Introduction
Between the vertebrae of the human spine are the intervertebral discs (Disci Intervertebrales), also known as intervertebral discs. These discs consist of a fibrous ring (Anulus Fibrosus) and a soft, gelatinous core (Nucleus Pulposus). In the event of a herniated disc, the stable fibrous ring is damaged, the holding function of the fibres is destroyed, the nucleus slips into the spinal canal and can affect the spinal cord and surrounding nerves. Often a herniated disc causes pain and numbness in the extremities (arms or legs). Depending on which part of the spine is affected, numbness results in different parts of the body.
Duration of deafness
Nerve damage caused by a herniated disc must be operated on if it causes numbness or paralysis. At the latest after the operation (see: Operation for a herniated disc), however, the symptoms of the herniated disc should then subside quite quickly, as the compressed nerve root was exposed again during the operation. Permanent damage can occur if the operation was waited too long and the nerves are already irrevocably damaged. In the worst case, massive damage caused by a herniated disc can also lead to paraplegia. Permanent damage after a herniated disc of the cervical spine can be numbness in the arms or muscle weakness.
Deafness in different parts of the body
A numbness in the face due to a slipped disc is rather rare. In the rare cases, it may of course be natural that a sensory disturbance in the face in the form of tingling and numbness is due to a cervical disc herniation (see: cervical disc herniation) or a cervical syndrome. Deafness then does not occur as an isolated symptom, but is associated with other complaints such as head and neck pain, vision problems and ringing in the ears.
In the clinical examination, it is important to precisely demarcate the deaf areas of the face. This makes it possible to rule out radical damage to the fifth cranial nerve (trigeminal nerve). This is because this leads to numbness in the face which is arranged like an onion skin.
The differentiation from a herniated disc with tingling and numbness in the face is therefore very important. Deaf arms, hands or fingers are the most likely indications of a herniated disc of the cervical spine. The nerves that supply the arm and neck area emerge from the spinal cord between the cervical vertebrae.
The nerves supplying the cervical vertebrae (C5-C7) and the first thoracic vertebra (Th1) form the so-called arm nerve plexus (Plexus Brachialis), which is responsible for the muscular and sensitive supply of the arms, hands and fingers. The three most important nerves of the arms are: Damage to such a nerve causes numbness and muscle weakness in the arm and hand. Deafness and muscle weakness in the forearm is usually caused by the median nerve, deafness of the fingers often results from damage to the ulnar nerve.
Deaf fingers therefore indicate an impairment of the lower intervertebral discs of the cervical spine, since the nerve is fed from these very same parts. – Radialis nerve (Nervus Radialis)
- Medianus nerve (Nervus Medianus)
- Ulnar nerve (Nervus Ulnaris)
Nerves from the lower lumbar (see: lumbar spine) and sacral spinal cord segments are responsible for sensitivity in the genital area – more precisely L1, L2, S2, S3 and S4. If the numbness is more in the upper area, approximately at the level of the pubic hair, there is usually a herniated disc in the segment L1.
The nerves from this segment also supply the sensitive skin area above the groin up to the genital area (see: dermatome). In men, for example, a numbness in the penis and testicles can indicate a herniated disc at the level of S2 and S3. It is more difficult to draw conclusions about the exact location of a potential herniated disc because nerves from several sacral spinal cord segments (S1-S5) are responsible for the sensitive supply of the skin in this area (see: dermatome).
A special feature on the subject of “numbness at the buttocks” is the so-called “breeches anaesthesia“. This is a sensory disturbance, for example in the form of a numbness in the dermatomes L3, L4 and L5. The naming is based on the fact that the numbness spreads in the areas where the trimming of a pair of riding breeches is also found, namely on the inner side of the thigh, the genitals and the anus.
The deafness only reflects the failure of the sensitive, not the motor, supply of the corresponding spinal nerves. If numbness occurs in the area of the legs or feet, a herniated disc of the lumbar spine should be clarified, since the skin areas are sensitively supplied by nerves from the lumbar spinal cord segments. It is not uncommon for a lumbar disc herniation to cause numbness in the genital area or on the buttocks.
Under certain circumstances, urinary or fecal incontinence may occur, since some nerves from the nerve plexus of the lumbar spine (plexus lumbosacralis) are also responsible for supplying the pelvic floor muscles. The so-called “saddlebag syndrome” is caused by nerve damage to the “horse’s tail” (cauda equina). The end of the spinal nerve roots is called the “horse’s tail”, which extends in the spinal canal to the first or second lumbar vertebra and resembles the tail of a horse in its appearance.
Thus, if symptoms of a saddlebags syndrome occur, conclusions can be drawn about a herniated disc in the area of the first two lumbar vertebrae (L1 and L2). Isolated numbness of the legs is usually due to damage to the lower lumbar intervertebral discs, since the nerves between the fourth and fifth intervertebral discs with the sciatic nerve and the tibial and fibular nerves (nervus tibialis and nervus fibularis) are the main suppliers of the leg. The nerves that supply the foot and toes also emerge from the fibula nerve.
Deaf feet and toes and sensory disturbances of the calf therefore also indicate a herniated disc in the lower lumbar spine. Most herniated discs in the lumbar spine are found between L4/5 and L5/S1. and numbness in the legDisplaced persons affected by a numbness in the knee, a herniated disc may be present in the spinal cord segment L3-L5.
The area of the sensitive supply (dermatome) by the spinal nerves from the L4 segment is located most extensively and relatively centrally above the knee. L5 supplies the outer part of the knee and L3 the inner part. In addition to numbness in the knee as a sensitive disorder, affected persons complain of a difficult knee extension as a sign of motor failure of the herniated disc at the level of L4.
A numbness at the shinbone is indicative of a herniated disc at the level of the spinal cord segments L5 and partly L4, which supply the skin above the shinbone sensitively (see: dermatome). The same nerves also supply the skin area from the thigh via the knee along the lower leg to the foot. Dermatome L5 covers a relatively large area over the shin, while dermatome L4 tends to extend more centrally over the tibia to the inner side of the lower leg.
Since both dermatomes extend over the entire leg, the numbness usually does not occur isolated on the shin. Rather, the sensory disturbances can be felt over the entire course of the disease, i.e. also in the feet if, for example, the spinal nerve L5 is affected. Otherwise, the differential diagnosis of a peripheral nerve lesion should be clarified, then the numbness can only occur on the shin, in contrast to the herniated disc. This distinction is very important and helps in the diagnosis of a herniated disc. In addition to the numbness as a sensitive disorder of the herniated disc at height L5, the motor failure due to foot lifter paresis can cause a classic “stepper gait”.
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