Illustration of brain surgery, showing the correct placement of an intracranial pressure monitor.

Illustration of a tissue plasminogen activator (TPA) dissolving a blood clot (left to right): 1) normal blood flow within an artery, 2) artery blocked by a blood clot, 3) TPA dissolving the blood clot, and 4) restoration of normal blood flow in the artery. TPA is an enzyme that catalyzes the conversion of plasminogen to plasmin, used to treat heart attacks.

Illustration of a lumbar epidural injection: 1) female torso showing the needle placement site in the lower back, posterior view, 2) detail of the spine showing the needle placement between L5 and S1 vertebrae with injection of anesthesia into the lumbar epidural space, sagittal section.

Illustration of a superficial lymph node biopsy in the neck, showing the incision site and a detail of the cervical lymph nodes and accessory nerve. This test is taken for suspected lymphoma and cancer cases.

Illustration of a Pap smear examination, a typical test for cervical cancer. Shown are a gynecologist's view of the vagina with a speculum in place to visualize the cervix (left) and a detail of a curette scraping cells from the cervix which will later be tested for cancer (right), cutaway view.

Illustration of a fractured (broken) male pelvis, showing fractures of the right superior and inferior pubic rami, anterior view.

Illustration of shoulder dystocia, or brachial plexus injury, during a vaginal delivery, midsagittal section of the mother's pelvis and abdomen. The fetal head has been delivered but the shoulder is trapped by the pubic symphysis.

Illustration of knee joint arthroscopic (endoscopic) surgery. Shown is the anatomy of the right knee, which includes the femur, patella, meniscus, tibia, fibula, and collateral ligaments. Also depicted are the placement of the stab incisions, arthroscope, and irrigation cannula during knee surgery.

Illustration of an external electronic fetal heart rate monitor (FHRM) with three types of output: a speaker in the back of the FHRM provides an audible report of each fetal heartbeat, the digital display indicates the heartbeats per minute, a paper printout shows the heartbeat and maternal contractions. The ultrasound transducer is strapped to the abdomen.

Illustration of a total knee joint replacement, anteromedial (frontal, inner) view. The surgical procedure describes cutting away the articular surfaces of the femur and tibia and cementing the prosthesis in place to restore the knee joint.

Illustration of the left knee joint showing chondromalacia where the patella articulates with the femoral surface, anterolateral (frontal, outside) view. Chondromalacia is a surface defect on the articular cartilage of a joint, usually caused by trauma.

Illustration showing the anatomy of the heart and great vessels alongside the location of a pacemaker device. Labeled structures include the left subclavian artery and vein, internal jugular vein, carotid artery, aortic arch, ventricle, atrial auricle, and lungs.

Illustration of a narrow pubic arch in the pelvis of pregnant woman. A narrow pubic arch can result in fetal head and shoulder injuries (dystocia) during labor and delivery of the baby.

Illustration of classic cardiac catheterization. The catheter enters through the leg and extends up the aorta to the heart.

Illustration of malignant melanoma (skin cancer).

Illustration of a torn anterior cruciate ligament (ACL) injury in the knee joint.

Illustration of a total left hip replacement, showing the prosthesis surrounded by the major arteries, veins, and nerves, anterior view. The prosthetic hardware is shown in place in the hip joint.

Illustration of a birth injury: shoulder dystocia, or brachial plexus injury, during normal vaginal delivery. In this case, the baby's left shoulder is caught behind the mother's sacrum, instead of the more typical shoulder dystocia injury caused by the mother's pubic symphysis (pubic bone).

Illustration of the brachial plexus nerves in an infant, anterior view, showing the regions of the shoulder, arms, and upper thorax affected by damage to the nerve roots, as is seen in a shoulder dystocia birth injury during delivery. Shown are the spinal cord and nerve roots for C5, C6, C7, C8, and T1.

Illustration of hypovolemic (low blood volume) shock, showing the sequence of events leading to death. Hypovolemic shock is a severe and acute metabolic disturbance caused by a reduction in blood volume, as from hemorrhage or dehydration.