P. Freger

Anatomical basis of the variable aspects of injuries of the axillary nerve (excluding the terminal branches in the deltoid muscle)

AbstractThe course of the axillary n. is complex with three points of angulation that may be used to delineate four segments and a fifth segment that corresponds to the intramuscular ending of the nerve in the deltoid m. The purpose of this study was to determine the precise anatomy of the nerve and of its branches, and some morphologic features for each segment. Thirty-two shoulders from embalmed adult cadavers have been studied. The axillary n. was divided in five segments: 1)from its origin to the inferior border of the subscapularis m.,2)from the subscapularis m. to the anterolateral border of the tendon of the long head of the triceps brachii m.,3)from the triceps to the posteromedial part of the surgical neck of the humerus,4)from the humerus to the entry into the deltoid m.,5)the intramuscular distribution of the nerve in the deltoid m.In each segment from 1 to 4 were noted the origins of the branches to the subscapularis and teres minor mm. and to the scapulohumeral joint, and the origins of the lateral cutaneous brachial n. and of the terminal motor branches to the deltoid m. The length and the diameter of the nerve in the segments and the distance from the segment S1 to the musculotendinous junction of the subscapularis m. were measured.The results showed that the mean diameters were about 4.1 mm in segment 1, 4.1 mm in segment 2 and 3.4 mm in segment 3. The mean distance to the musculotendinous junction was 7.7 mm. Many variations in the levels of origin of the different muscular, articular or cutaneous branches were found without symmetry between the right and left sides. The lateral cutaneous brachial n. was absent in four cases.The results are compared with those in the literature. The division into five segments is proposed to radiologists and surgeons for evaluation or operative procedures on the axillary n., and to provide a hypothesis about the variable aspects of injuries of the nerve.

Vascular anatomical basis of clavicular non-union

The middle third of the clavicle is commonly involved in any injury and account for 5–10% of all fractures in adults. Although non-unions are rare, their treatment has not been well defined yet. This report describes the arterial supply of the clavicle to clarify the pathological mechanism and the surgical procedure of non-unions. This study was based on delineation of the thoraco-acromial and suprascapular arteries with colored latex on 17 specimens (ten cadavers). Observations were made after macroscopic dissection and maceration. The main blood supply to the middle third of the clavicle was the periosteal. This supply came from the two branches of the thoraco-acromial trunk that penetrated the pectoralis major muscle and the deltoid muscle. In 13 cases, these two periosteal branches were anastomosed between these two muscle attachments. Periosteal vascularization was always seen on the superior surface and the anterior border of the bone, but never on the inferior surface or the posterior border. The suprascapular artery contributed to supply the middle third of the clavicle by several periosteal branches and also by an independent branch. This branch was born proximally near the internal, middle thirds union and passed along the posterior face of the subclavius muscle and pierced the bone through the nutria foramina located near the external, middle thirds union. Nevertheless, intraosseous arteries were noted only in four cases. In these cases, they were never more than 2cm long. Our results showed that the periosteal blood supply located between the muscles insertions and the arterial supply from the suprascapular artery could be twice compromised in case of important displacement or severe fracture. If treatments of clavicular fractures or non-unions cannot preserve the periosteal blood supply, bone grafting should be indicated.

The article critique as a problem-based teaching method for medical students early in their training: a French example using anatomy

In France, “article critique” became a particular teaching method in the second part of the medical curriculum. It approaches a reading exercise of scientific medical papers similar to that of journal club. It could be compared to reviewing a paper as performed by reviewers of a scientific journal. We studied the relevancy of that teaching method for the youngest medical students. Our questions were about the understanding and the analyzing ability of a scientific paper while students have just learned basic medical sciences as anatomy. We have included 54 “article critique” written by voluntary students in second and third years of medical cursus. All of the IMRaD structure items (introduction, materials and methods, results and discussion) were analyzed using a qualitative scale for understanding as for analyzing ability. For understanding, 89–96% was good or fair and for the analyzing ability, 93–100% was good or fair. The anatomical papers were better understood than therapeutic or paraclinical studies, but without statistical difference, except for the introduction chapter. Results for analyzing ability were various according to the subject of the papers. This teaching method could be compared to a self-learning method, but also to a problem-based learning method. For the youngest students, the lack of medical knowledge aroused the curiosity. Their enthusiasm to learn new medical subjects remained full. The authors would insist on the requirement of rigorous lessons about evidence-based medicine and IMRaD structure and on a necessary companionship of the students by the teachers.

Traversée durale de l’artère carotide interne : mise en place embryologique et foetale

L’elaboration embryologique de la region paraclinoide anterieure au sein de la loge parasellaire est decrite dans une etude qui repose sur une collection de coupes histologiques representant une serie continue de 48 specimens embryonnaires et fœtaux couvrant les six premiers mois de la vie intra-uterine. La periode embryonnaire permet la mise en place du contenu vasculo-nerveux de la loge latero-sellaire. Les parois superieure, mediale et lateral apparaissent definitivement constituees a la quinzieme semaine d’amenorrhee. L’artere carotide interne rejoint les espaces sous-arachnoidiens accompagnee d’un manchon de cellules mesenchymateuses qui la fixe a l’apophyse clinoide anterieure. La paroi mediale est double, composee de la loge hypophysaire et du perioste sphenoidal. La paroi laterale est composee de deux feuillets de nature identique mais d’architecture distincte. Le feuillet superficiel correspond a un feuillet de dure-mere epais qui accompagne les nerfs oculomoteurs vers la fissure orbitaire superieure, le profond a un reseau plus lâche donnant une cohesion a l’ensemble de ces nerfs. Les rapports fœtaux entre dure-mere et artere carotide interne different de ceux decrits chez l’adulte, traduisant une periode de maturation post-natale. Les resultats de cette etude sont en faveur d’une evolution de la nomenclature, le terme de defile inter periosto-dural traduisant plus fidelement la nature des parois du compartiment latero-sellaire. L’existence d’une communication entre les deux regions latero-sellaires remet en cause les theories precedentes. Enfin, le reseau veineux, reparti autour de l’artere carotide interne, s’immisce au sein de la paroi laterale, permettant d’expliquer certaines complications hemorragiques chirurgicales.