about so you might imagine what nerves these are going to supply right we said axillary and radial nerve so fill in some of the gaps here and now we've got the entire bracho plexus are originating C5 to T1 terminating in musculous all the way to olar nerves I hope that helps you to just straight memorize this neurology and here we see it again the only new thing I want to show you with this picture is that in addition to these five um terminal you know branches you've got the long thoracic nerve here and then the suprascapular nerve here and then another aspect of the long thoracic nerve so um and what muscles do these um nerves Supply well suprascapular nerve it lives above the scapula so that must be the superspinatus right and a little bit of the trapezius so in some patients you'll have weakness in the in those muscles and atrophy well something's going on with the C5 nerve root that supplies the super scapular nerve that's why it's important to know where these nerves originate and where they terminate and then this long th classic nerve supplies the seratus anterior so some of your patients with upper extremity issues like um like scapulothoracic dysfunction they could have a long thoracic nerve pathology okay let's um follow these nerve Roots out into the muscles that they Supply okay so what you're looking at with this slide um all refers to the anterior aspect so those anterior divisions of the bracho plexus we're going to talk about poster in the next slide and so these anterior divisions Supply the anterior compartment so if we're in anatomic position and let's say with our right hand we're we're um palpating our left side so we're going over our biceps and our forearm and our hands so these are all the flexors um of the upper extremity okay and so really we're talking about the muscular cutaneous nerve the median nerve and the olar nerve all three of those come out of this anterior division and so muscular cutaneous nerve I have highlighted here in yellow that nerve supplies the well the flexors of the shoulder elbow and and um and the wrist so the Coro brachialis and the biceps brachii and the brachialis okay The Three Bs we're going to call those when we go into the elbow and shoulder all right and then the median nerve goes and and supplies all of the wrist flexors okay and so you it's hard to see all of these U muscles here but the flexor pronator group right the pronator terries the flexor carpy radialis the flexor carpy um naris and the Palmer palaris longus okay as well as the flexor digitorum muscles so all the wrist and elbow flexors originating from C5 all the way to C8 and T1 T1 is more of a finger AB ductor but I love this slide because we're taking them from the nerve Roots all the way to the the peripheral nerves and the muscles um supplied by those peripheral nerves and finally the onar nerve this is way medial right so this is your your classic uh Funny Bone which we all know you don't have a funny bone sorry we all know you don't have a funny bone it's your onar nerve and so what does the onar nerve Supply well it supplies those flexors on the very medial side of the elbow so flexor carpol NYS did I say the median nerve supplied flexor carp carpys lied to you it's the olar nerve if I did in fact say that ear earlier and then the flexor digor profundus so the Deep deeper compartment of the flexors the profundus whereas the median nervous flexor um digitorum superficialis okay so two different compartments there and then these adductor muscles of the hand okay so that's all anterior let's go posterior so the posterior division then gives rise to to the radial nerve well before I even go over here you you must know right that if you're if you're kind of tracking with me that radial nerve is posterior remember we said it dips in your axilla your armpit and then it wraps On The Backs Side by your triceps so it's got to supply the triceps and then what else down here behind the elbow those are all the extensors of the wrist and fingers right exactly so EXT extensor carpy radialis extensor carpy uh radialis longest and brevis um extensor digitorum right so good I hope this helps you with Neurology okay so let's finish up with the lower quarter screen in just a couple minutes because I'm going to do it quickly because I'm going to show you this in lab and so this is from your starky book we're we're well C4 is not part of the bracho plexus right so it's not that we shouldn't focus on that uh or I mean you know do something with that but we're going to focus on C5 to T1 so C5 the dermatome to D5 is the shoulder I'm going to unpack these in the in the um next slide so I'll just go really quickly C6 supplies the lateral aspect of your forearm into your thumb and a little bit of your index finger C7 applies the the middle finger and half of the ring finger C8 supplies the other half the lateral half of the ring finger and the pinky and then up into a little bit of the forearm and then T1 is the um lateral elbow into the axela okay the motor supply will take care of and the reflexes will take care of in the subsequent slides but this if you're studying the entire uh upper quarter screen this is um your standard uh cheat sheet for studying for the upper quarter screen for your exam learn this from a spinal surgeon a quick way to remember dermatomes um C5 is the skin supply to the shoulder C6 supplies the thumb C7 the middle finger C8 the ring finger and then T1 the axilla so that's kind of a quick and easy way to remember it this is a more if you want to map out the entire C6 dermatome right whereas um Dr Watkins would just say the thumb that's kind of the distinguishing part of C6 but really the entire map of C6 is all on this purple so I hope that helps and then myoms real quickly C5 shoulder abduction try to do this while while um I'm talking to you while you're listening to this video so AB duct your shoulder your your deltoid muscle is supplied by the fifth cervical nerve rout okay now let's Flex our elbows and do the opposite to our wrists that's the sixth cervical nerve rout what else does C6 contribute to if any of you have studied this out it actually externally rotates the shoulder that's what's happening in B here so elbow flexion wrist extension it's easy to remember because whatever the elbow's doing the wrist does the opposite okay so C6 contributes to both of those C7 here it was elbow flexion now we're in elbow extension so that must mean wrist flexion okay C7 nerve root contributes to both of those C8 and T1 there is some co-mingling here both contribute to finger AB duction but C8 also contributes to finger flexion so flexing the digits that's the C8 nerve root and then T1 abduction you can see here have the patient kind of splay out their fingers and then you resist AED duction here's another uh kind of good way to remember all of those myotomes so this is just another way for you to remember the myotome supplied by the bracho plexus and it agrees with the starky textbook and the slides that we just went through so I hope this helps on the anatomy discussion uh this is going to be really good for us as we um talk about pathologies and then it will prep us for lab where we can do a neurologic exam on each other thanks for listening