The following muscles are supplied by posterior rami of spinal nerves EXCEPT

Correct Answer: D

Rationale: The scalene muscles are innervated by the anterior rami of cervical spinal nerves, not the posterior rami. The posterior rami supply intrinsic back muscles like the erector spinae.

Correct Answer: A

Rationale: The thymus gland, which plays a role in immune system development, is often abnormal in patients with myasthenia gravis. Thymic hyperplasia or thymoma is commonly associated with the condition, and thymectomy (surgical removal of the thymus) can improve symptoms in some cases.

Correct Answer: B

Rationale: The epididymis is the correct answer because it is the coiled tube where sperm mature and gain motility after being produced in the testes. This maturation process is essential for sperm to become capable of fertilizing an egg. The epididymis also stores sperm until they are ejaculated during sexual activity.

Correct Answer: B

Rationale: Synapse is the correct answer because it is the junction between two neurons where electrical or chemical signals are transmitted. Neurotransmitters are the chemicals that facilitate this transmission, but the gap itself is called the synapse.

Correct Answer: D

Rationale: Positive Rinner & Weber test is the correct answer because these tests are used to assess hearing and are not related to cerebellar function. The cerebellum is involved in coordination and balance, so tests like Romberg's, finger-to-nose, and heel-to-knee are used to evaluate cerebellar integrity, while Rinner and Weber tests are auditory assessments.