Axial Skeleton _ Learn Skeleton Anatomy

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The axial skeleton forms the central framework of the human body, comprising the skull, vertebral column, ribcage, and sternum. It provides support, protection, and flexibility, housing vital organs like the brain and spinal cord. Understanding axial skeleton anatomy is crucial for medical professionals and anyone interested in human biology. This knowledge helps diagnose and treat various conditions affecting the body's core structure

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00:00The human skeleton is broadly divided into two main groups, the appendicular skeleton and the

00:05axial skeleton. The appendicular skeleton comprises the bones of the upper and lower

00:11limbs, along with the shoulder and pelvic girdles. These bones append to the central axis of the

00:18body. In contrast, the axial skeleton includes all the bones positioned along the body's central

00:24long axis. This vital framework provides support and protection for internal organs. It consists

00:31of the skull, the laryngeal skeleton, the vertebral column, and the thoracic cage. The skull is a complex

00:38structure composed of two main parts, the cranial bones and the facial skeleton. The cranial bones

00:44form the top and back of the skull, creating a protective enclosure for the brain. These eight

00:50bones include the occipital, parietal, temporal, frontal, sphenoid, and ethmoid bones. The facial

00:57skeleton, as its name suggests, forms the face of the skull. It consists of 14 bones that define the

01:05entrances to the respiratory and digestive tracts. Key facial bones include the mandible, maxillae,

01:12zygomatics, lacrimals, nasals, vomer, palatines, and nasal conchae. In fetuses and newborn infants,

01:19cranial bones are connected by flexible fibrous sutures and large regions of fibrous membranes

01:24called fontanelles. These fontanelles allow the skull to enlarge, accommodating the rapidly growing

01:30brain. Over time, fontanelles close, and sutures develop into immobile joints where cranial bones

01:36are connected by dense fibrous tissue. The four major cranial sutures are the lamdoid, coronal, sagittal,

01:44and squamous sutures. Beyond the skull, several other bones are commonly categorized with it due

01:50to their proximity and function. These include the hyoid bone, the laryngeal skeleton, and the tiny bones

01:57of the inner ear. The hyoid bone is a unique U-shaped bone located in the neck, providing an anchor point

02:04for the tongue and muscles involved in swallowing. The laryngeal skeleton, also known as the larynx or

02:09voice box, is composed of nine cartilages. It is crucial for speech as its movements regulate

02:16the tension of vocal folds to produce sounds. Inside the petrius part of the temporal bone are

02:23the three smallest bands of the body, the malleus, incus, and stapes. These inner ear bones articulate

02:30with each other, transferring vibrations from the tympanic membrane to the inner ear, which

02:35is essential for hearing. The vertebral column, commonly known as the spine, is a flexible column

02:42formed by a series of 24 individual vertebrae, plus the sacrum and coccyx. It extends from the base of

02:49the skull down to the pelvis, providing the body's central support and protecting the spinal cord.

02:55The spinal cord passes through the vertebral canal within the column. The vertebral column is divided

03:02into five distinct regions. These include the cervical spine, thoracic spine, lumbar spine,

03:08the sacral spine, and the coccygeal spine. Each region has unique characteristics and functions,

03:15contributing to the spine's overall flexibility and strength. The thoracic cage is formed by the ribs

03:22and the sternum, creating a protective enclosure for vital internal organs such as the heart and lungs.

03:29It also provides crucial attachment points for muscles involved in respiration and upper limb

03:35movement. The sternum, or breastbone, consists of three parts, the manubrium, the body of the sternum,

03:42and the xiphoid process. Ribs 1 through 7 are classified as true ribs because they articulate

03:49directly with the sternum. Ribs 8 through 12 are known as false ribs as they either connect

03:55indirectly to the sternum or not at all.

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