gluteal region, posterior thigh, & hip joint

iliac fossa

the concave surface of the ilium on the inner (medial) side of the pelvis

• origin: iliacus muscle → thigh flexion at hip joint (hip flexion)

iliac crest

the superior border of the ilium ; anatomical landmark to locate the L4 - L5 intervertebral space lumbar punctures & epidural anesthesia

• ligaments: iliolumbar ligament + inguinal ligament

• origins: tensor fasciae latae + latissimus dorsi + quadratus lumborum

• attachments: external oblique + internal oblique + transversus abdominis

pubic tubercle

a bony prominence located on the superior part of the pubic bone

• important attachment point - inguinal ligament

• providing stability to the inguinal canal

posterior superior iliac spine (PSIS)

prominent bony structure on the ilium located at the back (posterior) of the pelvis

• ligaments: sacrotuberous ligament + posterior sacroiliac ligaments

• muscles: gluteus maximus + multifidus muscles + erector spinae

ischial spine

a bony projection on the ischium of the pelvis

• ligaments: sacrospinous ligament

• muscles: superior gemellus muscle + coccygeus muscle + iliococcygeus muscle

• define the boundaries of the pelvic cavity

greater sciatic notch

a large indentation on the posterior border of the ilium

• converted into the — foramen by the sacrospinous ligament & sacrotuberous ligament

greater sciatic foramen

an opening formed by the greater sciatic notch, sacrospinous ligament, & sacrotuberous ligament

• allowing passage of structures between the pelvis & the gluteal region

  • origins: piriformis + superior gemellus

  • vasculature: superior gluteal artery & vein + inferior gluteal artery & vein + internal pudendal artery & vein

  • nerves: superior gluteal nerve + inferior gluteal nerve + sciatic nerve + posterior femoral cutaneous nerve + pudendal nerve + nerve to obturator internus + nerve to quadratus femoris

lesser sciatic notch

a concave indentation on the ischium, located below the ischial spine.

• converted into the — foramen by the sacrotuberous ligament & sacrospinous ligament

lesser sciatic foramen

an opening formed by the lesser sciatic notch, sacrospinous ligament, & sacrotuberous ligament

• allows passage of structures from the gluteal region to the perineum

  • passage for structures

    • musculature: tendon of obturator internus muscle (→ greater trochanter)

    • nerve: pudendal nerve + nerve to obturator internus

    • vasculature: internal pudendal vessels + inferior gluteal artery

ischial tuberosity

“sit bone” - the bony prominence on the ischium

• ligament: sacrotuberous ligament

• origins: biceps femoris (long head) + semitendinosus + semimembranosus + inferior gemellus

• attachments: adductor magnus (parts) + quadratus femoris

posterior inferior iliac spine (PIIS)

prominent bony structure on the ilium located at the back (posterior) of the pelvis

• ligaments: posterior sacroiliac ligament + sacrospinous ligament

• muscles: gluteus maximus + piriformis

anterior superior iliac spine (ASIS)

prominent bony structure on the ilium located at the front (anterior) of the pelvis

• ligaments: inguinal ligament

• origin: sartorius muscle

• attachment: tensor fasciae latae

anterior inferior iliac spine (AIIS)

prominent bony structure on the ilium located at the front (anterior) of the pelvis

• ligaments: iliofemoral ligament

• muscles: rectus femoris (straight head)

ischiopubic ramus

bony structure formed by the fusion of the ischium & pubis

• contributes to the formation of the obturator foramen

obturator foramen

large opening in the pelvis formed by the pubis & ischium

• obturator membrane → obturator canal

  • obturator artery + vein + nerve

sacrum

triangular bone at the base of the spine, formed by the fusion of five sacral vertebrae (S1 - S5)

• connects the pelvis to the vertebral column

• origin: gluteus maximus + piriformis + iliacus + multifidus

• attachment: erector spinae + latissimus dorsi

coccyx

small, triangular bone at the base of the vertebral column, formed by the fusion of four coccygeal vertebrae (Co1 - Co4)

• ligaments: anterior sacrococcygeal ligament + posterior sacrococcygeal ligament + lateral sacrococcygeal ligament + intercornual ligament

• origin: coccygeus + levator ani (iliococcygeus and pubococcygeus)

• attachment: gluteus maximus + sphincter ani externus

femur - head

the rounded proximal end of the femur that articulates with the acetabulum of the pelvis

• forms the hip joint

femur - neck

the region of the femur that connects the femoral head to the femoral shaft

• angled to allow for greater range of motion at the hip joint

greater trochanter

a large, protruding bony prominence located on the lateral aspect of the femur

• insertions: gluteus medius + gluteus minimus + piriformis + obturator internus + gemelli (superior & inferior)

• arteries: primarily from the superior & inferior gluteal arteries

lesser trochanter

a small, conical bony prominence located on the medial aspect of the femur

• insertions: iliopsoas (psoas major & iliacus)

• arteries: primarily from the medial circumflex femoral artery

femur - shaft

the long, cylindrical portion of the femur that extends from the neck to the distal end of the femur

• provides structural support

• serves as an attachment site for various muscles

patellar surface

the smooth area on the distal femur where the patella articulates with the femur allowing for knee joint movement

femur - lateral epicondyle

bony prominence located on the lateral aspect of the distal femur

• origins: gastrocnemius (lateral head) + popliteus

• ligaments: lateral collateral ligament (LCL)

femur - medial epicondyle

bony prominence located on the medial aspect of the distal femur

• insertions: adductor magnus

• ligaments: medial collateral ligament (MCL)

femur - medial condyle

rounded prominence located on the medial aspect of the distal femur that articulates with the tibia via the medial meniscus forming the medial femorotibial joint

• origins: gastrocnemius (medial head)

• insertions: adductor magnus

• ligaments: medial collateral ligament (MCL) + posterior cruciate ligament (PCL)

femur - lateral condyle

rounded prominence located on the lateral aspect of the distal femur that articulates with the tibia via the lateral meniscus forming the lateral femorotibial joint

• origins: gastrocnemius (lateral head) + popliteus

• ligaments: lateral collateral ligament (LCL) + anterior cruciate ligaments (ACL)

adductor tubercle

small bony prominence located on the superior aspect of the medial epicondyle of the femur

• insertions: adductor magnus

• vasculature: primarily from the medial superior genicular artery & vein

• nerves: saphenous nerve (sensory) + obturator nerve

gluteal tuberosity

roughened area on the posterior aspect of the femur

• insertions: gluteus maximus

• vasculature: primarily from the superior and inferior gluteal arteries & veins

• nerves: inferior gluteal nerve

pectineal line

a ridge on the posterior aspect of the femur

• insertions: pectineus

• vasculature: primarily from the medial circumflex femoral artery & vein

• nerves: femoral nerve

linea aspera

prominent ridge on the posterior surface of the femur

• insertions: adductor longus + adductor brevis + adductor magnus

  origins: vastus medialis + vastus lateralis + biceps femoris (short head)

• vasculature: primarily from the profunda femoris artery & vein + perforating arteries & veins

• nerves: femoral nerve (anterior compartment) + obturator nerve (medial compartment) + sciatic nerve (posterior compartment)

popliteal surface

flat region on the posterior aspect of the femur located above the knee joint

• provides space for the popliteal vessels & nerves

hip joint movements

flexion, extension, abduction, adduction, lateral (external) rotation, medial (internal) rotation, circumduction

posterior sacroiliac ligament

ligament connecting the sacrum to the ilium on posterior surface providing stability to the sacroiliac joint

sacrotuberous ligament

ligament extending from the sacrum to the ischial tuberosity providing stability to the pelvis & sacroiliac joint

sacrospinous ligament

ligament extending from the sacrum to the ischial spine helping to stabilize the pelvis & sacroiliac joint

inguinal ligament

a band of connective tissue that runs from the anterior superior iliac spine to the pubic tubercle

• forms the base of the inguinal canal

acetabular labrum

a rim of fibrocartilage attached to the margin of the acetabulum

• deepens the socket for a better fit with the femur head

transverse acetabular ligament

crosses over the acetabular notch creating an encircled formation with the lunate surface of the acetabulum for a better fit with the head of the femur

capsular ligaments

thicken parts of the joint capsule of the hip that wind around & move femoral head tightly into acetabulum

• iliofemoral ligament

• pubofemoral ligament

• ischiofemoral ligament

iliofemoral ligament

connects the ilium with the femur that is located anteriorly & superiorly

• prevents hyperextension of the hip joint during standing

pubofemoral ligament

connects the pubic bone part of the acetabulum to the neck of the femur that is located anteriorly & inferiorly

• prevents over-abduction of the hip joint

ischiofemoral ligament

connects the ischial part of the acetabulum to the neck of the femur & is located posteriorly

• stabilizes hip joint posteriorly

• limits hyperextension

ligament of head of femur

ligamentum teres femoris / round ligament of the femur - functions to conduct the artery to the head of the femur (branch of the obturator artery)

medial circumflex femoral artery

main blood supply to the hip joint head of the femur

• branch of the profunda femoris artery (deep artery of the thigh)

lateral circumflex femoral artery

blood supply to the greater trochanter & the lateral aspect of the thigh

• a branch of the profunda femoris artery (deep artery of the thigh)

• contributes to the anastomosis around the hip joint

• ascending, transverse, & descending branches

trochanteric anastomosis

formed between the ascending branch of the medial & lateral circumflex femoral artery + descending branches of the superior gluteal arteries

• inferior gluteal arteries usually also joins

• supplies: femoral head & neck

femoral neck fracture

a fracture of the neck of the femur

• can be caused by various factors like car accidents, osteoporosis, or falls

• affected limb will be shortened (due to pull of other muscle attachments) & laterally rotated (due to pull of lateral rotator muscles of hip joint)

avascular necrosis of femoral head

results from reduced or stopped blood flow of the medial circumflex femoral artery causing bone tissue of the femur head to die

• common complication in femoral neck fractures in the elderly

hip dysplasia

a congenital (developmental) disorder of the hip joint leading to improper formation & alignment

• femoral head not properly located within acetabulum

• often results in joint instability & arthritis

acquired hip joint dislocation

results from a strong force that pushes the femoral head out of the normal position within acetabulum

• often due to high-impact trauma (e.g. motor vehicle accidents)

• may result in joint capsule / ligaments rupture

posterior hip dislocation

occurs when the femoral head is displaced posteriorly out of the acetabulum

• most common type of dislocation

• affected limb presents as shortened, medially rotated, & adducted

• SCIATIC nerve may be injured

• joint capsule / ligaments rupture

gluteus maximus

action: main muscle for thigh / hip joint EXTENSION (extend thigh at hip joint) + assist in LATERAL rotation of thigh

• stair climbing, rising from seated position, running, walking uphill

nerve: inferior gluteal nerve (L5 - S2)

blood supply: superior & inferior gluteal artery + vein

origin: posterior gluteal line of ilium + posterior sacrum & coccyx + sacrotuberous ligament

insertion: iliotibial tract / band + gluteal tuberosity

gluteus medius

action: main muscle for thigh / hip joint ABduction (ABduct thigh at hip joint) + MEDIAL rotation of thigh

• stabilizes the pelvis (keeps pelvis level) to prevent tilting to opposite side when standing on 1 leg

nerve: superior gluteal nerve (L4 - S1)

blood supply: (deep branch) superior gluteal artery + vein & trochanteric anastomosis (tendon)

origin: posterior & anterior gluteal lines of ilium

insertion: greater trochanter

gluteus minimus

action: thigh / hip joint ABduction (ABduct thigh at hip joint) + MEDIAL rotation of thigh

• stabilizes the pelvis (keeps pelvis level) to prevent tilting to opposite side when standing on 1 leg

nerve: superior gluteal nerve (L4 - S1)

blood supply: (deep branch) superior gluteal artery + vein & trochanteric anastomosis (tendon)

origin: between inferior & anterior gluteal lines of ilium

insertion: greater trochanter

tensor fasciae latae

action: thigh / hip joint ABduction (ABduct thigh at hip joint) + MEDIAL rotation of thigh + FLEXION of thigh at hip joint

nerve: superior gluteal nerve (L4 - S1)

blood supply: ascending branch of lateral circumflex femoral artery & superior gluteal artery + vein

origin: between inferior & anterior gluteal lines of ilium

insertion: iliotibial (IT) tract / band (superficial & deep layers)

iliotibial (IT) tract / band

a thick band of dense connective tissue that extends from the anterior superior iliac spine (ASIS) down to the lateral condyle of the tibia running along the lateral aspect of the thigh

• provides lateral stability to the knee joint during weight-bearing activities + assists in hip movements

• serves as an attachment point for gluteus maximus + tensor fasciae latae

piriformis

action: LATERAL rotation of extended thigh + ABduction of flexed thigh

nerve: nerve to — (S1 - S2)

blood supply: superior & inferior gluteal artery + vein & internal pudendal & lateral sacral

origin: anterior surface of sacrum

• exits pelvis via greater sciatic foramen

insertion: superior part of greater trochanter

• located inferior to the gluteus medius / minimus muscles

superior gemellus

action: LATERAL rotation of extended thigh + ABduction of flexed thigh at hip joint

nerve: nerve to obturator internus (L5 - S2)

blood supply: internal pudendal & inferior gluteal artery + vein

origin: ischial spine

insertion: trochanteric fossa (medial aspect)

obturator internus

action: LATERAL rotation of extended thigh + ABduction of flexed thigh at hip joint

nerve: nerve to — (L5 - S2)

blood supply: internal pudendal & obturator artery + vein

origin: internal surface of obturator membrane & foramen

insertion: trochanteric fossa (medial aspect)

inferior gemellus

action: LATERAL rotation of extended thigh + ABduction of flexed thigh at hip joint

nerve: nerve to quadratus femoris (L5 - S1)

blood supply: medial circumflex femoral artery & inferior gluteal veins

origin: ischial tuberosity

insertion: trochanteric fossa (medial surface)

quadratus femoris

action: LATERAL rotation of extended thigh at hip joint

nerve: nerve to — (L5 - S1)

blood supply: inferior gluteal artery + vein & medial circumflex femoral artery

origin: lateral border of ischial tuberosity

insertion: quadrate tubercle on intertrochanteric crest

posterior [compartment] thigh muscles

“hamstrings” - muscles located at the back of the thigh responsible for extending the thigh at hip joint & flexing the leg at knee joint

• main, powerful KNEE flexors + extensor muscles of hip joint

• important during running & walking

true hamstring muscle

posterior thigh muscles that attaches to the ischial tuberosity & is innervated by the tibial division of the sciatic nerve

• biceps femoris - long head

• semitendinosus

• semimembranosus

biceps femoris - LONG head

true hamstring muscle

action: EXTEND thigh at HIP joint + FLEX leg at KNEE joint + LATERALLY rotate leg (when flexed)

nerve: TIBIAL division of sciatic nerve (L5 - S2)

blood supply: perforating arteries of profunda femoris artery (deep artery of the thigh) + deep veins & medial circumflex femoral artery & inferior gluteal artery

origin: ischial tuberosity

insertion: head of fibula

biceps femoris - SHORT head

action: FLEX leg at KNEE joint + LATERALLY rotate leg (when flexed)

nerve: COMMON FIBULAR division of sciatic nerve (L5 - S2)

blood supply: perforating arteries of profunda femoris artery (deep artery of the thigh) + deep veins

origin: linea aspera & lateral supracondylar line

insertion: head of fibula

semiTENDINOsus

true hamstring muscle

action: EXTEND thigh at HIP joint + FLEX leg at KNEE joint + MEDIALLY rotate leg (when flexed)

nerve: TIBIAL division of sciatic nerve (L5 - S2)

blood supply: perforating arteries of profunda femoris artery (deep artery of the thigh) + deep veins & medial circumflex femoral artery & inferior gluteal artery & inferior medial geniculate artery

origin: ischial tuberosity

insertion: medial surface of tibia

semiMEMBRANOsus

true hamstring muscle

action: EXTEND thigh at HIP joint + FLEX leg at KNEE joint + MEDIALLY rotate leg (when flexed)

nerve: TIBIAL division of sciatic nerve (L5 - S2)

blood supply: perforating arteries of profunda femoris artery (deep artery of the thigh) + deep veins

origin: ischial tuberosity

insertion: medial condyle of tibia (posterior part)

cluneal nerves

group of nerves that provide sensory innervation to the skin over the gluteal region

• posterior rami of L1 - L3 + S1 - S2 & anterior rami of S2 - S3

• superior - posterior iliac crest + upper buttock (upper half of gluteus maximus & medius)

• middle - posteromedial fifth of gluteus maximus

• inferior - inferior half of buttock

posterior femoral cutaneous nerve

a nerve that provides sensory innervation to the skin of the posterior thigh & part of the popliteal fossa

• originates from the sacral plexus (S1-S3)

sciatic nerve (L4 - S3)

the largest nerve in the body that travels through middle of posterior thigh entering lower limb via greater sciatic foramen & inferior to piriformis muscle

• tibial & common fibular divisions

  • divides into tibial nerve & common fibular nerve in popliteal fossa

• motor innervation (divisions) - muscles in posterior thigh, leg, & foot

• sensory innervation (nerve branches) - majority of skin in leg & foot

damage = impaired HIP EXTENSION + KNEE FLEXION

sciatica

a condition characterized by radiating pain along the path of the sciatic nerve

• typically affects the lower back, buttock, & down the leg

• caused by disc protrusion / herniation, external source compressing nerve, or hypertrophy / spasm of piriformis

superior gluteal nerve

provides motor innervation to the gluteus medius, gluteus minimus, & tensor fascia latae muscles for hip/thigh abduction + stabilizing the pelvis

• damage = POSITIVE TRENDELENBURG’S SIGN

Trendelenburg Sign

clinical test for superior gluteal nerve injury / weakness in hip abductor muscles

• patient stands on 1 leg and raise the other leg off the ground

• pelvis tilting or dropping on the unsupported leg side indicates weakness or paralysis of the gluteus medius on weight-bearing (OPPOSITE) side

inferior gluteal nerve

provides motor innervation to the gluteus maximus muscle for hip / thigh extension

• injury / damage

  • difficulty / weakness rising from sitting position &/or climbing stairs

  • significant weakness of hip / thigh EXTENSION

  • weakness in hip / thigh LATERAL rotation

EXIT - GREATER sciatic foramen

• piriformis

• superior gluteal artery / vein / nerve

• inferior gluteal artery / vein / nerve

• nerve to quadratus femoris

• sciatic nerve

• posterior cutaneous nerve of thigh (posterior femoral cutaneous nerve)

EXIT - LESSER sciatic foramen

• tendon of the obturator internus muscle

EXIT - GREATER & ENTER - LESSER sciatic foramen

• pudendal nerve

• internal pudendal artery / vein

• nerve to obturator internus

superior lateral quadrant of gluteal region

the recommended region for administering intramuscular injections in the gluteal area (into gluteus medius) to avoid injury to the sciatic nerve & gluteal neurovasculature