Archive for February, 2007
neck pain| nerve levels| C6
February 28, 2007 11:29 amWednesday, February 28, 2007
neck pain| nerve levels| C6
Sensation: Outer aspect of the forearm supplied by the musculocutaneous nerve.
Muscles: The following muscles have C5 and C6 nerve root innervation but most of them may have stronger C6 nerve root innervation in some individuals. The muscles in the forearm such as the extensor carpi radialis brevis and the pronator teres are C7 nerve root dominant.
The clinical and dissection anatomy photographs of the muscles supplied by the C5 and C6 nerve roots listed below can be located in the book index as well is in previous posts under upper body topics.
C6 is the most commonly injured nerve root since most of the cervical mobility occurs primarily at C5-C6 level.
- supraspinatus (C5, C6)
- infraspinatus (C5, C6)
- deltoid (C5, C6)
- teres major (C5, C6)
- biceps (C5, C6)
- brachialis (C5, C6)
- coracobrachialis (C5, C6)
- brachioradialis (C5, C6)
- extensor carpi radialis longus (C5, C6)
- extensor carpi radialis brevis (C6, C7)
- supinator (C6, C7)
- pronator teres (C6, C7)
Reflex: Brachioradialis
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Dissection photograph showing arm muscles supplied by the C6 nerve root.
neck pain| nerve level| C4
February 27, 2007 9:34 am Tuesday, February 27, 2007
neck pain| nerve level| C4
C4 Sensation: Front of the upper chest including the upper part of the shoulders, back of the lower neck. Upper slope of the shoulders is supplied by supraclavicular nerve (C3, C4).
Muscles:
- Trapezius (C3, C4, especially C4). Trapezius also receives innervation through the spinal accessory nerve (cranial nerve number 11).
- Levator Scapulae
- Diaphragm is supplied by the phrenic nerve which consists of the C3, C4 and C5 nerve roots.
Reflex: None.
C3, C4 dermatomal distribution and the upper trapezius muscle (below)
Sidelying position showing the C3, C4 dermatomes and the upper trapezius muscle
neck pain| nerve level| C3
February 26, 2007 9:17 am Monday, February 26, 2007
neck pain| nerve level| C3
C3 Sensation: Front and back of the neck and the upper shoulder slope. Together with the C2, C3 nerve root supplies the area at side of the head behind the upper part of the ear via the lesser occipital nerve (C2, C3). The area of the external ear to an area behind the lower part of the ear and side of the jaw is supplied by the greater auricular nerve (C2, C3). Front part of upper neck including the undersurface of the chin is supplied by the anterior cutaneous nerve (C2, C3).
Upper slope of the shoulders is supplied by supraclavicular nerve (C3, C4).
Muscles: Levator scapulae (C3, C4 especially C3)
Reflex: None.
© 2007 copyright all rights reserved www.stopmusclepain.com neck pain| nerve level| C3
Dissection showing the area of the back of the neck supplied by C3 sensory nerve root as well as the levator scapulae muscle supplied by the C3 motor nerve root (below).
neck pain| nerve level| C2
February 25, 2007 4:35 pmSunday, February 25, 2007
neck pain| nerve level| C2
C2 Sensation: Entire back of the head via the greater occipital nerve (C2). The area at side of the head behind the upper part of the ear is supplied by the lesser occipital nerve (C2, C3).
The entire external skin of the ear to an area behind the lower part of the ear and side of the jaw is supplied by the greater auricular nerve (C2, C3).
Front part of upper neck including the undersurface of the chin is supplied by the anterior cutaneous nerve (C2, C3).
Muscles: Sternocleidomastoid (C2, C3), also receives innervation through the spinal accessory nerve (cranial nerve number 11).
Reflex: None.
© 2007 copyright all rights reserved www.stopmusclepain.com neck pain|nerve level| C2
Picture showing the sensory distribution of C2 root (below)
neck pain| nerve levels| C5
February 24, 2007 7:31 pmSaturday, February 24, 2007
neck pain| nerve levels| C5
C5 Sensation: Outer aspect of the arm supplied by the axillary nerve.
Muscles: The muscles to test clinically include the rhomboid major and minor which have only the C5 nerve root supplying them. In fact, rhomboid major and minor are the only two muscles in the body which have only a single nerve root supplying them.
All other muscles in the body are supplied by at least two roots and more. Muscle such as the supraspinatus, infraspinatus, deltoid (anterior portion) and the biceps (long head) may have stronger innervation from the C5 nerve root although both C5 and C6 nerve roots supply them.
The muscles that have both C5 and C6 nerves supplying them are:
- supraspinatus
- infraspinatus
- deltoid
- biceps
- brachialis
- coracobrachialis
- teres major and minor
- brachioradialis
- extensor carpi radialis longus and brevis.
Reflex: Biceps
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Anatomical dissection showing muscles supplied by the C5 nerve root. Please check the book index in the blogroll also (below)
Lower back pain| sensory | lower limb
February 23, 2007 2:31 pmFriday, February 23, 2007
Lower back pain| sensory | lower limb
When your lower back hurts and you feel tingling, numbness or abnormal sensations in the lower limb limb including the foot and toes, there may be irritation of the sensory portion of the lower back nerve roots and/or the peripheral nerves supplying those regions.
However, pain in an area is often related to tightness and spasm of the underlying muscles due to motor nerve root irritation that may not correspond to the dermatome in that area from sensory nerve root irritation.
The sensory distribution (dermatomes) of the lower limb are carried through by the peripheral nerves of the lumbosacral plexus. At a later date, we will talk about the lumbosacral plexus (a network of interlacing nerves going to the lower limb from the lower back).
Dermatomes:
Front and outer aspect of the thigh: L2 (via the lateral femoral cutaneous nerve of the thigh)
Inner aspect of the thigh and front of the knee: L3 (via the obturator nerve)
Inner aspect of the leg: L4 (via the saphenous nerve)
Outer aspect of the leg and top of the foot and first three toes: L5 (via the peroneal nerve)
Middle area of lower half of the back of the leg, heel and last two toes: S1 (via the sural nerve)
Back of the thigh to the middle of the upper half of the calf: S2 (via the posterior femoral cutaneous nerve of the thigh)
© 2007 copyright all rights reserved www.stopmusclepain.com lower back pain| sensory| lower limb
Front and outer aspect of the thigh is L2 dermatome; inner aspect of the thigh and front of the knee is L3 dermatome (below)
Back of the thigh to the middle of the upper half of the calf is S2 dermatome (below) Inner aspect of the leg is L4 dermatome; outer aspect of the leg and top of the foot and first three toes is L5 dermatome; middle area of lower half of the back of the leg, heel and last two toes is S1 dermatome (below) Dermatomes at the back of the leg (below) 
Neck pain| sensory | arm
February 22, 2007 12:33 pmThursday, February 22, 2007
Neck pain| sensory | arm
When your neck hurts and you feel tingling, numbness or abnormal sensations in the upper limb including the hands, there may be irritation of the sensory portion of the neck nerve roots and/or the peripheral nerves supplying those regions.
However, pain in an area is often related to tightness and spasm of the underlying muscles due to motor nerve root irritation that may not correspond to the dermatome in that area from sensory nerve root irritation.
The sensory distribution (dermatomes) of the upper limb are carried through by the peripheral nerves of the brachial plexus. At a later date, we will talk about the brachial plexus (a network of interlacing nerves going to the arm from the neck).
Outer (lateral) aspect of the arms: C5 (via the axillary nerve)
Outer (lateral) aspect of the forearm: C6 (via the musculocutaneous nerve)
Thumb, index and the outer half of the middle finger: C6 (via the lateral head of the median nerve)
Middle finger: C7 (via the lateral head of the median nerve)
Ring and little fingers: C8 (via the ulnar nerve)
Inner (medial) aspect of the forearm: T1 (via the medial cutaneous nerve of the forearm)
Inner (medial) aspect of the arm: T2 (via the medial cutaneous nerve of the arm and the intercostobrachial nerve)
© 2007 copyright all rights reserved www.stopmusclepain.com neck pain| sensory| arm
The sensory distribution of the arm, outer (lateral) aspect of the arms is C5; inner (medial) aspect of the arm is T2
The sensory distribution of the forearm: Outer (lateral) aspect of the forearm is C6 and inner (medial) aspect of the forearm is T1 (below)
The sensory distribution of the hand: Thumb, index and the outer half of the middle finger is C6, middle finger is C7, ring and little fingers is C8 (below) 
Neck| muscles| flexion| extension
February 21, 2007 7:47 pmWednesday, February 21, 2007 Muscles primarily responsible for bending the neck down (flexion) is the sternocleidomastoid muscle. The secondary muscles are the scalenes and the deep muscles at the front of the neck spine.
The primary muscles responsible for pulling the neck up as in looking upward to the ceiling are the trapezius, splenius capitis and cervicis and semispinalis. Secondary muscles are the small short muscles of the head and neck known as the intrinsic neck muscles.
Rotating the neck sideways is performed primarily by the sternocleidomastoid muscle.
Side bending of the neck primarily involves trapezius, levator scapulae and scalene muscles.
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Trapezius overlies the cervical paraspinal muscles
Neck pain| muscles| range of motion
February 20, 2007 10:03 amTuesday, February 20, 2007
Neck pain| muscles| range of motion
You can feel and see the muscle that is most prominent at the front of the neck. This is the sternocleidomastoid muscle. This muscle is usually in pain after an auto accident when stretching occurs to this muscle as the head and moves backward and forward. The head can be abnormally tilted to one side due to spasm. For example, if the right sternocleidomastoid muscle is in spasm, the face and chin will be turned to the left. This is known as torticollis.
The trapezius muscle is at the back of the neck. This muscle gives the contour to form the slope of the shoulder. It stretches from the base of the head to the tip of the shoulder. The upper portion of the trapezius is commonly very tender in most people. If one side is more in spasm, you can see the swelling very obviously from the front.
The neck movements include looking down (flexion), looking up (extension), neck rotation and bending or inclining the neck sideways (lateral flexion).
The normal range of motion of the neck: At least 50% of flexion and extension occurs between the occiput of the skull bone and C1 vertebra. This is called the “yes” joint as in nodding the head to agree. The remaining 50% is distributed between the movements occurring between C2-C7 levels. Most of the movements occur at the C5 and C6 vertebral levels.
In the normal situation, you should be able to bend your neck down such that you should be able to touch your chin to your chest.
You should be able to bend your neck upward such that you should be able to directly look at the ceiling above you. All these movements should be able to done without hesitation or halting movements. You must not lean back to perform this motion.
When you rotate the neck as in saying "no", at least 50% of the rotation movements occur between the C1 and C2 levels which is thus known as the “no” joint. The remaining 50% of the rotation movements occur between C3 to C7. In the normal situation, you should be able to turn your head in such a way that your chin is in line with the shoulder, almost touching the shoulder. You must be careful not to elevate your shoulder to perform this motion.
Bending or inclining the neck sideways, involve all the cervical vertebrae. To perform this motion, the neck has to also rotate. Normally, you should be able to incline the neck sideways for about 45° from the midline of the head from the starting point which should be a plane perpendicular to the floor. When you have restriction to perform this motion, you will usually have a tendency to elevate the shoulder.
Difficulties with neck range of motion can occur with fixed deformities from having arthritis in the neck. However, pain and/or discomfort with tightness of the muscles will further restrict the range of motion. Relaxing the muscles of the head and neck is essential to regain the loss in range of motion due to pain and spasm of these muscles.
© 2007 copyright all rights reserved www.stopmusclepain.com neck pain| range of motion| muscles
Neck rotation showing both heads of the sternocleidomastoid muscle. The trapezius forms the slope of the shoulderand is seen behind the sternocleidomastoid muscle (below).
neck pain| back| landmarks| vertebral levels
February 19, 2007 2:21 pmMonday, February 19, 2007
neck pain| back| landmarks| vertebral levels
Feel the back of the head. This area is called the occiput. In the center of the back of the head is the bump called the inion. If you move your fingers away from the bump, the ridge that you feel is called the superior nuchal line. The trapezius muscle attaches to the superior nuchal line and you may feel tenderness as you feel this muscle.
There is a big prominence in the skull bone at the back of the ear, near the angle of the jaw and this prominence is the mastoid process. This is the bone from which the sternocleidomastoid muscle that rotates the head arises from. Also, the longissimus muscle coming all the way from the lower back region attaches there (you can thus appreciate the myofascial connection between head, neck, lower back and vice versa). If there is pain and spasm in these muscles, you may feel tenderness in the region of the mastoid process.
If you bend the neck down, you can feel the spinous processes of the vertebral bodies. Since the spinous processes are not covered by muscles, you should be able to easily feel them.
Beside the spinous processes in the neck region are the paraspinal muscles and the trapezius muscles. The first spinous process that you can feel is that of the C2 vertebra and this is felt at the base of the head in the midline.
If you have a tight trapezius, you may feel a tight cord that stretches from this skull to the lower part of the midback. The largest and most easily felt spinous process is that of the C7 vertebral body and the one immediately below it which is also easily felt is the spinous process of the T1 vertebral body.
Transverse skin creases across the spinous processes may be noted corresponding to the level at which disc space narrowing maybe present.
The normal cervical spine has a C-shaped curve with the hollow of the C at the back of the neck. This is called cervical lordosis. If you put your hand at the back of the neck between the base of the skull and the C7 spinous process you should be able to cup your palm and fingers into the hollow of the C-shaped curve of the cervical spine.
Presence of spasm in the muscles at the back of the neck will flatten the cervical lordosis and cause straightening of the neck spine.
Pain in the neck may also come from the facet joints. You may be able to feel the facet joints if you move your fingers outward about 1" away from the spinous processes. The facet joints lie under the edge of the trapezius muscle. They may be tender especially at the level of the C5 and C6 since arthritis is more common at this level.
© 2007 copyright all rights reserved www.stopmusclepain.com neck | lower back| back landmarks| vertebral levels
C7 and T1 spinous processes are very prominent, C7 is more prominent (below) Side view showing the C shaped curve of the neck known as cervical lordosis (below)
