This lab finishes the appendicular skeleton: the pelvic girdle, every bone of the lower limb, and the knee joint. On models and loose bones you will name bones and markings, tell a right bone from a left one, sex a pelvis, and point to the menisci and ligaments of the knee. Lab Exam 2 follows Labs 4–7.
Your lab manual wins. Lab sections vary in which models, slides, and terms they use. If anything here differs from your lab handout or what your instructor emphasized, go with your lab material and tell your tutor so this review can be updated.
Pelvic Girdle
The pelvic girdle is the two hip bones (also called os coxae or coxal bones). Each starts as three bones — ilium, ischium, and pubis — that fuse by adulthood, and all three meet in the acetabulum, the socket for the femoral head. The hip bones join the sacrum posteriorly at the sacroiliac joints and each other anteriorly at the pubic symphysis. Together with the sacrum and coccyx they form the bony pelvis.
| Part / landmark | Where it is | How to identify it on a model |
|---|---|---|
| Ilium | Superior, wing-shaped part | The big flared blade; forms the upper two-fifths of the acetabulum |
| Iliac crest | Superior border of the ilium | The curved rim you rest your hands on ("hands on hips") |
| ASIS / AIIS | Anterior end of the crest / just below it | Anterior superior iliac spine is the front point of the crest; the anterior inferior spine is the smaller bump below it |
| PSIS / PIIS | Posterior end of the crest / just below it | The posterior pair; the dimples of the lower back sit over the PSIS |
| Greater sciatic notch | Posterior border of the ilium | Deep, wide notch above the ischial spine (the sciatic nerve passes through it) |
| Iliac fossa / auricular surface | Medial (inner) surface of the ilium | Smooth hollow inside the blade; the ear-shaped auricular surface joins the sacrum at the sacroiliac joint |
| Ischium | Posterior-inferior part | The thick lower back part you sit on |
| Ischial spine / lesser sciatic notch | Posterior border, below the greater sciatic notch | Pointed spine, then the smaller, shallower lesser notch below it |
| Ischial tuberosity | Lowest, roughest part of the ischium | Big rough bump — the "sit bone" |
| Ischial ramus | From the tuberosity forward | Thin bar that joins the inferior pubic ramus (together: ischiopubic ramus) |
| Pubis | Anterior-inferior part | Body plus superior and inferior rami; meets the other pubis at the pubic symphysis |
| Acetabulum | Lateral surface, where all three bones meet | Deep cup for the femoral head: smooth horseshoe lunate surface, rough central acetabular fossa, and the acetabular notch opening inferiorly |
| Obturator foramen | Below and anterior to the acetabulum | Largest foramen in the skeleton, framed by the pubis and ischium; mostly closed by a membrane in life |
Spine vs. notch, top to bottom along the back edge: PSIS → PIIS → greater sciatic notch → ischial spine → lesser sciatic notch → ischial tuberosity. Say it out loud while running a finger down the posterior border of a model.
Pelvic Girdle
On the practical you may be handed a pelvis and asked its sex. Start with the subpubic angle (the angle under the pubic symphysis): make an L with your thumb and index finger — if the arch is wider than your L, it is likely female. Then check the inlet shape and overall heaviness. The female pelvis is built wider and shallower for childbirth.
| Feature | Female pelvis | Male pelvis |
|---|---|---|
| Subpubic angle (pubic arch) | Wide, greater than 90° (U-shaped) | Narrow, less than 90° (V-shaped) |
| Pelvic inlet | Wide, oval/round | Narrow, heart-shaped |
| Overall build | Lighter, smoother; ilia flare outward | Heavier, thicker, rougher markings; ilia more upright |
| Ischial spines and tuberosities | Farther apart, turned outward | Closer together, turned inward |
| Sacrum and coccyx | Sacrum shorter, wider, less curved; coccyx more movable | Sacrum longer, narrower, more curved |
| Acetabulum and obturator foramen | Acetabulum smaller; obturator foramen oval/triangular | Acetabulum larger; obturator foramen round/oval |
| Greater sciatic notch | Wide, shallow | Narrow, deep |
True vs. false pelvis: the pelvic brim (from the sacral promontory along the arcuate lines to the top of the pubic symphysis) divides the false (greater) pelvis above, between the iliac blades, from the true (lesser) pelvis below. The opening at the brim is the pelvic inlet; the opening at the bottom, framed by the coccyx, ischial tuberosities, and pubic arch, is the pelvic outlet.
Label It · Hip bone
Click a numbered pin (or its row), choose the structure it points to, then press Check answers. Wrong answers show the correction in green.
Thigh & Leg
The femur is the longest and strongest bone in the body. The patella is a sesamoid bone inside the quadriceps tendon. In the leg, the tibia is the medial, weight-bearing bone; the thin fibula runs along its lateral side, joined to it by the interosseous membrane. Learn which landmarks are anterior and which are posterior — that is how you orient a loose bone.
| Bone | Landmark | Where | How to identify it |
|---|---|---|---|
| Femur | Head and fovea capitis | Proximal, medial | Smooth ball; the small pit (fovea) anchors the ligament of the head of the femur |
| Neck | Below the head | Angled bar joining head to shaft — common fracture site in older adults | |
| Greater / lesser trochanter | Proximal, lateral / posteromedial | Greater = big lateral knob at hip level; lesser = small knob below the neck, posteromedial | |
| Intertrochanteric line / crest | Between the trochanters | Line = faint ridge on the ANTERIOR side; crest = prominent ridge on the POSTERIOR side | |
| Gluteal tuberosity, linea aspera | Posterior shaft | Rough area below the greater trochanter (gluteus maximus); linea aspera = long rough ridge down the back of the shaft | |
| Medial and lateral condyles | Distal, mostly posterior | Two large rounded knuckles that sit on the tibia; the intercondylar fossa lies between them posteriorly | |
| Medial and lateral epicondyles | Distal sides, above the condyles | Bumps for the collateral ligaments of the knee | |
| Patellar surface | Distal, anterior | Smooth groove where the patella glides | |
| Patella | Base, apex, articular facets | In the quadriceps tendon, anterior to the knee | Sesamoid bone: broad base superior, pointed apex inferior; posterior surface has a larger lateral and a smaller medial facet |
| Tibia (medial, weight-bearing) | Medial and lateral condyles; intercondylar eminence | Proximal | Flat "plateau" with a raised ridge (eminence) in the middle where the cruciate ligaments and menisci attach |
| Tibial tuberosity | Proximal, anterior | Rough bump below the knee for the patellar ligament | |
| Anterior border (crest) | Front of the shaft | Sharp shin ridge you can feel under the skin | |
| Soleal line | Posterior, proximal shaft | Oblique rough line running down and medially (soleus muscle) | |
| Medial malleolus; fibular notch | Distal | Inner ankle bump; the fibular notch is on the lateral side of the distal end where the fibula fits | |
| Fibula (lateral, thin) | Head, neck | Proximal | Knob below the lateral tibial condyle — NOT part of the knee joint |
| Lateral malleolus | Distal | Outer ankle bump; sits lower than the medial malleolus |
Label It · Femur
Click a numbered pin (or its row), choose the structure it points to, then press Check answers. Wrong answers show the correction in green.
Label It · Leg
Click a numbered pin (or its row), choose the structure it points to, then press Check answers. Wrong answers show the correction in green.
Foot
The foot has 26 bones: 7 tarsals, 5 metatarsals, and 14 phalanges. Mnemonic for the tarsals from posterior to anterior and medial to lateral: "Tiger Cubs Need MILk" — talus, calcaneus, navicular, medial / intermediate / lateral cuneiforms; the cuboid sits lateral to the cuneiforms, in front of the calcaneus.
| Group | Bones | How to identify them |
|---|---|---|
| Tarsals (7) | Talus, calcaneus, navicular, cuboid, medial, intermediate, and lateral cuneiforms | Talus sits on top (its trochlea forms the ankle joint with the tibia and fibula); calcaneus is the heel, the largest tarsal; navicular is boat-shaped, medial, in front of the talus; cuboid is lateral, in front of the calcaneus; three cuneiforms line up in front of the navicular |
| Metatarsals (5) | I–V, numbered from the big toe (medial) to the little toe | Base proximal, head distal; the first is shortest and thickest; the fifth has a flared tuberosity at its base on the lateral edge |
| Phalanges (14) | Proximal, middle, distal in toes 2–5; hallux has only proximal and distal | Same pattern as the fingers; the big toe (hallux) is like the thumb (pollex) |
Label It · Foot
Click a numbered pin (or its row), choose the structure it points to, then press Check answers. Wrong answers show the correction in green.
Left or Right?
Lab practicals often hand you a loose bone and ask "right or left?" Right and left always mean the specimen's own right and left, not yours. The method is always the same: put the bone in anatomical position (proximal end up, anterior surface facing you), find one feature whose medial/lateral position you know, and read the side.
| Bone | Orient it like this | Then read the side |
|---|---|---|
| Hip bone | Acetabulum facing laterally (toward you), iliac crest up | The pubis and ASIS point anteriorly. If anterior is on your right, it is a right hip bone |
| Femur | Head up, patellar surface (smooth groove) facing you | The head points medially. Head on your left = left femur; head on your right = right femur |
| Patella | Apex down, articular (posterior) surface facing you | The larger lateral facet is the side cue. Larger facet on your right = right patella |
| Tibia | Plateau up, tibial tuberosity facing you | The medial malleolus is medial. Malleolus on your right = right tibia |
| Fibula | Head up; the flat, triangular articular facet on the lateral malleolus faces medially (toward the tibia), and the malleolar fossa (pit) just behind it faces posteriorly | View it from behind (fossa toward you): facet pointing to your left = right fibula; facet pointing to your right = left fibula |
| Foot / tarsals | Toes away from you, dorsal surface up | The big toe and navicular are medial; the cuboid and fifth metatarsal are lateral. Big toe on your left = right foot |
Quick self-check: stand in anatomical position and hold the bone against your own leg on the side you think it came from. If the head of the femur points toward your midline and the patellar surface faces forward, you guessed right.
Knee Joint
The knee is the largest and most complex synovial joint in the body. Functionally it is a hinge joint (some textbooks say "modified hinge"): the main movements are flexion and extension, with slight medial and lateral rotation possible only when the knee is flexed. At full extension the femur rotates slightly medially on the tibia, "locking" the knee so you can stand with little muscle effort; the popliteus muscle "unlocks" it to begin flexion.
| Structure | Where | Job / how to identify |
|---|---|---|
| Articulating bones | Femur, tibia, patella | Three articulations: medial and lateral tibiofemoral (condyles on condyles) and the patellofemoral joint. The fibula is not in the knee joint |
| Medial meniscus | On the medial tibial condyle | C-shaped fibrocartilage pad, wide open; fused to the tibial collateral ligament, so it is torn more often |
| Lateral meniscus | On the lateral tibial condyle | Smaller, nearly circular (O-shaped); not attached to the fibular collateral ligament, so it moves more freely |
| Anterior cruciate ligament (ACL) | Inside the joint capsule (outside the synovial cavity), in the intercondylar fossa | Anterior intercondylar area of the tibia → medial side of the lateral femoral condyle. Stops the tibia sliding forward and limits hyperextension |
| Posterior cruciate ligament (PCL) | Same space, crossing behind the ACL | Posterior intercondylar area of the tibia → lateral side of the medial femoral condyle. Stops the tibia sliding backward |
| Tibial (medial) collateral ligament | Medial side | Broad, flat band from the medial femoral epicondyle to the tibia; resists forces that push the knee inward (valgus) |
| Fibular (lateral) collateral ligament | Lateral side | Round cord from the lateral femoral epicondyle to the head of the fibula; resists forces that push the knee outward (varus) |
| Patellar ligament | Anterior, below the patella | Patella apex → tibial tuberosity; the continuation of the quadriceps tendon (often called the patellar tendon) |
| Bursae | Around the front of the knee | Fluid sacs that reduce friction: suprapatellar (between quadriceps tendon and femur, continuous with the joint cavity), prepatellar (between skin and patella), infrapatellar (deep: between patellar ligament and tibia; subcutaneous: in front of the tibial tuberosity) |
| Fat pads, popliteal ligaments | Infrapatellar fat pad behind the patellar ligament; popliteal ligaments on the back of the capsule | Cushion the joint; the popliteal ligaments reinforce the capsule posteriorly |
Cruciate memory trick: each cruciate is named for where it attaches on the tibia. They cross like an X: the ACL runs to the lateral femoral condyle, the PCL to the medial one. ACL stops the tibia moving Anteriorly; PCL stops it moving Posteriorly.
Clinical link: a hard blow to the lateral side of a planted knee can tear the tibial collateral ligament, the medial meniscus (fused to it), and the ACL together — the "unhappy triad." ACL tears are among the most common sports injuries.
Label It · Knee
Click a numbered pin (or its row), choose the structure it points to, then press Check answers. Wrong answers show the correction in green.
Check Yourself
Rapid Recall
Say the answer out loud, then tap the card to check. Shuffle and go again until every card is automatic.
Practical Simulation
This runs like a real lab practical: one pinned structure, picture, or question per station, a timer, and you type the answer — no word bank. Each attempt draws 22 stations at random from a pool of 81, so run it several times. Spell names fully; common synonyms (ASIS, MCL, LCL, ACL, PCL, patellar tendon) are accepted.
22 stations · 60 seconds each · stations come in random order every attempt.
| # | Station | Your answer | Correct |
|---|
Watch Out
| The mistake | The fix |
|---|---|
| Siding a bone from your own point of view. | Right and left are always the specimen's. Put the bone in anatomical position first, then find a medial feature (femoral head, medial malleolus, big toe). |
| Calling the ischial spine the ischial tuberosity. | Spine = small, pointed, higher, between the two sciatic notches. Tuberosity = big rough "sit bone" at the bottom. |
| Mixing up the greater and lesser sciatic notches. | Greater is the big, deep notch on the ilium above the ischial spine; lesser is the small notch below the spine. |
| Swapping the intertrochanteric line and crest. | Line = anterior and faint; crest = posterior and raised. If the linea aspera is facing you, you are looking at the crest side. |
| Listing the fibula as part of the knee joint. | The knee is femur + tibia + patella. The fibula only anchors the fibular collateral ligament. |
| Reversing the cruciate attachments. | Named by tibial attachment: ACL starts anterior on the tibia and runs to the lateral femoral condyle; PCL starts posterior and runs to the medial condyle. |
| Calling the medial meniscus the lateral one on a superior view of the tibia. | Medial is C-shaped and larger; lateral is nearly a closed O. On a right tibia seen from above with anterior at the top, medial is on your left. |
| Confusing the navicular (foot) with the scaphoid (hand). | Both are boat-shaped, but navicular = foot, between the talus and the cuneiforms. Scaphoid = wrist. |
Cheat Sheet
Print it or screenshot it for a last look before the lab.
| Topic | Know this |
|---|---|
| Hip bone | Ilium + ischium + pubis, fused at the acetabulum; joins sacrum (sacroiliac joint) and other hip bone (pubic symphysis) |
| Ilium landmarks | Iliac crest, ASIS, AIIS, PSIS, PIIS, greater sciatic notch, iliac fossa (medial), auricular surface (medial), gluteal lines |
| Ischium landmarks | Ischial spine, lesser sciatic notch, ischial tuberosity, ischial ramus |
| Pubis landmarks | Body, superior and inferior rami, pubic symphysis; obturator foramen framed by pubis + ischium |
| Acetabulum | Lunate surface (smooth horseshoe), acetabular fossa (center), acetabular notch (inferior) |
| Female vs. male pelvis | Female: subpubic angle over 90°, oval inlet, light build, wide sacrum. Male: under 90°, heart-shaped inlet, heavy |
| Femur | Head, fovea capitis, neck, greater/lesser trochanters, intertrochanteric line (ant) and crest (post), gluteal tuberosity, linea aspera, condyles, epicondyles, intercondylar fossa, patellar surface |
| Patella | Sesamoid; base superior, apex inferior; larger lateral facet |
| Tibia | Medial and lateral condyles, intercondylar eminence, tibial tuberosity, anterior border, soleal line (post), medial malleolus, fibular notch |
| Fibula | Head, neck, shaft, lateral malleolus; not in the knee joint |
| Foot | 7 tarsals (talus, calcaneus, navicular, cuboid, 3 cuneiforms), 5 metatarsals, 14 phalanges; hallux has 2 |
| Siding | Femoral head medial; tibial tuberosity anterior; medial malleolus medial; big toe medial; patella larger facet lateral |
| Knee joint | Synovial hinge (modified); femur, tibia, patella; flexion/extension, slight rotation when flexed; locks in full extension |
| Menisci | Fibrocartilage. Medial = C-shaped, fused to tibial collateral. Lateral = O-shaped, mobile |
| Knee ligaments | ACL (stops anterior tibial slide), PCL (stops posterior slide), tibial (medial) and fibular (lateral) collaterals, patellar ligament, popliteal ligaments |
| Knee bursae | Suprapatellar, prepatellar, deep and subcutaneous infrapatellar; infrapatellar fat pad |
Debrief
You have now covered the pelvic girdle, the whole lower limb, and the knee joint. When the practical feels easy, move on to the Lab Exam 2 review.
💭 Before the real thing: run the practical simulation until you score 90% or better twice in a row. Then do it once with the timer on.