Items tagged “anatomical variant”

The 5th metacarpal pit refers to the normal exaggeration of the pit-like depression in the head of fifth metacarpal 1.  Differential diagnosis It should not be mistaken for a boxer fracture (old or new) or an erosion.

An azygos lobe is a normal variant that develops when a laterally displaced azygos vein creates a deep pleural fissure into the apical segment of the right upper lobe during embryological development. It is not a true accessory lobe as it does not have its own bronchus or corresponding specific ...

Concha bullosa (plural: conchae bullosae) (also known as middle turbinate pneumatization) is a common finding and although associated with deviation of the nasal septum, it is usually of little clinical importance. Epidemiology Concha bullosa is a normal variant and is one of the most common v...

Os acromiale is an anatomical variant and represents an unfused accessory center of ossification of the acromion of the scapula. Epidemiology Os acromiale is relatively common, seen in ~8% (range 1-15%) of the population 1,2 and can be bilateral in 60% of individuals 5. Clinical presentation ...

A bifid median nerve is an uncommon anatomical variation in the forearm and has an increased association with a persistent median artery 4. Epidemiology It has an incidence of 9-19% 4. A persistent median artery is present in approximately half of those with a bifid median nerve 4. Gross anat...

Popliteal artery entrapment syndrome refers to symptomatic compression or occlusion of the popliteal artery due to a developmentally abnormal positioning of the popliteal artery in relation to its surrounding structures such as with the medial head of gastrocnemius or less commonly with popliteu...

The extensor digitorum brevis manus (EDBM) muscle is an accessory muscle in the hand and is a normal anatomical variant.  Summary origin: distal radius and posterior radiocarpal ligament insertion: extensor hood of 2nd or 3rd digits (variable) innervation: posterior interosseous nerve actio...

Anomalous pancreaticobiliary junction, also known as pancreaticobiliary maljunction, describes the abnormal junction of the pancreatic duct and common bile duct that occurs outside the duodenal wall to form a long common channel. Epidemiology The incidence varies from 1.5% to 3.2% 11. The esti...

Some ostiomeatal complex anatomical variations, which do not cause disease by themselves, can promote narrowing and even obstruction 1: concha bullosa ~10% (range 4-15%) - aerated middle turbinate intralamellar cell: air cell within vertical portion of the middle turbinate  oversized ethmoid...