Middle ear contains three ossicles: malleus, incus, and stapes. Hollow tympanic cavity surrounded by temporal bone. Auditory tube connects middle ear to nasal cavity. Eustachian tube equalizes pressure between middle ear and throat
The rib cage consists of 12 pairs of ribs, sternum, and thoracic vertebrae. True ribs connect directly to sternum, false ribs indirectly via cartilage. Floating ribs (11th and 12th) are not attached to sternum. Each rib has head, neck, and shaft with articular facets
Vertebrate circulatory system includes heart, blood vessels, and blood. System has two main circuits: pulmonary and systemic. Blood contains plasma, red blood cells, white blood cells, and platelets. Average adult contains 4.7-5.7 liters of blood
Ribs form the axial skeleton and protect vital organs in the thorax. Humans have 24 ribs in 12 pairs, with 1 in 500 having cervical ribs. Ribs connect to vertebrae at costovertebral joints and sternum via costal cartilage. Ribs consist of head, neck, body, tubercle, and angle
Vocal cords are horizontal folds of mucous membrane in larynx. True vocal cords are delicate, false folds produce deep tones. Adult vocal cords are 12-24mm long and 3-5mm thick. Vocal folds are attached to arytenoid and thyroid cartilages
Internal jugular vein collects blood from brain and neck to right atrium. Vein has three layers: adventitia, media, and intima. Originates from skull's jugular foramen and runs vertically in carotid sheath. Left jugular vein is generally smaller than right