Bones of the Axial Skeleton & Deep Back Muscles

Flashcards covering key vocabulary related to the bones of the axial skeleton, including vertebral column structure, curvatures, typical and atypical vertebrae, intervertebral discs, the sternum, ribs, and the erector spinae muscles.

Vertebral Column Function (Protection)

Protects the spinal cord.

Vertebral Column Function (Support)

Provides support for the trunk.

Vertebral Column Structure

Consists of 33 vertebrae.

Cervical Vertebrae

7 vertebrae located in the neck region.

Thoracic Vertebrae

12 vertebrae located in the chest region.

Lumbar Vertebrae

5 vertebrae located in the lower back region.

Sacral Vertebrae

5 fused vertebrae forming the sacrum.

Coccygeal Vertebrae

4 fused vertebrae forming the coccyx.

Primary Curvatures

Thoracic and sacral curvatures, present from fetal development. They are concave anteriorly.

Secondary Curvatures

Cervical and lumbar curvatures, develop after birth. They are convex anteriorly.

Kyphosis

An abnormal exaggerated posterior curvature of the thoracic vertebral column (hunchback).

Lordosis

An abnormal exaggerated anterior curvature of the lumbar vertebral column (swayback).

Scoliosis

An abnormal lateral curvature of the vertebral column.

Vertebral Body

The anterior, weight-bearing part of a vertebra.

Vertebral Arch

The posterior part of a vertebra, enclosing the vertebral foramen, composed of pedicles and laminae.

Pedicle

Short, stout processes that project posteriorly from the vertebral body, forming the lateral walls of the vertebral arch.

Lamina

Flat plates that extend medially from the pedicles, joining to form the posterior part of the vertebral arch.

Transverse Process

Lateral projections from the vertebral arch, serving as attachment points for muscles and ligaments.

Spinous Process

A single, posterior projection from the vertebral arch, serving as an attachment point for muscles and ligaments.

Superior Articular Process

Paired projections from a vertebra that articulate with the inferior articular processes of the vertebra above.

Inferior Articular Process

Paired projections from a vertebra that articulate with the superior articular processes of the vertebra below.

Vertebral Canal

The canal formed by the vertebral foramina of successive vertebrae, containing the spinal cord.

Intervertebral Disc

A fibrocartilaginous cushion between adjacent vertebral bodies, providing flexibility and shock absorption.

Anulus Fibrosus

The tough, outer fibrous ring of an intervertebral disc.

Nucleus Pulposus

The soft, gel-like inner core of an intervertebral disc.

Functional Discs

Intervertebral discs found between C2-C3 up to L5-S1.

Cervical Vertebrae (Typical Features)

Small body, short bifid spinous process, triangular vertebral foramen, and contain transverse foramina.

Transverse Foramen

A hole in the transverse processes of cervical vertebrae for the passage of vertebral arteries and veins.

Thoracic Vertebrae (Typical Features)

Larger, heart-shaped body, long sharp spinous process pointing inferiorly, circular vertebral foramen, and bear costal facets for ribs.

Lumbar Vertebrae (Typical Features)

Massive, kidney-shaped body, short blunt spinous process pointing posteriorly, triangular vertebral foramen, and thin, tapered transverse processes.

Atlas (C1)

The first cervical vertebra, supports the skull, lacks a body and a spinous process.

Axis (C2)

The second cervical vertebra, distinguished by the dens (odontoid process).

Dens (Odontoid Process)

A tooth-like projection from the body of the axis (C2) that serves as the pivot for the rotation of the atlas and head.

Rib Head Articulation

The head of the rib articulates with the body of the thoracic vertebrae.

Rib Tubercle Articulation

The tubercle of the rib articulates with the transverse process of the thoracic vertebrae.

Sternum

The breastbone, a flat bone in the central chest, consisting of the manubrium, body, and xiphoid process.

Manubrium

The superior part of the sternum.

Body of Sternum

The middle and largest part of the sternum.

Xiphoid Process

The inferior, smallest part of the sternum.

Sternal Angle

The articulation between the manubrium and the body of the sternum.

Costal Cartilage

Hyaline cartilage connecting ribs to the sternum.

True Ribs (Pairs 1-7)

Ribs that attach directly to the sternum via their own costal cartilage.

False Ribs (Pairs 8-10)

Ribs that attach to the sternum indirectly, via the costal cartilage of the rib superior to them.

Floating Ribs (Pairs 11 & 12)

Ribs that do not articulate with the sternum or costal cartilage of other ribs anteriorly.

Rib Head

The posterior end of a rib, which articulates with the vertebral bodies.

Rib Neck

The constricted part of a rib between the head and the tubercle.

Rib Tubercle

A protuberance on the posterior surface of a rib, articulating with the transverse process of a thoracic vertebra.

Costal Groove

A groove on the inferior border of a rib, protecting the intercostal nerve and vessels.

Erector Spinae Muscles

A group of deep back muscles, including Spinalis, Longissimus, and Iliocostalis, responsible for extending and laterally flexing the head and vertebral column.

Spinalis Muscle

The most medial column of the erector spinae muscle group.

Longissimus Muscle

The intermediate column of the erector spinae muscle group.

Iliocostalis Muscle

The most lateral column of the erector spinae muscle group.

Erector Spinae Action (Bilateral)

Extends the head and vertebral column.

Erector Spinae Action (Unilateral)

Lateral flexion of the head and vertebral column.

Erector Spinae Innervation

Dorsal rami of spinal nerves.