Precentral Sulcus:

1.      Patterns (Figure-1, 2)

The Precentral sulcus (green line) marks the boundary between the Precentral gyrus and the three frontal gyri. It lies rostral and roughly parallel to the central sulcus. Typically, it is divided into two segments: the Superior and Inferior Precentral sulci. (incidence rate right-48% left-64%)(Ono90-43A).

 

Figure-1

From the section image (Figure-2) we can easily see the Inferior and Superior Precentral sulcus.

 

Figure-2

2. Pattern of the Superior Precentral sulcus and its superior end (Figure-3, 4)

The pattern of the Superior Precentral sulcus here is the T-shaped side connection with the Superior Frontal sulcus  (Incidence rates: right-20% left-32%)(Ono90-46C) without extension to the medial surface.

 

Figure-3

 

Figure-4

3. Pattern of the Inferior Precentral sulcus and its inferior end (Figure-5, 6)

The pattern of the Inferior Precentral sulcus (green line) has the Bayonet form in this case (Incidence rates: right-28% left-20%)(Ono90-47C). The inferior end of the Inferior Precentral sulcus extends into the Sylvian fissure (Incidence rates: right-28%, left-20%)(Ono90-47AC) with a straight end (Incidence rates: right-72% left-84%)(Ono90-47BC), which is the most common situation.

 

Figure-5

Figure-6

4. Side branches (Figure-7, 8)

We can see there are 3 side branches crossing the Precentral gyrus and 3 side branches crossing to the Frontal gyri.

 

Figure-7

 

Figure-8

5. Connections (Figure-9-11)

The main branch of the Precentral sulcus directly connects with the Superior and Inferior Frontal sulci (Ono90-48BD).

 

Figure-9

 

5.1 Connections with the Superior Frontal sulcus

The red circle represents the common point and also corresponds to the intersection of the two dashed lines on the image at the right. (Incidence rates: right-92% left-100%)(Ono90-47B)

 

Figure-10

5.2 Connection with the Inferior Frontal sulcus

The red circle represents the junction point and also corresponds to the intersection of the two dashed lines on the image at the right (Incidence rates: right-92% left-88%)(Ono90-47D).

 

Figure-11

 

Click here for another example of Precentral sulcus