Hip External Rotation 20th Lecture PDF

# 20th Lecture, Theoretical Part: Hip External Rotation ## Objectives At the end of this lecture the student will be able to: 1. Identify the primary muscles involved in hip external rotation. 2. Identify the range of motion of hip external rotation. 3. Describe the effect of weakness of hip ex...

# 20th Lecture, Theoretical Part: Hip External Rotation ## Objectives At the end of this lecture the student will be able to: 1. Identify the primary muscles involved in hip external rotation. 2. Identify the range of motion of hip external rotation. 3. Describe the effect of weakness of hip external rotation. 4. Describe the effect of contracture of hip external rotation. ## Content 1. Primary muscles involved in hip external rotation. 2. Range of motion of hip external rotation. 3. Effect of weakness of hip external rotation. 4. Effect of contracture of hip external rotation. ## Hip External Rotation ### Primary Muscles: 1. Piriformis. 2. Quadratus femoris. 3. Obturator internus. 4. Obturator externus. 5. Gemellus superior. 6. Gemellus inferior. ### Range of Motion: - With the knee in flexion the hip lateral rotation is of 45° of motion. - With the knee in extension the range of motion will have a tendency to be of less amplitude. ### Factors Limiting Motion: - Tension of the medial band of iliofemoral ligaments - Tension of hip medial rotator muscles. ## Anatomy of Piriformis Muscle ### Origin: It arises from the anterior surface of the sacrum, between the sacral foramina. ### Insertion: It inserts onto the apex of the greater trochanter (Fig. 1) ### Nerve Supply: Sacral plexus. ### Action: External rotation of the hip joint, in addition to abduction of the thigh while in the flexed position. ## Anatomy of Quadratus femoris Muscle: ### Origin: - Lateral border of ischial tuberosity. ### Insertion: Quadrate tubercle of femur and a vertical line below this to the level of lesser trochanter (Fig. 2). ### Nerve Supply: Sacral plexus. ### Action: Laterally rotates and stabilizes hip. ## Anatomy of Obturator Internus Muscle: ### Origin: Inner surface of obturator membrane and rim of pubis and ischium bordering membrane. ### Insertion: Middle part of medial aspect of greater trochanter of femur (Fig. 3). ### Nerve Supply: Sacral plexus. ### Action: Laterally rotates and stabilizes hip. ## Anatomy of Obturator Externus Muscle: ### Origin: Outer surface of obturator membrane, rim of pubis and ischium bordering it. ### Insertion: Trochanteric fossa on medial surface of greater trochanter (Fig. 4). ### Nerve Supply: Obturator nerve. ### Action: Laterally rotates and stabilizes hip. ## Anatomy of Gemellus superior Muscle: ### Origin: Spine of ischium. ### Insertion: Middle part of the medial aspect of greater trochanter of femur (Fig. 5). ### Nerve Supply: Sacral plexus. ### Action: Laterally rotates and stabilizes hip. ## Anatomy of Gemellus Inferior Muscle: ### Origin: Upper border of ischial tuberosity. ### Insertion: Middle part of medial aspect of greater trochanter of femur (Fig. 6). ### Nerve Supply: Sacral plexus. ### Action: Laterally rotates and stabilizes hip. ## Effect of weakness of hip lateral rotators: - Weakness of the lateral rotators of the hip will produce a medial rotation of the femur. - Pronation of the foot. - Knock knee (or valgus) position (Fig. 7). ## Effect of Contracture in the lateral rotators of the hip: - The contracture of the lateral rotators of the hip is usually occurring in an abducted position of the hip. - The range of medial rotation of the hip will be limited and in the standing posture. - A lateral rotation of the femur and out-toeing are observed.