A 35 year old female patient presents to the orthopaedic clinic with complaints of pain and stiffness in her right thumb. On examination, the clinician assesses the patient's awareness of joint position using the right thumb.

Which of the following anatomical structures receives proprioceptive information from the right thumb?

Options:
explanation: This is the correct answer. An assessment of joint position tests proprioception, transmitted in the dorsal column pathway. Signals from peripheral sensory receptors in the upper limbs (T6 and above), including from the thumb travel to the fasciculus cuneatus in the medulla, where the first-order and second-order neurons synapse. Eventually, the second-order neurons synapse at the thalamus and proprioception signals are transmitted to the post-central gyrus.
name: Fasciculus cuneatus
label: a
answer: yes
explanation: An assessment of joint position tests proprioception, transmitted in the dorsal column pathway. The spinal lemniscus transmits signals in the spinothalamic pathway to the thalamus. In the dorsal column pathway, proprioceptive signals from the upper limbs (T6 and above), including from the thumb travel to the fasciculus cuneatus in the medulla, where the first-order and second-order neurons synapse. Eventually, the second-order neurons synapse at the thalamus and proprioception signals are transmitted to the post-central gyrus.
name: Spinal lemniscus
label: d
answer: no
explanation: An assessment of joint position tests proprioception, transmitted in the dorsal column pathway. The nucleus proprius is where the first-order and second-order neurons synapse in the spinothalamic pathway. In the dorsal column pathway, proprioceptive signals from the upper limbs (T6 and above), including from the thumb travel to the fasciculus cuneatus in the medulla, where the first-order and second-order neurons synapse. Eventually, the second-order neurons synapse at the thalamus and proprioception signals are transmitted to the post-central gyrus.
name: Nucleus proprius
label: c
answer: no
explanation: An assessment of joint position tests proprioception, transmitted in the dorsal column pathway. The arcuate fasciculus is a white matter bundle that connects the temporal and inferior parietal lobe to locations in the frontal lobe. One of the key roles is connecting Broca's and Wernicke's areas involved in the comprehension of language and production of speech. It is not related to the dorsal column pathway. In the dorsal column pathway, proprioceptive signals from the upper limbs (T6 and above), including from the thumb travel to the fasciculus cuneatus in the medulla, where the first-order and second-order neurons synapse. Eventually, the second-order neurons synapse at the thalamus and proprioception signals are transmitted to the post-central gyrus.
name: Arcuate fasciculus
label: e
answer: no
explanation: An assessment of joint position tests proprioception, transmitted in the dorsal column pathway. Although fasciculus gracilis is one of the anatomical structures in the dorsal column pathway, it only transmits signals from the lower limbs (below T6). Signals from the upper limbs (T6 and above), including from the thumb travel to the fasciculus cuneatus in the medulla, where the first-order and second-order neurons synapse. Eventually, the second-order neurons synapse at the thalamus and proprioception signals are transmitted to the post-central gyrus.
name: Fasciculus gracilis
label: b
answer: no

Correct answer: a