Posterior Thigh

• Origin (long head): Ischial tuberosity
• Origin (short head): Posterior shaft of the femur

Insertion: Head of fibula

Action: Knee flexion, the long head also does hip extension

• *Commonly known as the "hamstrings"*
• *Most effective exercise is prone hamstring curls*

Origin: Ischial tuberosity

Insertion: Medial tibial plateau (on anterior side)

Action: Knee flexion

*Exercises: Squats (work hamstrings eccentrically on the way down and concentrically on the way up)*

Origin: Lateral femoral condyle

Insertion: Posterior surface of tibia

Action: Unlocks "screw-home" mechanism of the knee (when the medial femoral condyle continues to roll forward and slide posteriorly because the medial femoral condyle is wider and longer than the lateral femoral condyle)

• *Laterally rotates the femur on the tibia
• *Pulls the lateral meniscus away from the rotating lateral femoral condyle
• *Once the femur is laterally rotated, the knee is said to be "unlocked" and knee flexion can proceed

• Locking of the knee
• Occurs at the end of the range of motion (ROM) of knee extension (femoral condyles roll and glide on the surface of the tibial condyles)
• "Unlocking" the knee - Reduce tension within the major ligaments of the knee

Origin: Pubis

Insertion: Medial 1/3 of the femur

Action: Hip AD-duction

*Synergist of hip flexion*

Origin: Pubis

Insertion: Medial femoral shaft, AD-ductor tubercle

Action: Hip AD-duction

*Features the adductor hiatus that allows blood supply*

Origin: Pubis

Insertion: Medial proximal shaft of femur

Action: Hip AD-duction

Origin: Pubis

Insertion: Lesser trochanter of the femur (interior)

Action: Hip AD-duction

*Rectangular in shape and most superior of the posterior thigh muscles*

Origin: Pubis

Insertion: Medial tibial plateau

Action: Hip AD-duction, Internal hip rotation (because of angle of pull)

*One of the 3 muscles that insert into the PES ANSERINE*

• 1. Sartorius
• 2. Gracillis
• 3. Semitendinosis

• Articulation of the femoral head and acetabulum in a ball-and-socket joint
• Surrounded by the acetabular labrum (fibrocartilage that adds a little thickness) to deep socket and features the fovea capitis (a small indention where the ligament of the head inserts)

• Iliofemoral ligament
• Ischiofemoral ligament
• Pubofemoral ligament
• Ligament of the head

Origin: Anterior Inferior Iliac Spine (AIIS)

Insertion: Anterior intertrochanteric line

Action: Resists hip hyperextension (because its located on the anterior aspect)

*Known as the "Y" ligament*

Origin: Ischial spine

Insertion: Greater trochanter of the femur

Action: Resists hip hyperflexion (because its on the posterior aspect)

Origin: Pubis ramus

Insertion: Intertrochanteric line and lesser trochanter of the femur

Action: Resists hyper AB-duction

*People who do side splits have loose pubofemoral ligaments*

Origin: Posterior/superior rim of acetabulum

Insertion: Inside in the fovea capitis of the femur

Action: Holds femoral head in acetabulum

Origin: Anterior bodies of T12 - L5 and iliac fossa

Insertion: Lesser trochanter of the femur

Action: Hip flexion

*Always contracted to maintain center of gravity which is located posterior to the hip joint*

Origin: Anterior Superior Iliac Spine (ASIS)

Insertion: Iliotibial band

Action: Hip flexion, hip AB-duction, and hip internal rotation

• *Originates on the anterior aspect while inserting more on the posterior aspect*
• *Contains a lot of vascular supply and innervation that makes it painful to stretch out and loosen up*
• *Gets very tight in sprinters*

Origin: Iliac crest (on posterior/superior aspect) and sacrum

Insertion: IT band and gluteal tuberosity

Action: Hip extension and hip external rotation

Origin: Ilium

Insertion: Greater trochanter of the femur

Action: Hip AB-duction and hip external rotation (due to its posterior position)

• *Becomes VERY weak after any lower extremity injury like knee, ankle, etc.*
• *Exercises: Lateral squats or lunges, lateral slides

Origin: Ilium

Insertion: Greater trochanter of the femur

Action: Hip AB-duction and hip external rotation

*Lies deep to the gluteus medius*

Hip and thigh muscles