human anatomy

piriformis

A small muscle located in the gluteal region, the piriformis originates from the sacrum and inserts into the greater trochanter of the femur. It is involved in the external rotation and abduction of the hip. innervated by branches of anterior rami of s1 & s2

gluteus maximus

The largest and most superficial muscle in the gluteal region. It originates from the posterior ilium, sacrum, coccyx, and sacrotuberous ligament, and inserts into the iliotibial tract and gluteal tuberosity of the femur. Its primary functions are powerful hip extension and lateral rotation. Innervated by the inferior gluteal nerve (L5, S1, S2).

gluteus medius

A broad, thick muscle located on the outer surface of the pelvis. It originates from the gluteal surface of the ilium between the anterior and posterior gluteal lines, and inserts into the lateral surface of the greater trochanter of the femur. Its primary actions are hip abduction, medial rotation of the thigh (anterior fibers), and stabilization of the pelvis during single-leg stance. Innervated by the superior gluteal nerve (L4, L5, S1).

gluteus minimus

The smallest and deepest of the three gluteal muscles, located directly deep to the gluteus medius. It originates from the gluteal surface of the ilium between the anterior and inferior gluteal lines, and inserts into the anterolateral aspect of the greater trochanter of the femur. Its primary actions are hip abduction, medial rotation of the thigh, and pelvic stabilization during single-leg stance. Innervated by the superior gluteal nerve (L4, L5, S1).

tensor fascia latae

A muscle located on the anterolateral aspect of the hip and thigh. It originates from the anterior superior iliac spine (ASIS) and the anterior outer lip of the iliac crest, and inserts into the iliotibial tract, which attaches to Gerdy's tubercle on the lateral condyle of the tibia. Its primary actions are hip abduction, medial rotation, flexion of the thigh, and tensioning the iliotibial tract to stabilize the knee and pelvis. Innervated by the superior gluteal nerve (L4, L5, S1).

rectus femoris

A prominent muscle located in the anterior compartment of the thigh, forming part of the quadriceps femoris group. It originates via two heads: the straight head from the anterior inferior iliac spine (AIIS) and the reflected head from the ilium superior to the acetabulum. It inserts into the base of the patella and the patellar ligament to the tibial tuberosity extends knee joint and stabilizes hip joint, innervated by femoral nerve L2,L3,L4

vastus lateralis

origin: greater trochanter & lateral lip of linea aspera

insertion: base of the patella and the patellar ligament to the tibial tuberosity and also attach to tibia & patella via aponeurosis

innervation: femoral nerve l2,l3,l4

action: extends knee joint and helps iliopsoas flex hip joint

vastus meduialis

origin: intertrochanteric line & medial lip of linea aspera

insertion: base of the patella and the patellar ligament to the tibial tuberosity and also attach to tibia & patella via aponeurosis

innervation: femoral nerve l2,l3,l4

action: extend knee joint and helps iliopsoas flex hip joint

vastus intermedius

origin: anterior& lateral surfaces of shaft of femur

insertion:base of the patella and the patellar ligament to the tibial tuberosity

innervation: femoral nerve l2,l3,l4

adductor longus

origin: body of pubis inferior to pubic crest

insertion: middle third of linea aspera of femur

innervation: obturator nerve l2,l3,l4

action: adducts hip joint

adductor brevis

origin: body & inferior ramus of pubis

insertion: pectineal line & proximal part of linea aspera of femur

innervation: obturator nerve l2,l3,l4

action: adducts to hip joint and to some extent flexes it

adductor magnus

origin: adductor part: inferior ramus of pubis, ramus of ischium

hamstring part: ischial tuberosity

insertion: adductor part: gluteal tuberosity, linea apsera, medial supracondylar line

hamstring part: adductor tubericle of femur

innervation: adductor part: obturator nerve l2,l3,l4

hamstring part: tibia part of sciatic nerve l4

action: adducts hip joint: its adductor part also flexes hip joint and its hamstring part extends it

gracialis

origin: body and inferior ramus of pubis

insertion: superior part of medial surface of tibia

innervation: obturator nerve l2,l3

action: adducts hip joint: flexes knee joint, medially rotating when flexed

sartorius

origin: anterior superior iliac spine & superior part of notch superior to it

insertion: superior part of medial surface of tibia

innervation: femoral nerve l2,l3

action: flexes, abducts & laterally rotates hip joint & flexes knee joint

semitendinous

origin: ischial tuberosity

insertion: superior part of medial surface of tibia

innervation: tibial division of sciatic l5,s1,s2

action: extend hip joint: flex knee joint & medially rotates it when flexed: when hip and knee joints are flexed this muscles can extend trunk at hip joint

semimembranosus

origin: ischial tuberosity

insertion: posterior part of medial condyle of tibia: reflected attachment forms oblique popiteal ligament

innervation: tibial division of sciatic l5,s1,s2

tibial division of sciatic l5,s1,s2

action: extend hip joint: flex knee joint & medially rotates it when flexed: when hip and knee joints are flexed this muscles can extend trunk at hip joint

biceps femoris

origin: long head: ischioal tuberosity

short head: linea aspera & lateral supracondylar line of femur

insertion: lateral side of head of fibia: tendon is split at this site by fibular collateral ligament of knee

innervation: long head: tibial division of sciatic nerve l5,s1,s2

short head: common fibular division of sciatic nerve l5,s1,s2

action: flexes knee joint& laterally rotates it when flexed: long head extends hip joint