Lumbar disc behavior under static & vibratory loading & it’s implications on spinal movement

-



The following Part of another my review…………

Lumbar disc herniations can be a direct mechanical consequence of prolonged sitting in static or vibration environments that challenges the stability of this region.

Static loading: A 1 hour exposure to static lumbar loading such as sitting cause significant changes in the mechanical properties of the lumbar intervertebral disc exhibited by a sudden, large flexion and/or lateral bend rotation response to an axially applied load. This further implies that a motion segment in the lumbar spine suddenly buckles and applies a tensile impact loading to the posterolateral region of the disc.

Vibratory loading (Driving a car, truck, tractor etc): A combined lateral bend, flexion, and axial rotation vibration loading could cause tracking tears proceeding from the nucleus through the posterolateral region of the annulus.

Mechanical impacts of static & vibratory loading on disc reveal that mechanism for disc herniation is mechanical change leading to instability of the motion segment.

Reference:
Wilder DG et al; J Spinal Disord. 1988;1(1):16-32.


Comments

Post a Comment

Popular posts from this blog

Entrapment of medial calcaneal nerve (MCN)

-
Image
Peripheral nerve entrapment is a rare, but important, cause of foot and ankle pain that often is underdiagnosed and mistreated. A peripheral nerve may become entrapped anywhere along its course, but certain anatomic locations are characteristic (2). The medial calcaneal nerve (MCN) The Tibial nerve is called the planter nerve in the sole. The tibial nerve passes to the sole of the foot takes a turn on the medial side of the calcaneum is called MCN. The medial calcaneal nerve arises from tibial nerve of the inner side of the ankle, perforates the laciniate ligament, travels downwards passing below the bony projection on the inner side of the ankle, and supplies the skin over the medial aspect of the heel. Hence it is the most important nerve for heel sensations. MCN have 2 branches. The anterior branch dominate the cutaneous sensation of the anterior part of the medial calcaneal and heel weight loading field, while the posterior branch dominate the sensation of the posterior an
Read more

Differential diagnosis of Anatomic (Radial) snuffbox pain: It is not always DeQuervain’s tenosynovitis.

-
Image
Tendon, Bone & Ligament causes: 1. DeQuervain’s tenosynovitis: Swelling of tendon of APL (Abductor pollicis longus) & extensor pollicis brevis at lateral wrist near anatomic snuff box.  The primary complaint is radial sided wrist pain that radiates up the forearm with grasping or extension of the thumb. The pain has been described as a “constant aching, burning, pulling sensation." Pain is often aggravated by repetitive lifting, gripping, or twisting motions of the hand. Swelling in the anatomical snuff box, tenderness at the radial styloid process, decreased CMC abduction ROM of the 1st digit, palpable thickening of the extensor sheaths of the 1st dorsal compartment and crepitus of the tendons moving from the extensor sheath may be found upon examination. Other possible findings include weakness and paresthesia in the hand. Finkelstein’s diagnostic test will present positive provoking the patient’s symptoms. If left untreated, the inflammation and progressive narro
Read more

Chronic fatigue syndrome

-
Introduction: Severe fatigue is a common complaint among patients. Often, the fatigue is transient or can be attributed to a definable organic illness. Some patients present with persistent and disabling fatigue, but show no abnormalities on physical examination or screening laboratory tests. In these cases, the diagnosis of chronic fatigue syndrome (CFS) should be considered. According to Centers for Disease Control and Prevention (CDC, USA) Chronic fatigue syndrome (CFS) currently is defined as: (1) fatigue of at least 6 months' duration, seriously interfering with the patient's life; and (2) without evidence of various organic or psychiatric illnesses that can produce chronic fatigue. The World Health Organization classifies myalgic encephalomyelitis/chronic fatigue syndrome (ME/cfs) as a nervous system disease. Together with other diseases under the G93 heading, ME/cfs shares a triad of abnormalities involving elevated oxidative and nitrosative stress (O&NS), activat
Read more