Bari M. Logan

Median artery revisited

This study confirms that the median artery may persist in adult life in 2 different patterns, palmar and antebrachial, based on their vascular territory. The palmar type, which represents the embryonic pattern, is large, long and reaches the palm. The antebrachial type, which represents a partial regression of the embryonic artery is slender, short, and terminates before reaching the wrist. These 2 arterial patterns appear with a different incidence. The palmar pattern was studied in the whole sample (120 cadavers) and had an incidence of 20%, being more frequent in females than in males (1.31), occurring unilaterally more often than bilaterally (41) and slightly more frequently on the right than on the left (1.11). The antebrachial pattern was studied in only 79 cadavers and had an incidence of 76%, being more frequent in females than in males (1.61); it was commoner unilaterally than bilaterally (1.51) and was again slightly more prevalent on the right than on the left (1.21). The origin of the median artery was variable in both patterns. The palmar type most frequently arose from the caudal angle between the ulnar artery and its common interosseous trunk (59%). The antebrachial pattern most frequently originated from the anterior interosseous artery (55%). Other origins, for both patterns, were from the ulnar artery or from the common interosseous trunk. The median artery in the antebrachial pattern terminated in the upper third (74%) or in the distal third of the forearm (26%). However, the palmar pattern ended as the 1st, 2nd or 1st and 2nd common digital arteries (65%) or joined the superficial palmar arch (35%). The median artery passed either anterior (67%) or posterior (25%) to the anterior interosseous nerve. It pierced the median nerve in the upper third of the forearm in 41% of cases with the palmar pattern and in none of the antebrachial cases. In 1 case the artery pierced both the anterior interosseous and median nerves.

Variant slips of psoas and iliacus muscles, with splitting of the femoral nerve

In bilateral dissections of 68 cadavers, four examples were found unilaterally of variant slips of iliacus and psoas major muscles. In three of them the femoral nerve was pierced by the variant slip. One of these variants was a previously undocumented accessory slip of iliacus, originating from the iliolumbar ligament, passing inferiorly anterior to iliacus, and traversing the femoral nerve; its tendon split to be attached proximally to the lesser trochanter of the femur and distally to an unknown insertion. Such anomalies might cause tension on the femoral nerve resulting in referred pain to the hip and knee joints and to the lumbar dermatomes L2,3 and 4.

Medial exposure for dissection of the cranial nerves in situ by medical students.

In this article, we illustrate and briefly describe a medial approach, in the sagittally sectioned preserved human head, to display all of the cranial nerves, in situ and in continuity. The method has been successfully used by more than six cohorts of our second‐year medical students, and can be completed within a 90‐min dissecting session. Clin. Anat. 13:387–391, 2000.