UNASSIGNED: Anterior cervical discectomy and fusion (ACDF) is a common cervical procedure with more than 137,000 cases in the United States (U.S.) each year. Historically, ACDF has been a relatively safe procedure despite encountering vital anatomical structures that can risk serious complications. One particularly dangerous sequela of ACDF is the risk of lacerating the vertebral artery (VA). While VA injuries are rare (0.5% of cases), it is crucial for surgeons to prevent this potentially deadly complication with thorough knowledge of VA anatomy. The VA is commonly protected within the transverse foreman; however, anomalies can exist with the artery potentially being found more medial or proximal within the surgical site than expected. The purpose of this article is to report an anomaly found in a cadaveric specimen, where the VA courses within 2 mm of an ACDF plate.
UNASSIGNED: A 66-year-old male with a past medical history of coronary artery disease passed away due to complications of a myocardial infarction. During cadaveric dissection, it was discovered that the donor had undergone a previous 3-level (C4-C7) ACDF procedure for an unknown reason. Under further examination, the left VA was observed to take an anomalous medially tracking course before eventually entering the transverse foramina of C5. Left anterior tubercles were absent at the level of C5 and C6 with prominent osteophytes found on the anterior tubercles/transverse foramina of the contralateral side.
UNASSIGNED: There are no studies published on the anatomy of VA variants and their implications on ACDF procedures. ACDF was found to have complication rates in 13.2% of cases. VA variants are observed in up to 20% of the U.S. population and VA injury in ACDF procedures has a rate near 0.5%. With anatomic variations leading to a higher risk of injury, surgeons are required to take further precautionary steps before operating including ordering computed tomography angiography or magnetic resonance angiography films. Understanding the detailed anatomy of the VA and its variants is critical. Using the perspectives of orthopedic spine surgeons, this study supplements the literature on potential VA anomalies encountered in ACDF procedures.

Variations at the junction of embryonic internal carotid and vertebrobasilar systems are rare and associated with a high incidence of stroke. During cadaver dissection, we demonstrated for the first time a case of hypoplastic right vertebral artery associated with partial duplication of the distal part of the right P1 segment of a partial fetal posterior cerebral artery (FPCA) and bilateral duplication of superior cerebellar arteries (SCAs), of which, the upper right SCA originated from PCA. We hypothesize that the poor development of the right half of the vertebrobasilar system caused the persistence of FPCA with anomalous origin of the right upper SCA as well as partial duplication of P1 segment of PCA as a remnant of the weak anastomosis between the embryonic right PCA and the basilar system. Such complex variations provide a huge challenge in their diagnosis and in choosing the suitable treatment modality for the stroke.

Awareness of unique path of the superficial branch of the radial nerve and its unusual sensory distribution can help avoid potential diagnostic confusion. We present a unique case encountered during a routine dissection of a Central European male cadaver. An unusual course of the superficial branch of the radial nerve was found in the right forearm, where the superficial branch of the radial nerve originated from the radial nerve distally, within the supinator canal, emerged between the extensor digitorum and abductor pollicis longus muscles and supplied the second and a radial half of the third digit, featuring communications with the lateral antebrachial cutaneous nerve and the dorsal branch of the ulnar nerve. Due to dorsal emerging of the superficial branch of the radial nerve the dorsal aspect of the thumb was innervated by the lateral antebrachial cutaneous nerve. To our best knowledge such variation of the superficial branch of the radial nerve has never been reported before. This variation dramatically changes aetiology and manifestation of possible entrapment syndromes which clinicians should be aware of.

Several accessory bones can be found around the wrist, which may pose a diagnostic challenge. Hereby, we report a unique case of a traumatic fracture of an aberrant os styloideum in a 66-year-old male. The patient presented with a swollen dominant right hand and a hematoma on its anterior and posterior aspects, as a result of a fall on an outstretched hand. The diagnosis was based on a CT scan, which showed a fractured accessory bone between the distal portion of the capitate bone and the base of the third metacarpus. Due to its typical location, the ossicle was identified as os styloideum. The patient was treated conservatively and the symptoms subsided on a short forearm cast after 2 weeks. At a 12-month follow-up, no other episodes were declared. Strong anatomical knowledge and sharing of such cases is essential for proper diagnosis and treatment of this very rare condition.

OBJECTIVE: Peroneus tertius (PT) or Fibularis tertius, a muscle of the anterior compartment of the leg is very distinctive to the Homo sapiens. This is because of the evolutionary acquisition of bipedal gait along with the eversion of the foot, which are unique to humans. It is considered as the fifth tendon of the extensor digitorum longus. Variations in the attachments of PT can cause stress fractures like the Jones fracture. PT has been extensively used in tendoplasty, tendon transfer and resection of the foot. The study aims to transpose the knowledge in variations of the morphology of PT from bench to bedside.
METHODS: Routine dissection of a 64-year-old male cadaver revealed bilateral variations in the insertion of PT. This was documented photographically. The findings prompted a systematic literature review on the morphological variations of PT. An exhaustive search was undertaken through PubMed and Google Scholar databases to identify the published literature related to variations in the morphology of PT. Related anatomical studies of the variations in peroneus tertius were identified and a review of the literature was performed.
RESULTS: Variations in the insertion of PT were observed bilaterally in the cadaver dissected by us. Statistical analysis revealed the absence of PT in 7.03% of lower limbs. 10% of studies showed accessory and duplicated PT each. Out of 20 articles reviewed, 51 lower limbs showed variation in origin, 230 lower limbs showed variations in insertion and 161 lower limbs showed other variations.
CONCLUSIONS: PT muscle flap and tendon grafts are used in correcting the laxity of the ankle joint and foot drop. Absence of PT plays a crucial role in altering the mechanics of stress fractures of the 5th metatarsal. Thus, knowledge of the morphology of PT is crucial for plastic surgeons and orthopedic surgeons.

We analyzed the double arch of a 51-year-old male patient who applied to the outpatient clinic with chest pain and shortness of breath and compared this rare case with the studies in the literature. Double aortic arch (DAA) is defined as a type of vascular ring malformation. The incidence of congenital heart diseases is less than 1%. DAA makes up 46-76% of all rings. We aimed to contribute to cardiac surgery by examining and modeling the diameters in the 2D and 3D images of the patient. For 3D modeling, an open-source software program ITK-SNAP 3.8 was used, which converts 2D images from MRI, CT, and ultrasound to 3D medical image volumes. CT images of the case taken from the SECTRA system of our hospital were uploaded to ITK-SNAP and segmentation was performed. With 3D modeling, a better understanding of the stenosis in the trachea and the double arch was achieved. The ascending aorta diameter was 30 mm. There were atherosclerotic changes in the aorta and its branches. The diameter of the right aortic arch was 22.2 mm, and the diameter of the left aortic arch was 14.5 mm. Trachea diameter was found to be 17 mm/13.2 mm. Esophageal diameter was 9.8 mm. The patient had no specific complaints and no medical or surgical treatment was recommended because his physical examination was normal. We think that a better understanding of such cases in 3D may contribute to cardiovascular surgery.

This case report describes a variation of the flexor digitorum brevis (FDB) with a separated muscle belly and tendon at the fifth toe. The narrow tendon and muscle belly for the fifth toe arose from the intermuscular septum between the FDB and abductor digiti minimi adjacent to the arising fibers of the FDB, separating from its other fibers. The tendon and muscle belly for the fifth toe became wider at the base of the metatarsal bones and narrower as it coursed toward the toes in a fusiform shape. The tendon and muscle belly for the fifth toe became thin at the midfoot and coursed just beneath the flexor digitorum longus tendon and entered the digital tendinous sheath. FDB variations including that described herein should be considered when performing various surgical procedures and evaluating the biomechanics of the foot.

OBJECTIVE: The report describes four cases of accessory bundles (ABs) or fibers connecting the muscles of the anterior with the posterior arm compartment. The ABs morphology (pure muscular or musculofascial or musculoaponeurotic) is described emphasizing their attachment points, characterized as muscles\' interconnections.
METHODS: Four formalin-embalmed donated male cadavers were dissected.
RESULTS: The muscles\' interconnections were unilaterally identified. In the first case, the two ABs originated from the coracobrachialis muscle (CB), received fibers from the biceps brachii (BB), and were inserted into the triceps brachii (TB) medial head. The ABs created an arch over the brachial vessels and the median nerve (MN). In the second case, an accessory musculoaponeurotic structure was identified between CB and TB medial head and extended over the brachial vessels. In the third case, the myofascial ABs between the BB short head and the upper arm fascia, coursed anterior to the MN, the brachial artery, and the ulnar nerve, with direction to the TB medial head. In the fourth case, the three muscular ABs originating from the CB superficial and deep heads, in common with the BB short head, joined the upper arm fascia and the TB medial head and possibly entrapped the musculocutaneous nerve, the MN, and the brachial artery.
CONCLUSIONS: ABs or musculoaponeurotic extensions may predispose to complications due to their potential compression on nerves and vessels. Clinicians should consider the possible existence of such bridging variants between muscles, in the differential diagnosis of a patient presenting with ischemia, edema, or MN palsy symptoms.

OBJECTIVE: The current cadaveric case series evaluates the coracobrachialis muscle morphology, the related musculocutaneous nerve origin, course, and branching pattern, as well as associated adjacent neuromuscular variants.
METHODS: Twenty-seven (24 paired and 3 unpaired) cadaveric arms were dissected to identify the coracobrachialis possible variants with emphasis on the musculocutaneous nerve course and coexisted neural variants.
RESULTS: Four morphological types of the coracobrachialis were identified: a two-headed muscle in 62.96% (17/27 arms), a three-headed in 22.2% (6/27), a one-headed in 11.1% (3/27), and a four-headed in 3.7% (1 arm). A coracobrachialis variant morphology was identified in 37.04% (10/27). A three-headed biceps brachii muscle coexisted in 23.53% (4/17). Two different courses of the musculocutaneous nerve were recorded: 1. a course between coracobrachialis superficial and deep heads (in cases of two or more heads) (100%, 24/24), and 2. a medial course in case of one-headed coracobrachialis (100%, 3/3). Three neural interconnections were found: 1. the lateral cord of the brachial plexus with the medial root of the median nerve in 18.52%, 2. the musculocutaneous with the median nerve in 7.41% and 3. the radial with the ulnar nerve in 3.71%. Duplication of the lateral root of the median nerve was identified in 11.1%.
CONCLUSIONS: The knowledge of the morphology of the muscles of the anterior arm compartment, especially the coracobrachialis variant morphology and the related musculocutaneous nerve variable course, is of paramount importance for surgeons. Careful dissection and knowledge of relatively common variants play a significant role in reducing iatrogenic injury.

The vertebrobasilar (VB) system, comprising two vertebral arteries and one basilar artery, is responsible for providing vital vascular supply to the central nervous system structures. Disruption in this network can lead to fatal neurologic outcomes, and variations in the origin of vessels may contribute to unexplained symptoms of clinical relevance. Therefore, an extensive understanding of the VB system\'s anatomy and its variations is crucial for diagnosing neurological disorders. Here, we report a case of a vertebral artery variant arising from the aortic arch proximal to the left subclavian artery in the cadaver of a 50-year-old male, discovered incidentally during a teaching dissection session. We also discuss the clinical pathophysiology and the relevance of the neurological symptoms in relation to the anomaly.