**2. Lower limb muscles**

#### **2.1 Iliopsoas**

The child should lie supine on the edge of the table. Mark the inguinal ligament, palpate the femoral pulse, and now mark the femoral pulse line at the inguinal ligament. The midpoint of these two (obviously lateral to the femoral pulse) just below the inguinal ligament is the entry point of the needle. Passive extension of the hip on the edge of the table will show the movement of the needle, and adjust the depth accordingly. Prior US evaluation is better. For injection to be a more effective translumbar approach is required, authors do not advocate this injection without image guidance (**Figure 1**).

#### **2.2 Adductor longus (AL)**

The child should be in a supine position with hip and knee flexed. The spastic adductor will stand prominent in most cases in the anteromedial proximal thigh, while doing hip abduction. One can hold the muscle between the nondominant thumb and index finger and insert the needle at about proximal one-fifth to one-fourth of the muscle (**Figures 2a** and **b**).

#### **2.3 Adductor magnus (AM)**

If we want to inject (less practiced). The position will be the same as AL. At about proximal one-third of the medial thigh, just medial to gracilis. (Bony landmark 3–4 inch anteromedial to ischial tuberosity). The US is helpful because the needle may be in the gracilis or a medial hamstring if the needle enters a more anterior or posterior. Sometimes it may be deeper. Needle movement with passive abduction in knee extension/flexion confirms needle entry in gracilis or adductors (**Figure 3**).

#### **Figure 1.**

*Iliopsoas (IP): ASIS: Anterior superior iliac spine, IL- inguinal ligament, FA- line of femoral artery pulsation. Plus sign denotes the injection point.*

(a)

(b)

#### **Figure 2.**

*a. Adductor longus(AL): red line denotes the prominence area of AL. b. Adductor longus(AL): plus denote vertical injection point, while holding the muscle in between fingers.*

#### **Figure 3.**

*Adductor Magnus (AM): in medial thigh inferomedial to AL point, at proximal one-third thigh plus demarcate injection point.*

#### **2.4 Semitendinosus (ST)**

(Authors preferred approach) Patient lying prone with knee slightly flexed (already in most spastic patients) allowing terminal 30–40-degree extension or child lying supine with hip and knee 90-degree flexion. Now, the knee is extended as much as possible to mark and palpate the muscle. Now palpate the muscle at the junction of *Anatomical Surface Guided Techniques for Botulinum Toxin Injection in Spastic Cerebral… DOI: http://dx.doi.org/10.5772/intechopen.107200*

the proximal one-third distal and half of the thigh. It lies on the line joining from ischial tuberosity to medial post knee crease (tendon of semimembranosus) can be appreciated here. Here, we find the maximum bulk. Here, another point of injection 2–4 cm proximal to the previous injection point may be taken.

#### **2.5 Semimembranous (SM)**

Position and line same as semitendinosus. At the junction of proximal two-thirds and distal one-third, ST will be standing out prominently. Just medial to the prominent ST tendon. The injection is given. Passive extension of the hip in both positions helps in appreciating the good needle movement, thus confirming the muscle.

#### **2.6 Biceps femoris (BF)**

Same position as ST/SM. But the line changed. Draw a line between ischial tuberosity to lateral post knee crease (BF tendon is palpable). The midpoint of this line will be the target of needle entry. Palpate the muscle here by passive extension flexion of the knee. If one is confident, enter at the above-described midpoint for an injection. Caution should be taken for entry either medial or lateral to the tendon, the muscle may be deeper or even it may be congenitally absent. The needle movement must be appreciated. The US helps locate in case of difficulty (common with beginners) (**Figure 4**).

### **2.7 Rectus femoris (RF)**

Make the child supine and draw a vertical line from the ant superior iliac spine to the center of the patella. The injection point is in the middle of it. It lies most superficial, just have to pass skin and subcutaneous tissue. So, adjust the depth accordingly. More deep needle insertion will go in vastus intermedius (**Figure 5**).

#### **2.8 Gastrocnemius (GN)**

The child should lie prone. Transverse mark the area/point where maximum calf bulk is there. Mark a vertical midline to differentiate the medial and lateral head. Now mark the lateral line corresponding fibular head and the medial line on the most anteromedial border of the tibia. The midpoint of the medial line and midline is the entry point of the medial gastrocnemius and the midpoint of the lateral line and the

#### **Figure 4.**

*Hamstring muscles: SM- semimembranosus, ST- semitendinosus, BF- biceps femoris. L1- line one joining ischial tuberosity to medial posterior knee crease. L2- line two joining ischial tuberosity to lateral posterior knee crease. Plus denotes the points of injection of mentioned muscle.*

**Figure 5.**

*Rectus femoris(RF): plus mark denotes injection point, which is middle of the line, joining ASIS and patella center.*

#### **Figure 6.**

*Gastrocnemius(GN): line marked at the area of maximum calf bulk. Plus denotes the entry of the needle for MG (medial head gastrocnemius) & LG (lateral head gastrocnemius).*

midline is the entry point of the lateral gastrocnemius. It is a very superficial muscle (needle vertical entry depth is only 0.5–0.8 cm in most children). Passive dorsiflexion beautifully elicits needle movement in both heads (**Figure 6**).
