Oculomotor nerve palsy produces the classic down and out eye position because the muscles normally controlled by the oculomotor nerve lose their function, leaving only the lateral rectus and superior oblique muscles unopposed. As a result, the affected eye drifts View Diagram Oculomotor Nerve Palsy Down and Out Position
The basal ganglia consist of interconnected deep brain nuclei including the caudate nucleus, putamen, globus pallidus, subthalamic nucleus, and substantia nigra. These structures work together to regulate voluntary movement, motor planning, and habit formation by modulating signals between the cerebral View Diagram Components of the Basal Ganglia
The superior, middle, and inferior cervical ganglia are sympathetic chain ganglia located in the neck and responsible for supplying sympathetic innervation to the head, neck, and upper thorax. The superior cervical ganglion is the largest and provides fibers to structures View Diagram The Superior Middle and Inferior Cervical Ganglia
The surface anatomy of the eyelids includes the upper and lower lids, which protect the eye and maintain the tear film. The upper eyelid is larger, more mobile, and contains the levator palpebrae superioris muscle that lifts it during opening, View Diagram Surface Anatomy of the Eyelids Uppper Lower
The median nerve supplies cutaneous innervation to parts of the hand, primarily the lateral three and a half digits on the palmar side and their corresponding nail beds. Sensory fibers travel through the carpal tunnel to reach the thumb, index View Diagram Cutaneous Innervation of the Median Nerve Skin of the Hand
Innervation of the nasal septum is shared among the olfactory, nasopalatine, and nasociliary nerves, which together provide sensory input and contribute to the sense of smell. The olfactory nerve occupies the superior portion of the septum, detecting airborne chemicals and View Diagram Innervation of the Nasal Septum Olfactory Nasopalatine and Nasociliary Nerves
A Bennetts fracture is a fracture-dislocation at the base of the first metacarpal bone where it meets the trapezium, usually caused by a sudden axial load through a flexed thumb, such as during a fall or high-impact grip. The break View Diagram Bennetts Fracture of the 1st Metacarpal
The femoral canal is a small, clinically important space within the femoral triangle and is bounded anteriorly by the inguinal ligament, posteriorly by the pectineal ligament, medially by the lacunar ligament, and laterally by the femoral vein. It contains lymphatic View Diagram Borders of the Femoral Canal
The distal humerus features several important bony landmarks, including the medial and lateral epicondyles, the trochlea, and the capitulum, all of which play key roles in elbow function. The epicondyles serve as attachment points for the forearms flexor and extensor View Diagram Distal Aspect of the Humerus Epicondyle Trochlea Capitulum
Posterior articulations of the ribs include the connections between the rib head and the bodies of the thoracic vertebrae, as well as the articulation between the rib tubercle and the transverse process. Each rib typically articulates with the superior and View Diagram Posterior Articulations of the Rib
The phrenic nerve provides the primary motor innervation to the diaphragm and is essential for normal respiratory function. Arising from spinal roots C3 to C5, it descends through the neck on the anterior surface of the scalene muscle before entering View Diagram Phrenic Nerve Motor Innervation to the Diaphragm
The posterior inferior cerebellar artery (PICA) usually arises from the vertebral artery and follows a complex course around the medulla and cerebellum. After branching off, it winds posteriorly to pass between cranial nerves and wraps around the inferior surface of View Diagram Posterior inferior cerebellar artery orgin and course
From an anterior view, the venous drainage of the heart is dominated by the great and small cardiac veins, which work in parallel with the coronary arteries. The great cardiac vein begins near the apex of the heart and ascends View Diagram Anterior View of the Venous Drainage of the Heart Small and Great Cardiac Veins
The submandibular ganglion is a small parasympathetic ganglion suspended from the lingual nerve beneath the mandible. Preganglionic fibers originating from the facial nerve synapse here before sending postganglionic fibers to the submandibular and sublingual salivary glands. These fibers stimulate saliva View Diagram The Submandibular Ganglion and Branches
Polycystic ovary syndrome on ultrasound typically shows enlarged ovaries with multiple small follicles arranged around the periphery, often described as a string of pearls. These follicles represent arrested development due to hormonal imbalance, particularly elevated androgens and disrupted ovulatory cycles. View Diagram Ultrasound Polycystic Ovary Syndrome
Synovial joints are highly mobile joints characterized by a synovial cavity filled with lubricating fluid, articular cartilage covering the joint surfaces, and a fibrous capsule that encloses the space. They come in several types, including hinge joints that permit flexion View Diagram Types of Synovial Joint
The posterior blood supply of the heart is primarily provided by the posterior descending artery and the branches of the circumflex and right coronary arteries, depending on coronary dominance. These vessels deliver oxygenated blood to the diaphragmatic surfaces of the View Diagram Blood Supply to the Heart Posterior
The musculocutaneous nerve arises from the lateral cord of the brachial plexus and contains fibers from spinal roots C5 to C7. It enters the arm by piercing the coracobrachialis muscle, which serves as an important anatomical landmark, and then travels View Diagram Anatomical Course of the Musculocutaneous Nerve
The pretracheal fascia is a layer of deep cervical fascia that extends from the hyoid bone into the thorax, enclosing the thyroid gland, trachea, and esophagus. It forms a distinct compartment in the anterior neck, separating these structures from the View Diagram Diagram of the Pretracheal Fascia Layer of the Neck Labelled
The trachea divides into the right and left primary bronchi at the level of the sternal angle, forming the main airway passage into the lungs. The tracheal wall is reinforced by C-shaped cartilage rings that keep the airway open, while View Diagram The Trachea and Bronchial Divisions
