Common Peroneal Nerve Paralysis

• An 18-year-old pizza delivery student experienced paralysis in the anterior and lateral compartments of his left leg after his knee impacted a car bumper.
• The student also had difficulty dorsiflexing his ankle (footdrop) and everting his foot.
• Sensation was diminished on the anterior and lateral leg, foot, and toes, including the medial big toe.
• Radiographs revealed no bone fractures.
• A physician diagnosed common peroneal nerve paralysis due to blunt trauma on the left fibula's lateral side.
• Radiographic examination dismissed a fibula neck fracture.
• Physicians must know the common peroneal nerve's detailed anatomy as it winds around the fibula neck to make such diagnoses.
• Knowledge of nerve branch distribution allows physicians to rule out other nerve injuries.
• Nerve damage severity can be assessed through strength tests of related muscles and sensory deficit assessments.

Lower Limb Overview

• The lower limb's main function is to support body weight and enable stable standing, walking, and running.
• The hip bones articulate with the trunk at the sacroiliac joints and with each other at the symphysis pubis, providing lower limb stability.
• The lower limb is divided into the gluteal region, thigh, knee, leg, ankle, and foot.
• The thigh and leg have compartments with muscles performing group functions and distinct nerve and blood supplies.

Gluteal Region

• The gluteal region (buttock) is bounded by the iliac crest superiorly and the buttock fold inferiorly.
• The region consists of gluteal muscles and a thick superficial fascia layer.

Skin of the Buttock

• Cutaneous nerves are derived from spinal nerve posterior and anterior rami.
• The upper medial quadrant is supplied by posterior rami from the upper three lumbar and sacral nerves.
• The upper lateral quadrant is supplied by lateral branches of the iliohypogastric (L1) and 12th thoracic nerves (anterior rami).
• The lower lateral quadrant is supplied by branches from the lateral cutaneous nerve of the thigh (L2 and L3, anterior rami).
• The lower medial quadrant is supplied by branches from the posterior cutaneous nerve of the thigh (S1, 2, and 3, anterior rami).
• The skin over the coccyx is supplied by small lower sacral and coccygeal nerve branches.
• Lymph vessels drain into the lateral group of the superficial inguinal nodes.

Fascia of the Buttock

• Superficial fascia is thick, especially in women, and contains significant fat, contributing to buttock prominence.
• Deep fascia is continuous with the thigh's fascia lata, enclosing the gluteus maximus.
• Above the gluteus maximus, it covers the outer gluteus medius surface and attaches to the iliac crest.
• The iliotibial tract, a thickened band on the thigh's lateral surface, attaches to the iliac crest tubercle and the tibia's lateral condyle.
• The iliotibial tract sheaths the tensor fasciae latae and receives the gluteus maximus insertion.

Bones of the Gluteal Region

• The ilium, ischium, and pubis form the hip bone, meeting at the acetabulum and articulating with the sacrum and each other.
• The iliac crest is palpable along its entire length, leading to the anterior and posterior superior iliac spines.
• The iliac tubercle is approximately 2 inches (5 cm) behind the anterior superior spine.
• Below the anterior and posterior superior iliac spines are the anterior and posterior inferior iliac spines.
• The greater sciatic notch, a large notch in the ilium, is located above and behind the acetabulum.
• The ischium is L-shaped with a body and a ramus, and the ischial spine projects posteriorly between the greater and lesser sciatic notches. -The ischial tuberosity forms the posterior aspect of the ischium's body.
• Ligaments convert the greater and lesser sciatic notches into foramina.
• The pubis consists of a body, superior ramus, and inferior ramus, connecting with the ilium and ischium at the acetabulum.
• The obturator foramen is filled by the obturator membrane in life.
• The pubic crest forms the upper border of the body of the pubis, ending laterally as the pubic tubercle.
• The acetabulum, a deep depression on the hip bone's outer surface, articulates with the femur.
• The acetabular notch marks the deficient inferior margin of the acetabulum and the acetabular fossa is the nonarticular floor.
• The symphysis pubis and anterior superior iliac spines lie in the same vertical plane in anatomical position.

Muscles and Ligaments

• The figure shows the Muscles and Ligaments attached to the external surface of the right hip bone.

Muscle Attachments

• The figure shows the muscles attached to the external surface of the right hip bone and the posterior surface of the femur.

Muscles of the Gluteal Region

• Gluteus maximus is the largest muscle in the body.
• Gluteus medius and minimus primarily abduct the thigh at the hip joint.
• Tensor fasciae latae assists the gluteus maximus in extending the knee joint.
• Piriformis, obturator internus, gemellus superior, gemellus inferior and quadratus femoris are lateral rotators of the thigh at the hip joint.

Nerves of the Gluteal Region

• Sciatic Nerve (L4-S3) is the largest nerve, emerges through the greater sciatic foramen below piriformis.
• Posterior Cutaneous Nerve arises from the sacral plexus and enters through the greater sciatic foramen and supplies the skin over the lower medial quadrant of the buttock.
• Superior Gluteal Nerve arises from the sacral plexus, leaves the pelvis through the greater sciatic foramen above the piriformis.
• Inferior Gluteal Nerve arises from the sacral plexus, exits through the lower part of the greater sciatic foramen below piriformis, supplies the gluteus maximus.

Arteries of the Gluteal Region

• Superior Gluteal Artery a branch of the internal iliac artery that enters the gluteal region through the greater sciatic foramen above the piriformis.
• Inferior Gluteal Artery a branch of the internal iliac artery that enters the gluteal region through the lower part of the greater sciatic foramen.
• Trochanteric Anastomosis provides the main blood supply to the head of the femur.
• Cruciate Anastomosis It provides a connection between the internal iliac and the femoral arteries. </