A 24 year old medical student was cleaning his room after having his bimonthly theoretical exams. As he was lifting up a pile of books from the floor, he suddenly experienced severe low back pain. He felt as if something had SNAPPED in the lower back and as if something had extended down the posterior aspects of his right thigh and leg. He also noticed some numbness and tingling over the lateral part of his right leg, big toe, 2nd and 3rd metatarsals. On consultation and examination at the school clinic, he was noted to complain of a dull ache in the lower back aggravated by straining and coughing. There was diminution in the spinal lumbar curve and a tilt of the trunk to the right side. Pain due to muscle spasm limited movement in the spinal column. Raising of his right extended leg produced pain. There perception over the dorsal side of the right fourth and fifth toes. He was diagnosed to have a ruptured intervertebral disk between the 5th lumbar and 1st sacral vertebrae with protrusion of the nucleus polposus and nerve root involvement of the first sacral nerve. 

3.Explain the “snap” the patient felt. What structure/s is/are involved? 

4.Give the anatomical explanation for the following signs and symptoms: 

4.1low back pain aggravated by straining & coughing 

4.2numbness & tingling sensation over the lateral part of his right leg, big toe, 2nd & 3rd metatarsals 

4.3diminution of the spinal curve & tingling of the trunk to the right side 

4.4pain in raising his right extended leg 

5.Explain the mechanism of sustained muscle contraction around the injured area. Describe the sequence of events in muscle contraction. 

6. Based on the structures involved in Q3, explain the mechanism of muscle spasm. What are the sources of ATP?