Illustration of a severe closed head injury with a bilateral stroke and an infarct of the brain stem, cerebellum, and occipital lobes of the brain.

Brain stem stroke damage resulting from partial occlusion of the pontine arteries and basilar artery and complete occlusion of one pontine artery. Tissue damage due to lack of blood supply of the pontine area of the brain stem is a cause of locked-in syndrome (basilar artery syndrome).

Arterial supply of the brain stem (including the pons and medulla oblongata). Shown are the vertebral, basilar, and cerebral arteries, and the pontine arteries that supply the pons. Tissue damage due to lack of blood supply (stroke) of the pontine area of the brain stem is a cause of locked-in syndrome (basilar artery syndrome).

Illustration of femur fractures in the hip region: a femoral neck fracture (left) and an intertrochanteric fracture (right), a fracture between the greater and lesser trochanters of the femur.

Illustration of osteoporosis in a middle aged female. Normal bone matrix is compared to that of osteoporosis in two comparative inset illustrations at right.

Illustration of a rhizotomy procedure performed at the cervical (neck) level of the spine. Rhizotomy is a type of neurosurgery used to selectively remove damaged nerve roots.

Illustration of an epidural block injection in the cervical spine, caudal (posterior) approach, shown from lateral view.

Illustration of an epidural block injection in the cervical spine, caudal (posterior) approach, shown from a superior view.

Illustration of an epidural block injection in the cervical spine, caudal (posterior) approach, shown from a lateral view.

Illustrations of surgical repairs to the cervical spine: A) anatomical orientation of the posterior surgical approach, B) laminotomy procedure and the decortication of the cervical spine, C) foraminotomy porcedure from a superior view.

Illustrations of spinal surgery, C4-C5 and C5-C6 cervical laminectomy and foraminotomy to treat chronic cervical disc herniation. The surgical steps involved in a laminectomy and foraminotomy to relieve the pressure from the C4-5 and C5-6 nerve roots are shown.

Illustrations comparing various methods for delivering a spinal nerve block (clockwise): median block injection, radiofrequency rhizotomy, epidural steroid injection, thermal nerve destruction.

Illustration of a skin ulceration (top). Also shown are layers of skin (red), muscle (pink), fat (yellow), and bone (beige) tissue.

Illustration of the uncircumcised penis and the scrotum, frontal view.

Illustrations of the surgical repair of a penis with phimosis, showing a comparison of dorsal slit reconstruction (preputioplasty) of the foreskin versus circumcision. Phimosis is a penile constriction in which the foreskin will not retract to expose the head of the penis (glans penis) during an erection.

Illustration of genital warts (detail) and the regions they affect on the penis (top left) and in and around the vagina (bottom left).

Illustration of genital herpes (detail) and the most common genital and anal regions of infection, shown on a male figure.

Illustration of a Nissen fundoplication (stomach stapling) procedure, used to treat obesity, gastroesophageal reflux disease (GERD), and hiatal hernia. Specific to this case are the presence of a hiatal ring hernia and an incidental injury to the esophagus, which were both repaired during the surgery.

Illustration of nasal polyps, saclike growths arising from the mucous membranes of the nasal passage and sinuses, side view. Symptoms include loss of smell (anosmia), congestion, runny nose, sinusitis, and headache. Nasal polyps are most prevalent in patients with asthma, hay fever, sinus infections, or cystic fibrosis. Large polyps may block the airway.

Illustration of bone marrow aspiration, showing the extraction of bone marrow from a female patient, with a detail of the needle in the marrow of the hip bone. This procedure is used to diagnose anemia, leukemia, lymphoma, myeloma, and unexplained fever.