The xiphisternal joint (or more rarely, the sternoxiphoid joint) is a symphysis between the inferior margin of the body of the sternum and the superior margin of the xiphoid process. In most people it ossifies with age, usually becoming fully fused by the age of 40 years, forming a synostosis.
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).
Yaws, also known as framboesia, is a tropical disease produced by the Treponema pallidum subspecies pertenue.
Yaws is a tropical disease. Infections have declined dramatically over the last century, however the disease is still present in several countries in Africa and Asia 1. Y...
The Young and Burgess classification is a modification of the earlier Tile classification 1. It is the recommended 5 and most widely used classification system for pelvic ring fractures.
It takes into account force type, severity, and direction, as well as injury instability.
Three basic mech...
The yo-yo on a string sign denotes the characteristic appearance of the torn, proximally retracted and superficially displaced ulnar collateral ligament (UCL) due to a Stener lesion.
The sign occurs as a consequence of the tear of the ulnar collateral ligament of the thumb (gamekeepe...
Yunis Varón syndrome is a rare skeletal dysplasia. It is thought to be autosomal recessive.
severe neurologic impairment include small cerebellar vermis and dandy walker malformation
diastasis of sutures
The Z deformity is one of the musculoskeletal manifestation of rheumatoid arthritis in hand:
radial deviation at the wrist
ulnar deviation of the digits, and often
palmar subluxation of the proximal phalanges
A mnemonic to remember the features of Z deformity of the hand in rheumatoid arthritis is:
Consider mnemonic to be pronounced "word up" to help remember it.
WR: wrist radial deviation
DU: digits ulnar deviation
PP: proximal phalanges palmar subluxation
The zebra stripe sign occurs where children with osteogenesis imperfecta have been treated with cyclical bisphosphonate therapy, e.g. pamidronate. When the drug is delivered in cycles, dense bone is formed while treatment is being given. This results in dense stripes across the metaphyses of bon...
Zimmerman-Laband syndrome is a rare congenital syndrome, characterized primarily by gingival hypertrophy and skeletal abnormalities.
The molecular basis of the syndrome is currently unknown. An autosomal dominant mutation with a high mutation rate and rare instances of germinal mosa...
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.
The zone classification of flexor tendon injuries divides injuries into five zones based on anatomical location. It is the most widely used flexor tendon injury classification system (c. 2007) 1.
Flexor tendon injuries were classified into five zones by Kleinart and Verdan in 19...
Z-scores are a way to translate individual data points into terms of a standard deviation.
Z = (X - Xbar) / σ
X: individual data point
Xbar: the arithmetic mean
σ: the standard deviation
The purpose of the Z-score is to allow comparison between values in different normal distributions. Two...
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 zygomaticus major muscle 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.
The zygomaticus minor muscle is a member of the buccolabial muscle group of the muscles of facial expression. Together with the levator labii superioris alaeque nasi and levator labii superioris muscles it is one of the main elevators of the lip, exposing the maxillary teeth 1. Along with its o...