Anatomical variants of the rectus femoris motor innervation

Prevention of motor ascending branch of the rectus femoris injuries in Bernese periacetabular osteotomy: a cadaveric study

The Bernese periacetabular osteotomy (PAO) is a surgical procedure used to treat hip dysplasia in young adults, but it carries the risk of neurological complications, including injury to the motor ascending branch of the rectus femoris (MABRF). This study aimed to describe anatomical considerations to prevent MABRF injuries during PAO. A cadaveric study was conducted on seven specimens. The original and modified PAO approaches were used, with and without disinsertion of the rectus femoris muscle origin. The femoral nerve was dissected in all specimens from the endopelvic position to the MABRF origin (T-point). The average distance from the anterosuperior iliac spine to the T-point was 10.2 ± 0.4 cm. To protect the MABRF, a safety zone was identified for the osteotome placement during the ischial cut. The osteotome was slid over the joint capsule, deflecting the iliocapsularis muscle medially and distally. This manoeuvre shields the MABRF with the iliocapsularis muscle, reducing the risk of neurological injury. Both the original and modified PAO approaches were considered safe techniques with low risk to the rectus femoris innervation. These findings offer valuable insights for surgeons performing PAO, emphasizing the significance of understanding anatomical relationships and implementing protective measures to enhance patient outcomes and minimize complications. In conclusion, implementing these anatomical considerations can help prevent MABRF injuries during PAO, contributing to safer and more successful surgical interventions for hip dysplasia in young adults.

Anatomical landmarks for ultrasound-guided rectus femoris diagnostic nerve block in post-stroke spasticity

Introduction/Purpose

To determine the location of the rectus femoris (RF) motor branch nerve, as well as its coordinates with reference to anatomical and ultrasound landmarks.

Methods

Thirty chronic stroke patients with stiff knee gait (SKG) and RF hyperactivity were included. The motor nerve branch to the RF muscle was identified medially to the vertical line from anterior superior iliac spine and the midpoint of the superior margin of the patella (line AP) and vertically to the horizontal line from the femoral pulse and its intersection point with the line AP (line F). The point of the motor branch (M) was located with ultrasound, and nerve depth and subcutaneous tissue thickness (ST) were calculated.

Results

The coordinates of the motor branch to the RF were 2.82 (0.47) cm medially to the line AP and 4.61 (0.83) cm vertically to the line F. Nerve depth and subcutaneous tissue thickness were 2.71 (0.62) cm and 1.12 (0.75) cm, respectively.

Conclusion

The use of specific coordinates may increase clinicians' confidence when performing RF motor nerve block. This could lead to better decision-making when assessing SKG in chronic stroke patients.