The Back - Vertebral Column and Muscles

These flashcards cover the anatomy, function, and clinical correlations of the vertebral column, its ligaments, and the various layers of back muscles.

Vertebral Column

A structure consisting of 33 vertebrae divided into 5 regions: Cervical (7), Thoracic (12), Lumbar (5), Sacral (5 fused), and Coccyx (4 fused).

Coccyx

Derived from the Greek word for 'beak of cuckoo bird'; it consists of 4 fused vertebrae, with the exception of C1 which sometimes fuses to the sacrum.

Primary Curvatures

The thoracic and sacral curvatures of the vertebral column that are concave anteriorly.

Secondary Curvatures

Curvatures that develop after birth: the cervical curvature (when raising the head in prone) and the lumbar curvature (when starting to stand or walk).

Kyphosis

An abnormal sagittal plane curvature characterized by an accentuated primary (thoracic) curvature, potentially leading to compression fractures if combined with osteoporosis.

Lordosis

An abnormal sagittal plane curvature characterized by an accentuated secondary (lumbar) curvature.

Scoliosis

An abnormal lateral curvature of the vertebral column in the frontal plane, which is named by its convexity.

Adam's test

A clinical test for scoliosis where a patient bends forward; a positive result shows asymmetry, such as a hump in the thoracic or lumbar region.

Cobb angle

A measurement used to determine the degree of curvature in patients with scoliosis.

Vertebral body

The part of a typical vertebra located anterior to the vertebral arch that serves to support body weight.

Spina Bifida Occulta

A condition where the neural arches (laminae) of L5 and/or S1 fail to fuse normally; it is often concealed by skin and may be marked by a tuft of hair.

Atlas (C1)

The first cervical vertebra, which lacks a body or spinous process and consists of a ring-like structure articulating with the occipital condyles.

Axis (C2)

The strongest vertebra, characterized by the dens (odontoid process) which acts as a pivot for rotation of the atlas and cranium.

Transverse ligament

A ligament that holds the dens against the atlas to prevent posterior displacement of the dens or anterior displacement of the atlas.

Foramen transversarium

An opening in the transverse processes (TPs) of cervical vertebrae that transmits the vertebral artery.

Uncinate processes

Elevated superolateral margins of the vertebral bodies found in C3-C6.

Vertebra prominens

The C7 vertebra, so named because it has the longest spinous process.

Thoracic Vertebrae

Vertebrae characterized by heart-shaped bodies, circular vertebral foramina, and facets for rib articulation.

Lumbar Vertebrae

Vertebrae with large bodies, short pedicles, and no costal facets; they accommodate the lumbar enlargement of the spinal cord.

Sacral hiatus

The opening at the end of the sacral canal caused by the absence of laminae and spinous processes of S5.

Anterior Longitudinal Ligament (ALL)

A strong, broad ligament connecting the anterior aspects of vertebral bodies and discs that prevents hyperextension of the spine.

Posterior Longitudinal Ligament (PLL)

A ligament that connects the posterior aspects of the vertebral bodies and helps limit flexion.

Ligamentum flavum

Yellowish elastic bands joining the laminae of adjacent vertebrae that help preserve spinal curves and assist the spine in straightening after flexion.

Ligamentum nuchae

An extension of the supraspinous ligament in the cervical region that provides a larger surface area for muscle attachment.

Superficial Extrinsic Back Muscles

Muscles involved in limb movements that connect the axial skeleton to the appendicular skeleton, including the trapezius and latissimus dorsi.

Trapezius

A superficial back muscle innervated by Cranial Nerve XI (Spinal Accessory Nerve) that elevates, retracts, and depresses the scapula.

Intermediate Extrinsic Back Muscles

Muscles primarily involved in respiration and proprioception, specifically the Serratus posterior superior and Serratus posterior inferior.

Intrinsic Back Muscles

Deep muscles innervated by the posterior rami of spinal nerves that actively move the vertebral column and maintain posture.

Erector spinae

A group of intrinsic muscles consisting of the Iliocostalis (lateral), Longissimus (intermediate), and Spinalis (medial).

Transversospinalis muscles

A layer of deep intrinsic muscles consisting of the Semispinalis, Multifidus, and Rotatores.

Suboccipital Triangle

A region located deep to the trapezius and semispinalis capitis that contains the vertebral artery and the suboccipital nerve (dorsal ramus of C1).

Greater Occipital Nerve

The dorsal ramus of C2 that exits below the obliquus capitis inferior muscle and pierces the semispinalis capitis.