MRI Anatomy Flashcards · MSK

Hips Anatomy

Learn to identify every labeled structure on a Hips MRI, plane by plane.

Studying as a guest, so progress saves on this device only.

Hips anatomy, structure by structure

Hip MRI is built on a small set of bony, cartilaginous, and soft-tissue landmarks, and reading it confidently starts with knowing the normal anatomy cold. This reference walks through every structure in our hip flashcard deck across the two standard planes (coronal and axial), with a plain-language definition, how each structure looks on MRI, and the pathology you will actually run into at the scanner.

Bones

The pelvic and femoral bones that frame the hip joint. Cortical bone is dark on every sequence; the marrow inside is bright on T1 from fat, so compare it side to side for asymmetry.

Ilium

The largest, fan-shaped part of the pelvic bone, forming the upper wing of the hip and the superior portion of the acetabulum.

On MRI: Forms the broad superior bone on coronal images, sloping down toward the acetabular roof. The cortex is dark; the wide marrow space is bright on T1 and darkens on fat-suppressed sequences.

Common pathology: Sacroiliac joint inflammation in the adjacent iliac marrow (sacroiliitis), marrow edema, and metastatic or marrow-replacing disease are commonly seen here.

Acetabulum

The cup-shaped socket of the pelvis, formed by the ilium, ischium, and pubis, that receives the femoral head to make the hip joint.

On MRI: A curved bony cup cradling the femoral head, best appreciated on coronal for the roof and on axial for the anterior and posterior walls. Cortex is dark; the lining articular cartilage is intermediate to bright on fluid-sensitive sequences.

Common pathology: Acetabular cartilage loss in osteoarthritis, dysplasia with a shallow socket, and fractures of the anterior or posterior wall after trauma.

Pubis

The anterior part of the pelvic bone; the two pubic bones meet in the midline at the pubic symphysis and contribute to the front of the acetabulum.

On MRI: Seen anteriorly and medially, meeting its counterpart at the midline symphysis on coronal and axial slices. Cortex is dark with bright fatty marrow on T1.

Common pathology: Osteitis pubis and symphyseal marrow edema (common in athletes), pubic ramus insufficiency fractures, and athletic pubalgia.

Ischium

The posterior and inferior part of the pelvic bone; its ischial tuberosity is the bony seat that anchors the hamstring tendons.

On MRI: A posterior bony prominence on axial images; the ischial tuberosity is the rounded posterior corner where the proximal hamstring origin attaches. Cortex is dark with bright fatty marrow.

Common pathology: Proximal hamstring avulsion at the tuberosity, ischial marrow edema, apophyseal injury in adolescents, and ischiogluteal bursitis.

Femur

The thigh bone; its proximal end (head, neck, and trochanters) forms the lower half of the hip joint.

On MRI: The long bone descending laterally and inferiorly on coronal images. Cortex is dark; the proximal shaft marrow is bright on T1 and suppresses on fat-saturated sequences.

Common pathology: Proximal femoral fractures, stress fractures, marrow edema, and metastatic involvement of the proximal shaft.

Femoral Head

The rounded, ball-shaped top of the femur that sits inside the acetabular socket to form the ball-and-socket hip joint.

On MRI: A smooth, near-spherical bone centered in the acetabulum on both planes, capped by intermediate-signal articular cartilage. Normal marrow is uniformly bright on T1.

Common pathology: Avascular necrosis is the classic finding here (early marrow signal change, later the subchondral double-line sign and collapse); also subchondral fractures and osteoarthritis.

Tip: On coronal, find the ball seated in the cup: the round bone in the socket is the femoral head, and the narrower bone below it is the neck.

Femoral Neck

The narrowed segment of bone connecting the femoral head to the shaft and trochanters of the femur.

On MRI: The tapered bridge between the femoral head and the trochanters, angled superomedially on coronal. Cortex is dark with bright marrow that should match the head and shaft.

Common pathology: Femoral neck fractures (including occult and stress fractures shown as a marrow edema line), and the bony bump of cam-type femoroacetabular impingement.

Greater Trochanter

The large bony prominence on the outer, upper femur that serves as the attachment site for the gluteal and short rotator muscles.

On MRI: A lateral bony bump off the proximal femur, best seen laterally on coronal and posterolaterally on axial. Cortex is dark; the overlying tendons attach along its facets.

Common pathology: Greater trochanteric pain syndrome, gluteus medius and minimus tendinopathy or tears at their insertions, and trochanteric bursitis with bright fluid on T2.

Labrum

The acetabular labrum is a ring of fibrocartilage around the rim of the socket that deepens the joint and seals it. Normal labrum is uniformly dark (low signal) on all sequences.

Superior Acetabular Labrum

The upper portion of the fibrocartilage rim around the acetabulum, sitting at the weight-bearing roof of the socket.

On MRI: A small dark triangle at the superolateral acetabular rim on coronal, hugging the bony edge above the femoral head.

Common pathology: Labral tears at the superior or anterosuperior rim are a frequent cause of hip pain and clicking; bright fluid or contrast tracking into the labral base indicates a tear, best shown on MR arthrography.

Tip: Look for the dark triangle perched on the bony rim just lateral to the femoral head; that is the labrum.

Anterior Acetabular Labrum

The front portion of the fibrocartilage rim around the acetabulum.

On MRI: A dark wedge along the anterior acetabular rim on axial images, in front of the femoral head.

Common pathology: The anterior and anterosuperior labrum is the most common location for tears, especially with femoroacetabular impingement; MR arthrography improves detection.

Posterior Acetabular Labrum

The back portion of the fibrocartilage rim around the acetabulum.

On MRI: A dark wedge along the posterior acetabular rim on axial, behind the femoral head, typically slightly broader than the anterior labrum.

Common pathology: Posterior labral tears are less common and are associated with posterior instability, dysplasia, and posterior wall impingement.

Tendons and soft tissue

The non-osseous structures surrounding the hip, including a major tendon origin and the adjacent pelvic viscera that fall within the field of view.

Proximal Hamstring Tendon

The conjoined tendon origin of the hamstring muscles as they attach to the ischial tuberosity.

On MRI: A dark, well-defined tendon arising from the posterior ischial tuberosity on axial images, just behind and medial to the hip joint.

Common pathology: Proximal hamstring tendinopathy, partial tears, and full-thickness avulsion off the ischial tuberosity (often with tendon retraction and surrounding fluid or edema).

Bladder

The urinary bladder, the midline pelvic organ that stores urine, seen on axial pelvic slices anterior and medial to the hip joints.

On MRI: A rounded, midline anterior structure on axial images; urine follows simple fluid signal, dark on T1 and very bright on T2. Its size varies with how full it is.

Common pathology: Mostly an incidental landmark on hip MRI, but wall thickening, diverticula, or masses may be noted; a very full bladder can be a comfort issue during longer exams.

Frequently asked questions

What structures are seen on a hip MRI?

A standard hip MRI shows the bones of the pelvis and proximal femur (ilium, pubis, ischium, acetabulum, and the femoral head, neck, and greater trochanter), the acetabular labrum (superior, anterior, and posterior), the proximal hamstring tendon origin, and adjacent pelvic structures such as the urinary bladder. This page labels each one with its MRI appearance.

Which planes are used for hip MRI anatomy?

Coronal and axial are the workhorse planes for the hip. Coronal best shows the acetabular roof, the superior labrum, and the femoral head and neck for avascular necrosis and fractures; axial best shows the anterior and posterior labrum, the femoral neck version, and the proximal hamstring origin. Many protocols add a sagittal or oblique series as well.

How do you spot the femoral head and acetabular labrum on MRI?

The femoral head is the smooth round ball seated in the cup of the acetabulum, with uniformly bright marrow on T1. The labrum is a small dark triangle of fibrocartilage perched on the bony rim of the socket; it should be uniformly low signal, so any bright fluid or contrast tracking into it suggests a tear.

Why is MR arthrography used for the hip?

MR arthrography injects dilute contrast into the joint to distend the capsule and outline the labrum and cartilage. The bright fluid tracks into labral tears and cartilage defects that are hard to see on a standard non-contrast hip MRI, which is why it is often ordered when labral pathology or femoroacetabular impingement is suspected.

Do I need an account to use these Hips MRI flashcards?

No. The interactive flashcards and this full labeled reference are open to use, with no account required to start. Creating an account lets you save your progress across devices and track which packs you have mastered.

Tesla MR Institute

Training to become an MRI technologist?

These flashcards come from our MRI tech program — learn online and train at a clinical site near you, in 12 to 18 months.

Explore the program