Paracentral Lobule

Paracentral Lobule Structure

Question 1. Define the paracentral lobule and mention its functions.

Answer. The paracentral lobule is the area on the medial surface of the cerebral hemisphere around the central sulcus. It is bounded above by the superomedial border of the cerebral hemisphere, below by the cingulate sulcus, posteriorly by the upturned posterior end of the cingulate sulcus, and anteriorly by the upturned ramus of the cingulate sulcus.

Paracentral Lobule Functions

• It acts as a cortical centre for micturition and defecation.
• It is responsible for the movements of the contralateral foot.

Paracentral lobule

Question 2. Write a short note on the Motor Speech Area.

Answer:

Motor Speech Area Location The motor speech area (Brodmann areas 45 and 44) is located in the pars triangularis (area 45) and pars posterior (area 44) in the inferior frontal gyrus of the frontal lobe in the dominant hemisphere.

Motor Speech Area Function The motor speech area is essential for the production of expressive speech.

Motor Speech Area Applied Anatomy. If the motor speech area is damaged, the individual will suffer from motor aphasia. In this condition, there is the inability to articulate properly, though there is no paralysis of the muscles of the lips, tongue, palate, and vocal cords.

The speech of a person becomes nonfluent, dysarthric, telegraphic, and incomprehensible.

Motor area for the lower limb

Question 3. Write a short note on the Primary Sensory Area.

Answer.

Primary Sensory Area Location The primary sensory area (Brodmann areas 3, 1, and 2) is located in the postcentral gyrus and posterior wall of the central sulcus.

Primary Sensory Area Representation of Body The body is represented upside down in the primary sensory area, similar to that in the primary motor area.

Primary Sensory Area Functions The primary sensory area is concerned with the perception of exteroceptive (pain, light touch, and temperature) and proprioceptive (muscle and joint sense) sensations from the opposite half of the body.

Medial surface of the cerebral hemisphere

Primary Sensory Area Applied Anatomy The lesions of the primary sensory area lead to a loss of appreciation of exteroceptive and proprioceptive sensations in the opposite half of the body.