Wandering spleen is a rare condition in which the spleen migrates from its usual anatomical position, commonly to the lower abdomen or pelvis.
Wandering spleen is rare, with a reported incidence of <0.5%.
Diagnosis is most commonly made between ages 20 and 40 years and is more co...
Ward triangle refers to a radiolucent area between principle compressive, secondary compressive and primary tensile trabeculae in the neck of femur.
It should be differentiated from Babcock triangle.
History and etymology
Named for F O Ward after his original description of the region in 1838.
The Weigert-Meyer law describes the relationship of the upper and lower renal moieties in duplicated collecting systems to their drainage inferiorly.
With duplex kidney and complete ureteral duplication, the upper renal and lower renal moiety is drained by separate ureters, e...
Wernicke's area (Brodmann area 22) is an area of the posterior temporal lobe in the dominant hemisphere concerned with the receptive components of speech.
Wernicke's area is located in the superior temporal gyrus, posterior to the posterior commissure line.
It is boun...
Wharton jelly refers to the gelatinous substance within the umbilical cord.
Wharton jelly is derived from extra-embryonic mesoderm and is largely made up of mucopolysaccharides (hyaluronic acid and chondroitin sulphate) while containing smaller amounts of fibroblasts and macropha...
The white matter is the substance of the brain and spinal cord that contains the fiber tracts of neuronal axons in the central nervous system. The term is due to the paler color of the lipid-rich myelin that encase the axons in the tracts compared to the grey matter, which contains predominantly...
White matter tracts in the brain, also known as white matter fibers, are classified into three categories:
tracts connecting the cortex with other area in the CNS, e.g. deep nuclei, brainstem, cerebellum or spine
may be efferent (motor) or afferent tracts (sensory)
The spinal cord has numerous tracts of white matter that ascend and descend in the peripheral substance of the cord. They can be divided by their location and function:
anterior corticospinal tract
medial longitudinal fasiculus
The Wolffian duct (also known as the mesonephric duct) is one of the paired embryogenic tubules that drain the primitive kidney (mesonephros) to the cloaca. In both the male and the female the Wolffian duct develops into the trigone of the urinary bladder.
In the female, in...
Wormian bones (a.k.a. intrasutural bones) is the name given to the additional small bones sometimes found between the cranial sutures of the bones of the skull vault, most commonly in relation to the lambdoid suture. Some reserve the term Wormian bones to just the intrasutural bones proximate to...
The intrinsic and extrinsic wrist ligaments play a vital role in the stability of the wrist joint. There are numerous ligaments but included below are the most clinically significant. Wrist ligaments are best assessed with dedicated wrist MRI.
intrinsic ligaments (only attach to ...
The xiphisternum (also known as the xiphoid process or simply the xiphoid) is the smallest of the three parts of the sternum (manubrium, body or gladiolus and xiphisternum). It arises from the inferior and posterior margin of the sternal body and projects inferiorly. It is a small cartilaginous ...
There is considerable anatomic variation in the shape of the xiphoid of the sternum:
xiphoid ending is classified as single, double, or triple.
xiphoid size varies (e.g. elongated process)
xiphoid morphology (e.g. ventral or dorsal deviation, hook-like, reverse S-shape).
The zona orbicularis are circular fibers of the hip joint capsule and form a collar around the femoral neck. Though partly blended with the pubofemoral and ischiofemoral ligaments, these fibers are not directly attached to bone.
Zuckerkandl tubercle is a normal variant of the thyroid and may be mistaken for a thyroid nodule, mass or lymph node. It is a projection of normal thyroid tissue from the posterior aspect of the lateral lobes of the thyroid gland.
The tubercle is also an important surgical landmark due to its ...
The zygoma (also known as zygomatic bone or malar bone) is an important facial bone which forms the prominence of the cheek. It is roughly quadrangular in shape.
Zygoma has three surfaces, five borders, and two processes.
anterolateral surface is convex, pierced at its...
The zygomatic arch is formed by the union of the temporal process of the zygomatic bone and the zygomatic process of the temporal bone at the zygomaticotemporal suture.
Le Fort type 3 fracture
zygomaticomaxillary complex fracture
The zygomatic nerve is a main branch of the maxillary division of the trigeminal nerve. It should not be confused with the zygomatic branch of the facial nerve.
The zygomatic nerve divides off the maxillary division just after emerging from the foramen rotundum to enter the ptery...
The zygomaticofacial foramen is a small foramen in the mid lateral surface of the zygomatic bone that transmits the zygomaticofacial nerve (a branch of the zygomatic nerve from the maxillary division of the trigeminal nerve) and zygomaticofacial vessels.
The zygomaticofacial nerve is the smaller of the two branches of the zygomatic nerve, from the maxillary division of the trigeminal nerve. It is sometimes referred to as the malar branch of the zygomatic nerve. It leaves the inferolateral aspect of the extraconal space of the orbit through the z...
The zygomaticomaxillary suture is between the zygomatic process of the maxilla and the maxillary process of the zygomatic bone. They are often involved in zygomaticomaxillary complex (ZMC) fractures.
The zygomaticotemporal foramen is a small foramen in the anteromediall surface of the zygomatic bone that transmits the zygomaticotemporal nerve (a branch of the zygomatic nerve from the maxillary division of the trigeminal nerve) and zygomaticotemporal vessels.
The zygomaticotemporal nerve is the larger of the two branches of the zygomatic nerve, from the maxillary division of the trigeminal nerve. It is primarily sensory but also relays parasympathetic fibers to the lacrimal nerve from the pterygopalatine ganglion which reach the lacrimal gland. It le...
Zygomaticus major is a member of the buccolabial muscle group of the upper lip1. It joins with the fibers of levator anguli oris, orbicularis oris and the more deeply placed muscular bands to move the side of the mouth upwards and sideways during facial movements such as laughing.
Zygomaticus minor is a member of the buccolabial muscle group. Together with levator labii superioris alaeque nasi and levator labii superioris it is one of the main elevators of the lip, exposing the maxillary teeth 1. Along with its other action of deepening and elevating the nasolabial furro...