Variations in size and in symmetry of foramina of the human skull.

The goal of this report is to define an average size and size range for many of the skull's foramina and to determine in which paired foramina asymmetry is commonly found so that researchers and clinicians examining foramina may have an anatomical reference. The incidence of foraminal variations is also discussed. Information on skull foraminal size and symmetry is increasingly important because of the advancements in radiologic techniques such as magnetic resonance imaging (MRI) and computed tomography (CT). These methods are making difficult diagnoses of pathologic conditions of skull foramina possible. The foramina of 100 randomly selected dry skulls were measured and the symmetry of paired foramina was noted. The average, largest, and smallest sizes for 29 different foramina and the length of one canal are listed. Information regarding the symmetry of 27 paired foramina and the length symmetry of the infraorbital canal was also gathered. Specific data collected for paired foramina include the percent of skulls in which (1) neither foramen of the pair was present, (2) both foramina of a pair were present, (3) both foramina of the pair are present and were both the same size within 0.5 mm, and (4) both foramina of a pair are present but there was greater than 0.5 mm difference in size between them.

Illustrated Encyclopedia of Human Anatomy Variation

It presents information and images related to muscular, cardiovascular, nervous, endocrine, gastrointestinal, genitourinary, respiratory, and skeletal systems, listed alphabetically or by region. It also presents referenced journals, bibliography, glossary of terms and synonyms.

Atlas of Microscopic Anatomy: a functional approach - companion to Histology and Neuroanatomy. Second edition

It presents images and information related to the microscopic anatomy of cells, epithelial tissue, connective tissue, blood, muscular and nervous tissues, integument, cardiovascular, lymphatic, digestive, respiratory, urinary, and female and male reproductive systems, endocrine glands, special senses, and central nervous system.

Atlas of Human Anatomy in Cross Section

It presents images (axial plane) and information related to the anatomy of the human body (head, neck, shouders, upper arm, upper and middle torax, upper limb, lower torax, abdomen, pelvis, perinium, hip, upper thigh, and lower limb), topography of the torax and abdomen, and bibliography.

The third head of gastrocnemius in CT images.

A 17 year old male patient was undergoing a CT scan for pain and swelling of the left knee. The CT images of both legs, taken simultaneously, revealed an asymmetry of the musculature in the popliteal fossa of the right leg. Serial images indicated the presence of a third head joining the medial head of gastrocnemius.

Human persistent left superior vena cava with doubled coronary sinus.

A heart with a persistent left superior vena cava was found in a 72 year old man during routine dissection. The right superior vena cava was absent. The right brachiocephalic vein crossed over the aortic arch and its branches to the left side of the heart. This variation reportedly occurs in about 0.16% of humans. The azygos vein was, as a result, also left sided with a hemiazygos vein on the right side. The left superior vena cava drained into a channel contained with the posterior wall of the left atrium of the heart above, and parallel with the coronary sinus. The channel of the left superior vena cava opened into the right atrium above the opening of the coronary sinus. The coronary sinus may have been doubled during embryonic development. The two vessels were joined by a small connecting vessel.

Musculus comitans nervi mediani (M. palmaris profundus).

Palmaris profundus muscles were found in two cadavers during routine dissection of the upper limb. This rare muscle was found in two forms. In the first case, the muscle resembled a diminutive palmaris longus with the belly arising from the common flexor tendon. In the second case however, a reversed muscle with the belly emerging from beneath the transverse carpal ligament and its long thin tendon extended to and inserted in the common flexor tendon. The similarity therefore of these muscles to variable forms of palmaris longus is remarkable but they differed in one very important aspect from palmaris longus. The muscles are of special interest because, in both cases, the muscles were found enclosed in a common fascial sheath with the median nerve. These unusual muscles, in spite of mimicking palmaris longus, may perhaps, be better named "musculus comitans nervi mediani" to denote their very important relationship to the median nerve, that of being the intimate traveling companion of the median nerve through the forearm and into the hand by way of the carpal canal beneath the transverse carpal ligament. In one case, a well developed median artery was also found which also entered the carpal canal along with the median nerve and its muscular companion.

A comparison of peripheral nerve repair using an absorbable tubulization device and conventional suture in primates.

Median nerve regeneration was studied in 30 adult primates after repair by microsurgical suture or tubulization with a nonwoven, bioabsorbable, polyglycolic acid device. The two methods were compared electrophysiologically and histologically 6 and 12 months after repair. The electrophysiology included recording of electrically evoked compound action potentials and subsequent determination of threshold, conduction velocity, amplitude, and area above the baseline for each component. Measurements were obtained before nerve transection and at the time of biopsy by stimulating both proximal and distal to the transection site. Analysis of all electrophysiological parameters revealed no statistically significant differences (p less than 0.05) between the two repair techniques. Histopathology included examination of cross sections proximal and distal to the repair sites and longitudinal sections through the coaptation site. End organs (Meissner's and Pacinian corpuscles and muscle) were sectioned to determine the degree of reinnervation. No significant differences between the repair techniques were observed by histological analysis of these sections. These evaluations indicated that the tubulization repair technique produced results comparable to that of the suture technique.

Pituitary metastases: MR findings.

Tumors metastatic to the pituitary gland are uncommon, and they are difficult to differentiate radiologically from pituitary adenomas. We retrospectively reviewed the MR examinations and clinical records of nine patients with radiographic and/or clinical evidence of pituitary metastases. The most common clinical symptoms included cranial nerve deficits (67%) and/or pituitary dysfunction (30%). Both occurred acutely and progressed rapidly over 1-4 weeks in all patients. Cranial nerve involvement was predominantly multiple (83%), a reflection of involvement of the adjacent cavernous sinus. In contrast to previous reports indicating a predilection for symptoms related to posterior lobe involvement (71%), our study shows that symptoms related to the anterior lobe are as common as posterior lobe symptoms. Useful MR findings included a relatively small, enhancing pituitary lesion (< or = 1.5 cm in 56%) that was relatively isointense to brain on both T1- and T2-weighted images (78%) and involvement of the hypothalamus/pituitary infundibulum (44%) or cavernous sinus (56%).

Human doubled renal and testicular arteries.

Doubled renal and testicular arteries were found in a well-developed 69-year-old caucasian male. The right kidney had two renal arteries, one at its usual midorgan (hilar) position and one inferior polar. One testicular artery arose from the mid-point of the usual renal artery, passed under the renal vein at its junction with the inferior vena cava, and then crossed over the inferior polar renal artery. The second testicular artery arose from the inferior polar renal artery near its origin from the abdominal aorta. The two testicular arteries remained doubled throughout their course and both entered the right testis at separate sites on the organ. The inferior vena cava passed under the inferior polar and over the superior testicular artery and the superior renal artery.

Target pedicle of T-12: radiologic-anatomic correlation.

The authors prospectively studied 250 consecutive thoracic and lumbar spinal radiographic examinations and 56 dried skeletons to elucidate the peculiar target appearance in the pedicle of T-12 and occasionally T-11. Target pedicles were seen in 13 of the spines (23%) and in 85 of the 250 radiographic examinations (34%). Similar target pedicles were observed at T-11 in two radiographic examinations and in one spine. Anatomic correlation revealed that the inferior and lateral tubercles contribute to the ring shadow within the pedicle.

Palmaris longus muscle substituting for the ring finger slip of flexor digitorum superficialis.

An unusual and unrecorded variation in palmaris longus muscle is described. The muscle had a normal appearance and origin from the common tendon arising from the medial epicondyle of the humerus and from the surrounding intermuscular septa. The distal tendon however entered the hand via the carpal tunnel medial and deep to the median nerve, split and inserted into the lateral and medial sides of the middle phalanx of the ring finger. It therefore substituted completely for the slip to the ring finger from flexor digitorum superficials, which was absent.

Direct branch of external carotid: a masseteric artery.

An additional branch of the right external carotid in the form of an unusual direct artery to m. masseter is described. It arose as a terminal branch along with the maxillary and superficial temporal arteries, ran in the substance of the parotid gland to supply the muscle on its lateral aspect. The pertinent anatomical literature is reviewed.

Congenital anorectal anomalies: MR imaging.

Twenty-one patients with anorectal anomalies were evaluated with magnetic resonance (MR) imaging. In seven preoperative patients, MR imaging demonstrated the level of atresia correctly by showing the rectal pouch and sphincter muscles. The exact location and development of the sphincter muscles were estimated and associated anomalies involving the kidneys and the spine and its contents were evaluated. In 14 postoperative patients, the location of the pulled-through intestine was examined in relation to the sphincter muscles. MR imaging demonstrated operative complications affecting rectal continence--such as a misplaced neorectum, inadvertently pulled-through mesenteric fat, and an implantation mucous retention cyst--and provided objective data for individuals with persistent incontinence after surgery who were under consideration for repeat surgery. The authors recommend MR imaging in all patients being considered for repeat procedures and in any patient without prior surgery who is suspected of having a high anomaly; any degree of sacral agenesis; or spinal, genito-urinary tract, or cloacal anomalies.

The accessory sacroiliac joint: a common anatomic variant.

We identified the accessory sacroiliac joint on 13 (13%) of 100 CT scans of the pelvis and in nine (16%) of 56 dried skeletons. The joint is situated between the medial aspect of the posterior superior iliac spine and a rudimentary transverse tuberosity just lateral to the second sacral foramen. Some joints are true diarthrodial joints and are present at birth, but more commonly they are acquired fibrocartilaginous joints that result from the stress of weight-bearing. Our experience suggests that the accessory sacroiliac joint is not rare and that it is visible on CT scans in many patients.

Anomalous fascicle and high origin of latissimus dorsi compensating for absence of serratus anterior.

The unilateral absence of the right serratus anterior muscle was found in a 78 year old white male subject. In addition, on the same side, a high origin (5th thoracic level) of latissimus dorsi with an accessory muscle fascicle which covered the inferior angle of the scapula and fused with teres major and with the deep fascia of infraspinatus was also found. The structural arrangement suggests that the absence of serratus anterior was compensated for by the anomalous latissimus dorsi.

Absence of the coronary sinus.

The rare absence of the coronary sinus is described in a 78 year old male cadaver. The veins of the posterior surface of the heart, including the marginal and small cardiac veins, drained into the right atrium through an ostium guarded by a valve. The great cardiac vein drained into the superior vena cava after passing upward and beneath the left coronary artery.